Full text of "Concrete and constructional engineering"

Umiv.qf

To H UNTO

CONCI2ETE

Volume IX.

1914.

Published at 4, Catherine Street, Aldwych, London, W.C.
Editorial Offices at: 8, Waterloo Place, Pall Mall, London, S.W.

INDEX.

BOOKS, NKW :

Architect's Standard Diary, The

Cement Lime or Trass Mortars in the
Construction of Dams. The Use of

Chadwick Public Lectures on Housing,
1913, The. By W. E. Riley, F.R.LB.A.

Clerk cf Works. By G. Metson

Concrete Pipes. By Riepert

Concrete Products. By " Hollie "

Elementary Building Construction, A
1 Text Book of. Bv A. R. Page and Wm.

E. Fretwell
\ Experiments with Built-in Beams. By Dr.
Fr. V. Emperger

Fire Tests with Floors

Handbook for Constructional Engineers
in Reinforced Concrete. By Jean Braive

Handbook of Structural Steelwork

Handling of th*; Materials in Concrete and
Reinforced (Concrete Construction, The.
By Riepert

Hydration of Portland Cement, Iron Port-
land Cement, and Blast Furnace Slag,
The. By Dr. F. Blumenthal

Influence of Moi'^ture in the Air on the
Volume of Cement Mortar, The. By Leo-
pold Jesser

Lockwood's Builders' and Contractors' Price
Book for 1914

Maintenance of Foreshores, The. By Ernest
Latham, A.M.Tnst.C.E

Making of High Roads, The. By Edward
Carey, M.Inst.C E

Manual for Ma-^on'^ and Bricklayers, A. By
J. A. Van der Kloes

Portland Cenient Manufacture. By Carl
Naske ...

Posts and Masts

Practice of Construction in Concrete and
Cement Mortar, Plain and Reinforced.
(Translated into French by M. Darras) ...

Reinforced Concrete Construction. Vol. II.
By Gtorpe A. Hool

Reinforced Concrete Construction. Theory
and Practice. By A. V. Magnv

Reinforced Concrete Railway Structures.
By T. D Ball

River Engineering and Drainage Work,
The LTse of Concrete and Reinforced Con-
crete in. By F Wichmann

PAGE

704
427

4-7

427

286

352

212
286

426
70

427

426

21 1

211

646

210

352
212

703
210

647
69

427

Silo Construction in Concrete and Rein-
forced Concrete
Spon's .Architects' and Builders' Pocket

Price Book
Strength of I-Beams in Fle.xure, The. By

Herbert F. Moo;-<»

Technical Studies of Mortar and Cement.

By Dr. Hans Kiihl

Tests of Bond between Concrete and Steel.

By Duff A. Abrams

Training and Employment of Boys in the

Building Trades of London

Transactions and Notes of the Concrete

Institute

CEMENT :

Hydration of Portland Cement, Iron Port-
land Cement, and Blast Furnace Slag,
The. (New Books)

Influence of Moisture in the Air on the
Volume of Cement Mortar, The

Portland Cement Manufacture. By Carl
Naske. (New Books)

Some Fallacies in Cement Testing. By W.
Laurence Gadd

CORRESPONDENCE (See MEMORANDA).

EDITORIAL NOTES :

Concrete Cottages

Concrete Cottage Competition, Our

76, 147, 222, 364, 435, 437,

Concrete Industry and the War, The

Concrete Institute, The ... ... 217, 293

Concrete fc>r Roads ...

Concrete for War Purposes

Concrete, The Uses of

Considere, Mr. Arniand. (Obituary Notice)

Cottages ..

Fire Resistance in Factory Construction ...

Important Reinforced Concrete Works dur-
ing the Past Year

International Association for Testing Mate-
rials 76,

Italy, General Concrete L^ses in

Labour Troubles and Concrete ...

Panama Canal, The ...

Rebuilding ...

704
646
287

426
426
352

123

219
204
75
145
651

Reinforced Concrete and International In

\estigation ... ... ... ... ... ... 219

Research Work and Concrete 76

Standard Method of Mea^urtment for Rein-
forced Concrete ... ... ... ... ... 146

Tanner, Sir Henry ... ... ... ... ... 2:1

Technical Profef-s-ions and the War, The ... 608

Timber Question, The 651

gi-:xi-;r.\l :

.-Mignm-nt Charts for Con'^tructicnal
Formul.-e By Ewart S. Andrew-, B.Sc.
Eng. 32

.Annual General Meeting, T!ie Concrete
Institute ... ... ... ... ... ... 374

Bell Telephone Manlacturing Co. at Ant-
werp. BuildicK for the ... ... ... ... 406

Bending Moment Problem, A. By Ewart S.
.Andrews, B.Sc. i-ng. ... ... ... ... 404

Calculations and Details for Steel-frame
Buildings from the Draughtsman's Point
of View Bj- Cyril W. Cocking 259

Central Arno Hydro-Electric .Station, Cede-
golo, Italy, Reinforced Concrete at the ... 182

Concrete Cottage Competition, Our, 3, 437,

518, 5S I, 620, C66

Concrete Institute, The ... 123, 176, 193

217. 259, 339.. 374, 410, 482, 553, 731

Concrete in Small Domestic Buildings . . 15

Concrete Masonry in the Panama Canal. By
John Geo Leigh 149, 223

Cross Hill Service Reservoir 503

Decorative Possibilities of Concrete, The.
By C. W. Boynton and J. H. Libberton ... 266

Deformation and Deflection in Concrete
Beams 662

Economical Design of Reinforced Concrete
T-Bc-ams, The. By J. E. Griffith ... ... 588

Elasticity of Compound Bars, with special
reference to Concrete Columns. Bv Her-
bert G. Taylor, M.Sc '.. ... 722

Electrolysis in Concrete 323

Enquiries (See Mt^morwda).

E.\tensions to the British Museum (Rein-
forced Concrete in the new King
Edward VII. Galleries) 7

Grand Stand, Hurst Park Racecourse ... 169

Harbour Improvements at Iloilo, Philippine
Islands. .\ Reinforced Concrete Wharf
with Grouted Foundations 114

Heimbach System of Combined Wood and
Reinforced Concrete Piles and of
Lengthening V/ooden Piles, The 189

H.M. New Stationery Office. By Albert
Lakenian, M.S. A. .. 36.5

Hvdro Electricity Works, Chester, Concrete
and Reinforced Concrete at the 108

Ice H<^«use at Pasco, Washington, Reinforced
Concrete .S48

Ilkeston Secondary Schools, Reinforced Con-
crete at the f'"9

International Association for Testing Mate-
rials, The .■•• 543

Institution of Civil Engineers and Rein-
forced Conciete, The 102

Lighthouse Construction, Reinforced Con-
crete V. Ca«t Iron for. By C. Wescmann 325

Municipal F-;nf.Mne<ring Works in San Fran-
cisco, TT.S.A., Reinforced Concrete in. By
E. R Matth'ws, A.M. Inst. C.E 95

New County I La II, The Use of Concrete in
the Substructure of the ... 653

New Law Courts at Kingston, Jamaica,
Reinffrced Concrete in the v

New Offices for the Boar<l of Agriculture
and Fi'-hcries, Reinforced Concrete in the 77

Panama Pacific E.xhibition. Reducing the
I'ire Hazard. By John Geo. Leigh... ... 383

Para Brazil, Reinforced Concrete Building
at - . .•" 332

Patents Relating to Concrete, Recent British

237, 4^'9, fii4

Presidential Address, The Concrete In-iti
tute 731

Pressures on liarth P-taining Walls ... ... 739

Prison Buildings, Reinforced Concrete in.
By AUxrt Laketnan, M.S. A . ... F,7S

Problems in th.- Theory of Construction.
Bv i:wart S. Andrews, B.Sc. Eng W'

Railvay Bridge for the Mestre-Merano
Road over the Upjier Venetian Railway,
and a Tramway Bridge, Mestre, Italy,
Reinforced Concrete

Reinforced Concrete 7\ Cast Iron for Light-
house Construction. By C. Wesemann ...

Reinforced Concrete Chimnev, .\. By John
W. Rodger '

Road at Chester, Reinforced Concrete

Roof Timbers, Westminster Hall

Rural Housing

Shearing or Diagonal Tension Reinforce-
ment in Beams. By Charles F. Marsh,
M.Inst. C.E.

Shear in Reinforced Concrete Beams. By
Rohintan N. Frarn Mirza

Slab Formulas for Reinforced Concrete De-
sign. By Ewart S Andrews, B.Sc. Eng.

Slender Struts. By H. Kempton Dy^on 160,

Steel Centering, Col'apsible

Standard Method of Measurement for Rein-
forced Concrete. Draft Report by the
Concrete Institute ..

Statues, Reinforced Concrete

Testing of Reinforced Concrete Beams, The.
Bv John A. Davenport ...

Theatre des Champs Elysees, Paris. Rein-
forced Concrete \\'ork. By Albert Lake-
man

Use of Concrete in Coal Mines, The

Usher Hall of Music, Edinburgh, The

Viaduct, Langwies, Switzerland, Reinforced
Concrete

Viaduct, Martin's Creek, U.S.A., Reinforced
Concrete

Wallace-Scott Tailoring Institute, Glasgow,
The. By .Albert Lakeman, M.S. A

What is the best Ratio of Steel to Concrete
in Reinforced Concrete Beams and Slabs
from the £ s. d. Point of View? By
Rohintan N. Fram Mirza

Zoological Gardens, Reinforced Concrete
Panorama. By .Albert Lakeman

457

325

48
540
463
594

307

509

396
242

741

176
678

451

631

475
295

316
711

INDUSTRIAL NOTES :

Concrete Piles

Concrete Tools, etc. ...
Machinery, Concrete

MEMORANDA

^ --•■>•,

353
754
694

^9\

Action of Sea Water on Concrete ... 213

Administrative Offices for the Port of Para 431
Annals of the Mexican Department of Public

Works lofi

Belgium, Harbour Work in 73

Blocks for Dwellings, Concrete 705

Blocks at Cfoodwick, Concrete .s'J9

Boat Ways, Rockhaven Harbour, N.D.,

Reinforced Concrete 141

Breakwater at Glenelg, South Australia,

Concrete 5^8

Bridge, Lingfield, Reinforced Concrete ... 705
British Fire Prevention Committee, The

496, 648, 705

Building By-Laws and Reinforced Concrete 213
Catalogues and Trade Notices ... 74, 144, 216,

359i 434. 500, 571. 606, 650, 708, 760

City and Guilds of London Institute ... 605

Concrete Forms, Removal of 359

Concrete Hardening Material 216

Concrete Institute, The 7>. 74. 429. 758

Conference of Mining ICngineers 497

Contracts '44

Correspondence 292,571,^149

Detroit Building Code, Concrete Specifica-
tions in , ••• 431

Drxjr in a Racket Court, Reinforced Con-
crete 5*39

Dundee Crait' Pier 43'

Dwelling House ;it Nnivvich. Concrete ... 359

JClrctrolicrs, Concrete 291

ICiicjui rics 292

I'irralum Notices 74.292

Fence- Posts for Dinas Way, II.ivc rfordwest,

Rc-in forced Concrete • •• '4'

Fence Posts, Concrete ;■■ ■■■ '"'^

Fire Preventive and Fire Service Work ... 49''

FirL--R<sisiiiij4 lluiuuu-

Firt- Wamiiiv^ I or Kaiinir^

Fo(ill)ri<li^c at llitiliiii, U«iiiloi< id Comrttc

l-'raimJ Com ritr l-jiniiK" Ht <l

Cicnii.iii Ri-^MilatioiJ> itKanliiiK Rciiiinn til
Ci)ti( n tf, S'Miic Ntw

Gonlwitk, I'onirttf Ulocks at

(irftnln'iisf Construction, Rcinlurnd Con-
iTfti- in ...

Hospital Arcliitt t tnrt- an<i C'on^trut tioii

Inqnirii's

Intirloi kiiiij Concrcti' liiiKk I'ipi", A Nfw ...

Jnti-rnational .Association lor Ttstin^ Mate-
rials

International ("oiiunss ol IJuililinjj; an<l
Public Works, Foiiitli

International I'nuiut cring Conyress, 1915 ...

Iron ami Stctl Instituti', The ...

Kirkaiav. The Late \V. G. ...

Li\i-rpool An'hi t'-'lnral Association ...

Manchester linihling Trades' l-xhihition, The

Mancluster School of Architects

Matthews. Prof. K. R

Modern Concrete Chutes

Newcastle Civil ICngineers' Students' Asso-
ciation

New Concrete and Steel Building in the City
Northern Polytechnic Institute

Oil Tanks, Concrete for

Paint Protection for Portland Cement Sur-
faces
Pontoon in Australia, Reinforced Concrete...

Port Talbot Dock Works

Posts for Vineyards, Reinforced Concrete ...
Quay Walls at Nantes, France ...
Racket C<nirt, Reinforced Concrete Door in a
Reinforced Concrete Telegraph Poles versus

\V(X)dcn Poles
Rheumatism, Reinforced Concrete and

Roads, Concrete

Roof Construction on Concrete Building ...

Rosyth Naval Ba'-e

Royal Agricultural Sh')w at Shrewsbury, The
Scottish National Portrait Gallery ...
Self-supportipg Concrete Towers
Shelter Sheds on an Australian Railway,

Reinforced Concrete
Sieving with Standard Cement Sieves
Society of Ivngineers, The
Specifications in Detroit Building Code,

Concrete
Special Fire Ser\ ice Force, The
Steel Cutting Fdges for Concrete Caissons...
Strength of Over-wet Concrete, Some Tests

on
Summer School of Town Planning, The
Survey Monument. A Concrete ...
Ten Concrete Road Essentials ...
Trade Notices and Catalogues ... 74, 144.

216, 359, 4i4, 500, 571, 606, 650, 708,
Treatment of Granolithic Floors, The
Trunk Sewer, Reinforced Concrete ...
Use of Concrete on Railways, The

Village, A Concrete

Wash for Concrete, A

W^at'?r Tank of 600,000 Gallons Capacity,

Reinforced Concrete
Westminster Technical Institute, The
Wire Ropeway Supports in Concrete and

Reinforced Concrete

PAGE

7'
7.S«
4.<'

.'H8

-y-'
708

49''
3.S'J
4.U
J.S'>
388
705
430
759

7«

70O
648
143

706

5<>9
289

571
497
569

359

2«9

706
144

430
566
291

759
215
140

431
648

357
496
649
433

760

705
706
605
291
706

74
648

213

NEW^ WORKS IN CONCRETE AT HOME AND
ABROAD :

Architectural Possibilities of Concrete, The 604
Bridge in California, Reinforced Concrete... 350
Bridge at Tipperty, .\uchenblae. Kincardine-
shire, Reinforced Concrete ... ... ... 421

Bridge at Wickham Market, Suffolk, A
Reinforced Concrete ... ... ... ... 133

Bridge, Yoshida, Japan, A Reinforced Con-
crete ... ... ... ... ... ... ... 691

Chimney and Sight-seeing Tower at Dres-
den, .\ Concrete ... ... ... ... ... 425

Coal and W^ater Reservoir for the Marseilles
Gas Works ... ... ... ... ... ... 487

Concrete Block Buildings at Norwich ... 285

Concrete Block Construction ... 68. 136, 209,

iSc, 2S5, .irS, 423, 486, 494
Concrete Block Houses, Newburn-on-Tyne ... 68
Concrete Blocks at Port Talbot 282

Concrete Blocks in West Africa
CcMicrele (41 the Farm

Cooling Tov.rr, Reinforced Concrete

Corn Crib, A Novel Concrete Block Circle
Dam on the Mississipjii River, CfK»n Rapids

Hydro I'lectric Plant, Concrete

Des;imparad(.-s Station, Lima, Peru, Rcin-

lorced Concrete at the New

Detroit Buihling Code, Concrete Spe( ifi-

eations in
Dome for the South Manchester New Syna-
gogue, Reinforced Concrete

Dome of Melbourne Public Library, Placing

of Concrete for
Gasholder lank at Hamburg-Fuhlsbultel,

Reinforced Concrete
Harrisburg Reinforced Concrete Protective

Wall, The

Hotel E.vtension at Margate, Reinforced

Concrete in ...
Irrigation System at Calgary, Alberta, Con-
crete Structures on the ...

Lamp Posts, Reinforced Concrete

Lodge and Enquiry Office, Concrete

Marconi Wireless Stations, Concrete Blocks

for

Metropolitan Railway, Reinf<jrced Jfoncrete

in the New O-fiees of the

Mill Construction, Concrete
Motor Garage, Whitby, A Reinforced Con-
crete

New Electric Power Station, Port Talbot,

Concrete Blocks in the

New Government Ship Lock in Black Rock

Harbour, The

Paper Warehouse, Reinforced Concrete
Raft and Fire-Resisting Floors in the Fac-
tory Extension for the Wolseley Tool and
Motor Car Co., Reinforced Concrete
Railway Station at Kuala Lumpur, Malay

States

Roof Construction at Liverpool Cathedral,
Reinforced Concrete

School Buildings, Concrete Block

Sea Point Beach Improvement Scheme, Cape

Tov;n
South .Africa, Some Concrete Works in
Steel Con^truTtion in the Palace of Fine
Arts at the Panama-Pacific International

Exposition

Talbot's Inch. Kilkenny, Further Concrete

W'ork at ... . .

Water Restrvvjir, Talbot's Inch, Kilkenny,

Concrete Block

Water Tower near Burton-on- Trent, Rein-
forced Concrete

.•09
418
1,0 J
4 -'3

74S

43«
4-'-'
2«3
'35
<'43
559

490

00
753

4-3

345
418

48^

04I

089
62

604

203

494

562
562

489
136
136
132

RECENT VIEWS ON CONCRETE AND RE-
INFORCED CONCRETE:

Aggregates for Concrete Roads. By Sanford
E. Thompson, A N. Talbot, and W. M.
Kenney 278

Architect and Structural Engineering, The.
By William E. Brown, A.R.I.B.A 482

Contraction and ll.xpansion of Concrete
Roads. By R. J. Wig, N. H. Tunnicliff,
and W. A. Mclntyre 277

Design of Steel and Reinforced Concrete
Pillars, with Special Reference to
Secondary and Accidental Stresses. By
Oscar Faber ...

Differential and Integral Calculi for Struc-
tural Engineers, The. By W'. A. Green,
M.A.

Examination of Concrete Failures for their
Determining Causes, By R. S. Greenman

Factory Construction. By Percival M.
Eraser. A.R.I.B A

Fallacies in Cement Testing, Some. By W.
Laurence Gadd

Finishing and Curing Concrete Road Sur-
faces

Forms for Concrete Work. By Allan Gra-
ham, A.R.I.B.A '

Mixing and Placing Materials for Concrete

Roads
S.and and Coars-; Material and Proportion-
ing Concrete. Bv John A. Davenport and
Prof. S. W^ Perrott

410

5-
744
193
123

639
339
685

553

Storage of Coal, The Bv Henry Adams,

M.Inst.CE. ... .^80

Testing Concrete Aggregates. By Cloyd

M. Chapman ... ... ... ... ... 599

Use of Concrete in the Design of Mine

Shaft Linings, The. By \\m. A. Weldin. 412
Weslevaa Methodist Hall. Westminster,

The. By H. V. Lanchester, F.R.I.B.A. ... 58

REINFORCED CON(^RKTE :

Bridge in California, Re'nforced Con-
crete ... ... ... ... ... ... ... 350

Bridge at Tippertv, Auchenblae, Rein-
forced Concrete ... ... ... ... ... 421

Bridge at Wickham Market Place, Suffolk,
A Reinforced Concrete ... ... ... ... 133

Bridge, Vo^hida, Japan, A Reinforced Con-
crete ... ... ... ... ... ... ... 691

Building for The Bell Telephone Manufac-
turing Co. at Antwerp, Belgium ... ... 406

Building at Para, Brazil, Reinforced Con-
crete .^ ... ... 33J

Central Arno Hydro-Electric Station,
Cedeerolo, Italy, Reinforced Concrete at
the ^ 18-'

Chimney, A Reinforced Concrete 48

Coal and"^Vater Reservoir for the Mar-
seilles Gas Works 487

Cooling Tower, Reinforced Concrete 602

Cross Hill Reservoir 503

Desamparados Station, Lima, Peru, Rein-
forced Concrete at the New 207

Dome for the South Manchester New-
Synagogue, Reinforced Concrete 422

Economical Design of Reinforced Concrete
T-Beams, The ... 588

Elasticity of Compound Bars : with Special
Reference to Reinforced Concrete Columns 722

E.xtensions to the British Museum ... ... 7

Gasholder Tank at Hamburg-Fuhls-
brittel, Reinforced Concrete ... ... ... 135

Grand Stand, Hurst Park Racecourse ... 169

Harri«-burg Reinforced Concrete Protective
Wall. The ... 643

Heimbach System of Combined Wood and
Reinforced Concrete Piles and of
Lentrthcning Wooden Files, The 189

H.M. New Stationery Office ... 365

Hotel Extension at Margate, Reinforced
Concrete in .. 559

Hvdro-Electricity Works, Chester, Concrete
and Reinforr-ed Concrete at the ... ... 108

Ice Hou'e at Pasco, Washington, Rein-
forced Concrete 548

Ilkeston Secondary Schools, Reinforced
Concrete at the . . ... ... ... ... 609

Inititution of Civil Engineers and Rein-
forced Concrete, The 102

P.\GE

Lamp Post^, Reinforced Concrete 66

Motor Garage, Whitby, A Reinforced Con-
crete ... ... ... ... ... ... ... 60

Municipal Engineering Works in San
I'rancisco, Reinforced Concrete in. By
E R. Matthews. A. M.Inst.CE 95

New Government Ship Lock in Black Rotk
Harbour, U.S.A., The 641

New Law Courts at Kingston, Jamaica,
Reinforced Concrete in the 40

New Offices for the Board of Agriculture
and Fisheries, Reinforced Concrete in the 77

New Offices of the Metropolitan Railway,
Reinforced Concrete in the ... ... ... 345

Panama-Pacific Exhibition, Reducing the
Fire Hazard .. ... ... ... ... 383

Panorama Zoolog'^al Gardens, Reinforced
Concrete ... .. .. ... ... ... 21

Paper Warehoiise, Reinforced Concrete ... 689

Prison Buildings, Reinforced Concrete in 575

Raft, Reinforced Concrete ... ... ... 62

Railway and Tramway Bridge, Mestre-
Mirano Road, Italy, Reinforced Concrete 457

Reinforced Concrete v. Cast Iron ... ... 325

Road at Chester, Reinforced Concrete ... 540

Roof Construction at Liverpool Cathedral,
Reinforced Concrete ... ... ... ... 203

Shear in Reinforced Concrete Beams ... 509

Slab Formulae fo^r Reinforced Concrete
Design ... .. ... ... ... ... 396

Standard Method of Measurement for
Reinforced Concrete ... ... ... ... 176

Statues, Reinforced Concrete 67S

Testing of Reinforced Concrete Beams,
The. By John A. Davenport 451

Theatre des Champs Flysees, Paris ... ... 631

Usher Hall of Music, Edinburgh, The ... 295.

Viaduct, Langwies, Switzerland, Reinforced
Concrete ... 250

Viaduct, Martin's Creek, U.S.A., Rein-
forcei Concrete ... ... ... ... ... 316

Wallace Scott Tailoring Institute, Glas-
gow, The ... 711

Water Tower nr-ar Burton-on-Trent, Rein-
forced Concrete i32'

Wharf with Grouted Foundations A
Reinforced Concrete : Harbour Improve-
ments at Iloilo, Philippine Islands ... 114

What is the Best Ratio of Steel to Con-
crete in Reinforced Concrete Beams and
Slabs from the £ s. d. Point of View? By
Rohintan N. Fram Mirza 85

TESTS :

Overwet Concrete, Some Tests on Strength
of 357

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CONCRETE

AND

COMSTRUCTIONAL ENGmEEmNG

Volume IX. No. 1. London, Janiakv, 1914.

EDITORIAL NOTES.

CONCRETE COTTAGES.

In accordani^e with thr announcenienl contained in our December number,
our present issue contains the C>)nditions of our Competition for obtaining
suitable designs for cheap concrete cottages. (See page 3.)

These conditions have been most carefully framed with a view to
obtaining the best possible results.

It is not necessary here to enter again into details regarding the
premiums offered, etc., as these points were raised in our editorial
columns last month and are fully set out in the Conditions.

Sufficient emphasis cannot be laid on the great national importance
of this question of the better and healthier housing of our industrial and
rural population, and every effort made in this direction should call for
attention and consideration. That the Authorities and the public are fully
alive to this all-important matter is evinced by the reports and articles
contained in our daily Press and from the numerous letters we have
received on the subject. We therefore hope that a large number of com-
petitors will enter for this competition.

In conclusion, we would draw attention to another article we are
publishing, in which w^e have reprinted the recommendations contained in
a Report recently issued by the Departmental Committee appointed to
inquire and report as to Buildings for Small Holdings in England and
Wales, and which should be useful to intending competitors.

IMPORTANT REINFORCED CONCRETE WORKS DURING THE

PAST YEAR.

In the past year considerable progress has again been shown in the use of
reinforced concrete for public buildings at home and in our colonies, and
anyone who has perused our journal during the last twelve months will
have realised on what important buildings this form of construction is
now^ being used economically and with quite practical results.

As pioneers in the advocacy of the use of reinforced concrete, we
cannot but emphasise again the value of this material, particularly for

B 2 1

IMPORTANT WORKS DURING THE PAST YEAR. [ CQNCKETE]

buildings that are simple and straightforward in plan and of considerable
area. For such buildings the advantages are considerable, and we hold
that all public departments and municipalities should follow the very
excellent example of H.M. Office of \W)rks, in adopting reinforced
concrete in the interests of the public purse. As far as the municipal
authorities are concerned, certain progress has been made in obtaining
longer loan periods for buildings in which reinforced concrete has been
used, and although this progress is a step in the right direction, w^e should
have liked it to have gone further, but we have no doubt the Local Govern-
ment Board will gradually develop a more modern policy.

We would only point again to our current pages to show the varied
uses of reinforced concrete, our articles this month including such im-
portant works as the Extensions to the British Museum, the Jamaica Law
Courts, and the structures demanding such exceptional requirements as
the Mappin Terraces at the Zoological Gardens.

L<VL.N(JNL1JJ1NG -wj

£125 CONCRETE COTTAGE COMPETITION.

£125 CONCRETE
COTTAGE COMPETITION,

The obieci of this journal is to contribute to the solution of the great rural housing
problem of the day, and thus the folloiving competition has been organised. — ED.

Tm: Propriclors of Coxckete and Construct ioxal Engineer ing invite com-
petitive designs for suitable detached or semi-detached labourers' cottages.
The materials to be used shall be largely or mainly concrete in some form.
It is to be assumed that the cottages would be erected in one of the Home
Counties of England (at least 30 miles from Charing Cross, London), at a prime
cost to the owners of £12^ per cottage. The Competition is open to all persons
residing in the British Empire, and the following premiums are offered : —

First Prize One Hundred Guineas.

Second Prize Fijty Guineas.

Third Prize Twenty-five Guineas.

Fourth and FiftJi Prizes .... Ten Guijieas each.
The Assessors appointed by the Proprietors are : —
Mr. Max Clarke, F.R.LB.A.
Professor Beresford Pite, F.R.LB.A.
Mr. Edwin O. Sachs, F. R.S.Ed.
The following are the conditions of the Competition : —

CONDITIONS OF THE COMPETITION.

I. — The object of this competition is to obtain a design suitable for a
detached or semi-detached labourer's cottage that can be erected at a prime
cost to the owner of ;^i25 when put up in a series of six in one of the Home
Counties on a site at least thirty miles from Charing Cross, the owner buying
his materials and employing labour without the intervention of a third party.

2. — Concrete is to be the primary building material used in the construc-
tion of these cottages, and solid concrete, reinforced concrete, concrete blocks
or hollow blocks, concrete partition slabs, or any other suitable form of con-
crete will be acceptable. Lintols, sills, hearths, sinks, etc., are to be taken in
concrete or artificial stone. Slates or tiles, if used, shall preferably be cement
slates or cement tiles. Thatch, wood shingles, etc., are not permissible for
roofing. Freedom from the usual restrictions of current bye-laws, etc., will be
granted with the view of securing up-to-date practice.

3. — It is understood that the cottages will be erected on adjoining sites,
each measuring 65 ft. frontage by 200 ft. deep, the front of the site being on
the east side of a 50-ft. main road running north to south and having a frontage

£125 CONCRETE COTTAGE COMPETITION. [CQNCKET ES

line set back 2j ft. from the bounclarv. Xu ftnciiiij or pailis or land drainage
are to be included for in tlie £^12^. Ground taken out for foundations shall be
spread at the back of the site. The subsoil is clay.

4. — It is understood that there is no main (hainai^c or g;as supply, and that
there is a local water-supply service, but the ;£..i25 shall iiot include for a water
supply to the house connected to the public water service or for any plumbing-
or sanitary work or cquijiment ; but tlie necessary equipment shall be show n in
the drawings, including- a length of 40 ft. of 4-in. drain in the direction of a
cesspool located at the back of the building, and the w.c, the sink, etc., shall be
shown in connection witli the drain leading to the cesspool.

5. — There will be no restriction as to the number or character of the
rooms, excepting as follows : —

(a) The principal living-room (or parlour) shall not have a less area
than 150 ft. sup., and the principal bedroom shall have a superficial area
of not less than 125 ft. sup.

(h) The entrance (outer door) of the building to the kitchen or living-
room sh.all ])e an indirect entrance, and not a direct entrance.

6. — There is no restriction as to whether the cottage should be a one-storey
building or com.prise a ground floor and a first floor.

7. — All plans shall preferably be drawn on not more than one sheet of white
W^hatman or Cartridge paper, size 27 in. by 20 in., mounted on cardboard or on
strainers, so as to be exactly 28 in. by 21 in. over all, but two sheets will be
accepted.

The drawings to I)e in black lines onl\- ; the plans, elexations, and sections
to be to a scale of J in. to the foot, details J in. to the foot, and the site plan
1-32 in. to the fool. All shading or the like to be done in hatching, sectional
parts on plans and sections, where the material is of concrete, to be tinted in
light Prussian blue, and no other tints or variation of ink or greys or the like
are permissible.

If more than one sheet is used, all ^-in. scale plans, at least one section,
the front elevation, and the table referred to in Clause i i shall be together on
one sheet. .\11 flrawings sh.all stanrl on the sheets with their base {paralleled
to the 27-in. edge oi the sheet.

One detail at least shall be gixcn, namcK , that of an I^xlernal \\ all.
A line perspective is o[)iiona], but shall not o<"cu|)\' moi-e than S in. bx' 6 in.
H')f the i^aper.

H.--;\ll the writing on tlie drawings shall be in plain black ])l()ck letters,
the capitals not less than J in. in si/c and tlu- small Icltc is in proportion.

The " headings " ol the sheets lo be in (•a|)itals not less than ',' in. Iiii^h.
Names shall not be used on an\' ol the rooms, but the loilowing abbri'N ia-
tions shall be applied :--

K Main ent ranee.

II Ilall, lobby, or anteroom (if any).

K Kitchen.

P I/uing-njoni or parJoui' (if any).

KP Combined living-room and k'ilehen (if any).

Sc .Seuller\ or wash-house (if an\').

/^'fncSPSK^ i^-^ CONCRETE COTTAGE COMPETITION

KNOlNKl-RlNti ^.

\i Hcdiooiii.

Bl lialiirooni (il' an}).

L Larder or lootl-storc (if any).

C C\ij)l)()ar{l or closet (if any).

W W'.C.

d Dresser (if any).

c Copper (if an\ ).

s Sink.

b Rath (if any).

m Manhole

9.- — In every room there shall he plainly written its superficial area in feet
in black ink. All numi'rals shall ])e in j)lain block numberin<^- not less than I in.
in size.

10 — The beds for the inmates shall be shown in dotted lines, 6 ft, by
2 ft. 9 in. for each adult and 5 ft. 6 in. by 2 ft. 6 in. for each child.

II. — On the sheet showing- the plans there shall be a list (table) of the rooms
with their two principal dimensions, their superficial area, their heig"ht, and
their cubic contents. The rooms shall be named in the same order as in
Clause 8.

12. — On tiie slicet on which the plans are drawn there shall be g^iven the
cubic contents of the building- measured from the bottom of the footing's up to
half the height of any sloping- roof, or to i ft. above any flat roof. In the case
of rooms a portion of which is formed by a sloping- roof the dim^ensions shall be
taken up to half way between the ceiling- of the room and the apex of the roof.

13. — All usual structural fittings have to be provided for in the price
of ;^i25, including- a kitchen range, fireplaces, mantels, but not the w.c, sink,
copper, or bath.

14. — Accompanymg; the sheet or sheets of drawing-s there shall be the
following- descriptive specification, typewritten (with a margin of not less than
ih in.) one side of the paper (foolscap size), and arranged as follows : —
Page I : Description of the building and anj^ remarks of the competitor.
Pages 2 and 3: Short specification, with an exact description of the concrete intended
to be used, and a specification of its method of execution.

Page 4: List of fittings, etc., and the net prime cost prices at which they have been
taken.

Page 5: An exact statement of how the competitor himself arrived at the cost, data,
measurement from plans, etc. Such statement, however, to exclude anj'thing like a bill
of quantities. This specification shall be strongly fastened together at the left-hand top
corner.

15. — Strict adherence to the conditions to be aimed at. The assessors will
be strictly guided by the limits of cost.

16. — Regarding architectural treatment, there shall be no unnecessary
features or ornaments, preference being given to simplicity of treatment and
avoidance of fads in joinery and glazing.

17. — The whole ot the designs will be exhibited in London. Delivery to
take place at the registered ofliices of Concrete Publications, Ltd., North British
and Mercantile Building, \\'aterloo Place, Pall Mall, London, S.W.

18. — The designs to which premiums are awarded shall become the pro-
perty of the proprietors of Conxrete and Constructional Engineering.

19. — The drawings shall be sent in between May ist, noon, and May i^th,
noon (1914) latest.

in:; concrete cottage competition.

iCQNCKETEi

20. — The decision of the assessors shall be linal.

21. — Should the proprietors of Concrete and CoNsiRit iion.m, Mnc.inkerinc.
be able to arrange, as they anticipate, for the erection of one or more cottages,
according to any of the premiated designs for which an inclusive prime cost
estimate not exceeding £12^ can be obtained, they will endeavour to have the
author or authors employed to superintend the erection at an inclusive fee of
10 per cent, on the estimate for the hrst cottage, and 3 per cent, on any further
ones, or some other form of remuneration which sliall be over and above any
premium awarded by the assessors.

22. — Competitors are not limited to one design, but each design shall be
presented on a separate sheet or sheets, and shall rank as an entirely separate
entry.

23. — All drawings submitted, excepting those to which premiums have been
awarded, will be returned to the competitors upon application at dates to be
announced in the public Press.

24. — Xo motto or device shall be added to any drawing or specification, but
with every set of drawings and specification handed in there shall be presented
in a plain foolscap envelope a bona fide statement that the design presented is
wholly the personal work of the author, and this plain foolscap envelope (con-
taining the full name and address inside) shall have no superscription or
distinguishing mark of any kind whatsoever on the outside. All the designs
and specifications will be numbered by the promoters in order of receipt.

NOTES.

The following literature may be of use io would-ljc competitors : —
(a) — Earlier copies of Concrete and Constructional Engineering, which f^ive
useful information and examples of concrete cottages and similar buildings, can be seen
at the principal architectural libraries or are obtainable from the publisher at is. each
(or post free is. 3d.), and they are as follows : —

Concrete Houses for die United States. (Xovember igoy, page 353.)

A Village Hall Constructed in Concrete. (Xovember 1907, page 402.)

A Concrete Industrial Village. (December igoQ, page 513.)

Reinforced Concrete for f^arm Buildings. (December igog, page 516.)

Concrete Blocks for Building Purposes. (March 1910, page 212.)

Cottages at Newbiggin Made of Concrete Blocks. (September igio, page 688.)

Reinforced Concrete Bungalows. (October igio, page 769.)

Cheap Cottages in Agricultural Districts. (December igio, page gog.)

Concrete House at Glencoe, HI., U.S.A. (March igii, i^age 230.)

Concrete Block House on Gidea Park Estate. (June igi2, page 471.)

Reinforced Concrete Buildings at Rowntree's Cocoa Works. (July igi2, page 528.)

(.'oncrete BlcKjk Houses on the Gidea Park Estate. (August igi2, page 633.)

Concrete ]ilock Cottages at Talbot's Inrli, Kilkc'nn\\ (Odohcr igu, l-rontispiece,

and page 785.)
Concrete Agricultural Cottages in Norfolk. (October igi2, page 732.)
Concrete JJlock Cottages, Kilkenny. (Novemhcr igi2, i)age 854.)
Concrete Cottages, (April igi3, page 288.)

Concrete Cottages in South Wales. (Septemhcr igi3, page 643.)
(Joncrete lilocks and Tiles in Norfolk. (.\o\ cinbcr 1913, page 7S().)
(b) — Woiild-bf! coiiijHt itors can ohlaiii, ii()<)n \\rilt«ii aj>|)Ii( alion, jxisi iVcc, .1 book
entitled " C'cnicnt Uses" from the Associated i'orlland Cement Maiudactiiicrs (i()()()),
Ltd., Portland llfjuse, Lloyd's .Avenue, E.C., which gives useful information as to
modern concrete practice.

(c)— .Some useful information as to (oltaj^es is contained in a Report iccenlh' issued
and entitled " Rfrport of the Drparlmentrd ('ommitlee on liiiildings for Small Holdings
in England and Wales " (Ol'licial Abstract reprinted from the Pai liamenlai \ Paper
[Cd. 6708], IS. 6d., obtainable from Messrs. \\'\nian .ind Sons, l'"etter Lane,
London, ICC).

K CONM PlIC"riONAi:
i. E,N(ilNKK«IN(f — 1

JiXriiNSIONS TO Tllh: HRiriSIl MUSEUM.

' ji>t?rai; EXTENSIONS TO THE
' ff.irMf..'^' BRITISH MUSEUM,

LONDON.

REINFORCED CONCRETE IN THE MEW
KING EDWARD VII. GALLERIES.

Some very interesting structiirjlii'ork hjs teen executed in connection ivith the extensions
to ttie British Museum, ivhich affords another striking example of the adT)antages of
reinforced concrete,— ED.

INTRODUCTION.

Ii is plcasino- and interesting to know that in a building of such high
importance as the new Galleries at the British Museum, which are to be
associated permanently with the memory of His late Majesty King Edward

Fig. 1. View showing Ceilinj^, etc., to Ground Floor Galltrv.
Extensions to the British Mlselm, King Edw.^rd VII. Galleries.

Vn., reinforced concrete has been used to a very considerable extent in the
internal construction. Due consideration was given to the sound and fire-
resisting properties of the structure to be erected and the Expanded Metal
systems of construction were adopted.

EXTENSIONS TO THE BRITISH MUSEUM.

The work comprises
the King- Edward VII.
Galleries facing* Mon-
tague Place, and the re-
constructed North Lib-
rary forming a connect-
ing block between the
new and the old build-
ings. The new wing
forms an extension to the
nijrth side of the Museum
and is the first portion of
an extensive scheme em-
bracing the south, east,
and west sides.

The new building is
approximately 320 ft.
long^ by 50 ft. wide and
80 ft. high from street
level to the top of the
parapet wall. The foun-
dation stone was laid in
June, 1907, and, as will
be seen from Fig. 2, the
work is now nearing'
completion. This illus-
tration also shows that
the north front is treated
in the Ionic order in
Portland stone ; there
are twenty Ionic columns
which start 14 ft. above
street le\'el.

FLOORS.

1" h e r e a r c f o u r
s u s p e n d e d reinforced
concrete iloors :- Sub-
ground lloor at entrance
level from Montague
Place ; gi'ound n<);)r ;
Mc//aninc lloor ; and top
gallerx' llooi- w ilh rool
oNcr. J'ig- 3 shows
some of ihc slrucMiu'al
sicclwork, and typical
tcmporai'\ limhciing and

, fCN-STWliCriONAl

CV t.NdlNL-l RlNd —

EXTENSIONS TO THE liRITISJJ MUSEUM.

expanded steel rein!orerimMil in i)<)sili()n ready to receive tlie concrete lloorin^.
At tlicir respective levels the llaors are supported by built-up steel

Fig. 3. Sho\vin{4 Reinforcement and TemporaryTiuiberint; to Flooring

Fii^. 4. \'ievv showin.ii Reinforced Conciete Floorin.^.
Extensions to the BE<iTii-H Mlseum, King Edward \'II. Galleries.

EXTENSIONS TO THE BRITISH MUSEUM.

IC^^CBETEJ

Stanchions, set at 16 ft. S in. centres k)ni;itu(linall\ , on wliich rest longitudinal
R.S.J, mains carrying- R.S.j. secondaries at 4 ft. 2 in. centres. The centre

long-itudinal bay is 25 fl. 6 in. wide, the two side longiUidiiial l)ays varying in
width as the main walls diminish in thickness towards the roof. Fig. 4 shows

KNdlNKl.RINfi — ,

EXTENSIONS TO THE HRfTlSH MUSEUM.

soiiu' of the rciiilon'ccl loncrctf liooriiiiL; laid and willi its loj) Kit to rcc-fivc
sand and (H-nu-nl hiHldiiij^- for tin- siirracc finislics.

Vhc sti'i'l staiuliioiis aio iMicascd in () in. brickwork coated witli lime and

hair plaster finished in lime putty; the R.S.J, mains and secondaries are
encased in concrete, splayed down From the flooring- to the bottom flanges.

The sofht of the flooring Is h in. below the top flanges of the secondaries,

1 1

EXTES'SIOSS TO THE BRITISH MUSEUM.

[CONCRETE]

and as the reinforcement is laid on top of the secondaries ii is thus embedded

h in. from the underside of the concrete flooring-.

All the floors are 4 in. thick and thev are reinforced throughout witli \o.

8, 3-in. Diamond Mesh Expanded Steel.

Due consideration was g-ivcn also to the question of the floor surface

finish to be used. In the first place, wood block flooring was chosen as a finish

for the g-round, top gallery and the north library floors, but it was discarded in

favour of cork plates,
fastened down by a
special preparation of
bitumen laid on sand
and cement bed-
ding, 2 to I, 2h in.
thick. The sub-ground
and the Mezzanine
floors in the galleries
and the floor to the
students' room over the
north library are
finished with cork car-
pet, ^ in. in thickness,
laid on sand and cement
bedding^. It was neces-
sary to have the sand
a n d cement bedding
2:t in. thick, otherwise
the finished floor levels
allowed for wood block
surface would not have
been maintained.

In order to obtain
the best possible re-
sistance to sound and
fire, consistent with eco-
nomical construction,
the upper floors are
j)ro\i(k'(l witli an air
sj)ace between them and
the ceiling^s below.

CEILINGS.

The ceilings to the sub-ground and the Mcz/anine floors are flat and
plain, and are of Expanded .Metal Lathing^ and plaster, suspended beneath
the R.S.J.'s in the florjring by means of flat mild steel bars s|)ace(l 12 in, apart,
hung- on edg-e in mild sKel hangers carried by mild steel clips fixed to the bott(jm
flang-es of the K..S.J.'s.

In the ground fl'K)r gfalkry, which is intended for the e\hibitii)n ol glass
rmcl ceramics, and in the north lil)rary I'ne ceilings are suspended in a simiK'ir

Pi;4

II 111 ' i.illcrie-.

Extensions to the Bkitish Miseum, Kino HmsAKD VII. Gai.i.ekies.

y,t'ONMPmriONAl
cvKNdlNhl.PlNd ^

HXTIiNSIONS TO TIIIi BRITISH MUSEUM.

\\;i\, l)ut llu'\ an- ornaincnlcd with ni()cl< l)cam>, Minl>: panels, cornicL'S, etc.,
as "-liown in h'iij^. 5. 'I'lii' iiu-lal i^iounds ol the inock Ixains, clc, (-(aisist
of tlat mild sU'fl bar (MMdlcs, hciU to llic lU'ccssai y siiapc ami li\;'d 3 in. a])arl
to llu' K.S.j.'s in the lloorinj^', and straii^lit round nald sUcl lods, srl u in.
ai)art aloni^; llu' c ladKs and wired to them, to act as stilleners lor the Expanded
Metal Lathiiii^, whieh is wiied to the rods and around the shaj)ed eradles.

The i-!x|)anded Metal ialhiiii^ and plaster eeilinm to the top g-allery is sus-

|) nded by means of
( li|)s, hanj4'ers, bars,
ete., from the steel roof
trusses abo\e. It is
(•ur\ ed and ornamenie;!,
and as prints ancl draw-
in<^s .are to be exhibited
in this g-allery, the ceil-
ing- is desig"ned for and
fitted with roof-lig^hts.

MAIN STAIRCASE.

The main stair-
case with its land-
ings is of reinlorced
concrete f r a m e d i n
rolled steel sections ; it
is primarily the means
of access to the gal-
leries, and is the cen-
tral feature of the
g-eneral scheme, par-
ticular!}' at the top,
where the lift grille is
enriched with the Royal
Arms in cast iron g^ilded
and lacquered.

The treads and
risers were constructed
ill situ in concrete,

in.

FitJ. 8. Details of Construction of Mock Columns in Galleries.
Extensions to the B.jitish Museum. King Edward VII. Galleries.

reinforced with

Diamond Mesh Expanded Steel embedded about | in. from the soffit, which
is flush and finished in Keene's cement. The balustrade also is formed in
reinforced concrete, marble facings are fixed on the treads and risers and on
the balustrade. The balustrade to the circular light well on the ground floor
gallery, shown in the foreground in Fig. i, is also of reinforced concrete
faced with marble.

The four steel columns in the staircase and the six in the north library

EXTENSIONS TO THE BRITISH MUSEUM. ^ NCRETEJ

are made of steel angles, riveted together with llat bar rings, filled in solid with
and encased in reinforced concrete.

MOCK COLUMNS.

Figs. 7 and 8 show clearl\- how the mock c-olumns in the galleries were
constructed; they are formed of small steel angles, riveted together with flat
bar rings, with Expanded Metal Lathing wired to them and covered with sand
and cement 3 to i , 3 in. thick.

ROOF TRUSSES, ETC.

The built-up steel trusses carrying the rooting and the suspended ceiling
to the top gallery are encased in reinforced concrete.

At the roof level on the Montague Place elevation there is a reinforced
concrete parapet wall.

Over the radiators in the north windows on the ground floor level, shelving
was constructed in sand and cement 2-|^ to i, 2 in. thick, reinforced near each
face and covered in marble f in. in thickness.

GENERALLY.

The concrete throughout was composed of 3-^ parts of crushed
clinker, i| parts of fine clinker, and i part of Portland cement; the plaster
throughout on expanded metal hithing was composed of three parts of lime
and hair mortar to one part of Portland cement, finished in Keene's cement;
the concrete is nowhere less than 2 in. thick and the plaster nowhere less than
f in. thick. Clean fresh water only was used for mixing purposes.

The galleries have been erected to the plans and specifications and under
the supervision of the architect, Mr. John James Burnet, LL.D., A.R.S.A.,
F.R.I.B.A.

The Expanded Steel reinforcement for concrete work and the Expanded
Metal Lathing for plaster work used throughout was supplied by the Expanded
Metal Company, Limited, o^ London and West Hartlepool.

Messrs. W. E. Blake, Ltd., of London and Plymouth, are the general
contractors for the undertaking, and they ha\e carried out the whole of the
work described in this article except the cork flooring finishes and the lift
grille.

1 I-

y, C-ON.STPUC-nONAll
A F.Nr.IMKI.RlN d -^J

COXCRETH IN SMALL DOMESTIC BUILDINGS

CONCRETE IN SMALL
DOMESTIC BUILDINGS.

From a Report of the Departmental Com-
mittee appointed to Inquire and Report as to
Buildings for Small Holdings in England
and Wales.

■S/"^.,

In 'vienv of the competition nve are instituting, and regarding nvhich particulars ivill te
found in another part of this issue, the extracts gi'ven telotu may be of interest and use to
those entering for the competition. — ED,

In recent numbers of this journal we have dweU on the question of cheap cot-
tag-es, and we have pointed out that the possibilities of concrete for this purpose
have not yet been quite realised. In the Report of the Departmental Committee
for Small Holdings, which was issued recently, considerable space is
devoted to the use of concrete for cheap cottages, and we gi\e l)el()w the parts
of the Report relating to this all-important question : — •

CONCRETE.

Ti6. We li.ive made careful inquiry into the value of concrete for struc-
tural purposes in connection with small holdings. \\'e have inspected examples
of concrete construction in its various forms, including- solid and hollow blocks,
monolith and reinforced concrete, and we have had before us a witness who has
specialised in work of this nature. We Uaxg also endca\ouif;d to ascertain
what economy, if any, was effected by using concrete instead of l)rick, and
whether any special circumstances accounted for its use in particular instances.
iVt the same time we ha\ e kept in view the question of the suitabilit}' of the
material for the purposes of dwelling'-houses, and the relati\e degree of com-
fort secured by its use.

117. Concrete has not been used so extensi\'el}- in England :ind Wales as
in some other countries; in fact, it may be said scarcely to ha\'e been used at
all for the building- of small houses, except in the form of concrete blocks.
Moreover, there are at present \ery few architects or builders w ho have devoted
much attention to its employment for building cottag^es.

Comparison of the cost of concrete construction with that {)f brick is some-
what dillicult, owing- partly to the fact that concrete work is usually carried out
under conditions differing from those applying- to the equipment of small hold-
!ng;s. For exrimple, it is seldom adopted unless there is a grouj) or block of
h(juses to be erected, whereas Ikjus'^s on small holdings are usualh" isolated, or
at most built in pairs. It is possible, of course, to estimate what brick
construed ion would cost under circumstances similar to those in which concrete
is used, and this is done in most of the following- instances, which, with the
exception of the last, are examples of some of the concrete houses that we
ha\e inspected :

COSCRETE IS SMALL DOMESTIC BCILDISGS.

[CONCRETE]

(i.) Coumy ....
Number and construction

of hcuses.
Cubic contents .
Cost
(ii.) County

Number and construction

of bouses.
Cubic contents
Cost ....

Remarks ...

(iii.) County ....
Number and construction

of bouses.
Cubic contents .
Cost ....

Remarks .

Essex.

20. Concrete blocks, tile roof.

11,500 cubic feet.

jCi62, or 3*4d. per cubic foot.

Essex.

Several semi-detached. Concrete blocks, Eternite slate

roof.
«;),6oo cubic feet.
;^i55, or 3"Qd. per cubic foot.
About id. per cubic foot cheaper than brick. Some have

been built for i^d. per cubic foot.
Northumberland.
120 at present. Concrete blocks, Eternite slate roof.

11,000 cubic feet.

£\2~. or 2"Sd. per cubic foot.

The aggregate for the concrete cost practically nothing.
The cost per house includes a due allowance for
depreciation and working expenses of the plant for
mixing the concrete and making the blocks, but nothing
for roads. Estimated saving, as compared with brick,
£\S per house.

Devon.

46 and two shops. Concrete blocks, Eternite slate roof.

10,900 cubic feet.

^167, or 3'7d. per cubic foot.

Eine granite chippings were close at hand. The saving,
as compared with brick, was stated to be 6d. per yard
super, for labour and mortar alone. Haulage i^ miles
up bad roads.

Glamorgan.

5. Concrete /;; situ, reinforced concrete roof.

7,630 cubic feet.

;^ioo, or 3' id. per cubic foot.

Slag from local steel works costs only is. 6d. per cubic

yard on site. No sand was required. Estimated cost

in brick, ;^i30.

It will be seen that some saving' is claimed to have been effected by the use
of concrete, but apart from the fact that its cheapness is partly explained by the
presence of suitable materials in the vicinity, or by other exceptional circum-
stances, it is clearly unsafe to conclude that the economy effected on a lar^e
contract could equalls well be secured if only a few houses were to be erected.
On the contrary, it is improbable that concrete can compete at present with
brick, especially in a district where bricks are cheap, unless a fair number of
houses are to be erected.

1 18. There are numerous patents for reinforcing concrete, but in i;ent.*ral
these patent methols are expensive, and there is the further drawback th.it
the firms supjjlying patent reinf<jrcements do not them.selves carry out tlu-
construction, so that res<irt must be had to ordinary builders and contractors
for the actual building of a house. If a large and experienced firm from a dis-
tance be employed on a small contract the expense may be prohibitive, while,
if a local builder be employed, the absence of technical knowledge, and the
difficulty of ensuring a proper specification and adequate supervision, make it
almost impossible to achieve a satisfactory result.
16

(iv.) County ....
Number and construction

of houses.
Cubic contents (average I .
Cost ....

Remarks ....

(v.) County ....
Number and construction

of bouses.
Cubic contents .
Cost ....

Remarks ....

CONCRETE L\ SMALL DOMESTIC liUlLDISGS.

I U). In the cast' of a lari;c hiiildinj^ sclicinc, liowcvcr, llurc is littli- doubt
tliat in inaiu dislriits of I'liii^land and Wales a suhslantial sa\inj4 could be
eficcti'd b\ llu' usr ol coik ri tc. II \\\v pi-cuuiarx' a(l\antaj4c to !)(• derived from
its eniplox nieiit iu plaee <>l l)ri( k (le|)en(ls to any extent upon ibe con-
centration of a laii^e amount ol work \\iliiin a small area, it is obvious ihal tlie
fullest econonu t^ould only be secured, so far as tbe e(|uij)ment of small liold-
ini^s is conc-erned, w iiere tlie circuiiistances permitted of a considerable number
of holdiui^s beini^- provided toj^elher on a lar^e estate. This system of
(lev eloimient is so much to be recommended on other j^rounds that the necessity
of resorlini;- to it, if concrete construcMion is to be carried out as cheaply as
possible, cannot in itself be rei^arded as an obstacle to the wider use of this
material, assumin*;- tliat its constructional suitahilitv is established.

Whatever opinion may be held as to the practicability of utilising^ concrete
on any extensive scale in connection with the eqliipmcnt of small holding's, it
cannot be doubted that there are likely to be g^reat develojjments in concrete
construction, and, in spite of all the difficulties that exist at present in securing"
a reliable result with single building's of concrete erected under ordinary rural
conditions, we have seen enough examples to convince us that efforts should
be made to develop the use of this material. \W' propose, therefore, to g;ive
some details of the v arious modes of constructi<^)n to which concrete is adapted.

METHODS OF CONCRETE CONSTRUCTION.

1 20. Concrete m.i\- be used for building" in the following" ways : —

(ij It n-.ay be moulded into blocks or slabs, and these used for building"
in much the same way as blocks of stone ; we have seen many
cottages that were built in this way.

(ii.) It may be filled in between wood sheeting", thus forming a monolith
structure built up in situ. A number of the Hollesley Bay cot-
tages were built economicallv in this manner, as the cost of the
sheeting" was distributed over several houses.

(iii.) It may be poured in a more liquid state into wood or iron moulds
erected complete to the form of the building. This method has
been a.dopted by Mr. Edison for his "poured cottages.''

(iv.) It may be filled into moukis laid horizontally, each mould pro-
ducing one side of the building; these moulded slabs, when set,
are put together to form the cottage. This method was described
to us by a witness, the main points of whose evidence arc given
on p. 19.

(v.) It can be used as reinforced concrete, in which case bars or rods of
iron or steel are used to take u\) the tensile strain. Such rein-
forcement can be used more or less w ith all the above methods.

CONCRETE BLOCKS.

12 1. This method of construction is the one which we have found to be
most commonly adopted. It is the simplest, and the existence of various
machines for turning out bk^cks on a large scale makes this system easier of
adoption than methods whicli inv(3lve m.ore continuous supervision as the- work
of construction proceeds; for this reason, perhaps, it is the method which

c 2 17

CONCRETE IN SMALL DOMESTIC BUILDINGS. ICQISCBETEJ

gi\es the niost uneven results. We ins])eete(l a (-onsiderable number of houses
built on this system, and nearh alwaxs found tliat wet had driven through the
walls ; in some few instanees the bloelvs w ere so ]>or()US as to make the houses
unfit for habitation. We also found that the majority of the houses inspected
showed a tendency to develop \ertieal cracks, extending- the whole height of
the walls, not only throug-h the joints, but across the blocks themseKes; these
cracks increased the diflficultv of securing a dry interior. In fairness, however,
to the builders of some of the concrete-block houses that we saw, and in defence
of the method itself, it must be added that we inspected one example of a
number of such houses which were entirely satisfactory, the houses being-
pleasing in appearance, well-proportioned (a result not always easy to achieve in
handling- a unit so larg-e as the ordinary concrete block), free from cracks, and
thoroughly dry inside.

122. In building- houses of concrete blocks, it is important that the lengths
of the \\ alls and the sizes of the openings for door and window frames should
be, so far as possible, exact multiples of the size of the blocks. The actual desig-n
of the concrete block has not been thoug-ht out so well in this country as in the
case of a patent block used in Sweden, which provides for almost continuous air
space. Hitherto blocks have usually been moulded with an air space in the
centre, the inner and outer portions being connected at the ends. If the con-
crete is porous damp is likely to strike through these solid portions; for this
reason, the method of laying- double slabs on edge so as tO' form a wall with a
continuous ca\ity is beings adopted in some places, and this method, if the
work is carried out properly, is calculated to ensure a dry wall, even with con-
crete that is slig-htly porous. If, however, double slab walls are necessary in
order t^) obtain a satisfactory result, there cannot be much economy, in ordinary
circumstances.^ in such a wall as compared with brickwork.

CONCRETE IN SITU.

123. In the second metliod it is usual to leave openings into which door
arid window frames are inserted subsequently. For simple work, such as the
foundations of farm building-s, this method is the best and most economical,
but for a wall that is to be carried up an}' considerable heiglit, as in the case
of a twfj-storied house, the cost oi framing- and sheeting is hea\'\-. K\'en if
se\eral hmises are to be erected (lose together, so that one set of sheeting- mav
suhice for them all, the cost of re-erection is considerable; at Holleslev Bav
it was estimated, in thie case of a one-storey cottag-e, that the cost of building-
iipuii this ni('thod was about cciual to that of a (j-in. bi'ick wall with bricks at
30s. j)er 1,000 delivered on the site.

MOULDED CONCRETE.

124. Ill i};c third method, the door and window frames may be placed in
p(jsition in liie nujuld, and the; concrete is liien jioured round them. Mr. I^dison
has in\-ented a system whereby an iron mould of the whole house is set up, and

the hi.ildiiig made by iKJiiring llic li(|ii!(l coiicrclc in ;il the top of the mould, the
house thus becoming- a c<)niplclc riioiiolilh. \\\ ihis inctliod all joints are
avoided, and it is claimed thai a house (an be linished in a lortnight. Since,
lun\'e\(r, the mould alone (■<)sls abont /.'i,joo, it is (|nile clear thai it could onl\
j8

r J, c-oN.N ruurrioNA I

L«i.KNCiINKKI^iN(. —

CONCRHTE IN SMALL DOMHSTIC /WILDINGS.

])v piofitahK cniplnx i(! il ;i l.n'i^c iiuinhcr <>l lioiiscs ol idcnlic.il pallcin were 1<>
])v iTi'cti'd ill close proximilv. A !• iciicli linn lli.il l);is iii;i(l(' use ol s;)nK' siicli
mould chiiins ihal •! s;i\iiii; ol Iroin jo to ^o per ccnl. ran be cllcclcd, hut \\c
l.avc no ex idv-ncc lo show how far this claim can Ix- siihstant ialcd.

HORIZONTAL MOULDS.

125. In the lourlh method each side ol the huildinj^ is cast in a iKM'i/ontal
mould, thus formini; a lai'i^c slab, which is I'aiscd into a vertical position when
it has set. The mould is \cr\- simple and inexpensive to make, as it is only
neo'ssarv to lav a le\cl staj^inj^-, lor which purj)ose the floor or rool boards can
be used. The door and window franies are laid on this staj^'inj^' and the mould
completed. Its horizontal position fa<Mlilates the arrang^ement of the reinforc-
ing- rods, and it is not nccessarx to make an upper side to the mould, as the
concrete can be evenly spread and screeded off to the required thickness. A
house al Letcdiworth was erected U|)on this system some years ag'o b\ the city
cn5.^"ineer of Li\erpv)()l, clinker from llie refuse destructor being used for the
aggregate. The method of construction was described to us by a witness, who
has adopted it for the erec^tion of one or two buildings, and reference may be
made to the Abstrav i of M\ idence (page 74) for detailed particulars.

126. ^^ ilh all the (liferent methods of construction, in addition to any
saving; effected in the actual cost of the concrete wall, as compared wnh one of
brickwork, there is usually a considerable reduction in the cost of plastering,
as a slight skimming coat is all that is required; indeed, it is possible in many
cases to smooth-trowel the surface of the concrete as it sets, so that colour-wash
may be applied direct without any plastering.

CONCRETE FLAT ROOFS.

127. The witness already referred to has also succeeded in making concrete
flat roofs perfectly waterproof. It is true that the work is of comparatively
recent date, but it has been completed long enough for defects to show them-
selves if any were likely to appear. There can be no doubt that if further
experience confirms the evidence that a flat roof of concrete 3 in. thick, without
anv covering, can be made thoroughly watertight, such a roof would be con-
siderably cheaper than any form of slate or tile roof. It was stated by the
witness that a saving of ^£^15 per house could be effected, and we have been
given figures sliowing an actual saving of ;£. 1 1 on the roof of a cottage with
dimensions 27 ft. by 16 ft. 9 in. as compared with the cost of an ordinarv- hip
or pitch roof of flat tiles.

Some further experience is needed to determine whether there w(;uld not
be a liability to excessive e^ondensation with solid walls and roofs not more than
3 in. or -I in. in thickness.

MATERIALS AND HANDLING.

128. Whatever be the form of concrete construction adopted, or the nature
of the work, the success of the result will depend on the use of suitable
materials and their careful mixing. Waterproof concrete can only be made
by using a thoroughly impervious agg-reg-ate, and so grading- it that the inter-
stices between the larger fragments may be entirely filled with smaller par-
ticles and clean sand; the function of the cement is then simply to bind the

CONCRETE IN SMALL DOMESTIC BUILDINGS. [CDNCBEJE]

whole together. While bricks and other porous materials may make excellent
concrete for fireproof purposes, or for ordinary foundations, they are not
suitable for external walls or roofs, where waterproof properties are essential.
For such purposes an aggreg-ate of j^ranite or g-ravel is best ; clean slag- or
clinker may also be used if it can be relied upon to contain no impurities
such as free sulphur or jDartially burnt material.

W'c are convinced that the need for building- concrete walls hollow is due
to the faulty work that so often results from the use either of an unsuitable
agg-reg-ate, or, what is equally disastrous, defective cement ; and that if the
fullest economv is to be obtained bv the use of concrete, it will only be by
the adoption of careful and intelligent methods by wliich this necessity may
be avoided.

129. The Engineering Standards Committee has fixed a standard specifi-
cation for cement, and none which fails to comply witli the British standard
specification for Portland cement should ever be used where it is desired that
the concrete shall be waterproof. This cement is usually supplied in three
grades — viz., quick, medium, and slow-setting. Detailed instructions on the
most scientific method of using cement of the quality known as British
Standard, and of mixing concrete for various purposes, are issued by the
Royal Institute of British Architects and bv the Concrete Institute.

I^r CTONyiPUCTIONAlJl
L<V KNCil N l-W 1 N( ■ — J

REINFORCED CONCRETE PANORAMA

REINFORCED CONCRETE

PANORAMA, ZOOLOGICAL

GARDENS.

By ALBERT LAKEMAN.

This -work is'quite unique, and as an example of reinforced concrete con sir action there
is nothing in existence -which in any -way resembles the problem -which has herein been
dealt -with, and m consequence it has much interest to those -who study the lanous
applications of this material. ED.

'Jhe scheme described in this article is the outcome of a bequest by
Mr. Mappin, who provided a sum. of money to defray all the expenses
nection with the work.

Tile primary object of the panorama is to show the animals m

the late
in con-

such a

Fig. 1. View showing Columns under Construction.
Rkinfokckd Concrkte Panorama, Z( ological Gardens.

manner that they appear in a state as nearly as possible resembling" the natural,

and avoid the caged appearance \\hich is generally associated with animals

kept in captivity. The architects for the scheme are Messrs. Belcher and

Toass and it will be seen in Fig-. 2 that the plan is that of a quadrant, and this

ALBERT LAKE}] AN.

ICQNCBETE

has a radius to tlie exlrcnie outside of about 288 ft., thus the whoU' scheme
covers an area of about 260,000 sq. ft.

The panorama is divided up l)y tliree icrraces for ^i^it<)rs, and these are at
varying- levels witii a wide flight of steps at either end for the passag^e from
one le\el to the other. The centre of the quadrant \\ ill be occupied by a tea-

■ ■ "'V-:-;

\-'

Fifi. 2. General Flan.

Kl IMORCKD CoNCRKlK PANOKAMA, Z()i )I 0(.I( \r (lARDhNS.

house, adjacent to which is the lower terrace, and imincdiatcly on the other
side ()\ the len-acc a large (hi(l<-pon(l is being formed. I>e1ween llu- (hu-l^-pond
.and the middle terrace there are four large ciiclosuies b)|- deer. A li-inforced
concrete wall se]3arat<'s the latK r from ihe tcirace, and on the othci- side of tlie
terrace iheie is a large drv diteii which is formed to ])r('\ent the Ix-ais Irom
jumping- out of tlx: enclosui'cs whi(li o<(ur b(lw(en tlie middh- and upper
terraces. 'i here are six lai'ge bca)' enclosures, and each ol these lonlains a
water tanlc in which the animals can dis|))rl ihemsehes, while ihe suilace of

Rl^:i\'F()RCliD CONCRETE PANORAMA.

till- ciiclosllic

iindu-

hitin^ :in(l constructed
l<) rcsc*ml)lc ii.it iir;il lix'ky
•ground ;is lar as
j)()sm1)1c. riic u|)])<'r Icr-
1 a((' s('])aratfs tlic hear
enclosures Ironi the ijoat
liills, wliich are cjuile one
<jf the most slril<in«4 lea-
lures of ll.c scheme,
these risin;^ up to a
height of about 70 ft.
from the ground le\ el
and being grouped to
form four distinct liills.

These hills are
shown in outlin'j in i1k'
section in Fi^\ 3, \\hi(^li
indicates somewhat the
uneven nature of the sur-
face and shows the ditli-
5 N cultv of the bracing for
s such an irregular con-
^ ^ tour. The photograph
^ cC in Fig. 4 gives a general
.^ H idea of this bracing
under construction, while
u one of the finished hills
g can be seen in the dis-
I tance, although the full
s height is somewhat lost,
as the view is taken from
the middle terrace and
not from the ground
level.

The section in Fig. 3
also shows the dens for
the bears, which are con-
structed under the upper
terrace. The i^ear en-
closures are separated
from eacli other by high
division walls, which are
formed with concrete
iKning a surface which
is just as it leaves the
centering, and a rustic

I §

O ES

t- ~

ALBERT LAKEMAS'.

ICDNCBET FJ

effect is obtained bv the use of wire nettinii'. wiiicli lias allowed the concrete to
bulge. At the same lime j^reat caie and thouiilit has been devoted to the work
in order to avoid any projections whicli would enable the bears to climb up the
walls and escape. Tiu' slal)s in ihc bear i-ndo-^urc are illustrated in Fig. 5,
and it will ]yv seen that thi- thickness \aries from 5 to 7 in.

Xo beams in the ordinary sense of the word could be formed owing- to the
irregular surface of the slab, but these were formed in the same thickness by the
introduction of additional bars for a width of alx)ut 2 ft. 6 in., and these beams
followed the same lines as the slabs. The reinforcement in the latter consisted
generally of |-in. bars at lo-in. centres in one direction, ^-in. ])ars at about

P/iotuKrap/i hy J:nicst AHlnei .\

l-'vA. t, Hraciii^i to Second (ioat Hill.

Kl.IMORCII) CoNCKfcTK I'ANOKAMA, /(OLOGICAL GakOI.NS.

I Luiulcn, S.W

3 {-in. cenlrL-s in ihc o])p;jsilc dircclioii. Some of the Ijars arc luriicd up and
passed o\'er the ixams, as shown, and slirru|)-^ arc also ))ro\i(if(l. 'llu cnlumr.s
were also made of diffcent heights, and the cciUcring for ilic slabs \\;is formed
parti}' with planking and j)ailly with wire uctling, the lallcr i)c'ing allowed lo
sag and tlius assisting in llic bninalion •)! ihc un(hilal ions.

'ihc, water tank's in lhc-.c cix losiircs lorm inlci'csling examples of rein-
forced concrete, as th(;\' are j^( neralK' susjx-nded from 1 he ( ohnnns .md sl.ibbing,
■.\])(\ arc lormed with a \ crv irregulai' sli.ipe, ;is will be seen in the
pliot<;graj)l)ic \\c\\ in /'/^^ 7, uliicli shows ilie andei'sidc of one lank.
Despite the I ict thai wo j)ai'li(ula!' j)rec.iul ions were taken with the

f, CONXIVUCrKaSAll
A KNGINKI-PINC. ^

REINFORCED CONCRETE PANORAMA

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ALBERT LA K EM AX.

[^^CCETEJ

' J, CTONM PIJC riONAl.l

REINFORCED CONCRETE PANORAMA

work, these tallies Ii;i\i' hccii Inimd lo he pcrrcctly u atcrlig'ht , aii<l
il will he iindi islood thai ihcrc was sonic diHicuIty in lanij)in^ ihc concrete
w lu-n poi lions of \hv su|)])()rlini4- cenierin*^- were C()m|)()sed ol wire neltinj;- only,
riu- lari^cs! lank is thai formed in ihe exlrenie eastern enclosure, which will he
occui)icd h\ till' |)olar hears, and this has a niaxinunn haij^th of ahout 40 ft. and
a width of ahout 17 ft., with a (le|)lh of water of O ft. This tank is fitted at
the deep end with four observation windows 2 ft. by i ft. <) in., throug-h which
the bears can be seen when under water and their moxcnienls noted.

The dens, which are formed under the upper terrace, are each about 12 ft.

Photograpli by Ernest Milnerl [London. S.W

Fi^. 7. Under side of Bear Pond, showing Suspension.

Reinforced Concrete Panorama, Zoological Gardens.

by 6 ft. and 6 ft. 6 in. high, and these ha\e floors, walls, and ro'uf of reinforced
concrete 5 in. and 6 in. in thickness, with reinforcement in both directions and
surfaces. The wall adjacent to the enclosure is continued up above the floor of
the upper terrace for a height of nearly 7 ft., to prevent visitors being seen
from the lower terrace levels, as this would detract from the natural appearance
as far as the animals are concerned ; but small windows are being formed in
the wall to allow a view into the enclosures from the upper terrace.

The construction of the goat hills required a great deal of careful considera-
tion and setting out, as they arc very irregular, and yet of necessity they need
to be rigid, on account of the height. Two typical sections are illustrated in

ALBERT LAKEMAN.

ICONCBETEJ

li;i. 'J. View showing Middle 1 cirace iit-ai JMicluMircs, etc.
REINFORCBO CoNfUl II I'ANOKAMA, ZoOI.OGlCAL GaKDKNS.

REIN FORCED CONCRETE PANORAMA.

.- c , , n . , .Irn llnoiwh llic Mvcnd and ihird hilN. Tin- lower part

"■'• ^' ^'^'^^" ^""' s n^.ral rows of columns, about .7 it. h^^h above

..I tlif construilion ronsisls 01 stxtiai n>\Nr> •, , • 1 1 •

,£:"i:::';.:;l>::::i:':.':n.:;::r:::;;,r f':i £
;l-;::::;-^i;^;''c;:;r-;:::;n:::.:j::::.'J;.-";t

»-?63

I I |i ij im millllllll V I lllliMmilj J ummma

__po-'»J

Fit5. 10. General Plan, showing Arrangement of Columns.
Rkinforced Concrete Panorama, Zoological Gardens.

scuu-c bavins a mininuini Uiicknoss at the otlicr edges of 9 i"-. increased to
,8 in 'at the intersection with the column shaft. The tops of the colutinns are
connected bv radial and tangential beatiis which vary in s,ze from 9 '". by in
to 14 in. bv' 9 in. according- to the position. .All the columns and braces above
these bcanis are 9 in. by y in. and reinforced with four ?,-m. bars and hnks

ALBERT LAKEMAX

[(jQNCBET D

Spaced :il 12-in. centres. 'I'he si)ace under the second hill is partially occupied
bv a lari^e water tank, shown in F/^^ 8 on the Diagram A, and this tank
supplies tlie ponds in the bear cm^losures. It has a mean width of 30 ft., a
length of 2- ^^-^ ^"d is 3 ft. 9 in. deep. The hoiiom and sides are formed with
5-in. reinforced slabs carried by 14 in. l)y 9 in. main beams, and 9 m. by h m.
secondar\ beams, reinforced g^enerall\ with four ^-in. bp.rs and iV-in. slirrujDS.
The water from the goat hills is collected and taken to this tank, and the over-
flow is connected to the main supplying the bear ponds, and the latter can be
quickly filled, as the tank is constantly full and a supply always available.

The trussing- under the third goat hill, marked B in Fig. 8, is somewhat
different ow ing- to the intermediate columns being omitted with the object of pro-

1 ■,.. 1 i-' •ir J.inJ'jMiiL- (lui in;; Coni.u iiuin-u.

Rl.INl OKf KI) C0N( KKTK PANOKAMA, XooLOdlCAL GaKDKNS.

xiding" a large iiall th.il (.in be utilised lor m;iii\- ])ur|)oses, such as lectures on
natural history. I uo rows ol coluiniis oiil\ .lu- cmploNcd here, ;iiid large rein-
forced <f>n'rcte Irusscs h;i\ing a s[):in ol .iboul 4J ll. are consl ru( led ;is shown
in the seeiioii. 1 he llii<kiiess ol the covering sl.ibs \;iiies soin.'w h.il accoiding
t(j the j)osili(jn and kjading, but ihe minimum ihickness emjiloyed is 3 ins. These
slabs were forj7";ed by ramming the com reie between two l;i\'ers ol wire nelling-
spaced .'il ihe distance apart i'ec(uired lor ihiikness, :in(l ilie rainniing of ihe
concrete caused the netting to bulge and produce ;m iiregul.ii- surl.ice, and in
addition iIh- line slull j)roj;(ted through the linles in the nelting. 'ihe outer
surface v\.is tre;it(d with .i still I)roi)ni, which c.iused iliis projecting stuff to
spread and cfj\er the iHlling eniirel_\, .md ;i! the s;inic lime ;i suil.ible surface

[/:LNr;iNK'p[K?Sg REINFORCED CONCRETE PANORAMA.

finisli \\;i.s ohl.iiiu'd. I he oiilcr surlacc is 1 IicrclOrc siiHi(iciill\ roii^li lor iIil*
*;"();its to cliinl), ;im(I is iciiilorci d i)\ lin- nctliiii^, wliicli is (juitc .idditional lo the
main rriiilorccnunt ol llu- slab itscll. Ilic wliolc apixaranct' is wrv pleasing,
and wlu 11 seasoned and loncd down hy ihc wiatlu-r slionld i)rescnt a very natural
effecl. A ladder is |)r<)\ ided in llie interioi- of the hill to allow the keeper lo
pass u|) to tlu' lop with lood, which is passed through a feeding hole at this
{X)inl, thus indueini; the ^^oals to elinil) well u|3 into the \ie\v of the visitors.
A safety railin*^- is fixed on the outside of the hill some wav down from tlu toj)
to prexent unfortunate i^oats from being- butted or fallin*^- to the ground belou .
The staircases leading- from the lower to the upper terraces are 14 ft. wide, and
they are reinforced with bars in the sofHts in both directions, and an intermediate
transverse l)eam is also j:)ro\i(led in the centre of each flight. The landings are
formed with 5-in. slabs also reinforced in the sofhts in l)()th directions, and the
bars in the flights are carried well into the landing concrete.

The whole of the concrete is being mixed by machinery, and the j)ro-
portions generally adopted are 1:2:4.

The Consulting Engineer for the scheme is Mr. Alexander Drew, of 64,
Victoria Street, and the contractors are Messrs. D. G. Somerville & Co., Ltd.,
of 120, Victoria Street, Westminster.

It will be readih' understood that the nature of the work necessitated a
great deal of ingenuity in the execution, and many points had to be left to the
foreman on the site, especially with regar 1 to the irregular surfaces of the bear
enclosures and goat hills. It was quite impossible to indicate the complete
contour of all these irregular surfaces on the drawings, and scale models were
therefore made for the guidance of the contractors, who are executing the work
in an excellent manner. It would not have been feasible to construct this
panorama in any material other than reinforced concrete, and for this reason the
w^ork probably illustrates its adaptability to any form of construction more
clearly than any other example in the country.

EWART S. ANDREWS.

[QONCBETE]

ALIGNMENT CHARTS FOR

CONSTRUCTIONAL

FORMULiE.

By EWART S. ANDREWS, B.Sc.Eng., M.C.I.

The foUoivlng article should call for the attention and consideration of Engineers ana
others interestea in this subject of Alignment Charts.— ED,

Within recent years an intereslinj^- method of plotting charts, known as the
Aliirnment Chart method, has been extended very successfully to use for
engineerini,'- formuke. As far as the writer is aw^are, the first use of these
diagrams in a British publication is to be found in the Structural Steel Section
Book recently issued by Messrs. Redpath, Brown and Co., Ltd. The method
is, I believe, of French origin, and has been developed very largely by Pro-
fessor Peddle, of the Rose Polytechnic Institute, U.S.A., in articles in the
American Machinist and in a book entitled "The Construction of Graphical
Cliarts " (Hill Publishing Co.), in whi(^h this and other interesting methods of
graphical representation are set out.

In the present article it is pro])osed to explain the nature of the.se charts
and to .show how they can be drawn, illustrating the method by constructing
cliarts for suitable well-known constructional formulai-.

Underlying principle of alignment charts.

'Jhe constructi(jn is based upon an unusual method of pk)tting (^o-ordinates.
The m.ethods commonly considered in co-ordinate gi^ometry are the Cartesian

or rectangular co-ordinate method
:in(l the polar co-<:)rdinate method.

The rectangular method is
shown in Fi^. i, which represents a
lin-ear function n.x \ hy~c.

1 1 w ill he rcMicmbcrcd that in
this inclhod ')! plotting x'alues a and
y arc liikcii in directions at right
angles to each other and (^or-
res|)on(liiig to simiill ;ineous \alues
of X and \ \\v gel a |)( )inl /'.

In llie method Innning llu' basis
ol llie alignment elKirl two |)arallel
lines, .V V, ) 1' (/''.i;'. 2), are <lra\\'n at
a conxcnient distance d apart, and

Fig. 1.

3^-

J. CONyiPlKTIONAn
tV t.NOlNKll^lNd — ^J

ALIGNMENT CHARTS.

.stiirlin;^ lioni llic l);isc liiir V ) we set ii|) A /' ((lual lo v ;iii(l lO, ((jiKil to y. In-
>U'.i(l<)l li;i\ ins^ ;i point lo ri'|>rcstiit ^iiniilt;invous \ allies ol a ;iii(l y uc now li.ive
llu' str;ii|L;hl lin<' /'fj,- Xou si'.pposiiii^ th;it .v .ind v .'H'l- ioniu'ctcd toj^ctlicr l)\ ;i
liiUMi' relation ol the loiiii (/ah l)y c (i), and supposing that new \ aiucs ol
V and y arc found and j)lotlcd lo j^ixv |X)ints 1*^, O.^, tlicn l*.JJ._. euts l$Jt in S,
and if cciuation \^$ holds, .S' will \h- a iixcd point called the support, so thai 1)\
])Utlini4 one straij^iil edi^c thioui^h an\ particular \alue ol a, and also ihrou^h .S ,
the cdi^i' will intersect the line ) ) at the ]H)int which will enable us to lead oti
at once llu- correspondiuLi' \alue ol y. I^( lore pr<jceedinj4 to the j)rool of this
lad it must be pointed out tliat an alteration of .S' upon the line AS, called the
" support line," will i^orr-jspond lo an alteration of the constant c in the fc^rmula,
and b\ obtaininj^' a suitable scale for lenj^''ths upon the line AS we can treat c
as a variable quantity, and so use the (diari for soKinij- an ecjuation in which
there are three variables.

Proof of construction : —

Oraw .S7^ and FT horizontal.

Then the A^-^ SOJ^ and PST are similar.
ST _ PT

' ' Q.R~ SR

z—x XA e

I.e.

y-z AY f
We will assume that S

is a fixed point — i.e., s = constant, and

constant.

Y ^

Fig. J

For convenience we will wTite this as

x^ —

a a

D 2

z — X _ e

y~z f
or /(:r-A-)^c(y-3),
i. c. , fx -r ey -^ ez ^- jz^
i. e. , fx -r ey -- z{e + /). (2)
\ow z, e and f are con-
stant, so that equation (2)
represents' a linear relation.
It is shown, therefore,
^ that by drawini^' from \alucs of
A- on the line A'A' through the
support, the resulting' value of
y on the line VY follows the
linear relation of equation (2).

Going' bacd<, therefore, to
the original equation (1) we
have

ax -i- bv = c.

(3)

EWART S. ANDREWS.

and \\ c will write (2) as

= ^(^-l)(4)

, ey z{e-\-f)

(5)

From (3) and (4) we gel
e ^± ^ 2^t

and

c _z (a^b)

•SO

i.c

or z

a + b
It will be noted that

.'■ re-writing (5) as
e _ b

[-(6)

-r

--50

e+/ C7 + 6

we see that
a Tb^

(7)

rs-

(8)

272

ICQNCKETEl

- ?'5

•4-0

-■/5

I*'

A? -I

'10

Fifi. 3. Chart for French"Reinforckd Concketf.
Formula.

A\ e n<jle also that the values of e and / are independent of the constant c,
whereas z depends on c, so that, as pieviously stated, by alterin^^ the constant
we do not alter the support line, but only vary the position of the support ujDon
the line.

Scai.es. ^ — Suppose that for the sake of convenience in certain problems the
X and y Icn^^ths ar(- plotted to different scales, say, i in. =.S'^. units for x and
I in. = .S^ units for y.

Then we shall ha\e

e =

bS.

aSx -f- bSy
and the scah- for the sup[)ort \alues will be

S, = ] inch=aS,-\-bSy
Example of Reinforced Concrete Column Formula.

(10)

It is now pr<;i)(jsed to illustrate the use of these diaj^n-ams or alignment
charts by drawing'- one for the formula for h<'lically r<inforce(l concrt le columns
specified by the French (iovernment, viz. : —

V V '

(11)

r J, CONM PlJC-nONAi;
L*VF:NrilMLF.WlN(. — .

ALIGNMENT CffARTS.

In this lormula

Q = l*criiiissi\ c coinprc^six t slnss jht >(\. in. on llic {(jlunin.

1^ =l'lliin;iU' coinijicssix (• stress on tin- <<)n(Ti'te.

\'^ — \\)lunu' of core.

)',, = X'olunie ol lulicMl reinforeenicnl.

\'^=\'olume of lonyiliuliniil reinforeeiiunt.
I lie reinforcements are usually sj)()k<n of as ])ercenta|^es.

. <. 1 •. r 1 • r . 100 \^,

Let j^/, = o longitudinal reintorcement —

^ _,. V r 1 ■ ( ,_100V^/

M pn— -> helical reintorcement— -

I'herefore, re-writinj^ our lormula, u e lia\e

— =•28(1 -ISPL+'iiPn)
u

= -28+ '0^2pL+ •090pH (12)

Starting- at a convenient point set out pj , the per cent, longitudinal rein-
forcement, to a suitable scale, say, i in. - '5 — vS^, taking a range of values from
o to 3 per cent. Then set out at a convenient distan(^e d = ^ in. away from this
line a scale of helical reinforcements —the same scale i in. = '5 = 5y will be
suitable.

In our formula a — "042, b =- 090.
Therefore by equation (9)

_ • 090 X • 5 ^ c _ o . - 9 • u

e = - X 5 — 2 /2 inches.

•042X -S+'OgOx -5

The scale for -^ is given by equation (10)
u

S,= -042X -S-h-OgOX •5=-066 = l inch.

The constant '28 shows us that when p^ and pn ^^^ each equal to O,

— ='28, so we know that the line joining the points 0,0 intersects the sup[X)rt
u

line at '28.

Since i in. - '066, '02 will be given by ^- --^o^ in., so settino- up --.o:; in.

•066 ^ 1 . ^

from the bottom we get the "30 mark for ^ , and so gel the other divisions as

indicated. The divisions are not continued bexond Oo because the regulations
state that the compressive strength shall not exceed '6 of the ultimate strength.
Suppose, for instance, that we have a column with i per cent, longitudinal
reinforcement and 2 per cent, helical reinforcement, we place a straight edge
across the corresponding ix)ints on the chart, as shown in dotted lines, reading

If, therefore, n = 2,000 lb. per sq. in., c will be about 1,000 lb. per sq. in.

Extension to Product Formulae.

The alignment chart may be applied to product formulae (which arc much
more common in practice than those which we have considered up to the pre-
sent) by taking logarithms, thus bringing the formula into linear form.

EWART S. ANDREWS,

[CDNCKETEJ

Take, for instance, P" 0"" = /?''x A, where .4 is a constant.
Taking log^s. we get : —

)i log-. P -- 111 log. O -= p \og. R + log-. A. (13)

\n aliL^nmcnt chart can then be drawn for this formula in the manner
pre\ iously explained, although gr-.-ater care is required for the plotting.

Example of Formula for Steel Beams.

This case can be illustrated In' th-e well-known formula for steel beams

where -Unsafe bending moment on the beam in inch tons,

/=safe stress m tons per ^q. in.,

Z-- section modulus of beam in inch units.

For a uniformly

distributed load upon

a span of L feet,

WxiUL)
M = ^ ' and

/ is usually taken
as 7-5.

Our formula,
therefore, comes to
12WL

7-5Z

TFL^SZ.

V\li. 4. (MART lOK StI I I. liKAMS.

(H)

(15)
log. IF + log.

L = \og.s + ^og. Z.

We \vill take a
range of W from
10 — 150 tons.

log. JV varies
from I to 2' 176. '^

A suitable s(\ale ^o
for this will be "^

1 in. = Sx = 5, and-^

Fig. 4 w as originally q

drawn to this scale. ^

With a lit lie jjractice ^

these logarithmic

scahs can be drawn

w i 1 h comj)arati\ (■

ease. Take, lor

instance, a coii-

\ enient point near the

bottom of the right-hand line of h'ig. -] and mark it 10. Xow log. 150 -log.

iO-hlog. I5 = l()g. 10, \\J<>, so lake a distant'' i(|ual to 5X|-|7() 5'SS ni.

above the 10 line and mark it 150. 'i"o lind inu rmcdiatc; pn'wWs \\v j^-ocei d in

exacth the saiiu manner. i'or ^(j, tor instance, we ha\c 1<

OiJ

J, OONMVUCn lONAl,

ALIGNMENT CHARTS.

-_l()_i;. u) I "477. "177 '<> <>i"' ^'iilc is ■-477x.S = -WJ i'i. iu';irl\ , so mark .1
point J\><) in. ;il>o\c ilu- 10 111. iik ;iii(l (.ill il ^o ; tlic s.iin; disl.ii.cc ;il)o\c this
j)oiiil will i;i\ i" t)o.

On tlic opptisiic side ;il ;i conx cnicnl (lisLiiuH' :ip;irl s:i\', 5 in.- uc draw
IJK' /. line ;in(l we will lake as a suilahh- ranj^c ol \ahu's ol /. 5; 11. lo 30 II.
Ia)^. 30 loi^-. 5: lot;. 10 I. riic same scale, 1 in.=.S"y= l, will he ron-
\cn'\vu\ lor this, so mark a cominicnt point 5 and set up 5 in. .ihoxc it and
mark that point 50, ohlaininj^ inti-rmrdiate pinnts in the manner jjrcN ioush'
deserihed.

'JO draw the Z scale we Inst lind ihc j:)osition of the supj)ort line as
follow s : —

By i^"C|u:ition (9) c^ ^_5>l ^ ^.

a Sx~\~b Sy
In the present ease a = b ^- i , d^z^, Sx = Sy = h

5 ' 5
We therefore draw in the Z line as shown. \e\t its scale is determined

by equation (10), viz. : —

Sg = (i Sx-^b Sy

Xo record has been kept of the zero points of the (T and L .scales, and we
do not require to know them, because it is ^een by putting TT^i^io and L=^^
in equation (15) that Z=io. We therefore join across the points 11':= 10 ;ind
L = 5 as shown in dotted lines and mark the intersection on the Z hne to.

The Z scale is then divided up as follows: — Take, for instance, Z^200,

log. 200= log-. 10 + log. 20^ log-. 10+ r^oi ; to our scale this is given by

1 * 301 X 5

in. =3'^5 in., so set up V-5 inches above the 10 ]>oint and mark it

200. The chart is then soon completed.

To use it, suppose that we want to hnd the section modulus necessarv for
a beam to carr\ a uniformly distributed load of 40 tons o\er a span of 30 ft. ;
place a straiglit ed^e across the points 40 and 30 as sliown in full lines and
read of Z = 240. From a table of standard sections a suitable section can 1x'
found at once, or if beams of a definite t} pe onl\' are used the sizes can i)e
marked on the Z line at the opposite side.

In actual use of the chart it is not necessary to draw the lines aci'oss ; it
is better not to do so.

Extension to Four Variables.

These charts can be extended for use with four \ariables in the following
manner. We will illustrate the point by a consideration of the same formula
for steel beams, but will take the stress as variable. Our formula is :- -

^^^=yz (16)

i.e., log. Z=^log. r5 f log. rr + log. L - log. /. (18)

Let i; = log. ir + log. L. (19)

EWART S. ANDREWS.

The loij-. 1-5 m:iy be neglected for the present because it has only the
eftect of shift ino- the zero for the Z scale. So we may write

log. Z = log. V - log. /. (20)

20-

l''i(4. 5. Chart i ok Sikki Hi ams uitm Xakiaiu.I'. Sikess.

Fig. 5 has been dr.iwn lo rcprcscin this fonmila, and bcfort; describing the
manner in which il is dr;,u.i it uoiiid be ucll to indic.ite the maimer in which
3«

fy,cr>N>ipm-nc;NAu ALIGNMENT CHARTS.

i- tNCilNhl-.lJlNd :--^

il is used. Sii|)|)<)sf ih.il we li.ixc ;i l<);i(I ol 70 tons on a span of 30 ft., tlie
working stress Ixiiij^ (> tons per s(|. in. IMa(<- a straij^ht vi\^v alonj;^ the* |x>inls
70 and 30 on tlu' IT and /. scales resi)e(li\ c*ly (as sliow 11 in dotted lines) and
mark the intersection of the 7' or common sU|)|>ort line; join this intersection to
the i)oint / (»; liien its intersi-ct ion on the Z scale f,^i\es the modulus required,
viz., 525.

To draw the s<\iles we first decide upi)n the ranj^'c of ahies and take
1 1 ' Irom 10 to 1 50 tons.
L Irom 5 to 50 i I.
f from 5 to 10 tons |)er scj. in.
Takinj^ d' and /. lines at 5 in. a|)art and plottin*^ each to a scale
1 in. =S/ = Sw "- "- i'l-. iJi^' loj^arithms of the \alues are plotted conveniently
by the method pre\ iously explained.

Since in this case a — b—i and .S\. =5^=2, we have

^ = 5X ''L =2-5 in.
•2+*2

Support scale i in. = 5^ — "2 + '2 = '4.

We do not need, however, to plot values on the support, because it is not
used for reading from, but we use this result later to obtain the Z scale. Now
draw our / line at, say, 4 in. from the common support and choose a suitable
scale, say, i \n. - S^ — 'i.

It will be noted in equation (20) that log-. / has to be subtracted, so we

set values of log. f downwards, as shown, instead of upwards.

1 X * 1
The Z support distance from tlie v line will tiien be e^^ 4 = 5 = *8"

• 1 + '4
The Z scale is i in. =r 5 , — i x ' 1 + 1 x '4 = '5.

We have kept no record of our zero points, so that to get a p)oint on the
Z scale we take convenient \alues in the original equation (19) — TF^ioo,
L= 10, /= 10.

^ 1-5X100X10 , -^

*; — "^

We therefore join across as shown in full lines and mark the mtet section
on the Z line 150, obtaining otlier points on this scale as previously described.

To e-et Z=^o, for instance, we have -^ =3. therefore log. i ^0 = '477 + log.

50
50. Xow "477, to a scale i in. = -5, is "954 in., so mark this distance down from
the point Z— 150 and mark it 50.

The endeavour of the above article has been to show how to draw and
use these alignment charts rather than to gi\ e a large number of charts of use
to engineers. Most of the formulae used by designers can be charted in this
manner, and such charts are very useful for designing.

NEW LAW COURTH AT KINGSTON, JAMAICA.

ICOSCBETB

REINFORCED CONCRETE

IN THE

NEW LAW COURTS AT
KINGSTON, JAMAICA.

A former ar'icle dealing ivith these ttr'ldinas ivas published in our Journal, Vol. VI,
p. 85, and the fol'oiung particulars, ^ith illustrations and drazu-ngs showing details of the
reinforced concrete construction, may therefore be of particular interest.— ED.

OuK readers will no doubt recollect ihat we have already published, in one of
our previous numbers, a short description of this new building, which was then

West Front in course of construction.
Nkw Law Coi'ins at Kinjisk^n, Jamaica.

in course ol consl ruriion, and wliicli has now been recently (■()nij)lcted. 1 lu;
enlire slriicture is in rcinloncd ( oncrclc on liie C'oij^nct System.

'J'his l)iiil(iing is llic third public luiildini^ crecMed on this s\stcm :it Kingston,
the architects apj)ointc(l b\ t he ( jo\ ( iiiiin nl Ix ini; Messrs. Nicholson <V C'orlctle,

A LN(UNLU/1N(, ^J

NHW LAW COURTS AT KINGSTON, JAMAICA.

NEW LAW COURTS AT KINGSTOX, JAMAICA.

ICQNCPFTFJ

\ I

r f

C j

^ f
-- t /

^:t

-f^-

Hir.

^4j

77^

. av«.»| V

His-.; -■•i; , I

o <
o s

o c

O z

a; "^

o <

OS D

«t-i o

O U

I ^

lu 1-4

r »^ oav.Trut jcnoKAq

NHW LAW COURTS AT KINGSTON, JAMAICA

ol I^nulon. I lie otiu'i- l)iiil(linj;s were the new Klnj^'s House, or Residence of
tlir (loNcrnor, ;in(l llu' l*(>sl Ollice ;incl Treasury building's.

All this i^rou]) ol huildinj^s, which has been desij^ned b}' the architects for
the special j)ur|)()se of olferinj^" the greatest pcjssible amount of resistance to
earthcjuake shocks and lire, has been designed on the same architectural lines.

y.Ach building is constructed ujion a strong; reinforced concrete raft distri-
buting the load uniformly upon tlie ground, and the entire building is braced
together in such a manner that it constitutes a thoroughly monolithic structure,
and it has been proved by actual experience that this method of construction is
the iK^st suited to resist earthquakes.

Interior View, Kingston Court.
New Law Colrts at Kingston, Jamaica,

As shown in the accompanying photographs, this building is surrounded by
spacious verandahs in order to prevent, as much as possible, the rays of the
sun penetrating into the rooms. All the roofs are flat and are protected from
the heat by a layer of gravel several inches in thickness. As shown in the
photographs illustrating the interiors of the court-rooms, the ceilings are kept
as high as possible to ensure proper ventilation. In fact, every detail of the
design has been carefully considered to suit the tropical conditions of the
climate. The wooden fittings, such as benches, platforms, and doors, are made
of solid mahogany.

The general dimensions of the building are as follows :— A total length

MEW LAW COURTS AT KISGSTON, JAMAICA.

ICQNCBETEJ

fy , rONSTkt Il-nONA 1 ,

NEW LAW COURTS AT KINGSTON, JAMAICA.

- I

U. I

NEW LAW COURTS AT KINGSTON, JAMAICA

ICQNCBETEJ

of about 258 ft. and a total width of 92 ft. in the smallest width and 136 ft.
in the larg-esr width, the heit^ht from the foundations to the roof being approxi-
mately 45 ft.

The building- is composed of a ground lloor, first and second floors, and
a Hat roof. The stairs are also constructed entirely in reinforced concrete.
The total area of each floor measures approximately 22,000 sq. ft.

The plans for the execution of the reinforced concrete were prepared b\

Section of Principal Reinforced Concrete Floor.

Cross Section of Reinforced Concrete Floor.
Nkw Law Coi kjs at Kin(.ston, Jamaica.

Messrs. I^dmond Cc^ignet, Ltd., of jo, \ ictoria Street, London, S.W., and the
contract for th(t cxccuti'^n of the work \\;is (\'irri<'d out by Messrs. Mais & Sant,
contracMois, of Kingston. The work w.is, of course, entirely executed by
native k'llKHir und( r skilled siipcrx isioii, and this is another ))rov)f ol the
adaptabililN' of reinforced (■on<r<t<: to colonial buildings.

The reinforced cone rete sNstem which was used for this building is com-
posed of a sp('cial arrangctment of ordinary round bars of mild steel, the columns

, CONMyUfllONAI

ti-ENdlNKKWlM, ^

NHW L^WV COURTS AT I<INGSTOy,JAMAICA

iH'iiii^' loriiH'd l)\ lour or iiiDrc iij)rii4lil l);irs siirrMiindrd l)\- spir;il lioDijin*^- of
siiKill (li;iin('U r. 'I he he. mis ;ii'c cninpDscd ol one or more slr.iii^lit h.irs at llic
1<)|) and hollom, (-omuclid IolicIIkt 1)\ xcrlical stirrups ol small diameter.
'1 lu'S'i- sit el hames heiiii; prepared in adxanee on tlie site, llie\ are simply
|)laeed in the moulds readx for (^oneret inj^'.

1 he llooi- slabs, usualh about -] in. in ihiekness, are composed of a mesh-
work ol bars spaced about 4 in. or 5 in. apart. The walls are made in a similar
mamua' and ri'inloi'ced 1)\ means ol hoii/ontal and x'erlieal bars lormin"' a
mesiiwork.

Some t\j)ieal sections are i^i\cn in this article showing" ihe reinforcement
ol columns, beams and floors, which clearK show the arrangement of the bars.

Interior View Supreme Court.
New Law Courts at Kingston, Jamaica.

JOHS W. RODGER.

[CQNCBET El

,i^^^T

■■>^^:&:;.

'V ^i-m^

<->'-4-.-:^'-' ^: '^m'i^^

A REINFORCED

CONCRETE

CHIMNEY.

By JOHN W. RODGER.

The question of the suitability of reinforced concrete for chimney construction has been
the subject of considerable debate ana also much doubt. Any information, therefore,
relating to such structures ivHl be ivdcomed, as it 'will add to our store of knowledge on the
subject. We, therefore, give below the following particulars of a chimney recently erected
in South Wales.— ED.

The South Wales Portland Cement and Lime Co., Ltd., are erecting a new-
rotary plant at their cement works, Penarth, near Cardiff, and have built a
chimney of a somewhat interesting description for carrying away gases from
the kiln.

The chimney is fourteen-sided externally and 220 ft. high above ground,
formed in two parts, the outer of concrete blocks and the inner part or lining
of bricks. The outer concrete shell and the inner brick lining are entirely
unconnected throughout their full height.

All steel concrete \v(jrk above ground was carried out by Messrs. Monoshaft,
Ltd., under their patented methods.

The blocks are composed of concrete in the proportions of 9 cubic ft. of
crushed granite to pass a f in. sieve, with all fine and dust removed, 5 cubic ft.
of clean coarse sand, and 3 cubic ft. of Portland cement, mixed by hand and
moulded in cast-iron nifmlds of varying sizes and shapes, care being taken
that the mixture was a wet plastic and of such a consistency as could be effi-
ciently worked into the moulds to form a dense concrete.

Each bkjck is reinforced with steel rods of varying diameter bedded in tlie
concrete during the process of moulding.

The blocks are set in a ir.orlar of ((■inciil and sand i : 2 with a steel ring
or joint rod the entire circumference of tlic chimiuy, bedded in eac^h horizontal
joint. Vertical reinforcement is obtained by steel rods fixed in tlie end joints
of the blocks and furllur |)role(le(l b\ eoner<'le neckings moulded as jjart ol
the blocks and showing as scrtical shafis on the linished slrueturi'.

Lach vertical lod is caiTied i) It. down into ihe (■()nei'el<' loundal ion and
there attached lo a horizontal steel ring, the full diainetei- ol ihe ehiinney at its
base. .Spc-cial reinforcement was used round and oxci- ihe Hue opening and
to the mrjulded corniee and neckings.

'i'he chimney slan(i^ on a conci-eie loLnidalion slab composed of cement
C(jncrete i : 0.

4«

A REINFORCED CONCRETE CHIMNEY.

Section.

SectionAB.

Section EF

Section CH,

COP^NICE.

CO*' «o»- ' *

OtTAlV. O

Plan at Base.

Reinforced Concrete Chimnkv at Penarth.

Detail or
Lower String.

E 2

JOHX W. RODGER.

[ CQNCBETEj

The g-eneral dimensions are : — ^t. ins.

Concrete foundation slab 23 6 square.

Heig^ht of cliininey abo\e i^round 220 o

Outside diameter of chimney al base -O ^:>

Outside diameter of chimney ai top 10 4

Thickness of blocks at base i ^

Thickness of blocks at top 5

Weig-ht on bottom course of blocks -=8i tons jDcr square ft.

Batter i i" 43

N'icw of Completed Struct inc.

KkINI 0K<;KI> C'fiNCRKTK ClIIMNKY AT Pl.NAKlll.

At tlie outset it was realised th.ii the chimney mij^ht at times be subjected
to excei)tionanv hi^^h temperatures, and it was deemed advisable to build the

J, CONM kMKTIONAl.
At^NCilNLlklNl. ^

A REINFORCED CONCRETE CHIMNEY.

brick liniiii;- to within 12 ft. of the top witli a substantial air space between the
concrete and brickwork as a special jiroti-clion to the (^oiKM'cte.

The ])rick lininj^' is () in. thick to a hcii^lu of \H] It. <> ins. and 4^ ins. thick
above that point, stren^tlicncd latcrail\' by buttresses projecting" into the cavitw
No bricl>:\\<)rl>: is allowed to come nearer than 6 ins. to the concrete, as a pre-
caution against damage to the lining by the swaying action of the chimne\' in
a high wind. The estimated maximum deflection is 81 mm. in a gale blowing
80 miles an hour.

The lining is built throughout of hard red Cattybrook bricks, made to
correct radius and set in cement and sand mortar i : 2 to the level of the bottom
of the intake flue, and above that point to the top of the 9-in. work in mortar
composed of ^ part Portland cement, i part slaked ground blue lias lime, and
2^ parts sand. The 4^-in. brickwork is set in cement and sand mortar i : 2.

The total weight ot the cliimney and concrete foundation is approximately
1,400 tons, equal to 2A tons per sq. ft. on the subsoil foundation.

The chimney was built under the direction and supervision of the writer,
acting as architect for The South Wales Portland Cement and Lime Co., Ltd.,
associated with Mr. W. J. Cooper, manag-ing- director of the company.

THE CONCRETE IXSTITCTE.

CQNCBETEi

RECENT VIEWS ON
CONCRETE AND REIN- jf|
FORCED CONCRETE. I

RECENT PAPERS & DISCUSSIONS.

It is our intention to publish the Papers and Discussions presented before Technical
Societies on matters relating to Concrete and Reinforced Concrete in a concise form, and
in such a manner as to be easily available for reference purposes.

The method lue are adopting, of dividing the subjects into sections, is, ive believe, a
neiu departure. — ED.

THE CONCRETE INSTITUTE.

THE DIFFERENTIAL AND INTEGRAL CALCULI FOR
STRUCTURAL ENGINEERS.

By W. A. GREEN, M.A., B.Sc, Eng. (St. Andrews), Assoc. M.Inst. C.E.

The foil oic ill g is mi abstract from a Paper read at the Fortieth General Meeting

of tlie I nstitute.
After a few introductory remarks, the author went on to say that we cannot avoid
definitions, and my first will be that of a " function of a quantit}^" which is shortly
defined as an expression involving that quantitj'. Thus we may say that the maximum
bending moment in a cantilever is a function of the length and also of the loading, and
generally Vv'hen the relationship between quantities can be expressed by an algebraic
e(}uation one quantity is said to be a function of the others. The symbol for
"function" is left to the personal predilection of the writer, and may, when applied to
the quantity ^, be/(^), ^{x), i^{x), etc.

Startmg with two related cjuantities, which we may symbolize as x and y, we may
express their relationship by an equation y=f(x) or x--(tAy).

As every engineer knows, we can, by taking in the e(|uation y=f{x) different values
for X, find corresponding values for y, and tabulate them — e.g., the safe load on
stanchions for different hei'-;l)ts.

A much more illuminating and often easier way of recording these tabulated

results is to plot them in a curve, letting
vertical distances from a fixed line
o(iual one (juantity to some convenient
scale, and horizontal distances to
anotlic;r lixcd line at right angles to the
first, the other (piantity. The two fixed
liiKis are known as the axes, and their
point of intersection the origin of co-
ordinates. There are, of course, many
other ways of representing graphically
the relationship betw(>en the two (|uan-
tities, but |)erliaj5s none more obx ions
and simple.

The C()rresi)()nding values of .v
and V are known as C()-ordinat( s, and
y=f{x) is termed the (;(|uatioii of llie curve so plotted.

In the diagram (l^'ig. 1) where O.V and OV arc our fixed axes, let OA7;=-v„,
P.,Mn—yn, Xn and y, b^;ing the co-ordinates of /^., a point on the curve whose
equation is y=f{x).
52

I'K-. I.

f7^

y, CONM Pllf IlONAf!

CALCULI FOR STRUCTURAL HNCINEERS.

TIkmi IrDin our previous dcfinilion we know that 1';/" /(v,,).

Siuiil.'irly let the co-ordinates of i'// j i be ^n+i and .V/( + i, connected by the
etjuation yn + \ =/(^,, + i).

As ;i point moves alon^' the curve i'roni J^n to J^n + i in the examj^le shown, its
distance f I oni both axes incTeases and it has moved a distance yu+\—yn up, and a
distance .v»; \ i .v„ to th(> right.

Pro\ idi>d this distance is small enough, its path will not diller greatly from a
straight line whose slope is the same as the line touching the curve at J^n and called,
for short, the tang(Mi(.

The slope of this line can be measured by tiie ratio of its vertical travel to its
hori;iontal travel, for a less obvious reason called the tangent of the angle the tangent
line makes with the axis OX, which angle, for reference, we will call iK

A short way of expressing ihe increase in the length of the y co-ordinate as the
point moves from /^; to Pn+i is 8y, and of the x co-ordinate, ox where o is not a
multiplier but a sign of a small increase in the quantity it comes before — o. by our
standard notation, standing for difference.

\\'hen 5.V and 8y are very small their ratio is termed the first differential coefficient
of y with regard to x, and its value is obviously the tangent of ".

\i y = ax and Xn and yn are the co-ordinates of a point on the curve, and (x-.i-rbx)
(v, + 5y) the co-ordinates of a point near it, we know that yn—'^^n and (>';; + ^yj =
ci{Xn-\-5y).

5v yu + ^y — Vn a{x„ + 5x) — ax„ 8x
5x Sx ox; 5x

i.e., the direction of the curve is constant; or, in other words, the curve is a straight
line which perhaps it did not need the differential calculus to demonstrate.
Taking another equation y = ax-. As before—

Sy ^ y^Sy — y ^ a{Xn-{-5xy^ — a{Xn)'
5x

a{Xn' +2x,:5x+ 5x-) — a^,r

2ax„8x
Sx

adx = 2(iX,: + adx^

When 8x is very small its value compared with 2nX;i may be neglected, and
2«^n, i.e., the tangent to the curve at the point whose x co-ordinate is x,, is 2<^-^;:.

We may express it more generally by saying that for every value of ^ the first
differential coefficient of cix'^ is 2ax,

This statement is equivalent to saying that the slope of the curve varies directly as
the X co-ordinate.

As everybody knows, this particular curve is our constant friend the parabola with
its axis vertical (see Fi^. 2) and as the slope of the tangent is 2cix, which equals

ax-

--,--, the tangent to the curve must halve the x co-ordinate.

XI 2,

Taking as our third example y = cix\ and
treating it for the general point whose co-
ordinates are x and y —

8y ^ y-|_ 5y _y ^ a{X-\- dX)'^

-ax'

8x Sx

a{x'^ + 3x-Sx+3x8x'^+Sx^) — ax-^

Zax-sx , 5.r-'

{3ax-\-a8x)

¥ir.. 2.

8x ' Sx
^5(ix--^8x, multiplied by an expression of

no further interest to us,
^3>''V- when dx is infinitely small.

THE CONCRETE INSTITUTE.

[CDNCBETEl

Summarizing. — The first differential coefficient

of ax =a
of ax'- = 2cix
of ax-^ = 3(ix''
and generally oi ax" = nax»-'

true for all values of " positi\ e and negative, including " = where ^"=1, y=ci and

Sy
dx

0, which is another way of saying that a line drawn at a constant distance from

another line makes no angle with it.

The process of finding the first differential coefficient is known as differentiation,

and the symbol for the operation is often written 4", t^ being the value of ^ when

dx' dx

both ov and ^^ are very small.

The values of the first differential coefficient can themselves be plotted to form
another curve, and the process of differentiating continued ad lib., the first differential
co-efficient of the first differential co-efficient of the original quantity being termed, for

short, the second differential co-efficient, and written ^ which indicates that the

ax'

operation has been twice repeated.
dx

Similarly, - need have no terrors for a reader if he is not expected himself to
dx'^
repeat the operation n times.

Perhaps one of the most valuable uses of the difterential calculus is the location of
maximum and minimum values of a continuously varying quantity.

On each side of a maximum or minimum there are two equal values, and at the
maximum, as in water-level at high tide, there is no change in one quantity as the other
varies ; in other words, the first differential coefficient is zero.

Reverting to the small increment Sx, let us, instead of examining its relation with
the small quantity or, discuss it as a multiplier of y.

ox and y bein? both represented by lines, their product ySx is obviously an area,
viz., that o^ the rectangle with base 5^ and height r.

In Fif(. 3, if the line MaMb, the projection on OX of the portion of the curve
y = f(x) between the points Pa and Pb, is divided into a number of small lengths, Sx, the
area of the figure, J'aMaMhPh, is greater than the sum of the areas of the rectangles of
area yox by an amount ecinalling the sum of the small triangular figures each of area
^ox y'oy, when ox is small enough to make the portion of the curve of which it is a
projection, a straight line.

We may write this eciuation symbolically: —

x=b

Area PoMaMhPo^

2r^.v+52

oyox

where - — the Greek S stands for the sum
of all such (|uantities at yox and oyox which
follow it, x = a and .v /; indicating the
limits between which the summation is
made.

When oy is infinitely small, each of th(>
terms yox is infinitely small, but as there
will be an infinite number of tlicin the sum
will he. a finite quantit>'.

The |)rodiict, however, of (wo infiiiiteK
small (juantities will bf; infinilel\- small
compared with either of lliem, so that even
if an infinite number of tli<iii are taken the
sum will be infinitely small.

5 +

I'lC. 3.

y, CTON> ryut-noNAiJ

<^ ENGJ N LluR 1 M » — J

CALCULI FOR STRUCTURAL ENGINEHRS.

Th(> last term (^f our ((iiialion ^^ill therefore vanish, and the area may be

oxi")r(^ss(>{l as : —

. h

x-a

where an old l'nt;lish / is nsed for the summation sign, and an English d is substituted
for the Greek 5.

This summation is termed integration.

There are, however, dithculties in the wa\- of
plotting curves and measuring areas, and a further
in\ estigation is necessary.

The shaded area in the diagram (/''/^^ 4) increases
as X increases.

Let the increment of x be ^x and the correspond-
ing increment of the area be ^A.

Then when Sx is verv small 5 A =ybx
M ' . dA

or the first differential coefficient of A=y ;

but .4 = / ybx the
-^ o

integral of y with regard to x.

i.e. if A is the integral of r with regard to x.

Fig. 4. y is the differential of A with regard to x,

so that integration and differentiation are inverse

operations.

In differentiating f{x) with regard to x we find the relation between ^x and oy at a

point whose co-ordinates are x and y. In integrating f{x)bx by finding an expression

whose first differential ccet!icient is f{x) we find an area of the figure enclosed between

the curve, the axis OX, the axis OY, and the vertical line through the point xy.

If we wish to integrate between two limits, e.s;- from x = a to x^b as in the previous

illustration — we can subtract the integral from ./^O to .r = a from the integral from

.r = to x = h.

We may tabulate our integrals as we tabulated our differentials —

adx =ax

I 2axdx = ax' or f axdx =
I 3ax'-dx = a.r'' or J a/'dx =

As — ax =a
dx

as — ax —2ax
d.r

as — ax =5ax-
dx

ax-

ax'^

and generally

as -^ ax'^ =nax'—'^
dx

fax

-^x = d

The above results satisfy our condition that the integral of a function is another
function whose differential is the original function, but to make the statement complete
we must add a constant to each, the value of which can be found later and may
be zero.

This constant will satisfy our condition as —

— constant = and .'. / 0<^f^ = constant.
dx -J

Just as we could repeat our differentiating operation to find the first, second, third, etc.,
differentials, so we may repeat the reverse operations to find the first, second, third.

etc., integrals so that the sign / / is really not so terrible as it appears —

THE CONCRETE INSTITUTE.

LCQNC^TE

e.g. fodx =C^

JjQ,dx'= f ^\^^
Odx'= J J C,dx

C,x-\-C,

f {C,x-^-C)clx= ^ H-CVv + C,, etc.,

the Iruth of which statement can be verified by differentiating the last expression three
times and arriving at zero as our final result.

It is unnecessary here to evolve from first principles the equation /= where the

letters have the significance set forth in Hie last word in standard notation —

/= intensity of fiexural stress at extreme fibre

« = distance of neutral axis from extreme fibre

7^ = bending moment

/ = inertia moment.
It may not, however, be out of place to examine a small element of length ox of a

deflected beam a distance ^ from some arbi-
trary origin whose neutral axis has been de-
flected a distance y from some arbitrary base
line through the origin {Fig. 5).

In the length Sx let the inclination with
our base line vary from the angle d to the angle
(e-\-80), where ^ is measured as the ratio of
the circular arc it subtends to the radius of the
arc.

When an angle is small the difference
between this ratio and the tangent of the angle
is negligil)le, so that 86 is the ratio of the con-
traction of the length 8x at the top of the beam
under the stress / to the neutral axis distance //.
A stress E (the modulus of elasticity) would
make ^^ contract an amount Sx if something
else did not happen first, so that/ would make

fdx

Fig. 5.

fox

it contract -^ , and the angle 50 may be expressed as

If, as is usually the case in structural engineering, ^ itself is small, its value is

dy
dx

so that —

but -r also equals r^,
dx hn

86 d dy d'y,
ox ~ dx cix~ dx-

d-y f lln I
dx-'~En~ I ^En

E
~BI

In the e(iuation — ^ = ,,,
dx' HI

we see on int(.'gratiii;-,' that , = / ...dx-\-C\,

i.e. the slope of the curve at any point x from the origin can be measured by the area of
the bending moment diagram, the value; of the constant C, depending on circumstances.
Integrating again we obtain the {l(;fl(!clion curve of the neutral axis as —

-ff^,

dx''-\-C,X'\-C.,.

Deflection, slope, bending moment, shear, and loading, may be expressed as a series,
in terms of any one of them.

CALCULI I'OR STRUCTURAL HNGINEERS.

I'siii^' hi'iuliiii; inoiiuMil ;is our hasis
III X DtMlertion

7:7 N Inrlinalioii

HeiidiiiiT niouicul /•-/ , .=/>

iiiy=J f iui.r--VCyi-\-c.,

Ll'' - flU.
(I.I J

if'v

Lo&d DtiU^rAm

0.1 r

</'v d'B
f/.r ax

Fig. 6.

for such part of it as is a function of '■.

From the above series it will be seen that deflection bears the same relation to
bending moment that bending moment does to loading, so to draw a deflection curve one
has simply to draw a bending moment diagram for the original bending moment diagram
considered as a load diagram.

Another problem presenting difficulties to many engineers is that of internal shear
which, with the aid of the calculi, we will attempt to investigate, making the usual
assumptions regarding a plane section before bending remaining plane in bending.

Consider a small length rf.r of the beam cut by two sections normal to the neutral
axis — at distances x and x+5x from the origin.

Take a section parallellto the neutral axis at a distance a from it.

_B2i

At X from the origin the extreme bending stress— j ;

at ./-r^./' from the origin the extreme bending stress =

where B and [B + ^B) are the bending moments .x: and .r + ^.r from the origin.

The total horizontal shear on the horizontal section w^y^^x a distance a from the
neutral axis equals the difference between the thrust to the right on the part of the
vertical section above a, x from the origin, and the thrust to the left on the part of
the vertical section above a, x-\-5x from the origin.

This thrust difference may be expressed —

{B-\-m)n

n n

J W zfSz LP JxCz (/+ 5/) ^Z ,

where ^z is the width of the cross-section z from the neutral axis and f and /-r ^/ are
the horizontal stresses there x and x-}-5x from the origin.

' B-\-SB

Then as ~

B , nsf

- and ^

/ z

the total change in horizontal thrust —

w —z^z cr / "'■c

B + 5B

z^z

= / ZOZ ^ — / WZdZ

= — X (Area moment about the neutral axis of that part of
■* the vertical cross-section above the horizontal

section a from the neutral axis).
This shear or change in horizontal pressure in the distance 5x is on a horizontal

area WaXdx, so that the intensity = (Area moment of that part, etc.), i.e., shear

li'aOXl

intensity = -^^- X (Area moment, etc.), as S the vertical shear =-- •
icl dx

THE CONCRETE INSTITUTE.

[ CDNCBETEJ

Consider a reinforced concrete beam (see /''/^<. 7) assuming no tension in the
concrete —

/= / zhzdz-\-ni X steel area X (cf — ;/) -

= ^ + ;;, X steel area x (J - n) "' ,
3

the letters having the standard significance —

hn'

= m X steel arei x {d — n)

n#rji-.^At A^iS i

and shear intensity, a maximum at the
neutral axis —

Cross Section. Shear Intensity.

Fig. 7.

As the stress in the steel x distance to centre of compression y^~y equals B, the
change in stress per length Sx —

dx , n

'-5 '-3

and the shear intensity per unit area

{-3)

the same as the concrete shear in-

tensity at the neutral axis, so that the theoretical internal shear is constant below the
neutral axis and decreases to zero in a parabolic curve above it.

THE WESLEY AN METHODIST HALL, WESTMINSTER.

By H. V. LANCHESTER, F.R.I.B.A.

The following is an extract of a Paper recently read before the Royal Institute of
British Architects. In an earlier issue of this Journal the Wesleyan Hall isjas fully
described as far as the reinforced concrete construction was concerned {see Vol. V.,
p 721). Our extract has been taken from the Journal of the R.I.B.A., Vol. XXL, No. 2.
In his ojjcning remarks, the author stated that there were a number of problems in
the design of this building, the solutions of whieh jn-esemt a certain degree of novelty
and may be of interest to architects.

After making reference to the comixlilion instiluled to |)r()curc dc signs, the diHuiilty
of planning and arrangement ar(; dealt with.

'J'he author set out the accommodation the hall was to contain; lie also described
the difficiillies to be overcome in the construction of tlic main staircase. Hrielly, the
princijjal requireuK-nts of the building were: — Largt; hall, seating 2,500. Small ludl,
switing 600. Library of the same size (these two to be thrown together on occasions).
Conference hall. A room of the same size (now occupied by the London City and
Midland Hank), 'i'ea room to s<'al j,ooo. I'"our committee rooms. A block of oHlces.

Leaving the minor deUai Is of |)lamiing, he passe<^l on lo the nielhods of consilriiction
emjjIo\(fl. Reinforced work has been exte^nsivcl)' use<i in the interioi,, for the reason
that it ']>> more homogeneous than -any of tlw; combinalions of steel rollings with
concrete and other materials. 'I'lie architects' choice fell on the Kahn system as
j)roviding a bar th.at once in }K>sii'ti(>n was visibly adjusted lo take uj) the .strains
provided for before Hlling-in comuK-nced. Of cour.se, there are other systems that

,CONMKM)C riONAl

W'liSLEYAN MHTlloniST HALL, WESTMINSTER.

;n liir\<- this ^liin, hiil not the slij^hli'^t i^round could he found to rc^^rd llir M-l<-(lion.
IiuK'i'd, the onh i)i>inls where slij^lu iracUs li:i\" sliow n tliciiiscKcs ;ii-<- when-, in
order to eeniioniise <lt|)lli, strel .sections \\<'re resorted to. 'I'lie aullior tliou^ht it
desirabk' to w.iin some ol those present thai I hi' puhhshed streni*tlis of steel beams
are not rehahle ; tlvou.-^li the) are well within the liniil of siifoty, j^reaK-r de|)th must
healUmcd w heie the slii^hlest dillection will disturb the work abov<' them.

In th<' i^ene'-al framing:: up of this building the hea\ iesl weii^hl aeeunuilaied at
the eij^ht ani>les of th<- main dome. Startini; from the to|), we have the outer dome,
a n"lativil\- lii^ht shell, the much heavier concrete inner dome, the concr»-te and
masonrv of the i)endentiv<'s and the arches across the trans<'ijts ; then the j^irders
carrvinj; the ox crliai.i^in.L; i;alleiies, a i)r(>p{>rtion (^f the walls and floors below this,
and, Iniallv, the w<"ii;ht of the i)i<M-s themselves. With allowances for wind pressure,
<'tc., the weii^lUs r(>achini; the foundations at each of these jioints ranj^e from 500 to
600 tons, and as it was, of course, desirable to equalise the weif*ht as much as possible,
a stec^l raft was j^rovided under each pair of jiiers, which j^ave a distributed weii^ht
of 2 tons to the foot super. Under the w hole of the remainder of the buildinLi ^vas a
reinforce<:l concrete raft of varying thickness, and the weight on this generally was
about i^ tons per foot super. The eight main piers were formed of steel sections,
at the angles of a 3-ft. square, tied together with stec^l lattice-work, and entirely
<'ncased and filled with ceir.ent concrete. The architects themselves worked out the
meth(xls of construction in these, but throughout the rest of the building they were
indebted to Mr. de Colleville, then with the Trussed Concrete Steel Company, for
checking calculations and supplying details of connections, ri vesting, etc. The remain-
ing piers were of reinforced work with vertical bars and horizontal lacing. The
basement floor is 7 ft. above the bottom of the concrete, which gave the requisite
depth for distributing the weight under the heavier piers and for the provision of
ventilating and pipe ducts. The large spaces on the basement floor were covered
with thin reinforced concrete vaults, carrying a flat floor about 8 ft. aboAc the street,
which is the ground floor of the main building. (The floors of other parts are at
different levels.) The flcx)rs above this are constructed i>f reinforced concrete, with
hollow tiles to reduce weight.

The galleries demand some description. They are nuiinly supj)orted by deep
girders connected to the lattice stanchions ; these form the fulcrum from which they
cantilever forward, while the back is built into the main walls. The ramps pass over,
and the sofilits under, these main girders, so that the cantilevering does not entail
excessive weight.

Over the galleries are the transept vaults, ellipticid in form, and thicknt-ssed into
strongly reinforced beams under the vertical walls of the outer dome. From these
beams and the pendentives springs the coffered inner dome of reinforced concrete,
with two rings of steel plate to resist the outward thrust.

Although the Large Hall is 70 ft. in height, its dome would hardly be visible
from outside; and the outer dome, relatively light in construction, rises some 50 ft.
higher, exclusive of the lantern above it. As the design based itself on the conception
of a square dome with the angles cut off, forming an irregular octagon, necessarilv
special constructive requirements had to be met. A circular dome is relatively easy
to construct, there being no tendency to distortion ; but all other forms have an inclina-
tion towards the circular, a straight-sided dome tending to bulge horizontallv between
the angles. The first step was to provide at the base a plate of great horizontal
rigidity firmly tied at the angles. As the weakest points were towards the middle of
the four long sides, the ribs were treated in this position as principals tied right
across; these are in pairs, connected together at the top with a braced ring, which
carries the lantern and links up the angle-ribs, which are also braced on similar lines.
These ribs and the intermediate ones carry the steel purlins and timber rafters of the
dome covering. The lantern is mainly of timber construction, but stiffened bv four
steel ribs steeply inclined at the four angles, these ribs carrving the finial rod, and
torsion IS guarded against by a horizontal bracing near the top of the lantern filled in
with cement concrete.

The lecturer closed with some remarks regarding the engineering requirements
and the architectural treatment.

NEW WORKS IN CONCRETE.

ICDNCBETEI

NEW WORKS IN CONCRETE

AT HOME AND ABROAD.

Under this heading reliable information ivill be presented of neiv -works in course of
construction or completed, and the examples selected 'will be from all parts of the ivorld.
It is not the intention to describe these -works in detail, but rather to indicate their existence
and illustrate their vrimary features, at the most explaining the idea 'which ser'ved as a basis
for the design. — ED.

A REINFORCED CONCRETE MOTOR GARAGE, WHITBY.

The accompanyinff illustrations show a motor garage recently erected at Whitby. The
structure is a concrete-frame building, with 9 in. brick walls around the garage and
II in. cavity brick walls around the house. The columns and beams to the front of
the building are moulded reinforced concrete. As will be seen from the accompanying

■i MH

■:>-."j!» ■m'^'*?'

View of Completed Structure.

RkINIORCKU CoNfRKlK MoKjK fiARA(.I., WllITHY

plans, in addition to the nujtor garage, th<' following rooms IikIvc been provid<Hl, namely,
a drivers' room, workshop, woodwork shop, lavatories, and showroom. 'Vhv hous(>
adjoining consists of two floors, comprising silling-room, cnir.incc h.ill, store, kilcheii,
scullerx , and ff)ur bedrooms and a l)athroom. All the lloors are of reinforced concrete,
whilst the rof)f is covered with asbestos tiles. I"\irther, the staircases are also built in
concrctf-. 'liie rontractors for Ibis building were Messrs. (ieorge Greenwood Sons,
of New Brunswick .Sfrr-et, Halifax, who carried out the work' on the Rigid S\stem of
reinforcement, according to drawings supplied l)\ Ilie Rigid keinforcement and
Concrete Rnginer-ring (Jo., Ltd. 'I'he architect was .Mr. Harold (i. Walker, of VVhitb\ .
We are indebted to .Messrs. Greenwood .Sons for our |)articulars .tnd illustr.ilions.

REINFORCED CONCRETE MOTOR (PARAGE.

t o

NEW WORKS IN CONCRETE.

1^^^^

REINFORCED CONPRftr- d a ^^

"""* " ■• " "■" ■■■ i.« .'■ .,-..i«„ „„,,, ,,. ,,

is also a
62

.'ind ;i /lew f,-i((or\' ;ii \r(lcn VV'fnl-. •

lhr<M;.storcy building ' •'l'l""^"".M.K ., ,„ f,. I,v .,„ f,

^\ i'i'', which

y, tX>NMDlR~TIONAi;
A bNQl N JAU 1 N( I — ,

REINFORCED CONCRETE FACTORY EXTENSION.

J
a

luO

UilL

UlUj

Lua

<o *■

« a

NEW WORKS IN CONCRETE.

ICDNCBETEJ

The site for the new pahit shop bcinj^ on ;in old clay j)it, filled in with rubbish, it
was found that ordinary concrete footini^s would not be satisfactory.

After a number of tests had been made to ascertain the carrying capacity of the
earth, it was decided to adopt a reinforced concrete raft, which would evenly distribute

the load over the whole of the site, pnllin;.^ a ma.\iniiini pressure of a lillle oxer i cwt.
per square foot cm the fcjundatioii,

'J"he building is a steel frame shu<line with ibiii (iiii.iiii walls, so thai I he whole
of th(; loads are coiK eufrat( d at |)oints 25 ft. from (entie to (eiitie in the olhei.

fTT^NM^wiKTioNAq R]^:iNr()RCt:i) concrete factory extjiNsion.

From llif i>l;in it will be scs'ii that the raft consists of a conlimious slab, rov<rin^
the whole of tlu' >itr, and s|)ainiini^ bclwoi-n the inverted beams, which, in turn, span
between the eoluinn marked " ('."

'I'h<' lop surface of the slab was finished with a i^raiiolilhic face and forms the
i<round lIcKir of the factory.

The suspended floors at the new factory, Arden Works, and the flat roof at the
paint shop were constructed in hollow Siegwart flooring.

Part of the floors were constructed to carry a live load of 6 cwt. per foot suj^er, and
the remainder i^ cwt. per foot super, while the flat roof was constructed to carry f cwt.
per foot super.

F 2 65

NEW WORKS IN CONCRETE.

(Concbete:

The great advantage claimed for the Siegwart flooring is that no centring is neces-
sary, and so the work, in sitUt is reduced to a minimum.

As will be seen from the accompanying illustrations, the hollow beams are brought
to the site in a thoroughly matured condition, ready for fixing.

These beams are placed side by side on the supporting steel joists and the joints
then grouted in with cement mortar when the floor is fixed complete.

The architect for this work was Mr. J. J. Hackett, M.S. A., of Birmingham; the
contractors for the reinforced concrete raft were the Empire Stone Co., Ltd., of London;
while the floors were carried out by the Siegwart Fireproof Floor Co., Ltd., of London.

Fit^. I.

ml .1 f;(;iiient. liti-2. Finished Post.

Kl.lNI OKCI.I) ("oNf KKIK I, AMI' PoSTS.

REINFORCED CONCRETE LAMP POSTS.

Cai'IAIN I). C)(;ii,vY, Assistant Conimandiiig i\o\aI l^ngiiiccr, Ahiucdnagar, Dcccan, has
recently designed and construct<'d a type ol reinforced concrete lamj) |)os(, which, for
simplicity of design, f,'icilit\- of manufaclure, and low cost will he welcomed by i-ngineers
to small urban councils at home and in I he ("olonies, ;ind to cantonuKMit authorities in
India.

The accomf)anving four phologiaphs will, it is hoped, make its general design and
mode of construction clear.

Fig. I shows the armouring, whieh ( onsisls of four mild st('<'I roads, ;' in. diameter,

r J, c-oNyruucTicMAn

L<v ENGJMEEJglNCi -*3

RHINFORCHD CONCRETE LAMP POSTS.

suitahlv lied witli ,-'« in. (liaiiicl(>r bracelets. Tlif jji-ojcrtin^ arms (to support a " lamp
lij^litcr's " ladder) have a dovihle reinforfenieiil of ^\ in. or .', in. diameter rods. The
l)oll which se(iir<s the famili.ir lamp ( radic is aKo sjiow ii, also four extra i in. rods are
i^ivi-n where the plinth nierjLjes iiilo the main (oliinin lo resist anv undue transverse
stiains durini^ <'rection.

hi'o, 2 shows the fmislKnl jxyst. Its cost, fixed in |)osition, is 12s. ConK-nt cost
us. per barrel (400 lb. not), and mild steel rods 10s. ])er cwt.

h'igs. 3 and 4 show the moulds, whic h consist of { in. mild steel plates, each taking

Fig. 3. Moulds with and without Reinforcement.

Fig. 4. Moulds tilled.
Reinforced Concrete Lamp Posts.

two posts laid head to foot. The shutterinj:^ of i in. Burma teak are fixed down by iron
straps and bolts to these pallets. As the post plinth is 7 in, by 7 in., and the column
5 in. by 7 in., the reduction of 1 in. is effected by telescopinj:^ side shutterini^ and by
fixing a I in. plank underneath the column.

The proportions of cement, sand, and ai^j^rei^ate are i to 2 to 4 (bv volume). The
sand is a finely i^raded quartz. The af^ijrei^ate, which is graded from f in. to | in., is
shingle obtained from neighbouring ravines, consisting of manv kinds of igneous rock.

NEW WORKS IN CONCRETE.

rCQNCBETEJ

CONCRETE BLOCK HOUSES AT NEWBURN-ON-TYNE.

The accompanying illustration shows; j^art of twenty-four concrete block houses
in course of erection at Newburn-on-Tvne bv Messrs. The Blaydon District Industrial
and Provident Society, Ltd., for their members. This Society liad already erected 48
similar houses at Blaydon-on-Tyne and these were so readily taken up it was decided
to pnx-eed with a further number.

C()>iCRL'LL Block Houses at NK\vbuKN-ON-TvNE.

The houses vary in size, havinj:^ sittinj:^-room, kitchen and scullery, or combined
kitchen and scullery, two, or three bedrooms, bath-room with hot water system and
conveniences in yard, and vary in price from ;^5oo each downwards.

The houses were designed by Mr. Wm. Crooks, Junr., Architect, Blaydon-on-
Tyne, and are built throughout with blocks made on one " Winget " machine purchased
by the Society.

j,coNMk>ufriaNAi;

NEW BOOKS.

NEW BOOKS

AT HOME AND ABROAD.

A short surnmjrv of some of the lejdtnq books tuhich hj've appeared during the last fcu) months.

The Glasgow Text Boohs. Edited by G.
Moncur.

"Reinforced Concrete Railway Structures."
by J D. W. Ball, Assoc. M.inst.C-E..
A.C.G.I.

London: Constable and Co., Ltd., 10. OranKe Street,
Leicester Square. W.C. 213 pp. + xiv 1913. Price
«/- net.

It is sometimes said that of all British
enj^ineers, those who control our railways
have been the most reluctant to adopt re-
inforced concrete. Mr. Ball in this work
gives reasons for this cautious attitude,
and he wisely advocates its use in the best
possible way — not by preaching reinforced
concrete in season and out of season, but
by showing where it is of the greatest
service to the railway engineer, and, on
the other hand, where its older rivals still
hold their own. After reading his book
one is struck with the variety of ways in
which reinforced concrete can be used in
railway work with the greatest con-
venience and with true economy, ,

In the first chapter, on " Preliminary
Considerations," this question of the con-
venience and economy of reinforced con-
crete is discussed, and an interesting com-
parison is given between a floor designed
as a reinforced concrete Tee-beam and one
designed in the older manner with steel
joists and concrete filling. Estimates of
costs are given in each case, which show
a clear advantage in the newer type of
construction. In the same chapter the
quality of the component materials —
concrete and steel — and the permissible
stresses to which they should be subjected,
are briefly dealt with.

Chapters 2 and 3 deal with the theory
of Bending and Shear Stress, and contain
a really useful enquiry into the subject of
the most economical proportion of steel to
concrete in a beam, having regard to the
actual costs of these materials.

Chapter 4 deals with Floors and Build-
ings, and incidentally gives an example of
a floor reinforced with old rails. On rail-
way works this is a cheap form of steel,
but it should be pointed out that if rails
are used careful investigation should be
made into the bond stresses, as rails are
weak in this respect and difficult to anchor.
Chapter 5 deals with Foundations and
Rafts. One of the most useful applica-

tions of r('inforc<'d concrete is in the for-
mation of rafts or foot-blocks under heavy
walls and columns, and the calculations
required to design such rafts are given at
some length.

Chapter 6, on Retaining Walls, will be
of great interest to railway men. It is
pointed out that in many cases the old-
fashioned gravity wall will prove cheaper
than one made with reinforced concrete.
The necessary calculations for the strength
of L-shaped walls are given and explained.
The stability of this type of wall is also
touched upon. But it is curious that this
work, like so many other text-books on
retaining walls, omits altogether to con-
sider the most common weakness of all
these structures, viz., their tendency to
slide forward on their bases. An L-shaped
wall, with its horizontal limb turned out-
wards, is described, and it is shown that
it is secure against overturning and
against crushing the ground beneath it;
but nothing is said about its tendency to
slide forward, and this wall certainlv
would do so if built on a slippery founda-
tion.

Chapter 7, on Bridges, gives nianv inte-
resting examples and an original investiga-
tion into the stresses induced in beams
with sloping ends, such as are commonly
used for station footbridges. An example
of a railway underbridge is very briefly
described, so briefly that the reader wishes
for some further information on this type.
Chapter 8, on Arched Bridges, contains
complete calculations of the stresses in
two-arched overbridges of 40 ft. span.

The last chapter, on Sleepers, Fence
Posts, etc., contains a most interesting
enquiry which the author has made into
the subject of the stresses induced in rail-
way sleepers, and explains the difticultics
attending the use of reinforced concrete in
their manufacture.

We are disappointed to find that the
author has not adopted the standard nota-
tion put forward by the Concrete Institute.
It is a great help when the symbols used
are familiar to the reader, and we hope
this defect will be remedied in later
editions. We should like also to see the
subject of live loads more fully dealt with.
The efl"ects of heavy rolling loads, and the

NEW BOOKS.

igONCBETEi

provision that should be made against
them in the way of shear and bond
strength, are subjects of the highest im-
portance to the railway engineer, and
deserve a chapter to themselves.

The book is well illustrated, and, besides
giving prices, in some cases the author
has added extracts from the specifications,
which will be found of service. We feel
sure that this is a work which will be read
with interest by every railway engineer,
and especially by those who desire to study
what has been accomplished in reinforced
concrete.

*• The Strength of I-Beams in Flexure." By
Herbert b . Moore

Published by the University of Illinois Arban i. European
Agent, Chapman & Hall, Ltd., London. 40 pp.
Price 20 cents.

Contents. — Phenomena of Flexural Failure

— Earlier Tests of I Beams — I Beam

Tests at the University of Illinois —

Yield Point of Structural Steel in

Tension and Compression — Failure of

I Beams by Direct Flexure — Inelastic

Action of I Beams under Low Stress —

Buckling of Compression Flanges of

I Beams — Tests to Failure of Beams

Restrained from Twisting of Ends

and Beams Restrained from Sidewise

Buckling — Effectiveness of Sidewise

Restraint of I Beams — Web Failure of

I Beams — .Stiffness of 1 Beams —

Summary.

These notes are published in the form

of Bulletin No. 68 of the University of

Illinois, and are an addition to the useful

literature that has already been published

by the University dealing with the research

work of the department which is under the

supervision of Professor A. N. Talbot.

The various tests that have been made
are important, as they deal with a form
of member which is so extensively used,
and they have been conducted with a
variety of method that is likely to cover
those conditions which obtain in practice.
The author states in the .Summary that
the separators commonly used between the
webs of I beams do not furnish a stiff
bracing against sidewise buckling, and
great stress is laid on tlu importance of

regarding the yield-point strength and not
the ultimate tensile strength, as the ulti-
mate fibre stress for structural steel in
flexure. The various tests are clearly
explained and presented in such a manner
that the results and recommendations are
readily available to the reader. The notes
and tests dealing with beams which were
restrained are of particular interest, and
we have no hesitation in recommending
this little book to our readers.

" Handbook of Structural SteelworK."

Redpath, Brown & Co., Ltd., 1913.

This handbook gives in a convenient
form the necessary general and detailed
information required in the designing of
structural steelwork, and will be found
most useful to <all those interested in the
subject. The book is arranged in parts,
each having a contents page and contain-
ing notes and formulae explaining in
detail the tables to which they refer.

Part IV. contains a very clear explana-
tion of the main principles of steel struc-
tural design.

Part V. gives suggestions and details
of construction with standardised connec-
tions, and by attention to these in design-
ing steel buildings considerable economy
may be effected. A selection of compound
girders is given obviating the making of
numerous minor calculations.

In compiling the parts attention has
been paid to the Acts governing steel con-
struction.

The whoU' of the definitions given are
very ck-ar and easy to follow, and the
various tables are well arranged.

" ClerK of WorKs "

G. Mctson. Price 2/6.

'I'his handbook deals with the duties of
a (]l<'rk of Works. It will be found of
great help, chiefly to those taking up the
position of Clerk of Works for the first
time,

Tliosc wilh previous experience of the
(hiiic-^ will i)rolial)ly gain some valuable
hints from reading th<' book, which in-
structs and also niak<'s cU'ar what is re-
ciuin'd of an <iricient Clerk of Works.

A KNdlNl 1 l^lNd — ^J

MEMORANDA

ii.iiiH|iili|iiii

MEMORANDA.

Memoranda and Netvs Items are presented under this" heading, with occasional editorial
comment. Authentic netvs iiyill te tvelcome.—ED.

The Concrete Institute.— A paper was read last month by Mr. Lawrence Gadd,
entitled " Some Fallacies in Testing Cement." A report of the paj)er and discussion
will be j)ublished in our next issue.

Newcastle Civil Engineers Students' Association. — An interesting address was
some time ago delivered at the opening of the winter session of the above Association by
Mr. C. H. Sandeman, M.Inst.C.E. In the course of his remarks the lecturer referred
to the atmospheric influences on concrete. He stated that its failure in sea water in the
past had been due to incorrect proportioning and mixing. Very great care was necessary
in the measurement of proportions, and in the quantity of water used. Unfortunately,
despite an improvement of late years, there was still a great laxity in these respects, and
one was inclined to fear for the future of some important sea works now being
constructed.

No other material, he concluded, offered such complete protection to iron and steel
as cement, and no material was more permanent than properly made concrete, so that he
looked forward with confidence to the extension of its use, in intimate combination with
steel, in almost every class of engineering structure.

Fourth International Congress of Building and Public Works.— We are
asked to announce that this Congress will take jjlace at Berne, August 23rd to 27th this
year, under the auspices of the Swiss Federal Government. It is hoped that the Con-
gress will be a thoroughly representative one, as important questions will be brought
forward for discussion. A full programme will be issued by the Organising Committee
at a later date. The headquarters of this Committee are at 13, Seidengasse, Zurich.

Fire-Resisting Concrete, — Of recent years complete confidence has been estab-
lished in the fire-resisting qualities of properly constructed concrete, says the Canadian
Engineer. These, combined with its durability and strength, render it particularly
suitable for the construction of buildings in which more or less hazardous occu])ations
are to be carried on, or which are to be erected in areas wherein it would be difticult to
cope with a conflagration.

For fire-resisting concrete quartz sand should be used, and broken trap rock is,
perhaps, more suitable than any other substance. Limestone is probably next in order
of suitability, although it will eventually run into a crude form of glass or be calcined ;
but that will not take place until the cement itself has been disintegrated. Contrary to
the commonly received opinion, cinder concrete is not unsuitable from a fire-resisting
point of view. The chief objection to its use is that it is far from strong. Heat does
not affect it to a great extent; indeed, it has been found that small pieces of coal
embedded in concrete have remained entirely unaffected by heat. That was due to the
low heat conductivity of concrete; indeed, it might almost be said that it is an insulator
of heat — so much so, at any rate, that the hand can be borne on the top of a slab of
concrete 5 in. in thickness under which a fierce fire has been raging for five hours or
more.

This non-conductivity is well shown by the following account of a steam conduit
built of concrete. The conduit was about 500 ft. long, and was built between a mill
and a boiler-house, and was made just wide enough to take two steam pipes 6 in. in
diameter and two smaller pipes. After the pipes had been laid in position a concrete
•cover was constructed over them, so as to render the conduit proof against any moisture

CDNCEETE^

CONSTRUCTIONAIT?
BIVGINE.ERI'NG

^x>=^^=^ ^^>-^^i=^ h>=^b>ocj ^o^.^j:^.<:^^^ bc-=^^=:^ k^^jj::^ t:o..^i=»<xr^^^

t\ .

Automatic P iling Hammers

^=^=^^=^=^^^^^= (Patent) ^=^=^^^=::^=^I=

IF YOU WANT TO DRIVE YOUR PILES
QUICKLY YOU MUST HAVE THIS HAMMER
—ITS THE ONLY ONE THAT WILL DO IT.

These Hammers
give from 500
blows in the
smaller sizes to
200 blows in
the larger sizes
Per Minute !

You just open a
valve and watch
your pile go
down. There
are no springs,
levers or cams to
get out of order.

MADE IN VARIOUS SIZES SUITABLE FOR
THE LIGHTEST TIMBER SHEETING OR THE
HEAVIEST PILES. THIS IS THE SIMPLEST
PILING HAMMER ON THE MARKET, HAVING
ONLY TWO MOVING PARTS. ONE OF WHICH
HITS THE PILE-:. IT IS ABSOLUTELY SELF-
CONTAINED, AND WORKS EQUALLY WELL
ON STEAM OR AIR.

Sent on Seven Days' Free Trial to any Contractor

A/j. I'Airricui.Aus and i'atai.ocuf.s from

THE BRITISH STEEL PILING CO.,

DOCK HOUSE, BILLITER STREET, LONDON, E.C.

Telephoiif; 5U>i AVKNLI.. I - I. )ii;iiiis— ' I'lI.INCiDOM lEN," LONDON.

.>.==ii^ h-^^xj \.^^M y^> ^r.^ k-^~4i^^- n^ V>-^-A \^^^r^ \-<=^^PM \^>'=^^^

Please rnenlion this /(xirrul •luheri •writinq.

c»,coNyiknic-riONAi3

fi KNC.INK t PtNd — J

MEMORANDA

4'Z. Id-It'
Four Forms of Cutting Edge for Concrete Caissons.

in I he >()il or surface water. The eonduit was carried some 2 ft. 6 in. below the surface
- not sulVicieiitly deep to he beyond tlie inlluence of the specially heavy frosts which
were periodically experienced in the neif^hbourhood in which the conduit was laid. The
concrete trou.iihin}^ was left open at both ends, to make it easy to ascertain whether
there was or was not an\ leakage. It was assumed that if any vapour was foimd to
escape from either end of the conduit there must be some leakajfe which would permit
the water to vaporise. The conduit was allowed to dry thoroughly, which took about
two weeks; but no vapour has at any time been visible, and th(; loss of heat, which has
been measured, throuj^h the concrete is so small as to be nej^liji^ible.

Steel-Cutting Edges for Concrete Caissons. Reinforced concrete caissons sunk
throui^h rock foi ni the foundation for the main part of the Tennessee River dam at
Hales Bar, Tenn. There are 26 caissons in all, in sizes from 30 by 32 ft. to 54 by 70 ft. ;
in sinkinii them there
was opportunity for try-
ing;' variations in design.
Several types of cut-
tin^-edi^e were tried,
sketched herewith. It
is stated by the enf^i-
neers in chari:je of the
contract work that the
last one sketched, the
round cutting-edge, proved greatly superior to the others; this, of course, applies to
zvork i)i rock only.

The rock under the cutting-edge was removed mainly by blasting. An important
matter was to clear the rock away well outside the outer line of the caisson, as other-
wise a projecting point might hang up the caisson. The round-edge style of cutting-edge
was the best adapted to this requirement, whereas the flat-bottom styles, especially the
first one (6-in. channel base), gave considerable trouble in clearing.

Blasting with light charges was done close to and right under the cutting-edge
in all the caissons, but in no case damaged the cutting-edge. The explosive was 60 per
cent, dynamite. — Engineering News.

Harbour Work in Belgium. — As a first step towards improving the port of
Nieuport, at the mouth of the Yser, the only natural port on the Belgian littoral, works
involving an estimated expenditure of i,7oo,ooof., are shortly to be undertaken.

According to the plans the existing floating basin is to be lengthened and improved
by the construction of reinforced concrete landing-stages, and a second head towards the
sea at the lock giving access to the floating basin will form a chamber-lock permitting
vessels to enter or leave at all stages of the tide. A diversion of the old western branch
of the Prunes Canal is to be constructed, which will cause the water from the interior,
now flowing into the harbour through five locks, to flow directly into the sea. Improve-
ments are also to be carried out in the roadstead of the port.

The Department of Public Works has decided to undertake the construction of a
sea dam betw^een Knocke and Duinbergen for a length of 2,009m. Including the
necessary staircases (28 in number) to give access to the sea, the cost will be about
7oo,ooof. The work is to be completed within 26 months. — Times.

Self-Supporting Concrete Towers. — Two self-supporting concrete towers with
90 ft. booms are being used to distribute mixed concrete for an eight-storey, basement,
and sub-basement reinforced concrete building now being erected at St. Paul, Minn.
The building is 100 ft. by 288 ft. in plan, w-ith the mushroom type of reinforcing, and
requires 15,000 cubic yards of concrete. As permission from adjoining property owners
to attach guy wires to their buildings could not be obtained, the towers had to be built
with sufficient stability to stand alone.

Next to the building an ordinary tower, made of heavier timber than usual, w^as
erected. In the rear an auxiliary tower, 10 ft. by 16 ft. in plan, was built to a height
of about 70 ft. The main tower will, at the time the building is completed, reach about
175 ft. above the pavement. To counterbalance the weight of the boom and three shutes,
which are suspended by cables, the rear tower is weighted with stone, its own weight
not being sufficient to serve as an anchorage. Within the rear shaft is an elevator skip
on which loaded wagons are driven and materials dumped. After the team is driven
off the material is hoisted and automatically dumped into elevated bins at one side of

MEMORANDA. ICQNCBETEJ

the auxiliary tower. A rectangular timber frame, slidin<4 on the two front timbers of
the main tower as i^uides, carries the boom and shutes on a pivoted connection. To
raise the frame a block and tackle is fastened to an overhanging timber extending from
the main tower, a lead running therefrom to the hoisting engine. The circle of these
booms is sufficient with the small pivoted shutes at the ends of the main shutes to cover
the whole area, and a hopper, carried in a sling in the main shaft, is raised or lowered
to a ])oint opposite any one of the three shutes. Two mixers are placed directly under
the material bins at the level of the second bend of the main tower, so that it is unneces-
sary for the elevator buckets to be lowered quite to the street level.

Reinforced Concrete Water-tank of 600,000 gallons Capacity.— A. reinforced
concrete water-tank and tower have recently be^n constructed at BerHn, Ont., Canada.
The tank has a capacity of 600,000 gallo'ns when the water-line is 2 ft. below the top.
It is 50 ft. in diameter, 40 ft. high, and is formed of a circular shell 12 in. thick at the
bottom and 8 in. at the top, standing on a reinforced concrete tower 81 ft. high from
the footings of the foundation. The tank is covered with a fiat-arched dome of
reinforced concrete 4 in. thick, and the bottom is made up of two domes which run
into each other, the outer one being inverted, with its low part resting on the support-
ing tower, from which point springs the inner dome, which is convex to the inside of
the tank. The bottom is well reinforced to prevent bulging. The inner and outer
domes of the bottom are so proportioned that the thrusts nearly balance. The thrust
at the junction of the bottom and the shell of the tank, due to the weight of the shell
and its roof, is provided for by a large amount of steel reinforcement. The tank
reinforcement consists of § in. and j' in. square bars of high carbon steel, placed in
two separate layers where the spacing was less than 4 in. In the inner dome of the
bottom there are ^-in. rods spaced from 6 in. to S in. apart, centre to centre. Concrete,
mixed in the proportion of i : i : 2, was used in all portions of the tank in contact
with water, whereas the proportion in all other places was 1:2: 4. As a means of
waterproofing the tank, three coats of mortar, gauge i of cement to i of sand, and laid
on \ in. thick, were u?,ed.—Enginecrino Record.

ERRATA.

The writer of the article on " London's Reinforced Concrete Regulations " points
out that in the first part of the article published in our issue for August there is an error
in calculating the deficction of a steel beam. It should be : —

4S LU00X/^4S 357

As a consequence of this the references to the limiting deflections on pp. 534 and
535 require modification.

Concrete Institute Presidential Address. — In reporting the remarks made by
Professor Henry Adams (page 847 of our December issue), the words given as air
slaking should have read " over slalsing.'"

CATALOGUES RECEIVED.

Richard Johnson, Clapham <Sc Morris, Ltd.- A new catalogue has recentlv
been jnibli^hed by the cfMUjjany's reinforcfd Concrete Department. Full descrijitions are
given, accompanied by illustrations of the Keedon and Johnson Lattice svst(>m, both of
which are well known to our readers. 1 he book also contains some excellent illustra-
tions of actual work carried out by the (onip.-inw

Especial attenticjn must, however, be (Ir.iwii to th.' carefullv c()in|)ile(l and \'erv
extensivf; tables, which are intended to assist engineers, architects, and others in fixing
sizes ffjr jjreliminary designs, and enabling them to arrive at the sizes of superstructure
without difficulty. Messrs. Johnson, Clapham is: Morris desire us to state that they
are, of course, prepared to suf)pl\ all necessary detailed drawings, and to add further
details not specified in the tables. ThcN' will gladU forward this book and give all
furthf-r informatir)n upon application lo tlun) at their ollices, 24 and 2(), L<'\'er Sli-eet,
Manchester.

The Standard Steel Co., Ltd. This (ompauN has recentl\' issued a handbook
of structural steel which will doubtless prove useful lo architects, engineers, buildeis,
and others. Every attempt has been luade to arrange the tables in such a manner that
any information needed can be easil\- found withoul having recourse to numerous calcu-
lations. The booklet (onlains tables for rolh-d steel sections used as beams, broad llange
beams, rolled steel channels usr-d as beams, steel angles used as beams, steel com|)oun(l
girders, (tc, etc. There are also useful tables for \ai ious kinds of columns, both
hollow^ and solid, 'i'he booklrt also conlains tables of \\(ights of different forms of
steelwork, as also various diagranis and illustrations. ('o|)ies of this handbook can be
obtained from the compan\ at I heir ofiices in Croydon.

•««

5 »

p > ■;«. ;

= S

o .o

!S
5 -"^

CONCRETE

AND

COMSTEUCTIONAL ENGlTSEEmNG

\oluine 1\. No. 2. LONDON, FeBRLAKV, 1914.

EDITORIAL NOTES.

LABOUR TROUBLES AND CONCRETE.

The regrettable differences that have arisen between employers and employed in
the building- trades must necessarily have serious eflects upon the skilled labour
market concerned in the erection of buildings. Whilst we fully sympathise with
the principle of the working man having his trade unions to protect his interests
and rendering services as a benevolent society, we are afraid that the policy of
some of the leading agitators is quite suicidal to the interests of the man who
has learnt a trade, and it is certainly not equitable in the matter of demands
against the use of free labour. But from the purely selfish point of view, as
advocates of the use of concrete and reinforced concrete, we see in this new
struggle between employers and employed great advantages for the development
of the concrete and cement industries. We have only to remember the quarrel of
some ten years back as between the Plasterers' Union and the builders, to see
how detrimental that quarrel was for the plasterers and what an excellent thing
it was for the concrete industries, for it is from that date that we have had the
enormous development of the concrete slab and the concrete block for partition
purposes and many other building requirements, which were formerly catered
for by the skilled plasterer.

The new strike will simply lead to a greater use of concrete for footings,
walls, floors, hearths, lintols and roofing, and the bricklayer, the joiner, the
mason, the slater and the tiler must be materially affected.

This is regrettable for these particular trades, for they contain some of
the very best elements of the British artisan class ; but, to repeat, the concrete
industries must gain, and unskilled labour in particular will naturally reap a
large benefit, for concrete work employs vast numbers of unskilled labourers,
excepting in certain forms of reinforced concrete. These men need have but
little experience, and concrete mixing is one of the simplest forms of labour open
to all unemployed.

It has often been commented upon what enormous strides concrete has
made, both in the United States and in Canada, and economy is generally given
as the reason ; this is true up to a point, and it is certainly true in respect of
larger buildings, but in small buildings it does not necessarily always happen
to be the case, and the great advantage accruing to the employer who is free
from the trammels of trade unionism has played no small part. Thus, whilst
the large majority may think the coming strike a great evil for the building

« 75

RESEARCH WORK AND CONCRETE. [CQNCBETEJ

trade, we see in it a future for more economic buildini^-s and less labour troubles,
combined with the g-reater possibility of using- unskilled labour to get up a
building rapidly.

RESEARCH WORK AND CONCRETE.

In our Memoranda we announce the formation of a British Section of the Inter-
national Association for Testing Materials, and we congratulate the promoters,
and particularly Professor Unwin, Mr. Leslie Robertson and Mr. Lloyd for their
successful efforts in this direction.

We trust the British Section is the forerunner of a British Association for
Testing Materials, similar to that excellent institution which exists in the United
States, and similar to other institutions that exist on the Continent. It is regret-
table indeed that we should, up to the present, not have had any -real centre for
research work affecting" constructional materials, and whilst other nations have
long had their sections or individual associations, and have been doing good and
continuous work enquiring into matters of the utmost importance, we have
practically marked time.

Some work has, of course, been done at the National Physical Laboratory,
mainly at the instance of certain institutions, and notably lately at the sugges-
tion of the Institution of Civil Engineers on the matter of reinforced concrete.
For consecutive effort in research on constructional materials, we have, in this
country, really only the British Fire Prevention Committee, with its somewhat
limited scope in relation to materials affording fire protection.

With the British Section of the International Association for Testing
Materials, duly formed — and, we trust, a National ^Association in embryo — we
hope the necessary funds may be collected to enable research work to be done,
so that we may not continue to take a back seat in the comity of nations in
this particular department of investigation. The subject is all-important for
concrete, reinforced concrete, and particularly cement, all relatively new
subjects, and a vast amount of experimental work is needed. This work should
be carried out on practical lines, rather than on the ultra scientific lines all too
frequently met with on the Continent. We again repeat that we welcome the
formation of this new section.

OUR CONCRETE COTTAGE COMPETITION.

We would remind our readers of our announc-emenl regarding a competition for
concrete cottages, j^artirulars c^f which will be foinid in our adxertisement
columns, and the full conditions of which can be obtained from the offices of
this journal, on application to the publisher.

The subject of our (V)m[)ct ilion appeal's to haxc awakened considerable
interest, and although to many of our readers, who haxc alread)- attained the
mf^re successful walks of lilc in ihcir prolcssion, coni|)('tilions cannot ap|)eal,
we trust they will bring this cjucslion lo tlic nolirc ol ihcii- xoungci' colleagues
and the members of their si a ft.

y, CTONXI PlR-nONAI
AKN(.INH l/IN(, --

rill-: HOARD Oi- AGHICULrURE <•- FISHERIES.

■'ii.^li REINFORCED CONCRETE' IN

,., fi^i THE NEW OFFICES FOR THE ,^

,^^j BOARD OF AGRICULTURE tr

aS-a AND FISHERIES. j|.

Although the building here described hjs not
been constructed of reinforced concrete throughout,
this material has nei>ertheless played an impor-

tant part in the 'work. Our article has been prepared for us by Mr. Albert Lakeman, Hon
Medallist Construction. — ED.

This new building is Ixjing constructed in W'hilcli.ill I'hicc for ilic accommoda-
tion of the Board of Agriculture and Fisheries, the various departments of
whicli are at present scattered \n different buildings in the West Mnd, thus
rendering the organisation and control more complicated and difficult. The
work of the Board is very extensive, and has grown considerably during recent
years, the vaiious additional duties imposed since its establishment in 1889
including the transfer to the Board of the Ordnance Survey Department, the
headquarters of which are in Southampton, the jurisdiction of the Ro\ al Botanic
Gardens, Kew, and the administration of the laws relating to the fisheries of
England and Wales. The estab-
lishment f;)r which accommoda-
tion has to be pro\ided consists
of a President, a Permanent
S e c r e t a r y, a Parliamentary
Secretary, Assistant Secretaries,
and a staff of administration and
technical officials.

The new building is being
erected under tlie superin-
tendence of Mr. H. A. Collins,
A.R.I.B.A., one of the Archi-
tects of H.M. Office of Works.
The designs were originally pre-
pared by the late Mr. H. N.
flawks, I.S.O. The site adjoins the Hotel Metropole, and is opposite
the Xew^ War Office, having a frontage of about 150 ft. to Whitehall
Place, loi ft. to Whitehall Place West, and 136 ft. to Great Scotland
\ ard. The total height of the building is about 95 ft. from the pavement level,
and the section illustrated in Fig. 2 is not quite correct, as an additional floor
has been added by carrying up the roof for another storey. The basement
floor IS 15 ft. below the pavement level, and in addition a lower ground floor
is constructed 6 ft. below the same level. The plan of the basement is illustrated
11^ P^g' 3> 'ind it will be seen that a corner of this is cut ofi" bv the Regent
Street sewer, which passes under the building at the level shown on the section.

B 2

Detail of
Brackets to
Columns.

The New Offices for the Board op Agriculture
AND Fisheries.

THE BOARD OF AGRICULTURE & FISHERIES.

ICQNCRETEl

This basement, which is to be utihsed for workshops, packing- rooms, and
stores, is well lij^htcd b}' lar',>-e skylights, which occur at the bottom of the
two larg-e light wells which are formed in the central part of the building-;
while the lower g-round floor is directly lighted by windows in the external
walls, in addition to the interior light wells. The principal entrance to the

CNTfeANCE

F'lii- 2. Cross Section.
TiiK New Oificks for ihk Boatu) ov AoKicii/rnKK and I-'isheries.

building- is situjited in VVhil( hall iMa(X', and the main staircase and lift arc
placed in the centre of the ijuilding, with direct light from one of the large
areas. Reinforced concrete is larg'-ely employed in the construction of the
building-, and lliis is designed according lo the llennebique system 1)\- Messrs.
Mouchel and Partners, i>td., of Victoria Street. It is not a C()in|)lclc' reinforced
concrete huikiing-, howexer, as the external walls are of brickwork, the facades

fcNdlNKKWlNl. --,

TIIIi BOARD OF AGRICULTURE <'- FISHERIES.

hciiii^ laced wilh roilland sloiic; and all iiilcinal walls in which fireplaces
were re(|iiirr(l wcii- also hiiill ol hrick. i he loads coming on ihcse walls are
('allied 1)\ blue hi iek i)ieis, and the relainin«4 walls are also ol ihis material.

Ft 3

= o
ft a

■St 2

Ihe reinforced concrete work consists of columns, beams, floor and roof
slabs, and staircases. Trial holes were made on the site to ascertain the nature
of the soil for foundation purposes, and these showed old brickwork and

THE BOARD OF AGRICULTURE & FISHERIES.

[CQNCBETEJ

concrete, mud, sand and ciay to depths varvino- from 20 to 2=^ ft. below the pave-
ment level, and below this a layer of gravel was found, varying- from 12 ft.
to 20 ft. in thickness, overlying the blue clay; whilst water was encountered
about 27 ft. from tlie surface. A concrete raft was constructed over the whole
site, this being in two thicknesses, the bottom of which was 6 in. thick and the

Phoiofirath by lirnesl Milncr. Wandswottli, London, S.W.

I'lti. 4. li.isement in Course of Conslriiction.
The Nkw Ofiici.s kor tmk Hcmrd oi Aoricui/iuke and Fishkriks.

upper lav(,'r i ft. () in. lhi(l<, wilh a conliiuious asj)hah damj) (M)urse belween.
This asphall was lakcn ihioiigh ihc siirroiiiHliiig wails and carried up on the
outside I0 form wliat is prad irnIK' a large as])halt tank, in which the
building is ccjnstructed. f lie raft is covered with paving to form the basement
floor and the retaining walls, and ()-\n. interior division walls are built directly
on to the raft uliich loims ihc foundation; while the foundations of the main
80

clONyryijc-rioNAi:

/:t^iV.iS!^li 1 TUB BOARD OF AGRICULTURE c'.; FISHERIES.

walls aiul columns arc taken down ahoiil ii ft. h in. hclow llic hascnu-nt to the
layer of i^raxel priw ioiislv mentioned.

I lie i^cneral (iisj)osit ion and lay-oiil of ilie beams and columns is shown in

the plan in Fig. 5, Axhich Is a typical floor plan, the reinforced members being
indicated by the thick black lines.

The columns are all designed on the Hennebique system, and the largest
of these in the basement is about 28 in. square.

THE BOARD OF AGRICULTURE S FISHERIES.

lOQNCBETEi

The floors gencrall}' have been
desii^ned to rariy an external load of
112 lb. per ft. super, but in some in-
stances the intended use of the rooms
is sucli lliat exceptional loads have to
be carried, and in tliese cases the floors
were each designed to suit the special
requirements.

The roofs generally were designed
to carr\- an external load of 50 lb. per
sq. ft. The floor slabs \'aried in thick-
ness from 5 in. to 6 in. for the ordinary
cases, and, except in the case of very
small bays, were reinforced in both
directions. Typical secondary and
main beams are illustrated in Fig. 6,
where the former is 15 in. deep and

in. wide, witli reinforcement as
indicated, and brackets 12 in. by 2 in.
were formed in every possible case
where the beam is continuous, as
shown in tlie detail. The main beam
here illustrated is 19 in. deep and 11 in.
wide, and it w ill be seen that one end is
su])j3orted on a wall and the other by a
column. In ail cases of beams abut-
ting on cohunns brackets 10 in. by

1 ft. h in. were formed as shown in
this t}pical detail. Another typical
detail illustrating the bracket connec-
tions between beams and column is
sh(j\v n in I'ig. i, where the arrange-
ment of the reinforcement can be
clearly seen. Reinforced (M)ncrete
templates were i)r()\ ided under the
ends ol scxcral reinlorced beams where
they rested on the walls. 'J'he roof
work- contains some interesting details,
and the method of arranging the
sloi)ii)g beams is illustrated in I^'ig. 7.
li will be seen that the (lei)lh of the
beam foniiing the abutment at the
foot is slightly increased to take the
thrust, and additional reinforcement
is pro\ ided.

Ihe shutlcrini'' and i-einror(H'menl

J, CX3NM PlIlTIONAl.
A. KNdlNKKWINC, -^.

THB BOARD OF AGRICULTURE & FISHBRIES.

in i).)siti()n lor a j^orlion of this roof work is shown in the i)h()lo^^r:ii)hic view
illustratcil in F/.i;. S. I'lu' coiuTi'to throii^liout was mac'hinc mixed, and two clcr-
1ri(' lioists wvvv installrd for raisinj^' \hv mixed eoncriMc lo the different h'\els.

.\Uhoui;li tliere aic no i-xcepi ional constructional features in tliis building',
it affords a tv|)ical c\aini)Ic of tin- application of reinforced concrc*le, and further
illustrates the exti-nsixe use of this material in (ioxernment l)uildin<4S ; and this

Fi'A- 7. Typical Detail showiag Arratif'ement of Roof Beam.
The New Offices for the Board of Agricultlre and Fisheries.

should have great influence with private building owners, a great number of
whom are so conservative that they are still dubious as to the efficiency of
reinforced concrete, and consequently do not avail themselves of the saving that
can be made on the initial cost of their buildings by the use of this material.

The foundations were constructed by Messrs. Holloway Bros. (London), Ltd. ,
of Belvedere Road, S.W., under a separate contract, and the work of the super-
structure is being executed by Messrs. Higgs and Hill, Ltd., of South Lambeth
Road, S.W. The aggregate and sand for the concrete were supplied by the

THE BOARD OF AGRICULTURE & FISHERIES.

fCONCKETEJ

Ham River Grit Co., of Ham and Wouldham, and the steel for the reinforcement
bv the Whitehead Iron and Steel Co., Ltd., of Tredegar. The concrete mixer
was a Ransome pattern electrically driven mixer, and the cement was supplied
bv the British Portland Cement Co., Ltd.

Photonrufih by lirnesl Miliicr, Waiidsxcorlh . I.imdon, S.W.

Pi«. 8. View sliowint! Reinforced Concrete Roof Slabs.
Thk Nkw Oi-ficks i'ok thk Hoako oi- Aokiclltukk and Fishkkies.

. trjN.vrytK'noKAL

THI-: BEST RATIO OF STEEL TO CONCRETE-

WHAT IS THE BEST RATIO
OF STEEL TO CONCRETE IN
REINFORCED CONCRETE
BEAMS & SLABS FROM £ s. d.
POINT OF VIEW ?

By ROHINTAN N. FRAM MIRZA.

B.EnH., A.M.I.C.E., M.I.M.H., Assoc. Royal T. Collene.

As the question of economy in construction is one th^t is of considerable interest to all
studying and dealing with reinforced concrete ivork, the folloiving article may pro've useful
and of assistance to our readers. — ED.

In the present article equations are given to prove that, in all reinforced concrete
structures designed to resist tensile stresses, there is only one ratio of reinforcement
which conduces to the lowest cost in construction. This will, of course, depend upon
the market values of steel and concrete, remembering that steel is by far the more
costly material.

The cost of labour and material will differ in various localities ; thus it is evident
that the minimum cost of construction may be obtained by the use of varying ratios
of steel according to the prices in the district. The ratio of steel that gives this
maximum economy in the total cost of structure is quite different from the ratio of
steel to concrete which develops the fullest stresses of steel and concrete. This latter
ratio is often termed wrongly the " economic ratio," which is a most misleading term,
for designers may easily misinterpret it to understand it as that ratio which gives the
minimum cost.

Although it may appear too previous at this stage to ask the reader to glance at
Chart No. 3 before going into further details, still it will arouse his interest, for that
chart represents the varying costs of a set of reinforced concrete slabs with reinforce-
ment varying from nil upwards. The sharp sudden turn at the bottom of the curve
will bring home the fact at once, how the total cost rapidly rises for any other ratios
of steel to concrete but for one particular ratio.

The charts accompanying this article give a rapid method of finding that particular
and critical value of reinforcement ratio which conduces to the lowest cost. By the
aid of these diagrams the required values of critical depth (of beam or slab), reinforce-
ment, etc., can be determined accurately, when the bending moment on the structure
is known.

Although the mathematical working out of the deduced equations is somewhat
complicated, application of the final results and the reading of the charts for designing
and checking purposes will be fouad to be extremely simple.

Let s denote the price of steel per lb. in pence, q denote the price of concrete per
cu. in. in pence, and G the price of centering per sq. in. in pence.

All these figures should include the cost of labour, fixing, etc., on the site. These
values are generally in pounds or shillings per cu. ft. or sq. yd. ; but they can be easily
converted. Further, the money unit need not be necessarily in pence ; it may be in
shillings, dollars or any unit, but it must be the same unit for s, q and G.

The basis upon which the calculations are made is the theory set forward in the
Report of the Joint Committee (Royal Institution of British Architects) on Reinforced
Concrete. The same nomenclature is here used, thus: — g-

ROHIXTAX N. FRAM MIRZA

ICDNCBETE]

h denotes the width in inches.

d denotes ihe effective depth in inches.

Es
m denotes the the ratio of the moduli of elasticity of steel and concrete (which

is generally taken as 15).
M denotes the Bending Moment at the section considered in in. -lb. units.
t denotes the tensile stress in metal per sq. in.
c denotes the con-ipressi\e stress in concrete per sq. in.
z denotes the distance of resultant thrust in concrete from compressed surface of

beam in inches.
kd denotes the distance of neutral axis from compressed surface in inches.
Ac=khd denotes area of concrete in -compression in sq. ins.
At denotes the area of metal in tension in sq. ins.

^^'jj~^' ^^^ ^^^^° °f section of metal to section of concrete, i.e., the ratio of

reinforcement.

P=100 p or the percentage of reinforcement.

/ denotes the span in inches.

w denotes the load per in. run of span.

\V denotes the load in lb. per sq. in.

On page 521 of the foregoing Report, when dealing with beams of rectangular
ection with single reinforcement, it is stated that—" In a homogeneous beam the
tresses are proportional to the distances from the neutral axis. In a discrete beam,
uch as a beam of concrete and steel, on account of the greater rigidity of steel, at a
iven distance from the neutral axis, the stress in the steel will be ni times as great as in
oncrete." The formula for the position of the neutral axis s is then worked out to —

k = \'{p'm' + 2 pm) —pin
hat is, the neutral axis is lower as the amount of reinforcement is greater, and passes
lie half depth for 2 per cent. The distance of the resultant thrust from the compressed
urface is ::=^-^^kd, and bending moment equation becomes —

M = h A^c (d-hlid)
= 1 kbd'c (1-U)

It will be nrjted, therefore, that the strength of a rectangular beam of reinforced
oncrete can be put directly into the form M = Cbd\ where C has a value which depends
pon the ratio of reinforcement adopted in the design, taking of course, into consideration
le maximum stresses allowed, i.e., in concrete and steel. In ordinary design, the usual
ractice appears to be 600 lb. per sq. in. for concrete in compression, and 17,000 lb.
er sq. in. for steel in tension.

I'or the sake of convenience with regard to further calculations, a simple ecjuation
, needed connecting C and p directly. The etjuation which the author has himself

educed, C = ,_ (\vh(;re /-» stands for th(; perc(;ntage of reinforcement) satisfies the

Dndilif>ns and differs at most by 1 or r5 percent, from Hk; accurate values obtained
y working owX the foregoing equations for C and A', and K and p.

Allowing (;ne inch of concrete as fire protection below the ix.'ani or slab, tlu; volmne
concrete used for this piirj) .>se would be //; en. ins., tlier(;f()r(; the total xolnme of
mcrete used would be dhd'\-lh) cu. ins.

VohniK; oi st(M:l used = /hd

100

Let/= weight of steel p-r en. in., then the weight of steel used = ■^^'"^^' lb

100
86

(a, coNyrvurnoNAn

THH niiST RATIO OF STEEL TO CONCRETE.

The necessary ainoiiiit of sluitlerin^,' or centering re(|nired for llie structnre will be
/ [2(/-i /;J, and the total cost of tlu^ structure, wiiether it he a beam or a slab will be

Ih</<1 -f Hui +-^''|'jjj^' H-67 (2J 1- /;) units (l)

The tcUal bending moment on a beam or a slab will be ecjual to that due to the

imposed loading plus the bending moment induced b}- its own weight. Taking the

weight of reinforced concrete as 150 lb.

per cu. ft., the w(dght of the beam or

slab will be ecjual to '0HC)5n)(l lb. If

therefore, \V is the load per s(|. in.,

the total bending nioment becomes —

jy,_Wlbxi o-0865ll)dyi . „
^ ^~+ ^ '"• l^^-

Where 'A may be equal to 8, 12, etc.,
according as to whether the beam is
freely or rigidly supported.
117-

Let -^

be denoted by a and

bv /3.

0'0865/-

It has been seen (page 86) that
.1/ = Clnf
:.Cbd'' = ab + lidb
and by the ordinary solution for quad-
ratic equations — -

2C ^ C 4C'
If an actual example is worked
out, it will be found that the term

—, becomes negligible, hence

20 C 2C

(2)

It has been shown that a ciirect
relationship between C and P may be

put in the form C =

P+m

where X =

FiGJ l/ennca/ Sca/e. I Cejnfiinefr^ jf 'O
nomonla/Sea/e / Centime/re = 7.C Oriifs

cctbu 40 suttbe \o'xio' XooA^ 0.6© Ibs/t)', »*^ ^ '^/a"

162 and /;i = '5, therefore P= "'^

N-C'
Substituting these values for d and
P in equation (1) the following value is
obtained :

Total cost = lbq

■'^+2N "CI , „ ,jnflbs
200

r^+2^^l^jj^^fnfibs ry:2^n

L 2C J ^ 200 L ,V-c J

[

S+ 2\^aC

]

(3)

The total cost could have been put as a function of d. but by making it a function
of C matters are much simplified. To find out at what value of C the total cost is a
minimum, it is necessary to differentiate equation (3) with respect to C, but it can be
shown graphically that there is a minimum bv plotting the cur\ es as shown in Fig 1

ROHINTAN N. FRAM MIRZA. [CQNCBEJE]

Representing total cost by the symbol T^ and differentiating with respect to C

' 200 L Vc{N-cY J ' L c- -I

To determine that valne of C which will make Tc a minimum, it is necessary to

i^\ ^ A ^ ( n M^ ; . cost of steel per lb. ,

equate equation (4) to zero and solve tor (. It i.e. — ,; 7, L)e

^ ^ q cost of concrete per cu. ft.

denoted bv symbol R, and — be denoted by 7, this minimum yalue is given by

' ' _ ^^

_ /i^+ y/aC , iTifR

C ^ 100

^+\/

V N y/a+ v^C (3+ y/«C) 1 ^ ^ [ _ /^+ v/^Cl ^n (5)

L Vc[N-cY -J ^ <^' -I
100 L sci^-cy J

(6)

The above equation is fairly complicated owing to the presence of i^. Now from
various examples it has been found that by neglecting /^ in the above equation, it reduces
the deduced value of C by very nearly 4 per cent. Hence to avoid unnecessary
complexity it is better to neglect /^ temporarily and then adjust the equation afterwards

It has been stated before that /3 = — -- — and is also equal ^ol — 7^ U.

Temporarily neglecting /^ equation (6) becomes

1 . mj R i N + C ) _ .^)

C ioori + 7) ^{N-Cf\

T , 100 . R _r.

Let -=;/ and , = Rx

mf 1 + 7

Solving the quadratic for C

U 7^', + 8/^,;i + /^, + 2^f) '

This equation shows that the va'ue of C and hence the ratio of Reinforcement
which makes Tc a minimum is dependent upon the ratio of s to q—i.e., the price of steel
to concrete.

It can be shown that the error involved in evolving the value P by neglecting jRf'
(under the srjuare root sign) is so small, as compared to the exact value from equation
(8) as it stands, that for practical purposes it is justifiable to neglect A^,' which reduces
equation (8) to a simple formula.

I'urther (-i has been temporarily neglected. To adjust for its loss, equation (8)
should be multiplied by r04. This increases the value of C to the necessary amount.

Thus neglecting A','

2A^;fXl-04 _

~ \2v'2R^ + Ri-]-2n]

2NnXV04 ....

or C = ; — } ; — /— ,., v '

iv Ri+V2ny

Substituting in the above e(iuation the vahujs of A*, and n

200WX1;04 , (,„,

,,,/rv «-+V2""'i

L 1-1-7 mf-'

K'tSr.iNKll^'^'^1 ^^^ /i/iSr RATIO OF STEEL TO CONCRETE,

This is the general (Mju.'ition of the economic C in terms of s\mboIs. Giving (he
constants .V, /// and / their respective vahies U)5, '5 and "29 (assuming that steel weighs
f )() 11). per cube ft.)

232900 (11)

C =

[^r^ ''-^y

where 7 = ~r '
qb

This ecjuation applies to both beams and slabs. In the case of slabs b is a very

arge quantitv, as compared to the depth, and the expression ~ becomes exceedinglv

small compared even to unity, and could be neglected ; therefore for slabs, formula given
by equation (II) can bj still further simplified by dropping out 7 and the expression
becomes

^^232900 (12)

(\ R ziiy

This equation can be put in. any convenient form ; thus if s were price of steel per
lb. and O price of concrete per cub. ft., then calling S Q=J, R in the above equation is
equal to 12' xj, and by substitution another formula can be evolved of the form

V^R + B-

The truth of the above equations for C can be conclusively proved by working out
arithmetically an actual example and by plotting various values of total cost with
corresponding values of C, to show that there does exist a minimum value of total cost.

Example I.

To take an actual example such as the following case of floor panels in a large
building, let s, price of steel = Id. per lb., price of concrete = Is. per cube ft., and
price of centering = 27d. per sq. yd. For slabs, there will be little or no centering
required along its depth, the chas3 in the walls acting same. In this case only the
centering for the superficial area will be considered.

c=r /^ — T n3)

La/p-urJ

Total cost =lbq , _l7;,^_l x — ;^- ^— ^ -fr^/'^O-l-/)]

'' 20 (^''^^^ 200 [162-C] ^^^^^^^^J'

w = 288 lb. per sq. f t. = 2 lb. per sq. in.
/ = 120 in.
6 = 120 in., and number of panels in the building be equal to 40.

Taking ^=12 a = -1^ = 2400.

r
/^+2\ ^=100(1+ \"C) very nearly.
Cost of concrete for 40 panels in £s.

_ 120x 120X100(1+ \'C) 40
144X2XC 240

-i:833[l^].

Cost of steel for 40 panels in ;^s.

^•29X120X120X'5 XIOO (1+A^O 40
200xi2x(l62-d ^20

Vi62-C/

ROHINTAN N. FRAM MIRZA.

^rjNCia^im

Fireproof one-inch concrete covering cost = ;^s 16'666. Cost of centerirg for
40 panels @ 27d. per sq. yd. = ;^50'000. The total costs corresponding with various
values of C have been plotted in Fig. 1, and are also given in the following table : —

Percentage of
Reinforcement.

0*224

0625

0'69

1+v/C

l + y/C

C
162-C

833(HVC)

174f l+s/c \

)2-cy

162
£

7-071

8-071

0-161

9-487
10-487

9-695
10695

0117 0114

112

134

68
£

97-46 950

1-04 1253 2523 27-14

\162

Centering Cost 500 500 50-0

Fireproof Cost 16-66 16*66 16*66

Total Cost CO 213-19 189-35

50-0
16'65

0'73

0'81

1*04

4-0

100

110

144

9-79

100

105

12*0

10-79

11*0

11*5

130

0112

Olio

0*105

0-090

52.

93-5

91-63

87*5

75-0

28-53

30*97

38-45

125-63

; 50-0

500

50-0

1 16*66

16*66

1666

188-69

189*26

192*61

267-29

162
12-72
13-72

0-085

71-0

50-0
16*66

Fig. 1 shows that the Tc has a minimum value somewhere between C = 94and
C = 96.

Instead of laboriously working out this table every time, the economic C can be
very quickly worked out from equation (12).

/? = -= 144 in this particular example, substituting this value for R in equation
Q

^ ^ 232900

and

C = 96 (by slide rule)

P= "^^^ = 72
162-C

This value of C agrees very closely to that given by plotting Fig. 1.

Example II.
Taking the same values for steel and concrete as given in Example I., and assuming
that price of centering per sq. yd. is 27d., to find the economic C for a beam whose
breadth is 12 in. In this case

232900

c=-

(V ^L +37-l)^'

R=\AA

L9 /. 144 J

144
/. =*5
12

= 9798

C= 108; therefore P=VQ>.
By using the proper value of C the most economical designs can be produced, and
a considerable amount of money can be saved. Undoubtedly cases may arise where the
designer will have to choose other values of C for the sake of gaining advantages in some
other direction, such as head-room, floor cut through by openings, etc., but in the author's
experience he has fmind that the use of this formula saves much time in the office and
yields very satisfactory results in practice.

CTON.vrUUCTIONAi:

THE ni^:ST RATIO OF STHEL TO CONCRETE.

Fir

-- ^

-Cc'ST 0» CoMCRr Tl PtM 1

Cubic Inch ^
C » 3oo L»» f\.i» S9o««t

(

Inck

t • /7noo

-life

-Ho—

-loo
-9o -

-80-

^°<

^->,

7o -

-C^r

Joo-

ifjK.

-I
<
>

-3o

-2o

U^]

too

1
2oo

l/.L.U or R '
300 AOO

1 1

Soo

Goo

Zoo

8c:

^/6 2 Vcytical Sca/e I Cof^ti/riefrc • 10 Units
m '•tLCti/o/ Sca/t / CenfimeJi-e • 6oUnifs

P+

'11 1 is v.'iluc of C to },'ive
a inininimn cost can be
obtained from a curve con-
necting' R and C {lu^^. 2),
and knowing C, the vahK; of
P i.e. the percentage of
reinforcement— can at once
be obtained from the
ecjnation

162-C
or by referring to the chart
given on paj^e 536," R.I.B.A.
Report on Reinforced Con-
crete, No. I.," or the curve
given in F//f. 4.

A General Review.

An examination of the
cost curve {Fig. 1) will show
that the total cost rises much
more rapidly for values
above the critical value of
C than for values below it,
and this unduly increases
the cost of steel.

A stress of 600 pounds
per square inch has been
assumed as the working
value for the stress (com-
pression) in concrete, but if
another value be chosen,
say 750 pounds per square
inch, an equation connecting
C and P would be obtained
of th ■ same form as before,
but with slightly different,
values for the constants as
follows: —

where c=compressive stress (working in concrete psr square inch).

A'=ratio of the distance of the neutral axis from compressed surface to the
total effective depth d.

c has been taken as equal to 600 lbs. per square inch, therefore

/v[l-Hv]=|q^ (14)

Changing the value of c for a higher value of 750 lb. per square inch in com-
pression.

c .. , , . 750 •54P 202*5P

C = '^K{1

--,,._750 _

(15)
91

RO HI NT AN N. FRAM MIRZA.

[CQNQgETEi

Similar changes will require to be made in the value of .V in equation (10).
If wrought iron were used instead of steel,/ which stands for the weight of material
per cubic inch will have a different value in equation (10).

A few words should be said with regard to the deduction of equation C = ^~t^

which has been used
throughout for deducing
various equations. This
equation traces the rela-
tionship between C and
P, so that the compres-
sive value for C, that is
600 lbs. per square inch,
may not be exceeded.
The exact fundamental
equations indirectly con-
necting C and P are

C=|x(l-iX)andX=

V {p-'m' + 2pm) -pm,
remembering that P is
the percentage of rein-
forcement, while ^ is the
ratio of reinforcement,

i.e. p= •

^ 100

If these fundamental
equations were to be used
in the total cost equation
for deducing the eco-
nomic C by differentiat-
ing, the mathematical
working out and the
results will be so complex
as to be of little or no
use in actual pra.ctice.

While admitting that
a certain amount of
approximating has been
done, it must be remem-
bered that it has been
done with great care, so
that the final result is
not affected.

The equation of the tr)tal cost can be represented in terms of the depth of the slab
or the beam. Probably it is easier to do so than to represent it in terms of C, but while
differentiating to find the solution of the most economic d, it was found that the problem
became somewhat complex, and making the total cost a function of C helped to simplify
the conditions.

Pi^

2—

•-

■^

-3So

-r^

-ibc

-ato

^-f

.°>^
s-^^

~i»y

.^^r

-27o
-250-

■Viio

I70
-lio

0°^

^^^

"^ —

\ —

'w ^

^ v^

-So-
-To

-(^

. f "

09 R

tiNFORCtfvtt.'

'^ 1

VvS C

U/lVi

iorizo
bo

4,ca/
rita/S

Sca/e
ca/e

/ Cer

nflmd

ne -
e '

S Ur,

a. c

Vatcx

a«

> vn

y, C"0NyrPUCT10NAi:

THE niiST RATIO OF STHHL TO CONCRETE.

In actual practice the value of d can be obtained directly from etjuation (2), i.e.,
^ ~2C r '^ ^'^^ bendinf? moment due to weight of concrete is to be considered, or

(i= p if this is neglected.

»5o

FmS'.^

Evolving the value of li in the foregoing example, to give the mininnim total cost,
100 , aA^^O
^x^"*" "qr^~^"^"^"^^'^^~^*^"^ inches. It will be noticed that the increment

in depth due to the bending moment of the weight of concrete is 0"521 inches, and it is

very advisable to calculate the value of d, which includes this value.

'50
When C=96 7^=72 from the equation, P=.^^_^, aiud from the table on page 90

a curve can be drawn showing how the total cost varies with P (Fifi. 3). This curve

will show the percentage of

reinforcement beyond which it
is advisable not to go, except
at the sacrifice of considerable
expenditure. The curve gives
the costs both at 1*7 per cent,
of reinforcement and 0*25 per
cent, as ;^210, the minimum
cost being, as before, seen
from the curve £l88'6 at 72
per cent.

In conclusion it may be
useful to summarise the various
results here : —

(l.) There is only one
value of the ratio of reinforce-
ment which gives the total cost
of reinforced concrete slabs as
a minimum, and this total cost
depends on the cost of steel
and concrete, including labour,
fixing, etc., on the actual site.

(2.) It is not always econo-
mical to develop the full
stresses of steel and concrete,
for although it may give a
higher mechanical efficiency it
may be at a considerable
increase in cost, which is not
always acceptable.

(3.) Similarly there is one
definite ratio of reinforcement
which gives the cost of rein-
forced concrete beams as a minimum cost. This value depends on the price of steel,
concrete and centering, including labour, fixing, sawing, etc.

(4.) The value of economical ratio of reinforcement for beams is higher than that
C2 93

o-OOS oo\o oo\5

o-Qru>

ROHINTAN N. FRAM MIRZA.

ICQNCBETFJ

for slabs, on the assumption that in slabs very little centering or none is required for
its depth, while in case of a beam, the centering' required along its depth is an important
item. If a special case of slabs arises which require considerable centering with refer-
ence to its depth, then such slabs should be treated as beams.

(5.) If a high price for steel has to be paid, it is better to buy the material having
a high tensile strength, for if on a job the steel cost is likely to be 2 id. per lb. owing to the
use of special bars, and concrete cost were to be Is. per cube foot, then from equation
(12) C=74. hence/) = *0045, which means that /v=*31, and from the fundamental equation

mc A'

f — 1 _ 7- (and as C is COO lb. per square inch for concrete in compression), t the

tensile strength for steel per square inch will be 20,000.

(6.) Special cases may arise with reference to this subject, and many correspondirg
formulae may be evolved with little effort from the primary equations. The main object
of the mathematical investigation is lo suggest a method by which other problems of the
same nature may be tackled. For example, the fundamental equations assum.ed here are
nic K
f —Y—j{ ^"^ 1 - cbKd=pbdt (see No. 1 R.I.B.A. report, page 521), but some other

authorities adopt the following, assuming that the stress strain curve of concrete is a
parabola and not a straight Ime : ~f^Y^K ^^^ ^^^ chKd=ph.dt.

This means t hat in the first case A'= '^^W+2 pm-pm, while in the latter case,

This will naturally mean a slight alteration in the

•547^ 162 P

p_|_-5 or ^— p 1 .5 and finally in equations (11) and

h'='75y^ p')ii- ^2.66 pni—pm
deduced equations A' 1 — 3 A'
(12), but the difference will not be very serious.

/ J, t"ON.vri.'IK"IIONAl-l

REINFORCrin CONCRETE IN SAN FRANCISCO.

REINFORCED
CONCRETE IN
MUNICIPAL ENGINEER-
ING WORKS IN SAN
FRANCISCO, U.S.A.

Fig. 1. Reinforced Concrete I'umpiny; Station,
San Francisco.

E. R. MATTHEWS, A.M. In I.e. E.

F.R.San. Inst.,
Borough Engineer of Bridlington.

Some interesting examples of municipal
ivork in reinforced concrete ha've recently
been carried out in San Francisco, and ive
are able to gi've a few particulars and illus-
trations of this ivork in the subjoined article.
—ED.

The use during- the past few years of reinforced concrete in the municipal works
which have been carried out by the City Authorities of San Francisco has been
\ erv extensive.

Servers. — This material has been used with marked success in sewer con-
struction, and in a previous issue of this journal a description and illustration
of its use for this purpose in the construction of the Minposa outfall sewer were
g-iven.

Since that sewer was completed, the City Engineer of San Francisco,
Mr. M. MacShaughnessy, has put in other sewers in this material, notably the
Lincoln \\'ay sewer (see Fig. 3), and the Division Street sewer outfall (see
Fig. 2). The former is a reinforced concrete circular sewer with invert lined
with brickwork; the latter consists of reinforced walls and floor and roof slabs
forming three openings, through which the sewage passes.

The Kentucky Street sewer has also been constructed. This is an egg-
shaped sewer (except that it has a flat top), and is 2 ft. 6 in. by 3 ft. 9 in. in
size (see Fig. 4), and is a plain concrete sewer with l)rick invert and reinforced
concrete slab roof.

Reservoir Construciion. — The Twin Peaks reservoir, completed about
eighteen months ago, is one of the finest examples of a reinforced concrete
reservoir tO' be found. It is oval in plan, and is di\ided into two parts by a
reinforced concrete dam, for which purpose the material used is admirable. Fig.
5 shows a portion of the floor of the reservoir, and is a good view of the reinforce-
ment, showing preciselv the arrangement of same. The completed reservoir as
now being used is shown in Fig. 7. These photographs illustrate a \ery excellent

£•. R. MATTHEWS.

CONCB ETE]

Fig. 2. View showing Sewer Outfall Construction.
Reiniorced Concrete Sewer, Division Street, San Francisco.

I-i»<. 3. Sewer Construction
Kki.'iIokcf.h Concbktk Skwi k, LiNf;oi.N Wav, San I'"rancisco.

REINFORCED CONCRETE IN SAN FRANCISCO

piece of cnj^inccriiij^ work, wliirli rcllccts ^rcat credit on the Cily lui^inccr,
who (k'sij^iied \hv works :in(l suj)cr\isr(l llu'ir construction.

A r<w partic iii;irs rci^ardinj^' this inlcrcstinj^- rrscrxoir may l)e usciul to
tliosc of your rcackrs wlio arc interested in waterworks cng'inccrin^.

'I'he rescrxoir is 750 ft. ahoxe the business section of San I'lanc^isc^o, and if
part of tile hii^h pressure system for fire extin^uisliinj^" |)uri)oscs, estai)iished in
consequence of ihe terril)le fire of 1906. The reservoir is 370 ft. f)y 2H5 ft.

Fig. 4. View showing Sewer Construction.
Reinforced Conxrete Sewer, Kentuckv Street, San Francisco.

in area, and allows for a depth of water of 2'^ ft., or a capacity of 11,000,000
gallons.

One half of the reservoir may be filled while the other half is being cleaned
or repaired, and the buttresses are spaced at 9 ft. centres, and are uniform on
both sides of the division wall. They are i ft. in thickness and 13 ft. wide at
the base.

On the completion of the work one half was filled to a depth of 25 ft. 6 in.,
the other being used as an auditorium in connection with the opening ceremony.

E. R. MATTHEW'S.

ICONCKETE]

Before being- filled, ihe reservoir was washed down with cement by means
of a cement *' g-un " ; this waterproofino- operation took eight days, and the
work was executed by the Pacific Cement (iun Co., of San Francisco.

Fig. 5. View showing Reinforcement.
Ki.iNiORrED C<jncrkte Rkskrvoir, Twin Peaks Reservoir, San Francisco.

I IK. G. Vitw of J'tiinpiiiK .Stati(jn in course of ccnstruction,

RKINIf>IU;KI) CONCRKIK I'l MI'INO SlATION. SaN FrANCISCO.

A^^S?.S£al^ RI^: IN FORCED CONCRETE IN SAN FRANCISCO.

E. R. MATTHEWS.

riant reinforced concrete work

been erected in the

^ »! II III III III Ml

Ik Ilk At ^k

ipri iRff flHi ilBI

.^^

Pig. 8. View showing Finished StriicUirc.

REINFORCKD CONCRKTK PfSMMNO StAT.ON. SaN FkANC.SCO.

and rcprcH-nls some cxrHl.nt ;.n Inf. , u,

:,1 uork. Fiv;. 6 shows the interior

and rcprcH-nis sonn . -n ,.,»„mru(Miun /mV. 8 shows

view of the machinery room m .ouisr ol .onshudum. ^

the

lOO

l^lNoiNhKRTS^g] RBINFORCED CONCRETE IN SAN FRANCISCO.

C()ni])li'li'(l slriicliiic, iiK'IiKiinL; tlu' rcinlorccd {-oncrt'lc' rhimncN-. {"i^s. i ancl 9
s)u>\\ tlu" l)uil(lini4' in course ol iTi'ction.

'I'lu' MUlIior would, in coiKlusiou, expicss Iiis inrlcljlcdncss to the City
I^ui^inrc-i- of S;in P'rancisco, Mi-. MacSh.iuj^'-hnc'ssy, for his l<indiu-ss in sending
hini ihc j)liot()i4raj)hs of llu'si- iinportanl \\()r]<s and for j^ixin^' him llic j)ri\ilege
ol rc'])roducini;" tlirni.

lie would slate that, in his oj)inion, reinforced concix'le is ihe best material
to use in reserxoir and cuherl construction in {his country, as well as in
countries subject to earthquake shocks.

Fig. 9. Building in course of construction.
Reinforced Concrete Pumping Station, San Francisco.

TOI

THE IXSTITUTIOS OF CIVIL ENGINEERS.

ICdNCBETEl

UMKUU

THE INSTITUTION OF CIVIL
ENGINEERS & REINFORCED
CONCRETE.

Second Report of the Committee on Reinforced Concrete.

In Volume V, of this Journal— October, No^)ember, December, 1910 (pp. 703, 707, 798 ana
880) — loe dealt 'very fully ivith the Interim Report of the Institution of Ci%>il Engineers
regarding Reinforced Concrete, The Second Report has noiv been issued, and although
someiv'jst disapDOinting as a ivhole, such points as are of interest in the report and ivhich
call for attention are dealt ivith in this article, the first part of Tvhich appeared in our
December issue. Giving to lack of space this article had to be omitted from oar January
issue, — ED.

CALCULATIONS FOR REINFORCED CONCRETE.

The calculations for reinforced concrete are dealt with in Memorandum F, and the
statement was prepared by Mr. F. E. Wentworth-Sheilds and Professor J. D. Cormack,
D.Sc, and generally speaking we find that it is somewhat disappointing. The notes are
incomplete and appear to be a repetition of portions of the Second Report of the Joint
Committee of the Royal Institute of British Architects, whereas we should have looked
for more originality in an Institution which refused to co-operate with other Societies,
and certainlv there is a lack of completeness and authority which is surprising when
the status of the Institution is considered. The usual assumptions were made in
deriving the formulae, and these were as follows : —

(i) The stresses in both steel and concrete are proportional to the strains (straight-
line theory). In other words, the moduli of elasticity are constant for both
steel and concrete, and hence the ratio of the moduli is const.ant.
(2j A plane cross section remains plane after loading. In a piece subjected to
bending this means that the strains in both concrete and steel are proportional
to the distance from the neutral axis, and hence from assumption (i) — the
stresses in l^oth concrete and steel are projjorlional to the distance from the
neutral axis.

(3) The tensile strength of the concrete is considered to be zero.

(4) 'Ihe stress in a reinforcing bar of small section is considered as uniform over

the whole section.
In addition, it is usual when designing to assume that :

(5) The initial stresses set up in concrete and steel owing to changes in volume of

concrete while setting are zei'o.

{()) 'Ihe stresses set up in concret(; and steel owing to changes of teni])erature are
zero, |>r(n'id((l the whole j)iec(' is free to expand or contract.

The ("omiiiittee ,'ipj>ear to l);i\'e l.'ikcn a great deal of Irouhlc in tr\ing to pro\'e that
these assumptions arc not strictly true in .ill cases, and \( 1 tli<y adopt I hem and have
no suggestions or recommendations to offer which aic the outcome of their lindings. In
dealing with the value of lis/ Id the siatenieiit is m.ide th.it this \ ai ies from 10 to 15,
but as a matter of f;icl it will be found to \ary e\iii more iIkhi this, and no mention is
mad(; of the influence cjf the r<inforcement such as we lind in ihe Report of the 1^'rench
Commission dii CinienI Anne, where it is staled that it is preferable to regard the
co-efficient as the result of experience on pieces with longitudinal and tiansverse rein-
forcement, and not as re|)resenting the ratios found from concrete and steel separately.

102

X'Soi™?iRg^'] report on reinforced concrete.

The results of lists on rciiiforccil hcains as ohsciNcd arc such ihal llicv aj^rcc with the
position of the neutral axis as found by usinj^ the value of Its / Ec= iz,, but there is a
certain vai^utMiess in tlu- manner in which tile notes of the Committee are jjresented
that has the effect of Icaviui^ the icader rather uncertain as to what is really recom-
mended. It is stated that (he icsuits obtained by assiuiiin^ )}i .1. m are in most cases
rather safei than if )ii 15 is assumed, althouj^h the majority of countries make the latter
assumj)tion. We assume that the latter fact accounts for tlie Committee adoj)lin^f a
value which ai)|)arenlly does not quite coincide with their own deductions.

b'ollowini; llu' assum|)tions that are ado|)te(l and the reasons for and aj^ainst such
assumi)tions, ten formula.' are t^iven for beams and columns which are stated and
obtained in the Second Rej)ort of the Joint Committee on Reinforced Concrete appointed
by the Royal Institute of British Architects, and some notes are then j^iven on
deflection.

Despite the importance of the subject, we notice that no recommendations are made
with reference to the values of the bending moments for fixed and continuous beams
and slabs under different conditions of loading, and there is some difference of oj>inion
on this question amongst engineers. It must be considered a great oversight on the
part of the Committee, who appear to commence in the middle of the subject, and
omit all consideration of those points which are the first to be dealt with in actual
design. It appears to us that some useful work might have been accomplished in this
direction, whereas the whole question has been entirely neglected.

The few general notes that are given in the calculations do not appear to be of
much value, and the Second Report of the R.I.B.A. has been drawn upon to such an
extent for the formulae which are stated that very little credit can be given to the
Committee of the Institution of Civil Engineers. Surely there is still a large field for
investigation which is open to a committee of this kind, and assuming that thev
approve of the work already done by other Institutions, this could be endorsed, and
attention devoted to the consideration of those matters which are at present in a more
or less unsatisfactory state. There is the question of the frictional stress between
concrete and steel which has not yet been sufificiently investigated, the bending moments
for continuous beams, the design of column foundations, the question of eccentric
loading on columns, and many other items which might with advantage be dealt with
and investigated thoroughly, with a view to deducing some reliable information which
would be of value to engineers.

Following the notes on the calculations are various tables giving in a brief manner
the results of some experiments made in France, Germany, the United States, and
Great Britain on columns reinforced in various ways, and comparing the calculated
safe loads with the actual loads required to cause failure. These results indicate that
the R.I.B.A, formula is quite satisfactory, and the notes attached and explanation of
the tests and the results are interesting, and indicate the range of experiments, the
manner of failure, and the effect of the longitudinal and lateral reinforcements. The
experiments conducted in Great Britain include those carried out for H.M. Office of
Works by Messrs. Kirkaldy in 1908-9, and described in our issue for March, 19 10, and
those carried out by Mr. \V. C, Popplewell at Manchester, 191 1, a copy of this table
being here given.

REPORTS ON WORKS EXECUTED.

The reports on works executed, which are contained in Memorandum " J," cover
a variety of structures in various countries, and they deal with the nature of the
structure, the age, external influences, general condition, materials used, and failures
or deterioration. Many of these reports are quite interesting, and they tend to show
in which direction failure or deterioration generallv occurs in the actual work, and
therefore the notes should be of some value to engineers.

103

THE INSTJTUTIOX OF CIVIL ENGINEERS.

ICQNCBFTFJ

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lire columns, gross area 30
both ends of column enlarge
inches. Longitudinal rein
Proceedings Inst. C.E., vol.

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104

f.^cousvmK'vioNAii REPORT ON RHINFORCIiI) CONCRETE.

/\. E-N01NKI-R1NC-. -- I

W'c ha\(' (Ir.'.wn upon the Report by quolin^ sonic of the icporls j^ivcn of work
cxocutcd abroad.

W'c <4iv(' Inst two New Zealand rxanipUs ; one a ntainin-^ wall, and the second
sonic reservoirs and tanks.

Retaining Wall at Miramar, New Zealand.
This report is presented b\ Mr. James Marchbanks, M.Inst.C.l^., and reads as
follows : —

General Descrifticn. — A wall in reinforced concrete, 1.430 ft. in length, erected on
the sea coast, partly serving as a retaining wall and partly ais a parapet, with foundation
at mid-tide level. The work has only recently been completed from the designs of the
author, and shows signs of vertical expansion cracks. No details of cost are given.
/. Age. — The wall was built in igio-ii.

//. External Influences. — As the average rise and fall of the tide is 4 ft., from
2ality. The Portland cement used was manufactured within a few miles of Allentown ;
the stone used was limestone. The proportion of aggregate was i part of cement, 2 of
sand, and 4 of stone. The pieces of concrete taken from the injured beams w-ere as sound
as that of the uninjured portions of the beam, no api)arent change having taken place in
the concrete.

Failure or Deterioration. — There were about 3,000 lineal ft. of beams ancl girders
showing cracks, and from some the whole lower surface of concrete had dropped oil,
leaving spaces between the rods and the uninjured portion of the beams.

Where the beams were damaged the most the intermediate floor slabs contained no
cracks, the reinforcement not being electrically connected with the beam steel.

The rods and stirrups were completely surrounded with scale of iron o.xide ranging
from 1-16 to i in. in thickness. Some of the stirrups were completely destroyed and only
oxide remained in their place. The oxide taking up a larger space than the iron caused
cracking and fiaking-oflf of the concrete. The concrete where ruptured had the same
appearance as it would if split with wedges.

There were some concrete piers containing no steel under the cooimg-pipes in the
cooling-room ; these were partially destroyed and crumbling.

Remedies.^ — Since the publication of Mr. Brown's article further investigations have
been made, and the following remedies have been carried out : —

The water, gas, and sewer pipes have been insulated just inside the building wall in
the basement. The sockets in the beams and girders have been connected by return wires
which lead to the dynamo and terminate in an indicator board, each room having a drop-
indicator. In case of an earth the indicator gives a warning, and the difficulty can be
corrected. If it is not corrected at once the lights are automatically dimmed.

Re-pairs. — In repairing the beams all loose concrete is removed, and the concrete and
steel are thoroughly cleaned by sand-blast. After this is done i-in. boards are clamped
to the sides of the beams to be repaired, and cement mortar to which a waterproofing
compound has been added is blown on the bottom of the beam by compressed air. The
trade name of the waterproofing material is " Starex." It is added to the mortar before
placing in the machine.

The bond between the new mortar facing and the old concrete is perfect, and the new
material is very dense and shows no shrinkage cracks whatever. Mortar applied without
the waterproofing substance showed shrinkage cracks and did not adhere to the old
concrete. The machine used for depositing the mortar is a new and ingenious apparatus,
and is doing ver}' excellent work.

The old conduits have all been removed and new ones placed which are insulated from
the structure. All junctions and joints being made waterproof.

The structural details of the buildings are apparently of good design and the work-
manship of construction is of the best, and the failure is not due to any such defects.

* H. P. Brown, Engineering Xeus, Vol. 65 (igii), p. 684.

t Ihe electrical tests are described in Mr. Brown's article. Experiment' indicating the relative
effects ot alternating and direct current, etc., on electrolysis of reinforced concrete were given in a
Paper by Mr. H. Barker and Prof. W. L. l^p>-on. Convention of .American Institution of Electrical
L-ngineers, June, 1911.

D 107

HYDRO ELECTRICITY WORKS, CHESTER.
C O

la)NCBETEJ

CONCRETE AND RE-
INFORCED CONCRETE

AT THE

HYDRO ELECTRICITY

WORKS, CHESTER.

The a}K)ve works are erected upon the site
of the old Dee Mills, which were in opera-
tion from about i too to 1909. The old
mills were erected upon the bed of the river,
which is of sandstone rock.

I-'or the purp;)se of the H\(lro Electric
Works it was necessary to excavate the
rock in the head race to a depth of 5 ft.,
and l<jr the draught tubes of the turbines,
to enable them to discharge into the lower
river, the rock was ex<\'i\aled lo a depth of
15 fl.

J he under-w alcr work forming" the
foundations for ihc turbines and the walls
ior liie turbine jjils are of concrele, slren*^-
thened by ^-in. diamclcr reinlorcinj^' bars,
as shown on the ^ciu ral arran<4cmcnt here-
with.

'Ihc j)i'0|><>ri ions for the, concrete are six
to <;ne, loiu' |jarls •iJ^'J^re^atc, Iwo j)arls
sand, and one |);ii'l (cmcnt. 'I lie ccnicut
used is of the best f)uali!\ I'orll.md c( nicnl,
of British manufaclurc, and in accor(lan<c
with the particulars of I lie Hriiish .Standard
Specification So. 12 foi nicdiuni scltinj^
cement.

108

An interesfing example of the usefulness
of reinforced concrete and concrete in electric
plants is that of the ivork recently carried
out in connection 'with the neiv Hydro
Electric Plant for the City of Chester, and
of "Which ive gi've a feiv particulars belonv.
We are indebted to Mr. S. E. Britton, City
Electrical Engineer of Chester, for our par
ticulars and illustrations, — ED.

\ icw sliowirifj K(;inf()lciIl^^ Hais in i>osition for
tli(; firsticourse of Concrete.

TiiK Cm.sTi'.K Hydro liLixTRiciiY Wokks.

r o, OON>TUlJrilC*«UlJ
|.<V ENCUME.tJJlNC'1 -^

HYDRO ELECTRICITY WORKS, CHESTER.

V\\v .s.iiul UM'd is cli'nn, sharp, and coarse ri\iT sand, comiKJScd ol grains
\ai\ inj; in si/c which pass ihroui^h a J -in. s(iiiart* nu-sh.

I he ai^i^rci^atc lor ihc ])lain t'onciclc is ol l)rol:('n I'cnniacnniau r and
C'arroLj- stone, xaryinij' in size from h in. lo i .^ in. (uhes, and tlie aj^greg^ale for
the reinforctment \aries in si/e Ironi '; in. to { in. cul)('s.

View showing s:eel joists in Power House.

View showing concreting of steel joists in floor of Tuibine Pits.
The Chester Hydro Electricity Works.

The power house walls are of red sandstone, lined with glazed brick.
The roof of the power house is of reinforced concrete on the Kahn System,
details of which are shown on the general arrangement drawing referred to
above. 109

HYDRO ELECTRICITY WORKS, CHESTER.

[CDNCBETB

c;^^^^.^:^^^^^

I lO

f y, CONM kMKTIONAl.

HYDRO ELECrRlClTY WORKS, ClIItSTER.

The i)()\\('r h>)usr is <S() ll. loni; 1)\ J4 I'l. h in. wide, aiul, iiicasurcd from
ihc 1)1)1 loin of llu- head raii', 3*) ft. liiL;h. It i.s mainly constructed of steel

View sh owing concreting of Turbine Pits.

View showinL" concreting for Turbine Pits and steel work for Sluice Gates in position.
The Chester Hvdro Electricity Works.

and concrete ; ihe exterior is faced with sandstone rock and the interior with
glazed brick. The foundation is on sandstone rock. The under-water work

I 1 1

HYDRO ELECTRICITY WORKS, CHESTER.

CQNCBETEJ

forming- the head race, the three turbine pits and the tail race are of concrete
and steel. On the external face of the down-stream side of the turbine pits
are placed three cut waters and Gothic arches, these and the filling-in of sand-
stone to harmonise with the adjoining bridge. The external of the above-
water p;irt of the building, including the dynamo, switch room, and stores,
is in sandstone, and contains twelve pairs of Gothic windows ; the interior
is lined with glazed brick. The building is covered with a flat reinforced
concrete roof covered with asphalte. There are three circular glass domes
in the roof, which admit of ample light and add to the general

Cross Section through Turbine Pit.
The Chkstkk Uvdku ELKcrtJiciTY Works.

beaulv <jf iht; l)uil(ling. I lie retaining wall bclwccn the biidge and the
power hou^e and 121 ft. ol ri\er \\all beyond the powci- house has
been entirely rebuill in ashlar, uilh sandslont; taken from the foundations of
the <;ld mills. 'I hat part oi the old bridge \\hi(-li stands in the head race and
former! [)art of tin; old mills has been restored, so as to liaiinonise with the
general character of tiu- bridge, and a glance ;it the undertaking at once
impresses one with the amount of ilioiiL;lit iM\ol\((l in carrying out this scheme
and the improvement to the ;inicnities.

A number of plu)togra|>liic iiliist i-;it ions :ii-e gi\cii in this article showing

1 I 2.

*»coivyrpuc-riaNAL;

±y KNdlNKI.klNO — ,

lirnRO ELECTRICITY WORKS, CHESTER.

View showing concreting oi Draught Fubes.
The Chester Hydro Electricity Works.

llu- concrcic .iiul rcinlorctnl corKTcIc
work. Tlu-y iirc ;is follows :

(i) I lie lornuTs in iK>.sili()n icady l-ir

(-') 'IIu- siindslonc f.icin^'- of ihc
(low M-slrciiin w.ill of \hv. j)o\vct Iiousl- ;iii(1
the slu'C'tini^- ;iii(l reinforcing- bar.s in posi-
iion lor the (irsl ( oursv of concrete for
ihc walls of llu' turbine jjils.

(3) Sk'cl joisls in llu- power house
lloor lo (-arr\- I he turbines and j^enerators.

(4) Concreting- steel joisls in floor of
turbine pits to carry the down-stream
wall of the j)()wer house.

(5 and 6) Concreting- for the turbine
•pits and the steel work for the sluice
g'-ates in position.

(7) The draught lubes being con-
creted and the reinforcing bars being
placed in position.

(8) A wooden draught tube former
being lowered into position.

The contractors for the building and hy-
draulic plant are Messrs James Gordon and
Co., Knighlridcr Street, London, K.C.

Showing Woodan Draught Tube Former being lowered into position.
The Chester Hydro Electricity Works.

i'3

REINFORCED CONCRETE WHARF, ILOILO.

ICQNCKETEJ

'MS^^^^

A REINFORCED CONCRETE

WHARF WITH GROUTED

FOUNDATIONS; HARBOUR IMPROVEMENTS AT

ILOILO, PHILIPPINE ISLANDS.

The folloiving is an af^siract from an article by Mr, Wilson T, Ho'cve (formerly Assist.
Ena'neer, Division of Port of Works, Bureau of Naiiigation, Manila), which appeared in
" Engineering News," U.S.A., and ii'e are indebted to that journal for their courtesy in
according permission for the reproduction. — ED.

The citv of Iloilo is situated on the southern coast of the island of Panay, about 330
miles south of Manila, and is one of the five ports of entry in the Philippine Islands.
The principal export is sugar, which is shijjped to Chinese ports and to the United

States.

FACILITIES.

The harbour of Iloilo comj)rises the Iloilo River and Iloilo Strait, the latter beini:^
a good anchorage at the mouth of Iloilo River, and protected by the islands of Panay
and Guimaras. Previous to the |)resent improvements nearly all the foreign cargoes
were handled bv lighters betwc en the ships in the Straits and the warehouses on the
river.

Iloilo River is not a river in the strict sense of the term, but is a tortuous tidal
estuarv, the lower 9,000 ft. of which is navigable and available for shipping. This
portion is in the shape of a huge letter S, and naturallx divides itself into three reaches,
each approximately 3,000 ft. in length. In former times the lower reach was merely a
channel through tide flats, but at various times in recent years this reach has been
inif^roved bv dredging, the material being deposited on the banks on either side, until,
at the present time, it exists as a ddinilc stream, 400 to 500 ft. in width, llowing between
permanent banks and discharging into Iloilo Straits between two ri|)rajj jetties.

The onl\- dr)cking facilities available previous to 1908 were on the middle reach of

the river, where most of the warehouses are situated. A marginal street, varying

in width from V' '^' ^''^ ^^■•> '-xt'-nded the whole length of this re.-u h, and it was sujjported

on th<; river side b\' a light adobe-stone retaining wall founded on the natural soil at

about low-tide level, and, eons<-c)uently, onl\ light irafl (ould moor directly alongside,

steamers being obliged to stand off, and passengers and cargo handled over long stage

planks betwren the wall and sjii],. The (Icplh on ihis reach was from 15 ft. to iS ft.

at low tide.

IMPROVEMENTS.

The first intprovem<'nt at Iloilo und<i llic Ann rican occupation was to dredge the
middle and lower reaches to |S f I . at low wal< 1, using the dredged mateiial to fill low-
land on the left bank of the ri\<r, o|)|)osiic the ( ily, and an area on ihc right hank on the
lower r<a(h, retaining the fill and |»rol<(ling the river i liann<l hy (l\Ues of small ri|)rap
sionc {I'ul. I) and building ripraj) jellies on either side of liir rixcr at its mouth. The
fill ,,p ij,,. left hank of the lower reach is now occupied l)\ llir Iloilo terminal of the
l'ana\ Division of ilw l'liili|»pin<- Railway ConipaiiN, a line 70 miles long, terminating
at Cai)!/., on the noiili coasi of the island ol Tanay. Tlw opposite fill has become a
valuable site foi- wart-houses.

C-ON.vrUn KTION A 1
V b.N( • 1 N KL-WtNCi —

REINFORCIin CONCRETE \VIIARl\ ILOII.O.

Fii^. 1. Stone Dyke Backed by Mats of Split Bamboo.
Harbour Improvements, Iloilo, Philippine Islands.

'Vhv pit'sciit ini|)r(.\timnt, iiiuli rt.iUcii in i()(.S, coiilciiipl.ilcs ;i ddinilc (1( \< lopniciU
ami i)r()viilcs .i 15-tt. d. ptli .il low w-iI'T in ihc u|)|)«i- i(;i(li, iS fl. in llic niiddlr r<;i(li,
and J4 ft. in the lower H'nch. 'ihc ciiiirc rixcr w.is dcixiK d lo lh(s<' li^uics in kjio.

TImsc d(|)tlis a I «•
prohahlv ihf ^rcalcst
which il is advisahh-
lo altcnij)! lo main-
lain in lh<' rc'^pcctivt:
reaches.

T h (' material
dredi^ed from t h e
river at this time was
used to extend the
|)reviously lllled areas
owned b\ the Insular
( jovernmenl, and lo
improve several low-
1\ in<^ areas wilhin the
city, and also to re-
claim a considerable
area of beach on the
left bank of the river,
frontini4 Iloilo Straits
and adjoinin<4 the
railway terminal. It is proposed to develop this area by buildinij a series of docks and
slips where steamers drawing 30 ft. can berth, and to lease the property for warehouses
or other puri)oses at the proper time.

QUAY WALLS.

For the quav walls a retainini^' wall was first built, but was later followed by a
reinforced concrete wharf.

CONCRETE
RETAINING WALL

The second step
of this improvement
consists in the build-
ing of suitable quav
walls along the river
as funds become
available, and t h e
most urgent require-
in e n t was the re-
placing of the old
wall on the middle
reach by a n e w
struct ure approxi-
mately parallel to it
and in front of it,
alongside of which

vessels drawing 18 ft. pjg 2. old method of Loading Su^ar : ' uan-gom?; Steamers,

could lie at all stages Harbour Improvements, Iloilo. Philippine Islands.

of tide, at the same time providing a marginal street with a uniform width of 80 ft. the
whole length of the improvement {Fig. 3).

»'5

REINFORCED CONCRETE WHARF, ILOILO.

ICQNCBETEl

A contract was let by the Insular Government for the construction of a gravity-
concrete retaining wall upon timber piles, but after doing a very small amount of work
and making unsatisfactory progress, the contract was annulled, the contractor's plant
purchased, and the work was comj)leted by Government administration.

When this length of retaining wall had been completed a point was reached where
the wall type of construction was becoming more expensive and troublesome on account
of the proximity of the old retaining wall. The new wall has a bottom width of 15 ft.
at the depth of iS ft. below low water, and as it was necessary to dredge to that depth
and width, the bank slope was not able to carry the old wall and the street behind it
without considerable expensive shoring, and it was desirable to leave the old wall and
its well compacted fill intact if possible. The marginal street is occupied its whole
length with storehouses and offices, and carries a heavy traffic, which could not wholly
be diverted during construction, and it was therefore essential to so conduct operations
as to leave the street in use.

Fifi. 3. Completed Quay and Marginal Street along Iloilo River.

HaKIJOI R ImI-KOVKMKNTS. iLrill.O, PlIILII'l'INK ISLANDS.

REINFORCED CONCRETE WHARF.

Plans were accordingly jHcparcd f(jr a icinlorccd concrete wharf structuic which
would take advantage of existing conditions to their fidlesl extent. The wharf
consists ess(;ntiall\- of a series of transverse gir<iers spaced 10 ft. apart, carrying a 12-m.
reinforced concrete floor. The outer ends of the girders are supjjorted upon reinforced
concrete columns 24 in. in diameter and H) It. S in. long, cast in the \ard, and s(>t in
place with a derrick upon a prei)are(l timber |)ile footing 17 ft. S in. below low water.
The inner ends (A the girflers are (arried h\ con( icte pedestals at 2 ft. ;iho\'e low water,
built against the old wall and carried onl\ to the natural slope of the hank.

Rear Fooliuf^s.- ICach rear pedestal is suppoitrd l)y from lour to six timber piles,
at least two of wlii<h are dri\-en on a halter, the heller to resist any hoii/.ontal thrust
that may come from the old wall. I his group of piles is diixcn to a total bearing of
So tons it h( ing alwa\s desired to drive each j)ile to 20 tons if possible, but as it was

116

fc,,ooN>Tync-rioNAii RHINFORCHD CONOR HTE WHARF, ILOILO.

froqiUMilK ini|)()ssil)U' to secure piles of suflieit iil It iij^lh lo (ievelo|) tliat he.irinj^, ( iiou^h
extr.i piles were Mdcled to insuic the lol.il n tjiiii<(i hearinj^ |)owei- per ^loup.

These pedest.ils \;ir\ in si/e .iiid position .leeordini^ to the .di^nnienl of th<' ol<l u.dl
.'ind the luiinher of piles necess.iry |)er i^i'onp, hiil the si/.e was usually dependent upon
the position of the halter |)iles whieh were dii\-en as close to the old wall as the leads of
the dri\'er in the hatlt red position would allow. ( 'onneetinj^ tlu' pedestals is a concrete
curtain wall j fl. in thickness, which serxcs to strengthen the old wall. The curtain
wall was huilt to the i^rade of the pedestals monolithic with them; al)o\c that i^rade
it was poured at the same time as the i^irdeis and lloor.

Fro)}! Fooliiii^s. — The most intei'estinif and important featuic of the work was th(;
construction of the front foundations, 'idle outer edj^e, or front of the wharf, as stated
above, is carried h\ the lin(> of reinforced concrete columns, spaced lo fl. a|)art, one
under th(- outer end of each of the transverse f^irders. This line of columns is so j)laced
as to i;i\'e a imiform width of street from the front of the wharf had-: to the huildinj^
line of 80 ft., and as there was considerable variation in the old street width out to the
irregular lin(> of the old wall, the sjjans of the main girders vary from 20 to 27 ft. The
latter length was the maximum nominal sj)an allowed in the design.

Each column is carried by a cluster of piles whose total bearing is not less than
60 tons. It was attemi)ted to drive each pile to a bearing of 20 tons, and this was
usually obtained, but often four piles, and sometimes five, were required. The reason
for requiring but 60 tons per grou]) in the front footings while those in the rear were
expected to develop 80 tons was due to the fact that it was uncertain what loads might
come to the latter through the weakness of the old wall, and which those piles would
have to carry in addition to the direct load from the new structure. When only three
piles were required they were driven at the apexes of a 20-in. equilateral triangle.
When four piles were necessary they were driven at the corners of a 20-in. square, and
if a fifth pile was required it was driven in the centre of the square. It could usually be
foretold how manv piles would be required for any column by the penetration secured
in the last cluster driven, and if the number were under-estimated those driven were at
once sawed off at the proper grade, their positions carefully located by plumbing above
the surface, and the additional pile needed was then driven in the most favourable
position to give good s])acing in the cluster. Since it is seldom possible to drive a pile
to the exact location required it was necessary to use more than ordinary care in spotting
these piles, and to hold them during driving, in order to keep them within proper limits.
Frequentlv after locating the driven piles it would be found that one or more were
so far out of position as to necessitate the driver returning to put in extra piles, those
too far from line being excluded entirely from the foundation.

After the piles were driven and cut off they were enclosed in a circular sheet-iron
casing, re in- metal, usually 54 in. in diameter and 4 ft. high, so placed that its top
w^as 2 ft. above the pile cut-off. To support the casing on the bottom it was necessary
to throw small riprap stone around the piles until a firm bottom was made. To set
the casings a wooden frame was provided, 4 ft. square and 22 ft. long, to the bottom
end of which the casing was fastened with wire. The frame, or template, carrying
the casing on its low^er end was then picked up by the derrick and set in place, a diver
guiding the lower end to ensure that the casing was at all points at least 6 in. distant
from the side of any pile, while the top, being always above water, was directly under
observation for line and grade. A gauge, with its zero mark 16 ft. above the top of
the casing, was fastened to the frame, so that at any stage of tide the casing was
easily set at the proper grade by noting that the gauge on the frame read the same
as the water height on the permanent gauge.

After the casing was set to line and grade, concrete was placed in it by means of

117

REINFORCHD CONCRETE WHARF, ILOILO.

[concbete;

a canva. bag openin- ai the bottom, to a point 6 in. below the tops of the piles When
the concrete had set a diver cut the wires holdin.^ the casing to the frame and the latter

was removed. , , j i

Grouted FounJatious.-^Whvn ihr column was about to be placed gravel was
deposited in the casing to the grade of the bottom of the column, and the latter was then

Fig. 4. View of Completed Reinforced Concrete Wharf.

i-iK. J- \i<:w Slii»wiii^i lii .1111 :.ii<l I lour KuiiifoiceiiKMil.
HakhouR Imi'KOvkmknts, li.oii.o, i'liii.ii'iiNK Islands.

(arcfulh s<l to line and gra.lc and br;i( < <1 to the falsework, it icsling meanwhile u|)()n
the gravel in the casing. Thin ( emeni -^roul was then poured iiilo the gravel through
a i-in. i)ip<- (arrying a funnrl at its upp. r end. .\s no pressure was used to force the
grout into the gravel except the sialic h* ad Ix l\\e( n the surface of the water and the
upper end of thr- pi|)e, whidi was never gi eater than about S ft., it was found necessary
to move the pi|>e around aixl grout at dilferent points in the L',r;i\el to insure that the
gravel was thoroughly (eniented. .\fter the gravel iirst placed was thus grouted,

Il8

'o, CTONyiVUCTlONAH

REINFORCED CONCRETE W/IARE, ILOILO.

more i^i;i\rl was dcposiltd aioiiiid (he column to luaUc a la\tr ahoiil i It. tliick, wliicli
was then i;rout((l as Ixloif. It was found necessary to thus j^rout the j^raN'el in lavcrs,

hecause in atteinptinj^ to force the
^routinj^ pipe throuj^h any considerahle
thickness of gravel it became cloj^j^ed,
.:^^ and Ihc pressure was not ^real enou^l''
to clear it. When the casinj^ had hec n
lilled with concrete in this mannei', and
had sei at least t went \ -four hours, tlv
liolJoA interior of the column was
punijx d free of water, and then lilletl
with concrete. The jnnnpin^ of the
interior served as a test of the j^routin^,
for if any part of the gravel had not
been thorou<^hly scaled, water would
soon ha\e appeared inside the column,
and indicated defective work. All the
columns were easil\- pumped b\' a small
hand pump, and remained dry for an
hour or more, before fillini^' with
concrete.

This method of building these foot-
ins^s was entirely satisfactory in everv

Fig. 6. A Reinforced Concrete Mooring Post.
Harbour Improvements, Iloilo, Philippine Islands.

but on account of the richness of the
concrete, and the unavoidable waste,
due to some of the grout escaping, it
would be expensive in a very large
mass. In this case, where it was neces-
sary that a perfect result be obtained,
several advantages are apparent. It
obviated placing concrete under water,
and it excluded the necessity of pump-
ing and the coffer-dani method, which
would have been out of the question
for such small foundations.

The setting of the columns was
rendered simple, as they were placed
on the gravel in the casing, and so had
sure support during the operation of
filling the casing. The difficulties of
setting columns on a bed of green con-
crete under water must be evident. The
manipulation of the column while
attaining line and grade would so
agitate fresh concrete as to cause it to
separate, or it would be necessar\" to
support the column from above and
then bring the concrete up to it. In
the method described the column was

way, and there are probably man\
similar cases where small well-confined
foundations can be similarlv treated,

Fig. 7. Concrete made under water.
Harbour Improvements, Iloilo, Philifpine Islands

119

REINFORCED CONCRETE WHARF, ILOILO.

ICQNCBETEJ

lowered directly on to soft gravel which- had previously been brought to the proper
grade. If the column proved to be too low it was raised slightly and more gravel
poured through the interior of the column. If too high, the column was dropped upon
the gravel to compact it, or it was twisted and moved to work it into place and nothing
was disturbed thereby.

That good concrete was made by this method was proved by experiment, and it
is thus described in a report made at the time :

An empty cement barrel {Fig. 7) was lowered into the same depth of water in which
the footings are made, gravel placed therein by means of a 6-in. pipe to a depth of about
S in., and then the grout |)ipe inserted into the gravel, care being taken to have the pipe
coincide with the axis of the bariel. The irravel was then grouted in the same manner as is

done in the foundation,
more gravel placed in
the barrel to the depth
of about 12 in., and
more grout poured, and
so on until the barrel
was filled with gravel
and grouted. The
sample was taken from
the water after about
40 hours, the barrel
was cut away, and the
result was an entirely
satisfactory block of
concrete. Some very
small pit holes ap-
peared in the surface,
but as a whole the sur-
face was as smooth as
is generally obtained in
ordinary form work.
The result shows that
the grout will flow
freely for at least 8 or
9 in. in all directions
from the pipe. Eight
buckets of grout were used in the barrel of gravel.

Backfill.— After the columns were set, riprap was placed along the front line of the
wharf to a depth of 16 ft. below low water, and the slojx- back-filled to the tops of
the rear foundation bUnks with rijHap and mud. The latter was to insure that the
piles supporting the blocks would ]>c fully j)r()lected from teredo, while the rii)rai) was
to make a stable and f)ermanent slojx- and to |)re\-ent scour.

Superslnnliirc. The construction of the supersliiiel m c olTcred no unusual
problems and followed th<- usual jjracliic in reinforced coiKrele. A len<^nh of 20 ft. of
wharf, or two sjK'ins, was made at e; eh o|)eralion, joints being broken in the centre
(A the llrKM- sjn-nis, a portion of the slab being figured to .k l w ilh the girders as a T-beam.
.\t expansion joints ihr- break was made at the (dge of the girders through (he floor
thence along the rear side of the spandK I ,ind ihrongh the (cnlre of the arch. The
concrete nuxjring frosts il'i^. 6) were cast in placr at I lie same time as the wharf lloor.
They are hH:al<d Oo ft. apart the whole h n^ih of the wh.irf. Mooring posts of concrete
have been used at various places on work done in the Philippines, and have proved
satisfactory. .As each niof)ring post contains less than one-third of a cubic ^ard of
concrete, and about 100 lb. of reinforcing steel, they aie nuich cheai)er than the ordinary
cast-iron posts or cleats.

F(ils('7uork. The whole consti ik lion was carried out b\ the use of falsewoik
Bents of three; or f(;ur piles each, as lecjuired by circunist.uices, were driven to i«rade
I 20

Via. 8. View of Pile Driver.
Harbour Improvements, Iloilo, Phimpi'Ink Islands.

^^'SGf™?iK?t3 REINFORCED CONCRETE WHARF, ILOILO.

U) fl. a|);ir( ini(l\\;t\ hitwccii j^irdci s, .iiul i;i|)|)((l ;il 7 fl. ;il)C)\c low water. I'^roni llicsc
raps the piles wcic (Irixcn for foundations hy a skid dri\(r. As the pile driver finished
its work and nio\(d ahead, ihe caps were removed, the piles cul oil at 4'5 ft. aho\c
low watei- and recap|)ed. h'roni this trestle as a woikint^ |)latloini the (oliinins were
set, and it also carried the forms for the superstructure.

It was not feasihle to operate the drix'er on this low trestle, as it was not only helow
hii;h tides twice e\( r\ (la\ , hut the drix'ei" had to work partially on the old street to
mancvuxre for position to drixc the halter piles, hence it was necessary to have th<-
trestle at that elevation for drixini;, while to caiiy the forms for the superstructure
it was necessarx to cul off helow the imdei-side of the deck. All hut the outside piles
of each henl w c ic lost, it l)ein<4 of course imjjossihle to recover them after the super-
structure was l)uill. A feature of the falsework was its arrani^emeiU whereby a
sup|)ort was left under the centre of the Hoor slab after the remainder of the forms were
removed. I-^orms were remoxcd from the i;irders and slabs after seven da)s, but the
centre sujjport was left at least fourteen days, and in most cases lonj^er.

Pile Driving. — Generally the jjile driver used was of special design in order to drive
the batter piles {Fig. 8). The head block was supported by the ordinar\- four-lej^j^ed
tower, 36 ft. hii^h, but the two forward legs were spread outward at the bottom to give
a batter of one horizontal to five vertical. Two brace legs extended backward from the
vertical legs at the rear of the head block. The head block overhung the front battered
l(>gs about fifteen inches and carried the swinging leads. The leads were made as light
as possible consistent with their duty and were of single 3 in. by 12 in. yellow pine,
with angle-iron hammer guides, and were 65 ft, long. They were connected together
at the bottom by a timber yoke, and at three other points in the lower half of their
length bv yokes of strap iron, and were fastened again at their tops. No connections
were possible in the upper half-length of the leads as they had to be free to slide up and
down over the sheaves in the head block.

Concrete. — Concrete was mixed bv hand and shovelled directly into the forms. The
concrete in the girders and floor was mixed on the floor last in place. The bottom of
the main girders was only 2 ft. above low water, but no attempt was made to make the
forms for them watertight, work being so arranged as to begin concreting on a falling
tide as soon as the form could be cleaned after the tide had left it, and by the time the
rising tide had reached the concrete it had been in place long enough so that no injury
was done to it.

The concrete in the rear footings was deposited under water by means of a 6-in.
tremie, and it ])roved more satisfactorv to finish the tops of the pedestals under water
at high tide, than to finish them in the dry at low water. The top of the finished
pedestals was only 2 ft. above low water, and when it was attempted to finish them
in the drv, the wash from passing launches so washed the concrete as to make it
extremely difficult to get good results.

Sand and gravel were piled always near the mixing platform, and were brought
to it bv men working in pairs carrying the materials in half cement barrels slung by
wire from a pole across their shoulders.

All reinforced concrete w^as mixed in the proportion of i : 2 : 4, while that placed
in the foundations under water was proportioned i : 2^ : 5.

Labour. — Nearly all the labour on this work was done by Filipinos, under a single
American foreman. There were on the rolls a Japanese blacksmith, and at times
three or four Japanese or Chinese blacksmith helpers and carpenters. The pile-driver
engineer was a Filipino, and as good an operator as could be desired, although he
was not alwavs as capable of keeping his engine in condition, or of making repairs
as a white. Night watchmen were East Indian Sikhs, who had usually seen service in

121

REISFORCED COSCRETH WHARF, ILOILO.

[CQNCBETE

3riti>h Indian Arnn ; th.s. nu-n are fcnuul .vnv.h.re in the East, and seldom work

Nvrll as all harbour xvork and the liohthou.e work in the

the B

except as watchmen.

bv Mr. Harrv A. Thompson as Assistant Kn.Liineer in local char^^e

Fi^. 9. Concrete Columns in Castinfi Yard with Assembled Iron.
Harbour Imi-rovements, Iloilo, Philippine Islands.

I 22

■ VKNCilNl-l WlNti — ,

SOME FALLACIES IN CEMENT TESTING.

ffg

"'''j''-''""'''!'""''''''''"*

RECENT VIEWS ON
CONCRETE AND REIN.
FORCED CONCRETE.

THE CONCRETE INSTITUTE,

The method "we are adopting, of dividing the subjects into sections, is, roe belie've, a
neiv departure. — ED.

THE CONCRETE L\STITl'TE.

SOME FALLACIES IN CEMENT TESTING.

By W. LAURENCE GADD, F.I.C.. M.C.I.. etc.

TJic following is an abstract of a paper read at the Forty-first Ordinary General Meeting

of the Institute.

INTRODUCTION.

The object in this paper is not so much to question the accuracy of the
testing performed by inexperienced operators as to draw attention to what are, in my
opinion, fallacies underlying some of the recognised or suggested processes of testing
Portland cement ; and at the outset I find myself at variance with the British standard
specification itself.

The standard specification stipulates that before any sample of cement is submitted
to certain tests it " shall be spread out for a depth of three inches for twenty-four hours
in a temperature of from 58 to 64 degrees Fahrenheit."

The object of this procedure appears to be twofold — i.e., (a) to cool the cement to
the normal temperature of the atmosphere, and (b) to obtain conditions similar to those
governing cement which has lain in sacks or casks for two or three weeks — i.e., during
the possible period between shipment and use.

As regards (a) this can be verv simplv done without exposing the sample to air
As regards (6) I have made the following experiments : —

EFFECT ON SETTING TIME OF STORAGE IN SACKS.

Two large samples of cement, one freshly ground and the other ground about a
month previously, were filled into sacks, tied up, and ])ut aside in the warehouse at
each of six different factories on the Thames and Medway and in the Isle of \\'ight.
Samples A, B, C, D, E, and F were rotary kiln cements; samples G, H, J, K, L, M
were chamber kiln cements.

Specimens of all these were despatched to me at the time of filling the sacks. After
two weeks the contents of the sacks were thoroughly mixed and a second set of samples
again sent to me, the remainder of the cements being returned to the sacks and stored
for a further two weeks, when the same procedure was again gone through.

123

THE COXCRETE INSTITUTE.

(CQNCBETEJ

The three sets of

ampU's were tested for setting' time with the following" results
TABLE A.

Sfttixg Time (^hNUXEs).

Cement.

Date
Ground.

iirst Samples.

Initial.

Final.

Second Samples.

Third Samples.

Initial.

I'inal.

Initial.

Einal.

I-

8/6/13
4/7/13
2/6/13
4/7/13
6/6/13
5/7/13
2/7/13
25/5/13
7/7/13
3/6/13
7/7/13
'( o 13

170

125

120

105

210

205

120

102

357

365

240

135

330

375

285

140

335

100

400

135

420

162

402

185

455

165

480

105

255

235

445

300

480

185

180

435

300

480

130

155

Not recei

ved

170

235

Not recei

ved

405

370

360

'"^5

'^ ■^

345

270

EFFECT OF AERATING IN LAYERS THREE INCHES DEEP.

.Samples of the cements as received from the works were laid out for twenty-four
hours, in accordance with the British standard specification, and then tested, with the
following results : —

TABLE

Sitting Time (Minutes).

I'irst Sample.

Second Sample.

Third Sample.

1
As

Aer.

Received.

24 h.

7d.

Received.

24 h.

7d.

Received.

24 h.

7d.

I no '

I 35

I 60

I-' 170

. 165

225

F 125

213

145

F 120

133

I 105

I 60

1" 210

145

160

1- 150

205

120

V 120

120

I 102

I 35

I 60

I" 357

365

430

!•' 365

365

245

L 240

233

240

I 135

I 60

I 90

J" 330

430

440

1- 375

445

43"

F 285

330

430

I 140

I 100

I 135

105

!■" r.5

315

435

b 400

380

505

1" 420

375

470

I l(>2 155

145

I 185

190

105

I 165

165

163

1- 402 4V>

445

1- 455

430

3KJ

I' 480

54«

510

I 105 100

I 235

185

I 300

210

I" 255 1 340

123

1- 445

425,

1 10

F 480

480

I 65 1 45

I 180

165

I 300

273

!•■ 185 200

!• 435

360

F 480

530

I 7" 50

1 35

—

I J ■/> 1 10

120

I' 155

233

—

I ho 1')

I 55

3<'

—

1- 170 XI5

!• 235

200

—

I 75 ; 60

I 55

I 90

103

!•■ 4"5

420

365

!• 370

410

!• 3O0

34 3

440

1 I H5

(>5

(>(>

I 45

I 60

()()

103

1 ]•■ 22'i

2f><)

'>,()')

1' 345

1 370

If»r)

!• 270

3 13

2f>S

The results of iIk- t<-sts show lliat llnri- is no rcl.iiion Ixiwccn the (Tfects of
ai'-rating cem<iit for iwenty-four hours and storing in sacks for two weeks or a month;
further that tin- setting tinn- is dirferently affected when tlu' same cement is aerated
or stored in bulk in (liffer<nt localities or at dilf( r< iil pf liods. in some cases the effect
of twenty-four hours' aeration is the (i|)p)Osite to that pnxluced by storage; and storage
or aeration at one period has an opf)Osiie effe( I to storage or ai-ration at another [)eriod.

!24

J, cTONyrkM KTiON A l;

AtN(.lNKt IJINC. —

SOME FALLACIES IN CEMENT TESTING

TABLE C
An:u\ii<)\ \-n\i TwicNTY-ForR Hours comi>aki;i) with Stora(;k in Sacks for Two Wkkks ;

I'.lMl 1 ON SlllINC. TiMI SHOWN IN MiNUII'S A( C I- I.I- RA II; I ) OK Rl lAKDI I).

J'irst 'Iw

'I'Us.

Second

wo Weeks.

—

Twrnl\-lour Hours
■ Air.

Weeks Sack.

Twenty-four Hours
Air.

Two Weeks Sack,

Inilial.

1-iual.

Initial.

I'inal.

Initial.

I"inal.

Initial. linal.

a. r.

A. R.

A. R,

A. R. A. R

50 —

5 —

—

•15 —

— 28

— 88

— 25 5 —

50 —

65 —

—

60 —

— 55

No change 30 —

65 —

— 100

(^7

—

— 8

5 —

No change

5 — No change

52 —

— 8

—

— 45

5 —

— 70

— 30

90 —

Gs —

20 —

—

— 65

5 —

20 —

— 35

— 20

7 —

— 38

—

— 53

— 5

25 —

— 5

25 —

5 —

— 85

—

130

— 1 90

50 —

20 —

— 65

— 35

20 —

— 15

—

115

— 250

15 —

75 —

— 120

— 4 5

20 —

—

— 25

— 10

— 100

Not rec

eived

40 —

55 —

—

— 65

5 —

35 —

Not rec

eived

15 —

— 15

—

35 —

5 —

— 40

— 35

10 —

20 —

— 40

-I

— 125

— 10

— 25

— 15

75 —

This appears to me to effectively dispose of the somewhat prevalent idea that
chanj^es in setting time are due to some inherent property of different cements. The
erratic behaviour found is common to all the samples tested, the composition of which
varied within considerable limits, the lime contents, for instance, rangini^ from 64 to 59
per cent.

The retardation or acceleration of setting time on storage or aeration cannot
therefore be due to peculiarities in the cements themselves, but must be due to chemical
changes brought about by the absorption of some constituent present in the atmosphere.

Cement has a strong affinity for moisture in the first place, and for carbonic
anhydride in the second place, and these constituents are present in the atmos])here in
variable proportions at different times and in different localities.

From former experiments and reasoning, I have held the opinion that absorption
of moisture results in a retardation of setting time; whilst absorption of carbonic
anhydride produces an accelerating effect. Cement exposed to both inlluences will
therefore have its setting characteristics affected one way or the other according to the
relative amounts of moisture and carbonic anhydride absorbed, the net effect being the
resultant of the two opposing forces.

In order to test this theory, I have made some laboratory experiments, where the
conditions can be under control and standardised, which is rarely possible in so-called
" ])ractical " tests.

The results indicated that pure dry air has no effect upon the setting time ol
cement, the loss constituents remaining practically constant.

On the other hand, the effect of moist air free from carbonic anhydride is distinctly
marked, although the percentage of moisture absorbed is comparatively small.

The acceleration of setting tinie b)' absorption of carbonic anh\"dride is clearly
proved.

Some further ex])eriments were made with a cement specialh' obtained, ground
from fresh rotatory clinker without any addition, in the form of gypsum or steam, for
the purpose of regulating the setting time. When received this sample had a practically
instantaneous set, and could not be gauged with 30 per cent, of water.

In this case the cement was subjected to successive treatment, a portion being
withdrawn from the tube for chemical and setting-time tests after each experiment,
the remainder being subjected to further treatment.

I do not put forward the results obtained from these tests as final, but the results
already given seem to clearlv indicate that the change of setting time which a cement
undergoes on exposure to air depends entirely upon the relative amounts of moisture

THE CONCRETE IXSTITUTE. [CQNCBET S

or carbonic anhydridt- which it absorbs. Therefore to aerate cement before siibniitlini;
it to a setting-time test is a misleadins^ Oj)eration,

FINENESS.

The British standard specification stipulates that the fineness of grinding shall be
such that not more than a certain i>ercentagc of residue shall remain upon a sieve of
a stipulated mesh, under the conditions of the test. It is obvious that the most
important point in this connection is to ensure that the sieves used shall be of standard
and definite dimensions, and this is provided for by the following clause : —

"The sieves shall be prepared from standard wire, and the diameter of the wire for the
5776 mesh shall be '0044 in. and for the 32400 mesh '002 in. The wire cloth shall be woven
(not twilled), the cloth being carefully mounted on the frames without distortion."

The standard specification therefore Stipulates that for the first-named sieve there
shall be 76 warp and 76 weft wires of a definite diameter ; and for the second sieve
180 warp and 180 weft wires of a definite diatneter per square inch.

When sifting cement through a sieve to obtain the proportion of particles too large
to pass through the interstices between the wires, the size or area of the individual
holes appears to be the only condition of importance ; and it is to be assumed that the
intention of the framers of the specification was to ensure this condition being standard.

If a definite number of wires of a definite thickness be equally spaced throughout
the unit of measurement, the spaces between the wires will be of definite and equal
area ; but the weaving of wire cloth has not yet attained such a standard of excellence
as to ensure that the wires (especially in the finer counts) are spaced equally throughout
the piece, or even throughout any individual inch.

I submit that the size or area of the holes in a sieve is the real standard and should
be stipulated, the actual diameter of the threads, or their precise number per inch, being
of secondary importance.

In the course of my duties, it falls to me to examine and to accept or reject
numerous pieces of sieving cloth for use in a number of cement works and testing
laboratories, and I have formulated a specification for my own use which aims at a
standard sieve, whilst at the same time recognising and allowing for the great difficulty
o{ wea'.ing cloth of this nature with extreme accuracv.

This specification, for iSo^ sieves, I state as follows : —

1. The standard area of the holes in inches is '003552,

2. The equivalent mesh, calculated from the actual average area of the holes,

as measured, shall fall between 1762 and 1852,

3. The mean variation from the standard width of holes shall not exceed

10 per cent.

4. S(){ more than 10 per cent, of the holes measured shall exceed a variation

(A 15 p(-r cent, from standard.
Ancjther j>c)int which ajjpears to be overlooked is the size of the sieve itself. ^Khe
British specifjraticjn stij>ulates that 100 grams of cement shall be sifted for a period
of fifteen minutes, but does not specify the total area of the sieve to be used. I have
.seen in use sieves varying in siz(; from 4 in. diameter to () or 10 in. square; and it is
obvious that the same weight of cement, sifted for the same period of time, will be
morr; effectively sifted over a larger area than over a smaller one.

SPECIFIC GRAVITY.

The specific gravity test is now used ifi pl.icc of ihc old mdliod of la]<iiig the weight
j>er striked bu'-liej, which has for some lime been discredited.

']"ln- weight per bushel had no real bearing upon or rel.ilioiisliip lo the de<>ree of
calcination, but was rhielly influenced by t!i< lim ik ss of grindin'f.

The specific gravity test is still retain. <j in ihr Rritlsh standard specification and
is considered by most people lo fullil llw fmutioris loim.rlv altribulcd to th(> bush(^I
weight test- viz., to delect the degree of burning to \vhi( h the clinker has been subjected,
or, in other words, it is a test for utider-burned cement. This, however is a fallac\-

The specific gravity of carbonic anlivdiidi' .ind of w.iicr hdno -SS and roo
respectively, it will Ix- readily seen th.il ( oniparat i\(|\- small proportions of these
substancr-s, absorlx-d frf)m tin- atmosphere, are sunici<iit to reduc^e the gravitv of
cement to a material extent.

I 26

r>r^^5i^E?V^?^^ SOME FALLACIES IN CEMENT TESTING.

Rutlcr Ii.is shown that if (he absoi Ixd water and taihonic anliydiidc be expelled
l)\ ii^nilinj^ the I'eineni, the specifir i*ra\ities of cements of \a^iou«^ makes become so
neai h' itlentieal as to afford no indication of cjiiality.

The conclusions reached 1)\ Uutler were: (i) That the specific gravity of cement
is no indication whatever of |)ropei- calcination. (j) That the s|)ecific fjravity depends
upon the aj^e of the cement and the op|)orlunities it has had of absorbinj^' water and
carbonic anhydride from the air.

These conclusions are tjuile in accord with the exjxiience and the o|)inion held by
nnself for some time |)ast.

In ic)o4 or i()05 I'. M. Me\'er fomid, as the icsult of some hundreds of tests on
freshh burned clinker, that the hij^hest specific ifravity was obtained when the clinker
was burned at a temperature of 1,290° to 1,370° C. 'J'his clinker j^ave cement which
was ex])ansi\-e and unsound.

.\s the burnini^ temj)erature was raised, the sjM'cific i^ravity w.'is decreased, but
th(> clinker became sound.

My own experience is that when taken freshly from the kiln, the specific j^ravity is
practically the same whether the clinker be well burned or under burned, provided the
carbonic anhydride has been all, or nearly afl, expeUed from the chalk. This is in
accord with some results published by Redi^rave, who found the specific j^ravities of
four samples, taken from one place in the kiln, to be as follows : —

Specific Gravity.

1. Yellow, slack burned clinker ... ... ... ... ... ... 316

2. Good clinker ... ... ... ... ... ... ... ... 3"i7

3. Very lightly burned, showing spots of lime ... ... ... ... 320

4. Over-burned vitreous clinker ... ... ... ... ... ... 319

The specific gravity of cement being merely a measure of the degree of aeration
which the sample has received, and the finer particles being naturally more absorbent
of water and carbonic anhydride than the coarser pieces, it follows that a finely ground
cement, containing much Hour, will more rapidly have its original specific gravity
reduced by aeration than will a coarsely ground sample, and would thus, falsely, aj)pear
to be the more lightly burned of the two.

It mav be thought that granting the specific gravity is merely a measure of the
water and carbonic anhydride absorbed, and is no indication of calcination ; it might
be advisable to retain the test with the object of detecting dangerous natural cements
manufactured on the Continent, which cements are characterised by a high loss on
ignition. Personally I am unable to agree with this for several reasons. Firstly, the
direct method of estimating the loss on ignition is more accurate than a determination
of specific gravity, which is an indirect method, and, moreover, a more difficult and
uncertain operation. Secondly, an artificial cement, especially if finely ground, exposed
to air or kept in a damp store for some time, may have its gravity reduced to a figure
quite as low as that of many natural cements. Thirdly, no single test of this nature
is sufficient to determine whether a sample is or is not a natural cement. The only
certain guide is a chemical analysis, and having this data, the specific gravity becomes
superfluous.

STANDARD SAND.

There is a somewhat general idea that tensile or crushing tests of cement with
standard sand represent the best results of which the cement is capable. This is
erroneous. .Sand tests do not give the highest results which can be got out of the
cement, but give results which are standardised, and therefore comparable with those
obtained by different operators.

The standard sands emploved and specified in different countries vary in size to
some extent, as shown in the following table : —

TABLE D.
Residue on Sieves, Per Cent.

German sand
French sand
Austrian sand
American sand
English sand

20^.

30Z

17-4

100

9i'o

100

—

100

lOO

40^

127

THE CONCRETE INSTITUTE. [CQNCBETE]

These differences in size of grain doubtless have their effect upon the results
obtained. Actual experiments indicated that the crushing resistance of concrete made
from the same cement varies not only with the size, but also with the character of the
aggregate. On comparing the results of the tests with standard Leighton Buzzard sand,
all passing a sieve of 20 mesh but retained on a 30 mesh, and those with pit sand passed
"through a 5-in. mesh only, an apparent anomaly is observed, as the apparently larger
grained pit sand gives a less crushing resistance than the standard sand. This is not
really anomalous, because although the pit sand was only passed through the 5-in.
screen, it contained a considerable quantity of very fine stuff which would probably have
passed a 5o=-mesh sieve.

The results indicated that the crushing resistance of concrete made from the same
cement varies not only with the size, but also with the character of the aggregate.
On comparing the results of the tests with standard Leighton Buzzard sand, all passing
a sieve of 20 mesh but retained on a 30 mesh, and those with pit sand passed through
a i-in. mesh only, an apparent anomaly is observed, as the apparently larger grained
pit sand gives a less crushing resistance than the standard sand. This is not really
anomalous, because although the pit sand was only passed through the 5-in. screen,
it contained a considerable quantity of very fine stuff which would probably have passed
a 502-mesh sieve.

The whole of the specimens were kept in damp air only until due for crushing.

AUTOCLAVE TEST.

This test, recently proposed by Mr. H. T. Force, in charge of testing materials on
the Delaware, Lackawanna, and Western Railroad, of Scranton, Pa., is merely a revival
of Dr. Erdmeyer's high-pressure steam test introduced in Germany about 1881, and
rejected by German cement experts as being unreliable and misleading. In the words
of Professor Gary, of the Royal Bureau of Material Testing, it is even less adapted to
distinguish useless cements from useful cements than the usual methods of determining
constancy of volume. According to Dr. Cushman, of Washington, the details of the
test have been several times revised during the last twelve months, but the procedure
is now as follows :—

For each test three neat briquettes are made, and after twenty-four hours in a moist
closet these are weighed and then placed in the autoclave, sufficient water being added
to cover them. Pressure is then raised bv heating the apparatus by gas burners or
other suitable means, the time taken to raise the pressure to 295 lb. per square inch
being not more than one hour.

The pressure is maintained at 20 atmospheres for a further period of one hour, at
the end of which time the autoclave is slowly blown off, the briquettes removed (when
their condition permits) and placed in the moist closet for one hour. They are then
re-weighed and broken in the cement-testing machine in the usual manner. The
tensile strength so obtained is compared with that of twenty-four-hour neat briquettes
kept in moist air, and must show an increase of at least 25 per cent, over the latter.
The autoclave briquettes must also develop a strength of at least 500 lb. per square
inch, and the gain in weight must not be greater than i per cent. Expansion bars,
I sq. in. in section and 6 in. long, are also made up and tested for expansion after
twenty-four hours in the moist closet .and two hours in the autoclave. The expansion
of these bars must not exceed one-half of i per cent.

I hold that growth of strength by age is of less importance and is not such a
critrrion of quality as is gencrall\- considered. Modern cements pre])ared froni j)urer
clinker and much more finely ground than formerly attain a strength ai)proximating
to the maximum much more quickly, and it is evident that a cement which attains,
say, 'S of its maximum strength at short dates, has less margin for growth than one
which only develofjes '5 of the maxinuim in the same time.

The stipulated pressure to be mainlained in the autoclave (20 atmosj:)h(M-es) is
needlessly high and serves no useful pui'|)ose.

Quite recently the autoclave test has been subjected to critical examination, both
in the United States rmd in Canada; and th(! conclusions arrived at are that a case
for its adoption has not been made out.

FREE LIME.

No theory conn<<ted with Portland cement has obtained a stronger hold, or has
attained such hoary antiquity, as the idea that unsoundness of cement is due to free
128

[^eS^jTeJ^nS^ so,!//-: FALLACIF^ IN CEMENT TESTING.

linif l(H-kt(l up within llic p.irticlcs ol ihc i^iound m.ilcri.il. In l.i<l, lliis ihcoiN has
been for so \on^ acccplcd lli.il lo qiicsiion ii in;i\ jjossibly he mk i with derision.

The improvcmcnl in soiuuhuss, hroui^ht .ihoiit l)v the cxijomhc of rcnicnt to a
(iain|) atinos|)h('r(', lends some appar(Mil support to the conlenlion that Urc lime is
thereby slak«'d and rendered harmless; but it is rather dirikult to understand iiow lh<-
small amount of moisture absoibed from the air penetrates the particles and slakes
the free lime when the enormously i^reatei- tjuantily of water used in j^au^in^ the
cement fails to touch it. b\!rlhermoi c, imsound cement stored for some time in air-
tii^hl receptacles, in which i)resumably no slakinj^ of free lime can occur, becomes
j)erfectly sound.

Exposure of cement to air for a few days sometimes residls in an increase in the
amount of expansion, as tested 1)\ the Le C'halelier method, and this increase is nearly
always proj)ortionate to the amount of aeration underj^one- 7.r., the thinner the la\er
in which the cement is laid out, the {greater th(^ increase of ex|)ansion.

\\'(> know ver\' little 3'et of the properties of lime in a state of solid solution. It is
stated to be crystalline and to hydrate slowly; but if the solid solution theory be correct,
crwstalline free lime is present in considerable quantity in all Portland cements,
whether sound or unsound, and it has not been satisfactorily explained why the lime
hvdrates without expansion in one cement but docs so with destructive force in another.

It is also well known that a low-!imed cement is often more unsound than a high-
limed cement, which aj^ain is antai^onistic to the free lime theory.

My own view is that unsoundness in cement is probably due to the presence of an
abnormal silicate, perhaps dicalcium silicate, which is an unstable compound and
slowlv disinteLjrates with an increase in volume. The phenomenon of " creepini^
clinker," known to cement makers, is an illustration of the disinte^^ration, with
increased volume, of dicalcium silicate, which is formed when clinker contains an
insuificiencv of lime ; and this or a similar compound is most likely to be found in
unskilfully made cement in which the proportions of lime, silica, and alumina are not
]:)resent in correct combining' weights, or when the temperature of burnini:^ is insuffi-
ciently hii^h to induce the formation of those silicates and aluminates which constitute
true Portland cement.

DISCUSSION.

Mr. D. B. Butler, Assoc. M.Iast.C.E., fully concurred that cement testing was a highly
specialised skilled work. Aeration was not so necessary as it was some years ago; if cement
would stand the British Standard Specification requirements as regards soundness, that was
the rotary test, aeration was unnecessary. Absolute accuracy in the preparation of wire sieves,
he believed, was almost impossible. The specific gravity test he considered practically of no
worth. As regards the autoclave test, what was the good of subjecting cement to a high
pressure of steam? The idea of testing cement for soundness, he thought, was to determine
whether or not that cement would eventually expand or cause trouble in work. The boiling
water test in niaie cases out of ten was unnecessarily severe. The conditions of the setting and
hardening of cement, the different conditions between hot water and cold water were quite
different ; and because a cement would expand in boiling water, it did not by any means follow
that it was going to expand under other conditions. To enable a cement to pass the standard
specification test, it had behoved manufacturers to greatly improve their methods of manufac-
ture, and in that way indirectly it had immensely helped the British industry, but at the same
time — it might be heresy to say so^ — he thought it was unnecessarily severe in the ordinary way.
After all, the idea of a soundness test was one which would show them unsoundness, and not
one which improved manufacture. The next point was free lime. Free lime in cement did
not exist; he did not think it ever had. The cause of expansion of cement occasionally, which
was much less frequent now than it used to be, was not free lime. Anyone who had tried to
burn or to place lime at a higher temperature in juxtaposition with acid bases would find that
it was impossible to prevent that lime from burning in places. His own theory as to the reason
of expansion was that it was not free lime, but that it was a highly expansive lime compound
of some kind, which very slowly hydrated, and expanded during hydration. He did not believe
that free lime could exist in an ordinary "Portland cement.

Mr. William G. Kirkaldy, Assoc. M.Inst. C.E., declared himself in favour of the Le
Chatelier test, although some years ago he regarded it as too drastic.

Mr. Percival M. Fraser, as an architect, remarked that the main object of the Paper
seemed to be to decry all known tests. The autoclave test seemed highly fantastic, but they
must remember that the Le Chatelier test was considered a freak test when it came m. In

129

THE COXCRETE INSTITUTE. tCQNCJ^lHd

regard to the testing in general, he was afraid his brother architects were satisfied with the
tes'ls that he was brought up on : filling a bottle full of cement at night, and if it did not either
burst the bottle or act as a sort of small rattle next morning it was all right. He considered the
crushing test should be developed and made a standard, as in time, he believed, it would replace
the somewhat futile tensile test. In regard to the test sieve, he agreed that the expanded sieve
was a verv immature method, and he suggested the substitution of a perforated sheet.

Mr. W. a. Perkins, District Surveyor for Holbora, did not think there was anything
in the Paper, with the exception of the boiling tests, and the question as to free lime, which
would guide them as to the soundness of any cement that they might wish to use in their works.
On the question of the sieves he agreed with all that had been said that evening. Some time
ago thev heard a good deal of a little instrument which was termed a " flourometer," by
means of which those iK)rtions of cement which were ground to an impalpable powder were
blown away from the coarser particles, and collected in a special vessel. Had that particular
instrument been dropped?

If not, would not that be a better way of obtaining a perfectly fine cement, and so get
something which was reliable on the score of fineness? He did not think there was much in
the autoclave test, but the Le Chatelier method of testing cement he regarded as a good one.
On the question of free lime, he thought they more often got free lime introduced into the
cement on the works, either by the careless stirring of the cement in close proximity to a bin
of lime, or they found it in the bricks or the tiles that were being used in conjunction with
the cement.

Mr. J. N. N. Sbi/lito urged that some time-limit should be fixed for the taking of
samples after the cement had been delivered on the job.

Mr. W. A. Short asked Mr. Gadd to give them some rough outline of the course he
pursued in testing the excellent cement which his firm turned out. Perhaps he might favour
them with what he would suggest as an ideal form of cement testing. With regard to the
question of sieves, possibly the National Physical Laboratory might be able to help them.

The President, in moving a vote of thanks to Mr. Gadd, said he should have liked to
have seen, in regard to the tests, an analysis of the cement used, in order that they might, if
possible, come to a definite conclusion as to the variation in the results. He had found a very
good method for measuring and also for determining over large areas the variation in sieves
was the use of the magic lantern. As the result of some experiments he made some years
ago he found that if concrete were made simply with residues only, and kept in dry air,
anything that would pass through a i6o sieve was absolutely useless. Briquettes made with a
residue coarser than i6o were all blown, and that was due entirely to the gypsum. With
reference to standard sand, he made his own from oolite or Portland stone, and he found that
he got very much better results from sanid that would pass through a 20 sieve, and be retained
in a 30 than he could get with the ordinary Leighton Ikizzard sand, and that was due entirely
to the fact that all sand that came from Portland stone was extremely porous and crystalline,
and that there was a locking action taking place between the cement and the stone. He got a
very much more uniform result, especially in tension. He was pleased to see tlie high results
Mr. Gadd got with an ordinary 4 to i concrete, where he had been using Kentish rock-stone.
With a limestone, and especially the oolites, they would always get a very much greater
strength in crushing resistance than they would with any of the smooth and the harder stones.
Personally, he should like to see all neat cement tests done away with except as to soundness
and setting time, so that they should rely entirely upon the 3 to i sands in tension and also in
compression, and he thought that before long that would be adopted in this country, as was the
case in Germun\'. 'J"he " flourometer " he considered was a very good thing for experimental
puri)Oses, but if one had to use a " flourometer " to get all the flour out of a ton of cement they
would have to wait a very long time, and when llie\- did get it it would be of very little value.

MR. LAURENCE GADDS REPLY.

Mr. (Jadd, in a( know Irdgiug the \oir ot thanks, rci)lic<l to several of the observations
whifh harl been made in the course ol the discussion. As to Mr. Hutler's criticism on the
aeration of samjdes, his i>oint was this, lli.ii for I he purijosc of making a setting lime test,
aeration was not only unnecessary, biil il was misleading. AiTaling the small sample of
cement ui^on which they were to make their test was subjecting that small sample to influences
to which the bulk cement was not subjected. Whether c c-ment contained gypsum or not, the
effect of water and GO^ respectively was ail the- same. Water wouici retard the setting time no
matter whether there was g\i)sum present or not, and c arhonic anli\ <lii<h' would accelerate the
setting time. If some <:entral authority c<Hild |)ro\i(h- ilicm willi standard sieves, which were
standarcl, it would i>e a very great convenience, anc] it would also be a very useful thing, if
they coulcj get an intern.it ional sand, to people who vvc-rc- sc-nding i cnienl out all over the
130

teScSS'^SK^ SOME FALLACIES IN CEMENT TESTING.

world, llr ( amc across inan\ sptN iinriis of (linker wliicli were quilr brown, ( olit'i-t oloureilj in
fact, due to tlu- reduction of iron salts, hut he did not find thai that clinker was any more
unsound than Lhc <>rdinar>' (linker. Mr. iVrcival Fraser was the s|)eak<'r who gave him the
greatest sluxk, when he said that the ohje'ct of his Paper api)eared lo he lo run down every
test there was. That was not his object. The object of lh<* I'ajjer was to point out those parts
of the t<"s( whifh, in his opinion, were faulty. He did not say do away with the tests,
but if an\ jxirtion of the test was misleading or faulty in an\' wa\, lei them do away
with the faulty i>art and improve it. He was further slux ke<l by the suggestion that
he decried crushiing tests. lie was ver_\- sorrv if he gave Mr. Fraser that impression, because it
was contrary to his view. He agreeti that if they mi.xed sulphuric acid with the cement they
would liave a retardation of setting time just the same as if they added gypsum, but no acid
got into the cement that he was experimenting with. Calcium sulphate in broken bricks or
anything else in any quantity was about the worst thing they could mix with Portland cement.
As to Mr. Shillito's suggestion, that was not a matter for him, as he did not represent the
Standard Specification or the Sijccification Committee. With reference to Mr. Short's (juestion,
he was Ixiund, like everybody else, by the Standard Specification. He made the tests according
to the Standard Specification, but if Mr. Short asked him what tests did he rely upon for his
ow-n information and his own judgment, he relied principally upon the crushing tests; and he
formed his opinion without the aid either of specific gravitj' or aeration. Several times he
had tried to do away, or to find the means of doing away, with wire sieves. There was no doubt
that if gypsum were added to cement, and it was not finely ground and ecjually distributed
all over the cement, they might get little particles or nodules of gypsum, and where those
occurred undoubtedly there was the nucleus of expansion, but that would take place in the
cold, and it did not need boiling to bring it out. He agreed with the President in his hope
that some day all neat tests would be abolished, and that they should rely entirely upon sand
tests.

131

NEW WORKS IS CONCRETE.

ICQNCBETEJ

NEW WORKS IN CONCRETE

AT HOME AND ABROAD.

Under this heading reliable information "Will be presented of neiv ivorks in course oj
construction or comoleted, and the examples selected ivill be from all parts of the 'world.
It is not the intention to describe these ivorks in detail, but rather to indicate their existence
and illustrate their primarv features, at the most explaining the idea 'which se^'ved as a basis
for the design. — ED.

REINFORCED CONCRETE WATER TOWER NEAR BURTON-ON=TRENT.

The water tower shown in our illustration has quite recently been erected entirely on
the Coii^net svstem of reinforced concrete at Rolleston-on-Dove, near Burton-on-Trent,
for Sir Oswald Moslev, Bart. This water tower is in connection with the water supply
for the villai^e, the engineer for the work being Mr. John Frith, of Basloy, Derbyshire.

View of Completed Structure.
Reini oRf I'D CoNCKi TK Watkr Towkr, Burton-on-Trent.

132

fy, CONN TkMin lONAi:
l/y I NdlNl ri^lNCi — ,

REINFORCIiI) CONCRETH WATER TOWER.

1 he

tank 1

las ;

capacity of

hi-l

1 ;iiul

2.S ft.

111 (

lianictcr. T

tow (

•r is

:;j II.

Ihr

inside of th

Reinforced Concrete Water Tower, Burton-on-Trent.

45,000 i^allons, and is in the sliajx' of a cvlindcr 15 ft.
ic total iK'iLjlit from the j^round level to tlic top of the
■ lowci' includes a fiisi ;ind second lloor, and lliere is a

balcony on >.«'(()nd floor, as shown
in the photo^iajjli. Access to the
iip|)ei' llooi's is ^ivcn b\ means (jf
a wooden staircase.

The water is forced into ihe
iaid< 1)\' means of piimj)s, the
inlet and overflow pipes beinj^
fixed inside the tower.

The work was carried out
1)\ the Derbyshire and Notts
("oi^net Contracting (.'0. (Messrs.
Ivvans Bros.) of Alfrelon, and the
worl-cini^ drawinj^s were ])re-
|)ar(d by Messrs. Edmond CoitJ-
nel, Ltd., of 20, Victoria .Street,
Westminster, S.W.

The reinforcement is com-
posed of round bars of mild
steel supj)lied by Messrs. The
Whitehead Iron and Steel Co.,
Ltd., Tredegar, Mon.

The tank was rendered on
the inside with sand and cement
and filled with water 14 days
after the concreting operation
was finished. A slight dampness
l3 appeared at first at the junction
of the wall in the bottom, but,
as usual in reinforced concrete
water tanks, these signs disap-
peared after a few days.

A REINFORCED CONCRETE

BRIDGE AT WICKHAM

MARKET, SUFFOLK.

The bridge over the River Deben
at Wickham Market, Suffolk,
which was partially destroyed by
the floods in August, 1912, has
recently been replaced by a new
reinforced concrete structure de-
signed by Mr, Henry Miller,
with Messrs. L. G. Mouchel and

M.Inst.C.E. (County Surveyor), in conjunction
Partners, Ltd., of 38, Victoria Street, S.W.

The new bridge, which is constructed on the Hennebique system, has a span of
48 ft. clear of the abutments, and an overall width of 28 ft., as against 36 ft. and 26 ft. in
the old bridge. The old brick abutments were taken completely away and new abut-
ments in reinforced concrete constructed, 6 No. 14 in. by 14 in. piles, and 35 No, 6 in.
by 12 in. sheet piles were driven on each side of the stream, the existing brick culverts
under the approaches and the wing walls being retained.

The bridge is constructed in two spans, the central support consisting of 3 Xo.
14 in. by 14 in. piles, with 14 in. by 6 in. diagonal bracings and 14 in. by 8 in.
horizontal cross bracings as shown in cross-section.

With regard to the reinforced concrete superstructure, the decking of the bridge
is 7^ in. thick, the main beams being 10 in. bv 22 in. at 10 ft. centres, and the

i.U

NEW WORKS IN CONCRETE.

lOQNCBETEJ

secondary beams 6 in. by 14 in. at 4 ft. centres, with a reinforced concrete parapet and
coping' as shown. The carriai^'eway is 20 ft. wide, paved with ffranite <=etts on ordinal y
concrete, the thickness of the setts and concrete liUing at the crown of the road beini^
14 in. and at the curbs 10 in. Footpaths, which are carried on reinforced concrete
corbels at 4 ft, centres and linished in i^ranoHthic, are provided on each side of the
bridge 2 ft. 6 in. wide, giving a total width between the copings of 25 ft.

.2 ^

The new bridge, which has taken .iboiil six nuMilhs to construct, was tested last
December, and aft;-rwards opened [o trallic in the presence of a larg(! representative
comjjany.

'Jhe contractors for the work wcrt Mcssis. IIoIIowmn' i^ioliiers (London), Ltd.,
Belvedere Road, Laiiibnli, S.I"..

134

J coN.^MJucriaNAi.i
rvKNr.iNhi.uiNd --J

REINFORCED CONCRETE GASHOLDER TANK.

REINFORCED CONCRETE GASHOLDER TANK AT H AM BURG-FUHLSBUTTEL.

Ml.SSKS. ClIKlMIAM AM) NlKl.Sl-N, d ( •. >! ). 11 1 1. 1^. 1, , ll.lX.' 1 . (CM 1 1> fOIlsl lUClcd t Ik •

louiul ition ;.iul l.niU l.>r a lar^o ^ashoUlr, in r.inlnicvd o.ncnK-, for the (.as Li^hUn^
Com.nittrc of I'uhlshullrl. As th<' d.-plh «.l wal.r is S nicli.s the containing nn^ is
suhjrclcd to a hmslin- pressure due to tliat h.ad of wat. r, whilst th<- n^id connections

at the base introduce considerable fixing moments. For the computation therefore,
the stresses in the rini^ due to these two causes are the deternTining factors 1 his inNOlxes
a special method of computation, the triangular area which represents the h>drostatic
pressure being divided in such a way that at every point the deformation due to the nng
stress is equal to that due to the fixing moment.

135

SEW WORKS IN CONCRETE.

fCQNCRETEl

The internal diameter of the containing tank is 57-4 metres, the thickness of the

Iiilciicr View.

J<,.,,MO.'.hl. CoNC.<l/iK GASnol.l>ER-TANK AT 1 I AM Hf Kr.-lM ' i 1 l.Slir 1 1 KI..

the gasholder a plat. 20 r.n. lliick, r.-infon.d wi.h wi.v nuslus, slrcngthened by 16
rl^^gs nclar to th' ou.-r c.ig.-. Tlw has. of ih. lank has a .uax.nuun thickness ol

I metre, dimiiiisliing outwards and inwards

T.'

FURTHER CONCRETE WORK AT TALBOT S INCH. KILKENNY

)SF Of the latest a<hli,ioM. .0 th- n>anv laiiMin^s rnrU.\ in -W.nget ^ oeks n
''iho's nch, for th. Kilk..>nv W oo.lwork.rs, und.r .h. aus,.,e.s of the K.-ht

136

foT cTON> rwwn ionaJ

Rh:iNF()RCIiD CONCRETE GASHOLDER TANK.

»37

NEW WORKS IN CONCRETE.

[CONCBETEJ

138

^ t-N(ilNt.I-RlNti — ,

CONCRliTlC liLOCK WATER RliSERVOlR,

I lonour.ihlr l'.ll«n (■(Uintcss Dow.i-ci ol D.s.n i, Is Ik !<• show ii. The w.ilc r t()\\<T canics
llic "o<)() i^.illon l.ink for the spiiiiklci insi;ill;irKm in the w nodw oik* rs" factorx, tho
basc'of same \n\\v^ i^ It. 1)\ M I'l-, \^ill> •' <«'>•'' Ixi.^l" (iiuIiidinL^ lank of i) fl.) of jusl

<»\('r \o W. , 1 1 • I

i'lu' " W'iii'Mi " Itlncks used in ihc cicrlion air doiiMr and sini^lr Hue blocks, which

Concrete Block Water Reservoir, Talbot's Inch, Kilkenny.

are reinforced at the inner corners with il in. bars, the inner space being filled in with
rough concrete mixed 7 to i.

At the top of the tower for about 23 in. the girders are placed supporting the tank,
all of which .are encased in concrete.

The blocks were made by Messrs. The (\)ncrete Hlock Co., of Talbot's Inch, and
the whole of the work designed and carrit d out under the supervision of Mr. F. \\ .
Kiddie, of Talbot's Inch.

1 ^0

MEMORANDA.

E CT^CRETEl

MEMORANDA.

Memoranda and Neivs Items are presented under this heading, with occasional editorial
comment. Authentic netos 'will be ivelcome. — ED.

International Association for Testing Materials.— A meeting of the British
Section of the Intcrnaiional Testing Association was held at the offices of the Iron and
Steel Institute, zS, X'ictoria Street, London, S.W., on Thursday, December i8th, 1913,
at 4 p.m.

The chair was taken bv Dr. \V. C. Unwin, and there were also present : Dr. H.
Borns; .Mr. S. M. Dixon'; Mr. F. W. Harbord ; Mr. D. Heap; Colonel Herbert
Hughes, C.B. ; Mr. \V. G. Kirkaldy ; Mr. R. Lessing ; Mr. G. C. Lloyd; Mr. J. T.
Milton; Mr. H. Moore; Mr. L. S. Robertson; Dr. F. Rogers; Dr. Walter Rosenhain ;
Mr. E. H. Saniter; Mr. J. Cruickshank Smith; Mr. F. Tomlinson ; Mr. Howard
C. Wolfe. Letters of regret at their inability to be present were received from
Sir H. F. Donaldson, K.C\B., Sir Robert Hadfield, F.R.S., Mr. E. O. Sachs, and
others.

The draft scheme of organisation, drawn u|) by the provisional Committee of
Management, was submitted to the meeting, and approved, subject to certain alterations.

The subject of the mode of dealing with such annual subventions from manu-
facturing firms, scientific and technical societies, institutions, and i)ublic bodies, as
might from time to time be made, and of the question of representation of such bodies
within the British Section, was referred to the Committee of Management.

On the motion of
Mr. J. T. Milton, a
cordial vote of thanks
w a s unanimously
passed to Dr. Unv/in
for jjresiding.

The Society of
Engineers (Incor-
porated) Status
Prize. The Council
(jf tlic Society 01 En-
gmff-rs (Incorpor-
ated) may award in
1914 a premium of
Dooks or instrumcnls
to the value of £\()
IDS. for an approvi-d
essay on " The Statu--
of the Engineering
Profession." T h c
Council reserve the
right to withhold
the premium if llw
essavs received are

I<KIMOI«(.IH CoN< KK 1 K I'1-.N(K PuS I S Al DiNAS WaV, H A\KK lORinVK^T.

140

i, (.ON.vrPUCTlONAI.
A LN(ilNt-l-kIN(i — ,

MEMORANDA

Reinforced Concrete Fence Posts, Dinas W'av, HAVLKhoKUWi.sx.

iidi nf ;i ^uHl^i»•llI sl.iiul.iid ol niciil. The (oiupct ii ion is open lo .ill, hut, Iv f(>i'-
cnli riiii^, ;i|)i)lii;il iiMi Icti (l( l.iilrd |):irl icul.irs should he iiiadf lo the Sccrctarv , 17.
X'irioii.i Slictl, W'csimiiisit T. The last date for i(C(i\in<^ css.'iNs is Ma\ 3<)lii, i:(i4-

Reinforced Con
Crete Fence Posts
for Dinas Way,
Ha verfo rdwes t.
\\\ reproduce ilere-
\\ i I h t w o photo-
i^iajjhs of sonic rt'lii-
forct'd concrete work
carried out in eon-
n e c t i o n with the
above new r o a d s.
'J'his new route lo
Fishj^uard has re-
cently been coni|)le-
led by the Pembroke-
shire Horoui>h Coun-
cil. For a consider-
able distance it skirts
aloni^ the hii^h cliffs
overlookini;' F i s h -
guard Harbour, and
then turns to the
right overland. It is
2,600 ft. in length,
with a carriageway
of 20 ft. and a foot-
path of 4 ft. The boundary fences on the land side consist of reinforced concrete posts
and wire strands. The engineer for this roadway was Mr. Arthur Thomas, of Haver-
fordwest, and the contractors were Messrs. Topham, Jones and Railton, of Westminster,
London. The whole of the fence posts were manufactured and erected by the
Reinforced Concrete F'ence Posts, Ltd., of Broadway House, Westminster.

Reinforced Concrete Boat Ways, Rockhaven Harbour, N.D.— In a short articl-
in the Eugiticcriiig Xeius Mr. S. R. Morrow gives some particulars of some reinforced
concrete boatways constructed by the United States Government at Rockhaven Harbour,
N.D. He states that the U.S. Engineer Office of Kansas City, Mo., has departed
from the old practice of building such structures entirely of wood. Rockhaven Harbour
is located on the west bank of the Missouri River about four miles above Mandan, X.D..
and is the site of the repair plant for the fleet of Government vessels used in the control
of the river. The new ways there, shown in the accompanying illustration, are of
reinforced concrete with a timber " butter board " on top for the sliding plane.

There are ten w.ays, each 270 ft. long, the lower 130 ft. being on a 1 to 7^ slope
and the upper 140 ft. level. They are spaced 14 ft. centre to centre, and are supported
on concrete columns 10 ft. centre to centre. The largest vessel for which they were
designed is a steel-hulled boat 155 ft. long and 24 ft. beam.

The columns, with the exception of those at ends and top of slope, are 12 in." square
and are placed to an average depth of 6 ft. in the ground. Where a good foundation
was not struck at this depth an 8 in. post-hole auger was used in boring a hole to solid
foundation. These holes were filled with concrete and were assumed to act as piling.
Witli the exception of a few of the columns at the foot of the slope a good foundation
of blue shale was generally struck at a depth of b ft. The columns were flared at
bottom to 20 in. square, thereby increasing the bearing surface. As the earth had no
tendencv to cave, no forming was used underground excepting with the columns at
water's edge, which were 4 ft. square and were built in the edge of a sand bar.

Each column was reinforced with four f in. square twisted bars which were bent
over and projected 2 ft. 2 in. into the beams. The aggregate used in concrete was a
native gravel which contained sufficient sand and some dirt. On account of this dirt
rich concrete was used, the mixture being i : 4. The water for concrete was pumped

CDNCELTEZ

CONSTRUCTIQNAI:^

PILE DRIVING PLANT

WE MAKE PILE DRIVING PLANTS SUITABLE FOR THE
LIGHTEST TIMBER SHEETING OR THE HEAVIEST FERRO-
CONCRETE PILE, FOR STEAM, AIR, OR HAND POWER

STEEL SHEET PILING

*' Universal Joist" - 43 lbs. per super, ft.
*' Simplex" - - 27 lbs.

''Simplex" - 22 lbs.

»» >»

»> »>

We buy the Piling Lack at tfie end ol the job, making the cost to the user approximately
1/10, 1/4, & 1/- per su[)cr. foot respectively

CATALOGUES AND FIRM QUOTATIONS ON APPLICATION

THE BRITISH STEEL PILING CO.

DOCK HOUSE, BILLITER ST., LONDON, E.C.

Telephonr ; 5463 Avcnur.

Tclciframs " I MmKdoii, " I ondon.

142

r J. CONMPDC-I lONALl
(.< V 1 M(.lNKl-klNt. — ^^1

MEMORANDA

tliitillx Ironi ilif ii\(i lo h.intis ;ii mi\iiiL; pl.illoim l)\ inc.ms (if sin.ill ijliini^cr |)iim|,
;iii(l hoisi hoilci . All concrclc w.is mixed l)\ ii.ind .ind disii il)ul( d in h.inows.

I'hc l)»;iius or \\;i\s propci-, which ;iic i .• I)\ 14 in., wci'c stalled .iftcr .dl t'olunins
w ( I < roniplclcd. The forms for tlicsc were m;i(lc in iwo sides .ind bottom. One set
ol -ides ;ind two sets oj bottoms Were m.lde foi" (()m|)lete w;i\, J70 ft. Tile bottoms
w ( r< su|)|)orted b\ il;im|)s on the colunnis. The sides w<Te ;dso supported b\ these
clamps. Ilini^ed cl.im|)s were plared around the whole form, thus transferring part of
the load Irom bottom to sides. The beams were allowed to set 24 hours with side-
forms in place, and Irom 4S to ()(> hours with bottom forms in place. It took
approximateh 11 hours to concrete one beam jyo ft. lom.^.

Ihe beams were reinfoi'ced with two bent-up rods and two sliai^ht rods 2 in. from
bottom. .\11 rods wore ^ in. square twisted steel. At lii'st no |)rovision was made for
t(Mnpt'ralure stresses, l)ut a lem|)erature cracU appeared at the top of the slope in the
first beam placed. This was jjartially overcome in succeedinj^ beams 1)\ |)lacim4 extra
reinforcement in lo|)s of beams.

The " l)utter boards " are 3 l)\ 12 in. by 20 ft. I'lr sticks sui)p()rted b\ 3 b\ 12 in, bv
12 in, fir blocks, s])ace(.l 3 ft. 4 in. c. to c. Roth blocks and "butter boards" are

•I

Reinforckd Concrete Boat Ways, Rockhaven Harbour, U.S..\

anchored to the concrete by means of f by 11 in. machine bolts imbedded 7 in. in the
concrete.

Major Herbert Deakyne, Corps of Engineers, U.S..\., is the district officer for the
Missouri River and tributaries. Fred \\ . Honens, Assistant Engineer, was in general
charge of the work on the upper Missouri River, and Mr. Morrow was in local charge
of the cotistruction of the wa\s.

Concrete for Oil Tanks. — Experiments have been made to determine the avail-
ability of concrete for oil storage tanks, and it was found that the material w-as entirely
suited for the purpose. Accordingly, a number of them have been built at El Paso,
Texas, by one of the railroad comj)anies of that stction which is engaged in extensively
handling oil from the fields of that State. Up to this time it was generally agreed that
the presence of oil had some serious effect on the concrete, but if this is true it was
not shown by the ex]Kriments. — Concrete Age.

1+3

MEMORANDA.

ICDNCBETEl

Roof Construction on Concrete Building.- Whvlhcr the structural part shall be
flat, and then covered wilh cinders lo ,<4ivc a proper pilch for drainage, or whether
the structural part, including the ct'ilin_<j;, shall be j)itched and the fill avoided, is a point
which niav be discussed to advanta^^e by eni>ineers, in the opinion of Mr. L. C. Wason^
President of the Aberthaw Construction (^o., Boston, in a paper read before the Boston
Society of Civil Eni^ineers.

In construction the most serious objection to the first method is based on the lajjse
of time between the casting of the roof and the placing of the waterproof cover of tar
and felt over the cinder fill. This usually i)ermits a quantity of rain to collect in the
cinder on top of the roof slab, which, while not absolutely watertight, will still hold
a considerable quantity of water. In some cases holes have to be drilled through the
ceiling to drain this slab. In one building water from this source dripped from the
ceiling five months after the roof had been waterproofed. In another case there was
some dripping even after two years.

CATALOGUES.

Fred Braby & Co., Ltd. — A new handbook has just been issued by this
companv, and it has been specially compiled for the use of architects and engineers.
Illustrations are given of various buildings where the company's products have been
used. The various tables as to weights, measures, currency, and calculations are a
special feature of the book. The book will be forwarded on application to the company,
at their offices, Petershill Road, Glasgow, or no, Cannon Street, E.C.

CONTRACTS.

Bell's United Asbestos Co., Ltd., Southwark Street, S.E.- — We are informed
bv Messrs. Bell that a notification has been issued by the War Office that this company's
tender has been accepted for the supply, during the three years 19 14, 1915, and 19 16,
of asbestos-cement (" Poilite ") roofing slates, wall and ceiling sheets, etc., made at the
companv's " Poilite " factory near London.

CHANGE OF ADDRESS.

Messrs. Geo. Sands and Son, Ltd., engineers and contractors, inform us that
their London office has been removed from 37, Strand, W.C., to 31, Old Queen Street,
\\ estminster, S.W. ^>lephone : X'ictoria 7854.

EDITORIAL MEMOS.

CONTRIBUTIONS.— Ori(^inal contributions and
illustrations are specially invited from enfiineers,
architects, surveyors, chemists, and others engafjed
in practical or research work. MSS. should be written
on one side of the paper only, giving; full name and
address of the author.

The copyrifjht of any matter accepted for pub-
lication is vested solely in the proprietors of the
journal to be used in any form they think fit. unless
there be a special arranf^ement.

MSS. and drawinfis or photof^raphs are sent in at
the author's risk. Kvory effort v,ill, however, he
made to return unsuitable communications.

PUBLISHER'S NOTICES.

DATES OF ISSUE.— This Journal is issued
Monthly. For Advertisement Rates apply to Pub-
lisher. Matter for displayed advertisements required
by 12th of month prior to subsequent issue, for
Wants column by 18th.

SUBSCRIPTION RATES (Prepaid —Post free)
Great Britain, the Colonies, and all Foreign

countries. 1 2/6 per annum.

The Triennial Subscription is 35/- (three years).

Address reniittances to Concrete Publications, Ltd

Telegraphic Address : " Concretius London."
Telephone No.: 657 7 Gerrard.

General Offices :
North British and Mercantile Building,

Waterloo Place, London, S.W.

Agents. — For Australia: Messrs. Gordon and Gotch. For South Africa: The Central News Agency, Ltd.
For Canada: The Toronto News Company and the Montreal News Company.

'4+

/yy

CONCRETE

AND

CONSTRUCTIONAL ENGINEERING

Volume IX. No. 3. London, March, 1914.

EDITORIAL NOTES.

THE PANAMA CANAL.

A SERIES of articles dealing- with some of the constructional features of the
greatest of the world's great works in which concrete has played such an
important part — viz., the Panama Canal — appeared in our Journal in 191 1.

In this issue and a subsequent number we present two further articles,
descriptive of other concrete and reinforced concrete work on the canal.
Although the canal is not yet open for traffic, for all practical purposes the
junction between the two great oceans has been formed, and it can only be a
matter of months until regular traffic commences, and, as Mr. Leigh mentions
in his article this month, " it is not unlikely that the canal will be in fit condition
for trial navig^ation throug-hout its entire length within a few weeks after these
words are in type."

Any examination of the plans or photographs of this gigantic undertaking
must vividly impress the observer of the enormous role played by concrete
and by" Portland cement, more particularly in the construction of the immense
locks whereby the difference of level, amounting to about 80 ft,, is overcome.
Rarely has Portland cement been applied with greater care. Everything that
forethought and science could devise has been done to enable the material to
be applied to the best advantage under the difficult circumstances of locality
and climate.

That the Portland cement used was of American origin is only a matter
of course ; m fact, the undertaking was American in every sense of the word,
and preferential use was made of national materials, even where there may have
been some slight difference of price against the purchaser when the home
product was compared with ihat of other countries. Would that we in this
country were as commercially patriotic as the American nation always proves
itself to be, And then we would not find large contracts going abroad on mere
fractional differences of price, and irrespective of the national aspects of all
home undertakings and of the difficulties of supervision.

At home, in our Colonies, and e\ en in such spheres of influence as Egypt,
there is all too great a tendency to ignore the national and economic aspects
of placing orders at home, and some of our Colonies are notorious for this
failing.

B 145

FIRE-RESISTANCE IN FACTORY CONSTRUCTION. [CQNCBET E]

FIRE-RESISTANCE IN FACTORY CONSTRUCTION.

Ax ocellent paper has recenll} been read before the Concrete Institute on
" Factory Construction," the lecturer being- Mr. Percival M. Fraser,
A.R.I.E.A.

It would lead us too far to deal with the whole of the paper in this editorial,
but we take one section entitled " The Fire-resisting Properties of Reinforced
Concrete," as it claims special attention. We concur entirely with what Mr.
Fraser indicates, that hrc" damage cannot be properly made g'ood with insurance
money where honest owners are concerned, having" regard to the dislocation of
business and its effect on the output of the firm, which, as a matter of fact,
may never properly be recovered. Again, office documents cannot be replaced,
skilled workmen thrown out of employment go elsew'here, and there is always
the risk that a fire w^ill be accompanied by loss of life.

Gi\ en a really well-considered design for reinforced concrete construction
and the careful selection of suitable materials, nothing better can be utilised
in factory construction than reinforced concrete from the fire point of view.

Mr. Fraser praises the rules of the fire insurance companies in the matter
of reinforced concrete, and these rules were originally devised by a disting-uished
fire insurance surveyor, the late Mr. James Sheppard, who associated himself
most actively with the tests with constructional materials undertaken by the
British Fire Prevention Committee, and his influence generally upon the
constructional rules of the insurance companies of the last 15 years w^as of the
utmost importance. These rules have been excellent and have done immeasur-
able gc^-od, and in presenting Mr. Fraser's paper we have made a point of giving
these rules in full.

If all reinforced concrete construction, even where it does not come under
insurance tariff rates, were constructed to these particular rules no great harm
could be done, and, as Mr. Fraser says, the absence of irritating detail is
particular]}- welcome, and it should be an object lesson to the London County
Council and the Local Government Board that these practical rules could be
devised ad hoc some ten years back and do great service to the community,
whilst the wise heads of these two authorities and the various professional
societies concerned have been for some five years debating over details.

Our own \iew is that from the fire aspect it might have been well to exclude
granite and granite chippings from the insurance specification, but obviously all
such rules lend themselves to improvement, and when the next edition appears
it might be well if some slight change were made in this direction.

STANDARD METHOD OF MEASUREMENT FOR REINFORCED CONCRETE.

I.\ this issue we publish ihc draft rc})()rt of the joint Committee of Representa-
tives from \h'i Ouaiilit)' .Surveyors' Association, the Quantity Surveyor
members of the Concrclc Institute, and the Reinforced Concrete Piactice
Standing- Committee of the. Concrete Institute on a ^Standard Method of
Measurement f(jr Reinforced Concrete; and we welcome this as an attempt
to deal with a jnosl important matter which, up to the present, has been
quite neglected, 'i'here is every mtcd to standardise some method of measure-
ment, as the material has not been in g-cneral use for very many years, and, in

146

^'S^wSK'iNo^] STANDARD METHOD OF MEASUREMENT.

fact, lluMC :\vc py()\):\\)\\ niany (Jiumtily Siir\cyc)rs who ha\(' never |)rt'pare(l
hills ioi' iciiil()i(H'(l coiuictc woik, and in coiiscfpicncc lhc\ would he aj)t to
j)i'o(H't'd in such a niannci' that Iriction would arise with the contract inj^'
cui^incci in llu- pioc c ss ol sclllcnicnt, and l)y the adoption ol a standard
nu'lhod this could be ,i\oided.

We do led, however, that the method should he agreed lo hy th( London
Master Builders' Association, and, in fact, a mandatory report issued under
tlie present cMrcumstanc^es would, in our opinion, he a mistake, and a recom-
mcndaloi) one would he preferable. The (juestion as to whether the Concrete
Institute rej)resents jirofessional eng-jneers or conlractini^- engineers is cjuite
oul of place, as the standard method sug-^ested should be a fair one and involve
the minimum amount of labour, consistent with a satisfactory result, for all
parties concerned. The question of piles and pile-dri\ in^- should n-iost cer-
tainly be dealt willi l)y the committee, as this cannot be considered to come
under the headinj^- of pillars. Also, why should not concrete pipes and other
special features of this nature be included in order to cover every possible
form of concrete work? Several interesting- points were raised in the discussion^
which we reprint m conjunction with the report, one of which was the question
of taking- out the centering for foundations in units of a square. Whv should
this not be billed in square yards, as the square foot is too small? The same
might be applied to that for stairs, landing-s, and small floor slabs; and, in fact,
to make it universal, this unit could be employed for all floor slabs, roofs, and
walls. With regard to the term to be adopted for the centering or shuttering
we consider the expression '' False Work " would meet the requirements
and apply to all timbering, whether in the form of plain shuttering or temporary
props.

We hope that these points will be considered by the committee before the
report is adopted and circulated.

CONCRETE COTTAGE COMPETITION.

^^'E have received various questions from would-be competitors in respect of the
above competition, and ue are issuing a printed slip to each competitor who has
applied direct to the office of this journal for the Competition Conditions, setting
out the questions we have received and the answers that have been given.
Clause 3. — Quite a number of questions have reached us regarding this clause.
Various competitors have asked whether —

(a) Each cottage is to have a frontage of 65 ft. or whether a series of six

cottages will have a frontage of 65 ft.
(h) Is it oi)tional to treat the six cottages as all in one block?

Answer. — (a) There are six plots adjoining one another, each plot is
taken at an area of 65 ft. frontage by 200 ft. depth, or, in other words,
65 ft. frontage for each cottage or 130 ft. per pair of cottages.

{b) It is not optional to treat the six cottages in one block. The
competition is for suitable detached or semi-detached cottages, and at
the most one pair of cottages could share a boundary line.
Clause 5b. — Is it necessary for cottages to have both a front and back entrance?

Answer. — It is not necessary for the cottages to have a front and back
entrance, but whether only a front entrance be given or both, the

B2 147

CONCRETE COTTAGE COMPETITION. [0GJNQ3ETE )

entrance must in cither case be an indirect entrance whether it be to
the livini^ room or to the kitchen. In other words, no direct entrance
to any living room is permitted.
Clause io. — (a) Must beds for the inmates be shown as separate single beds, or are
ordinary double beds 6 ft. by 4 ft. 6 in. allowable?

{h) Beds 6 ft. by 2 ft. 9 in. are given for adults and 5 ft. 6 in. by 2 ft. 6 in. for
each child. Would it not be better that the dimensions be 6 ft. 6 in. by
4 ft. 6 in. for adults, and 6 ft. by 4 ft. for children?

Answer. — (a) Single beds must be shown, not double beds.
(b) The sizes for the beds must be strictly adhered to.
Clause 14. — Will a copy of the cubing figures satisfy the requirements for page 5 of
descriptive specification ?

Ans-wer. — A statement must be given by the competitor, beyond the

simple cubing figures, as to how he himself has arrived at the cost,

data, measurements, etc.

Prices of Materlals and Cartage. — A number of competitors have asked whether a

schedule of prices is issued as to the cost of materials, such as cement, sand, gravel,

etc., and the cost of cartage.

Answer. — It is not intended to issue a schedule of prices; it is left to
competitors to use their own discretion in this respect.

148

J, tTONMi?i)c-naNAi;

*V KNC.lNKl-RlNt. --.

CONCRHTli: MASONRY IN THE PANAMA CANAL

CONCRETE MASONRY

IN THE

PANAMA CANAL.

By JOHN GEO. LEIGH.

In 1911 this journal published a series of articles on the Panama Canal, but since the
publication of those articles, much additional concrete -work has been carried out, and ive
are therefore publishing tivo further articles on this great 'work,— ED.

For iIk' expeditious completion and relatively economical constriution of the
Panama Canal, the people of the United States are indebted in no small
measure to a judg-ment delivered by President Roosevelt on February 19th,
1906. Durino- the years which had elapsed since Congress authorised the
acquisition of the rights and property of the second French Canal Company
there had developed in the United States a strong movement in favour of the
completion of the enterprise as a highway at sea level. With a view to closing
this unwelcome controversy and so enable the workers on the Canal to pursue
their operations and studies to indubitably useful and well-defined ends, the
President convened a Board of Consulting Engineers, consisting of nine
Americans, a high ofHcial of the wSuez Canal, and four experts nominated by the
British, French, German and Netherlands Governments, to consider and report
upon the various plans proposed to and by the then existing Canal Commission.
This Board, as arranged, met at Washington, subsequently proceeded to the
Isthmus, and in due course presented to the Commission majority and minority
reports. These, in turn, were considered by the Commission, with the result that
there were found in favour of a sea-level cr.nal a majority — eight in number, in-
cluding the five foreign members — of the Board of Consulting Engineers and
one member of the Canal Commission ; while five of the eight American members
of the Board and a corresponding number of the members of the Canal Com-
mission, together with the latter's chief engineer and Mr. Taft, then Secretary
of War, strongly supported the construction of a canal with locks. It was
after careful study of the various papers embodying these divergent views and
exhaustive consideration of the whole subject that President Roosevelt, on the
date mentioned, transmitted to Congress a recommendation that the Canal should
be built on substantially the plan outlined by the majority of his .American
advisers.

There can to-day be no question as to the wisdom and foresight shown by
President Roosevelt on this occasion. As he pointed out in his Message to
Congress, there appeared every likelihood that a high level canal with locks
would not cost more than half as much and might be built In half the time,
that the risk connected with its construction would be less, that for large ships
the transit would be more rapid, and that, taking all the circumstances Into

1+9

JOHN GEO. LEIGH. tPQINCkii:! jlj

account, the victual cost of maintenance would be less. Concerning- the

prophecies of disaster in which the majority of the Board of Consulting-
Eng-ineers had indulged, he said little, contenting- himself with the remark that
they appeared to be vitiated by failure to pay proper heed to the lessons taught
by the construction and operation of the Sault Ste. Marie Canal, the great
traffic canal of the Xcw World, which, although closed to navigation during
the winter months, carries annually three times the traffic of the sea-level Suez
Canal. He might have added, in the same connection, that insufficient regard
had been devoted to the merits as constructional materials of concrete and
reinforced concrete.

EXPERT ERRORS.

Speaking- g-enerally, it may be said that work on the Isthmus has been
divided into two parts — destructive and constructive, and that it is upon
completion of the first, and not the second, that depends the date when the
great highway will be available for the use of the commerce and navies of the
world. \\>11 within, and frequently considerably in advance of, the estimates of
time required lor their completion, the locks and other massive structures,
together with the wonderful installations of operating machinery hidden in
their walls, are virtually ready for service. That the same cannot be said of
the highway as a whole is due to miscalculations of possible difFiculties and
dangers not less remaikable than those to which reference has been made.

The amount of excavation required to complete a navigable channel across
the Isthmus has greatly exceeded expert anticipations. The minority report
of the Board of Consulting Engineers in 1906 estimated the total excavation
necessary for a canal with a summit level of 85 ft. at 95,955,000 cub. yards,
of which 53,765,000 cub. yards w'ould be taken from the Culebra Cut; and the
majorit)- report of the same Board held that for a sea-level canal with a depth
of 40 fi. the corresponding requirements would be 231,026,477 cub. yards and
109,891,710 cub. yards. To show how deceptive were these estimates it is
sufficient to note that at the close of last year the material already removed
from the Cut, or awaiting- dredging, was double the amount originally estimated
for the entire Canal and 22,000,000 cub. yards greater than the revised and
more careful estimate of 1908. This increase has been due partially to the
widening of the bottom of the channel in the Culebra section from 200 ft. to
300 ft. and to other enlargements of the original plan. Primarily, however,
it is the rcsull of tlic additional excavation of over 25,000,000 cub. yards
consequent upon the development of slides and breaks in the banks of the Canal
prism in the Culebra Cut. To meet the c()ntingen(>y of such cavings-in, the
international experts in 1906 made wliat llie)' no doubt considered the generous
allowance of 500,000 cub. \ards! I I.'i|)|)il\', at the moment of writing, the Cut
has bc('i) .'ilmost wholly cleared, .'ind there a])])('ars every reason to believe that
the slides have r^eached ihe .-mglc of i-cjjosc .tnd will, hereafter, give little
trouble. This being so, it is not unlikely that llic Canal will be in fit condition
for trial navigation ihroughoul its cnlirc hnglli within a few weeks after these
words ar(; in 1\pe.

Under these cin unistaiKcs, il seems oppoitune to recall the series of
articles devoted to features of consl lucl ion.'il woi'k likeh to j)r()\e of special

150

l/v-Sa.Ty.',r^-| COSCRHTli MASONRY IN THE PANAMA CANAL.

.'^surasftaif

I ;i

JOHN GEO. LEIGH. [CQNCRETEJ

interest to readers of this journal which it was my privilege to contribute to
the pages of the latter some three years ago.^ All the more important
structures and installations of operating machinery to which attention was
devoted in these articles have been completed, with results so satisfactory that
there has been no hesitation in any quarter in commending the judgment of
those to whose advocacy of concrete as a building material may be ascribed
much of the success and economy of this side of canal construction. Referring
to the locks, it may i)e noted that, at Gatun, owing to the greater depth of the
foundations deemed desirable for the approach walls, and at Pedro Miguel and
Miraflores, for various reasons, the estimates of concrete required have been
subjected to the following revisions : —

1910. 1912.

Cub. yds. Cub. yds.

Gatun Locks 2,000,000 2,050,000

Pedro Miguel , 837,400 890,750

Miraflores 1,362,000 1,412,736

The actual amounts placed in the several locks and auxiliary works up to
January ist of this year were : —

Cub. yds.

Gatun locks 2,068,089

Gatun spillway 231,410

Hydro-electric station ... ... ... ... ... 7j'^^7

Gatun control house, ducts, etc. ... ... ... 2,993

Pedro Miguel locks ... ... ... ... ... , 923,438

Miraflores locks ... ... ... ... ... '1,500,525

Miraflores spillway ... ... ... ... ... 79,004

Pedro Miguel-Miraflores duct line ... ... ... 6,193

Xot the least remarkable circumstance associated with the building of the
locks has been the expedition with which the work has been accomplished.
The placing of concrete began at Gatun on .August 24th, 1909; at Pedro Miguel
on September ist of the same year, and at Miraflores, with the exception of
ro2 cub. yards laid in July and August, 1909, and 500 cub. yards placed during
February to May following, in June, 1910. Yet all the mass masonry at Gatun
locks — the largest concrete structure in the world — as w^ell as at Miraflores was
completed before llu (^nd of .May, 191 3, while that at I'edro Miguel was finished
several months earlier. Subsequent work, for which, generally speaking, only
portable mixers were requisitioned, has consisted of relatively small operations
around machinery, etc. The auxiliar\ plant of two 2-cub. yard mixers, which
li;id been ii^ service about 1 vventy-sexcn months east of the upper approach to
(ialun locks, was closed on March iilli, i(ji2, :\n(\ on August ]6th, 1913, the
dismantlement was begun of the l<'Ug<; installation on ihe west side of the locks
known as plant \o. r, a description of which, with its electric services from
the stock piles and to the ca))l(:\vays, appeared in CoNCRi-rPK and Constriic-
TIONAT, Excij\EP:Ri\(; of May, rc)r(. This plaiil dniing its four years' service

* " CoiicrcU; Constrnclioii m ilic )'aii;im;i (.;iii;il. ' ' ( ONCKKTI'; AND (^o.NSTlU'CTlo.VAL ICngINEERING,

May, Juiu;, and August, I'^ll.

I s2

ry,cr;NMPiK-noNAil CONCRETE MASONRY IN THE PANAMA CANAL

IkkI mi\i-(l ()\cT i,()00,ooo ful). y;ii(ls of roncrrtc. A tliir<l l;ii-c i)l;mt, r(iiii|)|)«(I
with 1\V(» j-rul). vard niixiis, icniaiiu-d in use a lew months longer, Ijul lor the
compUtioii of the liych-()-ck>rlri(^ power house two i-ciih. yard jiortahlc mixers
have hiH-n used. llie two l)erni and four chamber eranes, of wliieh illustrated
deseriplions were j^iven in this jouinal of June, 1912, employed at I'edro Miguel
from April, ic)io, were transferred to and i)la(-ed in ser\ ice at Miraflores
l)etw(>en Aj)rii, ii)ii, and Marc-h J()th, i()i2; and, with other herm eranes, used
lirsl at Miiallores, wimc linallv disimmtled after July of last year.

ATLANTIC TERMINAL DOCKS.
Concrete will figure very j^ruminently in the construction ol the docks at
the Atlantic entrance of the Canal and of the more extensive terminal facdities

Panama PP.

PANAMA CANAL

Fig. 2. Dock Accommodation at Cristobal.
CoNCRKTE Masonry in the Panama Canal.

planned at the Pacific end. As will be seen from the accompanying- illustratiort
{Fig. 2), the docks and anchorag-e basin provided and contemplated south of
Colon will enable vessels to discharge and take on cargo without entering- the
Canal itself. The preliminary borings at the site having indicated a good
bottom, it w^as decided to adopt the method of concrete bulkhead construction.
In the case of the works already completed or in hand, steel cylinders 10 ft. in-
diameter and spaced 20 ft. from centre to centre, were sunk to bed rock, then
filled with concrete and connected by a solid bulkhead of reinforced concrete
sheet piles, 12 in, by 20 in., driven to a point 15 ft. below^ the lowest dredging
of the channel. A steel girder encased in concrete, joining the tops of these
cylinders, and a 24-in. I beam, similarly encased and placed 15 ft. below the
water line, take the thrust of the piling. The cylinders are tied together in
pairs directly across the width of each pier, and the area with bulkheads are
filled to floor level, 10 ft. above mean tide, and co\ered with a floor of surface-

153

JOHN GEO. LEIGH.

[CONCBETEJ

hardened concrete havino- a total sustaining- capacity, including- live and dead
loads, of I, GOG lb. to the sq. it. The project provides for two docks or quay
walls on Cristobal Point and for a number of piers jutting- into the ship basin
from a mole. For the present, however, only the two docks, a part of the mole
and one pier have been constructed, the remainder of the work being- left

COROZAL

BAY OF PANAMA

Fiti 3 Kerlaimed Land at tlie Pacific Entrance. The area bounded by the main line and the Balboa branch of
the Panama Railroad has been reclaimed by hydraulic filling. See also Frontispiece.

CoNCRKTK Masonry in thk Panama Canal.

for execution as need for it may develop. The docks are 426 ft. and
1,042 ft. long- and 209 ft. wide, while the pier has a length of 1,1 gg ft. and a
width 01 75 ft. f) in. The dock superstructure is entirely fireproof, the walls
being- oi reinforced concrete, 5 in. thick, and the roof of concrete slabs,
reinforced with cxjjanded metal. In tlie su|)erst ructure there have also been used
u\)()U\ 3S^j trms of slc'l. i'or other parts of the work there ha\e been, or will
be, refjuired Oj^ steel cylinders, 152,565 cub. \ards of concrete, 402,000 lin, ft.
of reinforced roncrctc sheet pihng-, 1,500,000 lb. of steel girder and ab(Hit
800,000 II). of sled I l)eani.

THE NEW PORT AND TOWN OF BALBOA.

The frontispiece in th<- j)r(srnt issue of ( "()\cki:'|-Iv .wd Constructional
I{\(;inf:f:rin(; is a view of the j'acilic entnince to the Canal and of the site of the
P'fM't and tfjun of Ualboa now in (oiirsc of const rucl ion. As (;viden(XMl by this

'S4

J, Cr>N>TP«KTIONAL

CONCRETE MASONRY IN THE PANAMA CANAL.

I)lu)l()i4r:il)h aiul, in liilirr (lfl;iil, 1)\ I'i^. ;,, iiiiicli of llic land iiniiu diatcly
i-asl of tlu' railwav \ai(l w liicli is to !)«■ l>iiill aloiijL; llu- iiiiuT ends ol Inc piers
(It'sii^iu'd to hound oiu- side ol llu" future harl)()ur is reclaimed swainj), formerly
rMiiidiuL; from tin- l>alhoa hiaiich of the Panama Raih'oad to the main hue.
ll CON tied an ,uea of 400 acres, and ahout 5,000,000 cuh. yards ol material
lia\c I)ccn used in raisini^ its surface' 15 ft. al)o\ c mean sea Icm'I. I'or exlendinj^
tin- inner haihoui to its uhimatc |)i()])osed dimensions other s\\am|) land will
recjuiie to he dredged.

Work on the reinforced concrete lumher wharf, or ])it'r No. 1 (see /m'/^.v. i
and S), the first of the permanent improvements taken in hand in the harhour at
the PatMlic end of the Canal, was commen(\'d in h\'l)ruary, 191 i. Kssential
features of tliis erection, the superstructure of which was he^un on Dccem-
iier 2nd, 1911, and completed in little more than two months, are (a) two rows,
35 ft. apart, of solid concrete caissons, 50 in number, 8 ft. in outside diameter,
and placed on 30 ft. centres; {b) main g-irders, resting on every set of caissons
and extending- the width of the wliarf, 55 ft. ; (c) eight axial beams, bridging
the spaces between the main g-irders and heavily reinforced at their junctures
with the latter, and [d) on these supports a concrete floor, 6 in. thick.

The tops of the caissons are 10 ft. above mean sea level, and the surface
of the floor at elevation + 17. The concrete filling for the caissons, which was
reinforced from ground rock to top with four double rows of old French rails
connected by fishplates, is continued into the forms for the main girders, the
latter and the caissons being thus set monolithically. The ends of each girder
are embedded in a block of concrete 5 ft. wide at the bottom, where they join
the caisson filling, the rectangular cross-section in the parts projecting beyond
the caissons being 2 ft. 6 in. thick and 4 ft. 8 in. deep. This is reinforced with
16 bars of i in. and ij in. twisted steel, enclosed in stirrups of twisted h in.
bars.

nr<> ^^ ^o i>' C:' I*'" -i' t

a.S-

JS.'O"

ss.o

r^7

Fig. 4. Cross- ection between Piers. Ball^oa Lumber Wharf.
Concrete M.\sonry in the P.\nama C.^nal.

In the following sketch, Fig. 7, is shown the juncture of a girder with a
caisson. On the water side of the wharf runs a railway, directly over the outer
row of caissons. All beams, except the two at the wharf edges, are 15 in. thick
and 3 ft. 9 in. deep, the edge beams being 14 in. thick and 3 ft. deep. 1 he

:>:)

JOHN GEO. LEIGH.

ICGNCCETEJ

Fig. 5. Gatun Upper Locks. Luukm^ North from tlie Lighthouse on Centre Wal

Fif4. 6. Sinking Caissons for Foinidations, Mirafl(jres Upper Locks. Construction of North Approach Wall.

C(JNCRI:TK MAStiNKV IN THK PANAMA CaNAI,.

i;6

CON.STUUCTIONA

CONCRETE MASONRY IN THE PANAMA CANAL

Juncture of Girder with Caisson,

main reinfonx'niciit in llu- middle of cacli beam
consists of ci^lit i-in. twisted bars, willi stirrups
of f in. twist placed about every j8 in., and the
rail beams ba\e, as additional reinforcement at
the junction with the main girder, two i|-in.
twisted bars, extending- into the j^irdcM' from each
side, or four at eacli caisson.

Four feet below mean sea level, or 14 ft.
below the loj)s of the caissons, the caissons c)f
Balboa Lumber Wharf. the outcr row are joined together with tie g-irders,

CoNCRKTE Masonry IN THE Panama CANA...3j^^j ^^ ^Y,^. same elevation a tie girder ex-
tends from the caisson across to its mate of the
inner row. These tie girders are 2 ft. deep and 22 in. thick, and are reinforced
witli eight I in. twisted rods, with J in. stirrups. Each caisson of the inner
row is anchored by means of a steel rod, 1;^ in. in diameter, extending- about
10 ft. to a *' dead man " buried 7-2- ft. underg-round. This " dead m.an " is of
concrete, ^^ ft. by 3 ft. by 3^ ft. in dimensions.

The junctions of successive panels of the superstructure are made midway
between main girders. The reinforcing- rods for the beams extend continuously
from girder to girder, and, accordingly, for each panel the girder and the
beams extending on either side were laid simultaneously as a solid mass of
concrete. For each uniform panel 102*4 cu. yards of concrete — cement, sand
and rock in the proportion of 1:2: 4 — were used. A panel was laid every
fourth day, the interval being required for placing- the forms and the reinforcing-
steel. In its complete form, the wharf, which is 656 ft. long, presents from
below an imposing appearance of strength and durability, with a graceful Doric
effect in the sweep of beams and g-irders.

For commercial use there will be built a quay w'all, or wharf, in two
sections, with a total length of 3,235 ft., in addition to 1,860 ft. in the neigh-
bourhood Oi the dry docks, together with piers at right angles to the axis of
the Canal, with their ends about 2,650 ft. from the centre line of the channel.
These piers will be 1,000 ft. long and 200 ft. wide, with slips of 300 ft. between,
and landings for small boats at the head of each slip for the full Avidth between
piers. The main dry dock, designed to accommodate any vessel which can
pass through the Canal locks, will have a usable lengfth of 1,000 ft., a depth
over the keel blocks of 35 ft. at sea level and an entrance wddth of no ft., the
entrance being- closed by mitreing gates similar to those used in the locks. The
sides of this dry dock, as well as of one near by, having a usable length of
350 ft. and a width at entrance of 71 ft., will be lined with concrete. At the
outer end of south-east approach wall to the dry dock will be a coaling plant
capable, in the first instance, of handling- and storing 100,000 tons.

The large quantity of caisson shell required as supports for the piers and
wharves has resulted in the evolution of a special plant for its manufacture.
Of this the essential feature is a movable mixer, mounted on a flat car, which
is shunted beside the platform on which the collapsible forms and the reinforce-
ment for the sections are set up. Coupled to the " flat " is a box car con-
taining- cement, and at the other end are alternate cars of sand and crushed

:>/

JOHy; GEO. LEIGH.

fCDNCBETEJ

158

y^coNMpncTioNAi.) CONCRETH MASONRY IN THE PANAMA CANAL.

rot-k, ;ill coniUHli'd in lr:iiji and moxcd as a iinil. Wlicn llu- train is brought
()ni)()sitf to a form which is ready the concrclc is poured into the latter tliroug-h
a cluile, tlu' sjK)ut l)eini^ al)ou! i^ It. ahoxe the platform. 'llu- concrete is
allowed to set for twent\-four houis, after w liich the foiins are remoxcd lo a
spiH-ial |)lalfoi-m to be cleaned and then relnrncd to the ()])eratin^- ])latlorm; but
the c-aisson shells remain foi" three days to hai'den befoic removal to a storage

\ard

At one v\m\ of the platform on which tlu' forms are set up and iilled is in
extension on which the reinforcing- steel is assembled. As the bars are unloaded
fron-. the cars thev are l.iid in a stock pile at the v\u\ of the platform and close
to a set of steel rolls. The rods are fed directly into the rolls, which are set
to l)end them into hoops of a diameter 4 in. kss than the outside diameter of
the finished shell. The bars are set up around a wooden cage and tied tog-ether,
after which the reinforcement is handled as one piece. A iig:ht derrick mounted
on a truck picks up a set of reinforcement, carries it to one of the erected inner
forms for the shells, and drops the reinforcement around it. Then six pipes
are placed vertically around the reinforcement at equal distances to make cores
for connecting- rods; the outer form is erected; the space between iorms is
adjusted with wooden blocks, and the completed form is then ready for the
concrete. Each section of shell is i ft. thick and 6 ft. high, has an inside
diameter of 5 ft. 6 in., and contains 45 cu. yd. of concrete. In all, about
28,000 linear ft. of concrete caisson have been used in pier No. i and the
adjoining- qua\- wall ; and both concrete and steel shells — the latter being- used
in deep water because of their greater length — are filled with concrete containing*
a well-protected reinforcement of steel rails.

Extensive, indeed, almost exclusive, use is being made in the construction of
the permanent buildings in the new town of Balboa of reinforced concrete and
hollow concrete blocks. The latter have been produced on the Isthmus by what
is known as the Pauley steam jacket process. During the early part of last year
Mr. Albert A. Pauley, the patentee, was appointed by the Canal Commission
to superintend the erection of the necessary manufacturing plant, and he
remained on the spot until the work of making the blocks was well under weigh
and others had been thoroughly instructed in the operation of the machines. Of
these fourteen were obtained from the United States — two for making- founda-
tion blocks, 12 by 12 by 24 in. ; six for main wall blocks, 8 by 8 by 16 in. ; two
for corner blocks, 8 by 8 by 16 In. ; one for partition blocks, 4 by 12 by 12 in. ;
one for interior columns, 3 by 12 by 12 in. ; and two agitators for stirring the
concrete before its passage into the block machines. It is stated that each
machine is capable of turning out a block every five minutes. The blocks are
kept under a constant spray for twenty-four hours, and are then allowed to set
for about a week, when, normally, they are ready for use.

{To be continued).

159

H. KE UPTON DYSON.

ICONCBETE!

TT^rw.-^^<t;

SLENDER STRUTS^

By H. KEMPTON DYSON.

The foUoiving article has been ivrHten by the Author to further explain the question
of loads on pillars, •which ivas touched upon by him in his articles Tohich appeared in our
journal last year on the London County Council Regulations on Reinforced Concrete, — ED.

A GREAT deal has been written about the strength of slender pillars and struts, and
many formulae have been proposed for calculating the resistance of such members.
The majority of these formulae are in the nature of practical rules of a roughly
approximate character. A few have been developed upon what may be termed rational
lines, although it is always ambiguous to speak of one formula as being rational and
of another as being empirical, because the fact that the latter word signifies something
resting upon trial or experiment, or known only by experience, makes it apply in a
way to that which is rational or reasoned, for the rule derived by reasoning from
observed facts is thus itself the outcome of experience, and can only be employed in
connection with factors the values of which are derived from experiment. The common
meaning, however, is that an empirical formula rests upon the records of tests on
model or full-sized members and/or upon the results of experience in the practical use of
full-sized members, while rational formulae are derived by the application of mathematics
to the properties of materials as determined by laboratory experiments. Perhaps a
better word than " rational " would be " absolute." The kind of formulae generally
known as Rankine's and Gordon's formulae for struts are of the empirical character,
while Euler's formula is of the absolute or rational type. Of course, Rankine's and
Ciordon's formulae have been drawn up upon some sort of reasoning, but they contain
constants which are ultimately derived from experiments on model or full-sized struts.
Neither absolute nor empirical formulae can, of course, be asserted as exact, because
they ultimately depend upon properties of materials about which the very nature of
physical science precludes us from surely dogmatising.

This article is the outcome of the consideration of the extremely onerous
rules for determining the loads permitted to be put on pillars by the pro-
jjos(-d Regulations for Reinforced Concrete made by the London C^ounty Council
after preliminary revision by the Local Government Board. It is not the
purpose of this article to deal in detail with the mechanics of struts, that subject
having been so often threshed out, but rather to aj)ply to reinforced concrete
what the writer consid(;rs to be the most scientifi(\'ill}' practical reasoning in respect
to the determination of the resistance of struts which has been put forward. In the
writer's opinion the most scientific analysis of the theory of the resistance and the prac-
ticnl dfsign of sU-nder columns is th.-it given by Mr. William Alexander, M.Inst.C.E.,
in his book entitled " ("olunins and Struts." Seeing that the subject is there discussed
in considerable detail, it will be unnecessary here to go into the matter so fully as he
does in that book. 'Jhe unsatisfactory n.'iture of the older type of rule, derived from
an inadequate analysis of the problem, lias made engineers nervous in the use of such
formuLx', especially in view of the failur(; of Ouebec Bridge in t()07, which, it has been
asserted, showed that we [)Ossessed inadec|iiate knowledge as to the behaviour of struts
that were considerably larger tli.-ui those upon w lii( li experimenis had so far been made,
thereby confessing that the customary formula' could only be applied with a feeling
of security so far as tested by exjx'riments on full-size members. That, of course, is

l6o

^1*, ClON.VIUlKTICMAi:
A KNGINKKRINCi —

SLENDER STRUTS.

;in iiin.ilc faull in llic ( iii|)iriiMl lormul.'i-, .ind, .illliou^h we should Icsl formula- of \he
absoluU' t\[)c l)\ cxpcriinciil in order to sec lh.it (hero is no fundanicnlal ciror in tlicir
dt'i'ivation, we ft'<l much moic c-onlldcnl in their use because they are certain to apply
to cases outsidt liu limits of known experiments, excn if they have to be modified
slii^hth. The absolute formula' have been xcrilied by such exf)erimental work, and
Mr. William Alexander, by making several sim|)lifyinj^ approximations which make no
appri'ciable difference to the values obtained, has succeeded in arrivinjf at a very
piactical tvpe of formula of i^'eneral ap|)Iication.

The [vuc curv(> into which a strut is bent by the application of a load apj)lie(l directly
at its ends is called the elastica or lintearia. A strut will not start to bend until a load
of a certain amount is applied. The absolute formula which j^ives the limits of loads
that will start bending' may be derived in various ways, but it was derived in one way
bv Euler and is known as Euler's formula. As a strut bends more and more its
resistance to bendini^ increases, and the load that will start bendin^j is therefore not
so great as the crij)plin£^ loads. Euler's formula makes it appear that the strenj^th of
a strut varies inversely as the square of the len<;th, but this is not absolutelv true,
thoui;h, within certain limits, is nearly so. Tredi^old ori<4inally developed the type of
formula known in two forms as Gordon's and Rankine's. He assumed a length of
rectangular strut of uniform cross section long enough for bending to be likely
to occur.

Referring to Fig. 1, let

P = the total pressure or load on the strut.
/ = the length.

■■i =the cross-sectional area.
^ =the deflection at the centre produced by the load.

P
pd = the intensity of direct pressure = . •

pb = the intensity of pressure due to bending.
^ = the least diameter of the strut.
b = the breadth of the strut at right ang es to d.
w = intensity of ultimate fibre stress.
C = a constant.

If we regard the cross section at the middle due to the bending
moment caused by the eccentricity of the line of application of the load, we have : —

pb vanes as -— :;>
ba-

it being assumed that the bending will take place in the direction of d.

Then assuming that the deflection varies directly as the square of the length and
inversely as the diameter, we have —

Fig. 1.

while
Therefore

^ varies as ^>
a

bd' varies as Ad.
P I

pb varies as

I'
, or as pd-.^'
a' a

But // =pd-\-pb. Therefore u

-li^-O

(1)

A strut with pin-connected ends being twice as flexible as one having its ends fixed
in direction, the constant for pin-ends needs to be four times as great as for fixed ends.
Therefore, as the fixed-end type is the stiffest possible, its constant will be the least,
and if we call this C,, the corresponding value for the pin-ended type is 4C,.

Transposing the foregoing equation, and including the constant for pin-ends, we
have —

iiA

^2»

161

H. KEMPTON DYSON.

[CDNCKETFJ

Hodf^kinson carried out numerous experiments on cast-iron and wrought-iron
pillars, from which Gordon suggested value> of the constant C ., and the formula

is generally known as Gordon's formula. The value of the constant as given by Gordon
varies ver}- much with the form of the j)illar, namely, as to whether it is rectangular
or circular, hollow or solid. Rankine therefore substituted for the factor d- the value
i2g'- (in which ^'^the radius of gyration of the section in the direction of bending)
because, the sections on which expi-riments were made being rectangular, (/-=i2o-.
Rankine 's formula is therefore —

P= ''^. (4)

'g'

and is often called the Rankine-Gordon formula.

The assumptions in it of the strength varying inversely as the square of the
length, II varying directly as P, and that bending will take place in the direction in which
g is least, are all untrue. The one constant employed in the foregoing formula has to
provide for all possible causes of departure from ideal conditions that are met with in
practice and for all the effects of variation in the form of cross-sections, while as
employed it is distinctly empirical in that the constant is chosen so as to make it agree
with the average results of as large a number of experiments as possible, without
discrimination.

\'arious modifications have been pro]3osed in this formula to cover observed deviations
from the predicted results, but fundamentally they are all inexact, being based on
assumptions which are not absolutely true.

Absolute formulae for bent struts entail the use of elliptic integrals and are not
very convenient of application. There is no need to give the formulas here — thev are
set out in detail by Mr. Alexander, who shows that Euler's formula is only a singular
value obtainable from the general equations by setting the limit that the deflection
shall be nil.

Euler's formula is

the meaning of the symbols being given later.

Mr. Alexander goes on to show how if values are assigned to the intensity of
ultimate fibre stress (such as limiting it to the value of the elastic limit or yield point)
and to the direct compressive stress the absolute equations become determinant as to
the ratio l^/^, giving results which show in an ( xtrcnic case '23 per cent, increase on the
value of Ic ^ obtained from Killer's formula a c|uile negligible amount as regards the
calculaticjn of the saf(; resistance, though making all the difference as regards the
determinatir)n f)f the deflection and curvatur(.'. For ideal conditions of loading, therefore,
we may substitute luiler's formula for all practical j)Ui[)oses, but we must remember
that if we set a limit trj the value of p,j \\c iinill llie value of ^j//c, which shows that
below the value thus obtained no bendini; will resull and we could load the section to the
full limiting dir(!Ct stress, in practice, howe\cr, we ne\'er obtain ideal conditions, the
departure therefrom being in respect to in<t|iialities in llic manufacture causing a want
of homogeneity in the material resulting in a \aiialion in llie value of the modulus of
elasticit\- from p(jint to [joitit of ;i section, ;ni(l the w.nil ol alignment in the longitudinal
axis resulting in th(* load at ihc end of the slrul being applied out of its longitudinal
axis. These main causes rmd some mitior ones rcNuIi in a sliut deforming more on one
side th;in on another, and m;i\ all be I.Mken togelher as accideiil.il ( ccentricilx' in the
application c>f the hjad.

Mr. Alexander shows how by an .-ipproxiniat ion lliat invokes a |)racticall\' negligible

163

' <V EN(.lNKKWlN(i ^.

SLENDER STRUTS.

error wf can (•\|)r('ss the cUccIs oI .suth tccciUric- applicalioii of ihc load by the loIlo\vinj4
moiiiru-ation of I"!iilcr"s fonmila : —

(7)

/' '2 ^ A' />J
whon^ .1 - rc.i of strut.

I'l inoclultis ol elasiicity.
£' = eccentricity of line of thrust (see 7-'/^'. 2).
^ = gyration radius.
/ = moment of inertia = ^^'.
/f = l(Mi,<;th from cen re point of a curve to a point of contrary

ti ex tire (sec F/^'.v. 2 and 3).
»= distance of extreme fibre of cross-section from the neutral axis.
P = total load.

/></ = direct pressure intensity =

^6 = pressure intensitv due to bending.
;/ = permissible ultimate strength of short concrete specimen =pd-\-pb.
= qualifier of reduction on direct compressive stress. Therefore (JuA —
maximum load sustainable.
Both this and Euler's formula will now be put in a form specially suitable for
plottinj^ on a diagram.

Thus, substituting Pb = i( —pd, pd = Qu and I = Ag', in (7) we have

]]. = \/EAg'^ "^ _e .n . pd ,\
"P '2 g g u -pd ^

pdi2 g g u-pd^

h'g =

-\/ E\

e n

^ Qit\2 g'g'u-Qu^

= V

e n

V O

'' <2a'0 ^ ^ (1-Q)

Also substituting in (6)

2 Pd Oil 2 u 2s O

(8)

(9)

A formula of the Rankine-Gordon type may also be derived in another way, which
gives a form more suitable for plotting in conjunction with the foregoing. Thus : —
If a column is very stiff, then it is true that

Ps = uA (10)

while, if it be very slender, Euler's formula will be true, and

Then the equation

P Ps Pe

(12)

fits the condition that when the strut is very short strut P = Ps nearly (for in this case

——becomes negligible), and for a long strut P = Pe nearly (for in this case — becomes
negligible). Therefore, by substituting (lo) and (ii) in (12) we can write —

1 1 //.4

Ps'P, nA^-n-'EI

4ulc'A

[u:

C 2

163

H. KEMPTON DYSON. ICQNCBETE]

and P= 4,,^^.4 (14)

From (13) we obtain Ranking 's formula —

nA 4n

P= ',■> where C, = -^^ (15)

1+cA ■ ^^

■g

and also (iordon's formula —

P= pr where ^]^ ^p^j ' ^ being the numerical

i + Cf,,

coefficient in the equation I = XAd'.

From (14) we see that the value of O by Rankine's formula is —

1 _ 1

Calculations of the resistance of struts by the foregoing formulae are most easily
performed by the aid of diagrams and Ruler's, Rankine's and the modified Alexander's
formulse have been plottc^d by the writer on Fig. 3

In using this diagram, except for the Euler and Rankine lines, we need to determine

11" ^
the value 01 a constant marked ~ • —

g g
The determination of this constant depends upon our choice of c because the value
of H and the value of g are strictly determinate, depending only upon the form of the
section. In giving values for e (which is the eccentricity of the line of thrust in the
strut) we have to bear in mind the practical conditions under which struts are employed
in practice. The causes of departure from ideal conditions of true axial thrust have
already been referred to. Of course an eccentricity obtained by design is known, but
we require to gain some idea of the accidental eccentricity. F'irstly, we may consider
the eccentricity that may be due to want of homogeneity in the material, which results
in a variation in the value of the modulus of elasticity from point to point of the
section, and causes a want of coincidence between the geometric axis and the neutral
axis. This is very clearly shown in the case of the ordinary theory of the position of
the neutral axis in a reinforced concrete beam where two materials of very different
moduli of elasticity are being used. In a steel strut we know that the material will
show a very appreciable difference in the modulus of specimens cut from different parts,
which means that if the section be loaded it will give way more in one direction than
in another, and the neutral axis will therefore be disjjlaced from the geometric position.
In a reinforced concrete pillar, as a rule, the steel sections are symmetrically placed,
but whfthcr due to incorrect placing, or whether from the somewhat greater risk of
want of homogencits' in the concrete, the neutral axis of the combined section, in which
the steel has a different elastic modulus to the concrete, will surely not coincide with
the geometric iixis. Internal stresses are, of course, another minor cause of irregularity.
.Such intf-rnal stresses may result b\' contraction of the concrete or b\- the rolling of
the steel and even by changes of teiiipeialure. The \ariation in the modulus of elas-
ticity will in all probability take place o\er a smaller range as the sectional area
increases, br•(au•^e witji the larger section the average value would he more uniform.
Then again, the longer the (olunin the grealei- |)i()hal)ilily of uniformit\', because as
the length increases the lunnber of ( ross-scclions increases, and with it the |)robability
that variations in the modulus will not lake place in the same direction in all of the
sections, so that one will iieutt;ilise the other and the resulting effect on the wdiole
will decre<ase. Therefore wc may say that any ( c( ( iitii(il\- in the load due to \'ariation
in the modulus of elasticity will show a decrease with an increase of the lateral dimen-
sions (which is the samr- thing as saying the radius of gyration) and with increase in
the length of the strut. The net residt is therefore j)robal)ly that variation in the ratio

164

y, C^UN.vrUMK-nONAL
»^ L.N(ilNhl.klNti — ;

SLENDER STRUTS.

Values of Q (Redact/ on c^ua//f/er for O/recf Stress)

Fig. 3.

[Copyriglit reserved by author.]

of Ic g ^"^'ill not appreciably effect any variation in the accidental eccentricity. The
second and most fruitful cause of eccentricity is inaccuracy in workmanship, whereby
the strut is not properly centred or put in true alif^nment. We should expect that any
difficulty in manufacturini^- the strut and putting it -nlo place so as to secure axial
loadin<:^ will certainly not be decreased with an increase of its length. Therefore it
should be assumed that the longer the strut the greater the accidental eccentricity due
to inequality of workmanship. Finally, we have eccentricity due to the application
by design of a load out of the centre. This, however, is of known value, and may be
ignored when we are endeavouring, as at present, to arrive at some reasonable values
for the two causes of accidental eccentricity before referred to.

In building work it is seldom that columns are fixed at one end and are free, or
merely hinged at the other, although, perhaps, in the majority of cases the colurnns are
not properly fixed at the ends. As to what value should be given to the accidental
eccentricity due to variation in the modulus and internal stresses, we can only go by
experimental data, from an inspection of which it would appear that we should set

i6;

H. KEMPTON DYSON. ItQNCKETE

the limit undtr the vei v best conditions — i.e., in the case of struts which are adequately

fixed at the ends — that the value— should never be less than o'l.

We now have to derive a reasonable value to take for the eccentricity that may be
due to a strut not beinif set in its true alignment. The mere placing of a strut out
of centre, apart from the question of it being inclined to the line of thrust, is not likely
to vary much in amount with variation in size, and consequently becomes less serious
as the lateral dimensions increase. Such variation is already sufficiently provided for
bv the foregoing allowances. The difficulty of setting a pillar upright is, however, an
important matter. If we assume that in practice a short pillar 5 ft. long may be put
h in. out of the upright, and that this might be increased to i in, in the case of a strut
10 ft. long, we couki express this as a rule by taking the eccentricity in inches as o'oi/.
The possible eccentricity due to variation in the modulus becomes negligible in such
cases compared with this eccentricity due to imperfect workmanship, and may be

ignored, so that the writer arrives at the conclusion that the accidental value of -

should in no case be taken as less than o'l, and otherwise that the value should be
derived by assuming e to be either o'oi/ or one half-inch, whichever is the greater. The
accidental eccentricitv due to inclined setting of the pillar derived in this way will be
fully effective in the case of a pilar fixed only at one end and perfectly free at the other,
as shown in Fig. 2, but will be reduced in the same proportion as the total length I is
reduced to J^. bv being forced to bend in various ways for various manners of end
holding.

In order to apply Alexander's formula we need to ascribe values to the other con-
stants, namely, Z^., E and u. As regards the latter, namely E and u, it must be recollected
that the formula applies solely to the limiting condition of the practical ultimate strength.
Indeed that also is the case with both Rankine's and Euler's formulae. In the case of
steel the modulus is only fairly constant up to the yield point of the steel, but as the
values we have taken above for determining the accidental eccentricity provide for
variations in the modulus, the limiting values become^ =30,000,000 lbs, per sq, in,,
and M = 50,000 to 55,000 lbs. per sq. in. in the case of steel, the latter being the yield
point, and the ultimate compressive resistance for ordinary mild steel. In the case
of cast-iron, timber, stone, and plain concrete there is no uniform value of the modulus,
this becoming less as the stress increases. We may, however, tak(^ the average modulus
over the whole period of loading; thus we derive the value of E by taking the ultimate
stress and dividing it by the ultimate strain. In the case of a compound section of two
materials like reinforced concrete, we are faced with the difficulty that the concrete has a
variable modulus while the steel has a comparatively imiform one, and therefore the rela-
tion of the one modulus to the other is constantly changing, which means that the equiva-
lent section, namely, that in which the ai ea of the steel is nuilli|)lied /u-fold, in being the
ratio of the moduli of elasticity, EslEc, '^^ likewise continuously changing. The diffi-
culty is, however, solved for us by the simple consideration of what happens to a
reinforced concrete pillar when it is loaded to destruction. We find that as the stress
increases the concrete is strained faster than the steel, and consequently the stress on
the steel is continually increasing at a faster rate than the stress on the concrete until
at the ultimate load the concrete is carrying all that it is al)le to sustain and the steel
is forced in turn to carry the remainder of the load up to its maximum resistance. The
two materials therefor(,' break down together. Assuming, therefore, that the steel has
a uniform mfjdulus, up to that j)oinl, of 30,000,000 lbs. per sq. in,, and that
stress-^strain ^modulus, as the strain is the same for both materials we have the
relation : —

Strain lu ! u c — Eslu $

tic
frfjHi which Ei E<,.

lis

Supposing, therefore, we li;i\c ,1 (OIK I etc wjiosc uliiinale compressive resistance is
2,400 lbs. per sq. in., win 11 iIh ujiinialc coiiiijressivc! strength of the steel is 50,000 lbs.
per sq. in., we find from the above thai the nuxluhis of the concrete

Ec = 30,000,000/ ^'^°^- - 1,440,000 Ihs./in,"

166

fj, CrJN.vrkMKTIONAI
L*^v t-NC.lNt-I RINC, — .

SLENDER STRUTS.

30.000.000
or He- 3^^^^^,^ .,/,-600..

Tlie niodiilnr ratio will, of course, be m

Rs Its 50,000

Hi u uc

'i"o juslify ilif ;uI()|)lion ol 5(),()()() ll)s./in- as the ultimate stress in the steel, the
spaeiiii^; of the links should he close tiioui^h to enahle this stress to he developeci in the
rods ici^ai'dcd as slender sliuls in themselves, i.e., the pitih of ihe laterals shoidd not
be i^ri'ater than \{) times the diameter of the least vertical bar.

In choosinj^ aN'eraj^e values for the idtimate (H)mpressive resistance of concret<', it
should be remembered thai the limits customarily set to the minimum strength required
by specifR'alions, re])orls and regulations to be shown 1)\ tests on moulded cubes do not
represent axcrage \alues nor the actual strength of concrete as put into the work in
practice. The author has already dealt with this in an article on pp. 604 and 605 of
the issue of C^oxcRiiiE and Constructional I^\(.infkking, Vol. N'lll., Xo. 9, Sep-
tember, 11)13. The average strength in practice \\ ill i)ossibly be 20 ])er cent, higher than
the values obtained from test cubes, while in the event of the maximum stress being
realised only on the extreme libre the ajjproximately parabolic stress distribution due
to variation in the modulus of elasticity of concrete as the stress increases will serve as
an additional reason for trd^ing a higher value than the limit set for test cubes.

It onlv remains to find the value of /, • This, of course, will vary for different
conditions of ends and for different values of the eccentricity and different ways in
which it is applied. An exact solution is difl'icult to derive, and the usual conditions are
generallv not de])arted from sufficient ]\- to make it worth while determining its exact
value. Indeed, to do so would mean emj:)lo\ing the long, unmodified absolute formulae,
and considering the other factors are not known with any great degree of accuracy it
would be in great part a waste of time. The value of I^ is therefore best derived for a few-
standard cases and under ideal conditions, namely, by Euler's method.

In the case of a strut fixed at one end and free to move at the top (as in Fig. 2) the
value of I ^ is obviously equal to /.

In the case of a strut hinged at bcnh ends and maintained in the same lateral
position, the value of /^ is I/2, the form of flexure being shown on Fig. 3.

If both ends of a strut are rigidlv fixed and held against turning, the elastic curve will
have two points of inflexion, and from symmetry the tangent to the elastic curve at the
centre must be parallel to the original position of the axis of the strut. Therefore the
portions of the curve must all be sxmmetrical, and consequently the points of inflexion
occur at one-fourth the length of the strut from either end, and we get h =?/4.

This may. however, be derived mathematically as follows (see Fig. 4) : Let both
ends be fixed against turning by a moment M at each support. Then the moment at a
point distant x from O is Mx = M — Py, and the equation of the elastic curve is

EI. '-j^l = M-Py.
ax'

Integrating w^e have

J ==^ sin ( ^ V£j^ + B cos ( X V£) + 1

in which .4 and B are constants, which can be determined by the conditions that y =

when A- = 0. We find thereby .4 =0 and B=—^—' Also i; = when x = L There-

P -^

fore we have B cos I /V — W— =0. Likewise — = when a = / : therefore

El P dx

From these conditions,

cos

V EU

167

H. KEMPTON DYSON.

lOONCKETEi

and

whence

from which
Also

and

M ( a/1^\ , M

r/-T

Equating "t^ to zero, we have

cos

xVl=0

P
EI

and

\ — =: - or —
El 2 2

But as /V" = 27r, then V — = -
EI EI I

whence x= ~ or -/.
4 4

.^^

Fig. 4.

Therefore the points of inflexion are situated / 4 away from the ends.

In the case of a strut fixed at one end and hinged at the other, but not maintained
bv the hinge in its original lateral position, being guided instead into a position where
the lateral movement of the free end is half the total deflection, the elastic curve has
ix>ints of inflexion at one-third and two-thirds of the length, as shown in Fig. 3, and

(To be continued.)

168

J, coN.vrymTioNAi

REINFORCED CONCRETE GRAND STAND-

,i$|,U /« GRAND STAND. 4

i. Vlit s-rT^-- HURST PARK

RACECOURSE.

^•---^

Reinforced concrete is f^st replacing timber for structures such as ttie one described in the
present article, and ive ha've already gi'ven -various examples of grand stands erected not
only in this country but in the United States. As indicated in the article, reinforced concrete
is particularlv suitable for buildings of this description, as there are practically no main-
tenance charges. Our article has been prevared by Mr. Albert Lakeman, Hon. Medallist
Construction.— ED.

Owixd to tlic limber stand liaxiiii^ hci-n destroyed by lire, it l)ecanic necessary
to reconstruct the t^rand stand <it Hurst Park Racecourse, and advantage was
taken of this necessity to increase the accommodation, and at the same time to
employ reinforced concrete as the material for the constructional m-embers, to
pre\'ent a recurrence of a disaster of this kind.

The new stand, as now completed, is one of the most up-todate and com-
modious in the country, and it requires no maintenance, which is a very im-
portant consideration. The total len^-th of the stand is 164 ft., and the width
52 ft., while ir has a heig-ht of 36 ft. from the ground-floor level to the eaves.
There are practically three floors, apart from the ordinary accommodation, which
is capable of taking 7,500 spectators, and these floors are utilised for luncheon-
and drawing-rooms and cloak-rooms. The luncheon-room on the ground floor
for members is 62 ft. 6 in. by 39 ft., and in addition to this there are two grill-
rooms, each 37 ft. 6 in. by 39 ft., one of which is for the use of members and
the other for reserved enclosure ticket holders. The kitchens are provided on
the first floor, and these are extensive and fitted up in an approved modern
style, with every facility for efficient and quick service and cooking. The
remainder of this floor is devoted to cloak-rooms for ladies and gentlemen.
The second floor is designed to provide a suite of drawing-rooms, which are
tastefull}- furnished and enclosed on both sides with glazed framing, which
enables the users to watch the races in complete comfort, even in the most
inclement weather. A splendid view of the entire course can be obtained from
these rooms through the front windows, and at the back a view is obtained of
the paddock, the casements being arranged to slide, thus enabling the rooms to
be opened up during fine weather. Every effort has been made throughout to
provide the maximum amount of comfort for members and others using the
stand, and a central heating- apparatus is installed for heating the building
throughout.

The general heights and arrangement of the different floors can be seen
in Fig. I, which is a cross-section of the stand. It will be noticed that the
existing retaining wall at the front is utilised, and that the kitchens conie behind
the tiers for the spectators, and thus no space is wasted. The whole of the

I 69

REINFORCED CONCRETE GRAND STAND.

ICQNCBETFJ

reinforced concrete work was desig-ncd and executed on the Mouchel-Henne-
bique system, from details and drawings prepared by Messrs. L. G. Mouchel
and Partners, Ltd., of Westminster.

The genera! effect of the back of the stand, whicli is shown in the photo-
grapli in Fig. 4, is interesting, as it will be noticed that the horizontal and
vertical lines are obtained hv the reinforced beams and columns, while the
panels are filled in with Mouchel patent monolithic hollow-block walling, rein-
forced throug;hout and finished on the exterior with rough cast. A cross-
section showing; the constructional members is g"iven in Fig. 3, and it will be

■STEEL STANCHION

EjriSTiNG
«?ETA'.NINQ WAuT

S - .';«i\

DRAWING ROOM

LUNCHEON ROOM

.j.^'^'-^'-*-

KITCHENS -^

''JFt-J.-'-^.'-'.^^Tr^

li^!. ] Cross Section of Stand.

RKINIORfEO CONCKEIK GkANI) StAND, HlKSl FAKK RaCKCOURSK

seen ili.il ihcre are three longitudinal rows of columns S])a(^e(l at 12 ft. 6 in.
centres. 'i"hc s];;icing was .dso (•(|iial to this amount in the longitudinal direc-
tion, thus di\i(iing the l);i\ s n|) into jxTlcct s(|uar('S.

These columns are all 1 ) in. sfpiarc, and they are reinforced with four
lines of x'ertlral rrinfort ( incnl , with links at 4 in. centres, and they have a
reinfijreed cont rele hjnnd.iiion ^l.il) .| ft. s(|nare and 5 in. lhi(-k at the extreme
out<;r i-(\^c, inrreased lo 1 ll. ] in. al iIk jyoint of inlerseelion with the column
shaft. TIh; slal.s aic reinlorccd wilh a lallice, consisting of rods in both direc-
tions in the undeisifle, with comieciing stirrn|)s lanniing up to a similar lattice

170

OON.STUIKTICMAL

REINFORCED CONCRETE GRAND STAND.

^Tlg 1)4 i^/^*

Se.c:T»or-* P' ' V^

Fif,'. 2. View Showing Section of Stand.

Fig. 3. Cross Section.
Reinforced Concrete Grand Stand, Hurst Park Racecourse.

171

REINFORCED CONCRETE GRAND STAND.

(CQNCBETFJ

at the le\'el of about the centre of the deptli. The ir.ain column rods are turned
out at right ang'les at the bottom to assist in tlie distribution of the weig^ht.
The slabs forming' the lloors are designed on tlic continuous principle, and these
are 4^ in. thick, with small bars in both directions and surfaces, and the main
beams, as shown in Fii:;. 5, arc ih in. or 14 in. deep and 7 in. or 8 in. wide,
and reinforced with cither lour !)r ciglil rods, according' to the load, half of the
number being- placed in ihc upper and half in the lower surface. The two sets
of reinforcement are connected by links, and where no rods are required in the
compression area some of the bars are cranked up at the ends, and stirrups
are provided at variable distances.

The stepped portion which slopes back at the angle shown in the section

V'\fi. 4. \'iew Shovvinf4 liack of Stand.
KEiNroRCEi) Concrete Grand Stand, 1 1 lust Park Racecourse.

is lorn"iC(i wilh treads 2 It. <> in. wide, and risers 1 It. 3 in. high. A detail of this
W(jrk is shown in I'l^. -', and il will be seen that two longitudinal rods are
placed ill llic sollii (lose to the intersection ol tread and riser, with stirrups
carried well ujj into the mass ol the concrete. in addition to this, transverse
bars are prtAided in the sollil which are cranked to pass o\er the longitudinal
r(jds in each case.

The raking" bf;ams supporling the slo|)ing |)orlion lake a b( :iring on the
retaining wall al the loot oi the slope, the old concrete at the top of the wall
being broken oil and rebuill wilh ihe beams to lorm a monolithic c-onsl ruction.
The whole ol tlw slniciiirc,- is coxcred by a tool ( omposed oj steel trusses and

I 7?.

J , CONyrUUCTlCMAU

RIiINFORCHI) CONCRETE GRAND STAND.

■ ~ H

'— r

, U

-«:::

1.?

EVA

. e .

. /,<«,

*** -

:>,

*•
1

•

l<o

._L4 ._

I m il

111

12 <«=> —

TT=?

J>L

Fif4. 5. Reinforced Concrete Main Beams.

i7crA.L Or <^-.iovi>i-i A.13^«cl<..

■ o

r 1

■

■y

■]

"s-

L 1

Fig. 6. Detail of Column. Detail of Slab.

Reinforced Concrete Grand Stand, Hurst Park Racecourse.

173

REINFORCED C0NCRETE2GRAND STAND.

[CQNCBETEJ

174

(K, OCffMM UUCriON A UI

RHINFORCHD CONCRETE GRAND STAND.

purlins, coNi'icd with wiouLjlil hoai'dini; , upon w liicli is l;ii(l ;i non-tl.inini.ihlc,
(lur;ii)lc' loolui*; in;iU'ri;il.

'llir whole schriiU' is well |)l;iMnc(l ;in(l consl rucl cd in such a niainifr that it
is hri'-rc'sistinj^ and durahlr, and will rcijuirc j)i'a('t icalK' no n^.ainlcnancf, while

Fii^. 8. A Corner of the Grill Room.
Reinforced Concrete Grand Stand, Hurst Park Racecourse

its appearance is simple and pleasing. The contractors for the general con-
struction and reinforced concrete work were Messrs. Stephen Kaxanagh and
Co. , of Surbiton.

»7S

STANDARD METHOD OF MEASUREMENT.

ICQNCKETEJ

"standard method

of measurement

for reinforced

concrete,

The following is the Draff ReportZof the'' Joint -Committee
of Representatives from the Quantity Surzieyors' Association,
the Quantity Surveyor Members of the Concrete Institute,
and the Reinforced Concrete Practice Standing Committee of the Concrete Institute,
presented at their 43rd Ordinary General Meeting, A Discussion folloived, of ivhich loe
gi've a short summary. — ED,

The follo\vinj4 Draft Report was presented after the Committee had held several
me€tin<^s, and the Report is accompanied by the followins:^ recommendation : —

''That the method of measurement as compiled by your representatives and as copy
enclosed be adopted, signed by the signatory bodies, printed, registered at Stationers'
Hall, and circulated among the Members of the Concrete Institute and of the Quantity
Surveyors' Association."

The Committee further recommended that in cases in which the working details
are not complete engineers indicate for the guidance of their surveyors when preparing
the quantities the thicknesses and weights of reinforcement as shown upon the
drawings herewith.

In submitting the report, Mr. S. Bylander (Vice-Chairman of the Reinforced
Concrete Practice Standing Committee of the Concrete Institute) stated that in order
to further the interest of reinforced concrete, simplification was necessary. The chief
thing to be aimed at was to obtain a result, and the means to this end should be as
simple as possible. If any part of the work entailed too much ex[)enso, it was their
duty to reduce that amount of work so that only useful work would be necessary.
Undoubtedly, when using a new malcrial, it afforded a better oj)jjortunitv to
standardise. He thought the Institute had done well in asking the Ouantitv Surveyors'
Association to join hands with them in trying to draw up something which would be
of mutual advantage to professional engineers as well as to quantity surveyors.

Th(; Quantity Surveyors' Association and the Concrete Institute would ultimately
deci(l<- on the final form, after having heard the criticisms of that meeting.

With referrnce to concrete generally, the Committee had, in carrying out the
general idea of siinplifKalion, decided to adopt the foot as a unit, and not the yard,
in order Ui a\'oid mistakes and unnecessary transference from one unit to another.
It w<is certainly to the intere^t of every professional institution to work together in
advancing the knowledge of the subject, and to nduce the amount of unnecessary
cU-rical work in order thai ihey might concenlralc their minds u|)()n things that
mattered, and by using one imit they could allain thai obj(ct.

As to the ta!)ulated form which aciompanies ihe second rej)()rt, this was not
intended as a bill of c)nantities to present to the buiNh r, j)ui onK' as a sheet in which
th(' details of the quantities were given fiom ihe diawings, so that they could at once
trace the quantities allow<(i for on the d. si^^n. lie tlicn <^ax(. ,-, dctaiU'd e.\j)lanati()n
of the various headings comprised in the sluct.

1-6

», CCJjSl.v I PI (CTTOJa L

STANDARD METHOD OF MEASUREMENT.

REINFORCED CONCRETE.

Suggested Method of Measurement.

'I'hc \V(irk on cich lloor to he k(|)l separate, slatiiij^ the heif^hl from the ji^round
to the se\-eial llooi^.. Keep concrete, centerinL,^ and reinforcement for each Hoor
toi^ether. No i(inloi"ceni( nl to he deducted from the concrete; otherwise all measure-
ments to he net unless stited, and notw ithsLindini^ an\ trade custom, to the contrary.

CONCRETE.

h'orxDA rioNs. |)er ft. cu.

Basks to pillars, jxr ft. cu.

Waii.s (.State each thickness separateh ), jxr ft. cu.

TiLi-AKS (.State " a\-eraj4ini4 " or " rauLdnj^" from to "), per ft. cu.

Floor .Slabs (Measure across heams; state each thickness separately), per ft. cu.

Hi:\Ms (Measure helow sol'lh of lloor slal) ; state " averai^ini^ " or " rani^inj^

from ti) "), per ft. cu.

RoOP'S (State slopes over 30 degrees sei)arateh- to allow for fdlin^ hetween double
centering), per ft, cu.

CiiASKS AND CiROOVK.s, Etc. (Whether cut or formed to be described), per ft. run.
HoLE.s, Mortices, Etc. (To be described as either cut or formed, and size, dejjth,
or thickness of concrete given), each.

CENTERING. SHUTTERING, etc.

Each variety of centering, shuttering, etc., to be measured separately. Poth
sides of concrete requiring double centering to be measured.

Foundations — Vertical, .splayed or circular, per sq.

Walls — \'ertical, battering or circular on plan, per sq.

1-^i.ooR .Slabs — Raking, circular on j)lan, or radiating (measure net between beams;
the radiating centering to be described as including all cutting to radiations), per sq.

Ditto, in S.mall Pieces, Landings, Etc., per ft. super.

Pillars — All centering, etc., to include for strutting, timbering, wedges, etc.;
square, circular, octagonal, or other shape, to include all cutting and waste; bases
and caps for pillars, giving size, to be kept separate, per ft. super.

Bea.ms — (To be measured as girth of beam from underside of floor slab onlv,
'■ including all labours"; state if radiating or circular on jilan or elevation, including
mitres), j)er ft. super.

Roofs.- — Flat, raking, segmental, semicircular or elliptical (measure both sides
if over 30 degrees slope), per sq.

Return Edges of Openings in walls, floors, or roofs, per ft. run.

Soffits of .Stairs — Raking, flewing or circular on plan (to be described as
including cutting and waste), per sq.

Mouldings — Over 12 ins. girth, per ft. super.

Ditto — 12 ins. girth and under, per ft. run.

Mitres, .Stopped Ends, Etc., each.

Return Edges of Concrete Floors, .Strings and Risers of Stairs, per ft. run.

Circular or Raking Cutting and Waste to be measured to all irregular surfaces
of walls, floors and roofs, per ft, run.

Key Blocks, Consoles, Etc., giving full size and description, each.

Splays, Chamfers, Reb.^tes, Rounded Angles, Etc., to be described as including
fillets and moulds, per ft. run.

REINFORCEMENT.

Ordinary steel bars from \ in. to 2 ins. diameter may be included under one
heading (stating the diameters). Bars under \ in. and over 2 ins. in diameter to be
kept separate. Bars over 30 ft. long to be kept separate.

All w'ire ties (exclusive of helical or horizontal binding or stirrups) to be included
in the description of the reinforcement.

D 177

STANDARD METHOD OF MEASUREMENT.

ICDNCBETEl

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178

y,CONMU>lKriONAl,

STANDARD METHOD OF MEASUREMENT.

The (.lilTcrtiit items of r( inforccnicnl lo he kept >(|).ir;itc as described for
*' (\)iKM('te " and " CenterinjLi, Sluil teriiiLi, etc."

SiKKi. Raks Slate " iiuludiiii^ all bends, hookeil ends, etc., and Jixin;^ at any
Ie\('l, in an\' position," |)ei' ewt.

SiiKiars \\n I>!\I)IN(. lloii/onlal oi- belieal, jxr cut.

M i:mi\\()KI>: Ri.im ()U( i:.Nn:N i sup|)lied in sbeets oi- rolls to be measured " ik t
{i.e., no allowance made in llie measurement for ]a|)s or for straight cuttinj^ and
waste), including all labours for bendin<f, elc, per \(1. sujxr.

Rakinj^' and ciri'ul.ar cuttini^ and waste 1o ditto, per ft. run.

.1 draft report was also prrsculed by the Reinforced Concrete Practice Standing Com-
mittee recommcndi)ig that a standard tabulated form for preparing quantities for
reinforced cofjcrete work be adopted. Hie CoDiniittee subi)iilted a form witJi Jieadings
for co)isideratioti and discussion.

DISCUSSION.

Mr. George Corderoy, Assoc. last. C.E., slated that with regard to reinforced concrete
they were happily not hampered with any ancient customs of measurement. Nevertheless, he
thought that if they left out any of the ancient practices in preparing a bill of quantities, unless
they were careful to safeguard themselves in some way, they gave opportunities for claims for
payment on the score of custom. He regretted that the Committee had not the full courage
of their convictions to adhere to the foot unit for centering and shuttering for foundations and
walls. There was really no merit in the term "square" as applied to a great many items of
foundation work, and the term " foO't " was very often used for centering. He gathered that
the guiding principle of the surveyors who had drafted the Report had been that which had
practically governed the preparation of ordinary quantities, namely, that no manufacturinsJ
labours were included, but only fixing labours.

In conclusion, he moved that the first recommendation should read, " That the method of
measurement as compiled by your representatives and as copy enclosed be recommended for
adoption by surveyors practising in measuring, and quantity surveyors, signed by the signatory
bodies," etc., thus making the resolution recommendatory and not mandatory.

Mr. G. C. Workman agreed with Mr. Corderoy that it would have been better to have kept
to the square foot in centering, shuttering, etc., for foundations and walls. He understood
that the reason for the adoption of the square was that contractors were in the habit of buying
their timber by the square. He thought that a medium might be found between the square and
the square foot; the square was too large, and the square foot was too small. That would
apply also to floor slabs, roofs and soffits of stairs.

Mr. Alan Paull, F.S.I. , suggested that, as bases and caps for pillars were of various
sizes, if kept separate, as recommended by the Committee, it would lead to a lengthening of
the bill. He further suggested they should omit the words " giving size," and substitute " in
so many," in connection with the measurements of pillars. He supported the Committee's
adoption of the square as against the foot because it showed that a large quantity was being
dealt with.

Mr. Bylaader pointed out that it was only intended that the bases and shuttering should
be kept sei)arate from the body of the column or shaft.

Mr. F. B. Wentworth Shsilds, M.Inst.C.E., thought that it would be well to standardise
as to whether the driving of piles should be charged as a separate item from the making of
them. He noticed that the Committee had ingeniously got over the difficulty of having six
different names for shuttering by inventing a new one. He suggested that, instead of coining
a new word, which was alwav^s difficult to popularise, they should adopt the American term
'' False Work," which covered all the Committee meant to convey. He inquirtJ whether it
would not be well, when describing the floor slabs under centering and shuttering, to state that
the price should include temporary props?

Mr. P. F. Gleed, F.S.I. , thought that their object as surveyors in preparing bills of
quantities was to give the contractor such information as would enable him readily to obtain
a correct value of the contract to be executed, and they should do that irrespective of tht
amount of trouble it caused themselves. He thought it ought to be cleared up in considering
the suggestions before them — whether the Concrete Institute represented professional engineers
or (ontracting engineers.

I) 2 179

TANDARD METHOD OF MEASUREMENT. [CONCRETE]

Mr. W. E. Davis felt that there was a good deal in the suggestion that the use of the
square as a unit in regard to shuttering for foiuidations, vertical, splayed or circular, was
rather a large order. The question of pile driving was a most complicated matter for a
quantity surve\or to deal with, and he was sorry that the Committee had not tackled it. He
thought that the diagram which the Committee had prepared would be of immense value to
quantity surveyors.

Mr. G. At. Nicholson, F.S.I., seconded IMr. Corderoy's amendment. He agreed with Mr.
Davis that it would be a benefit if some suggestion were given for dealing with concrete piles,
as the latter could hardly be considered the same as pillars. It would be an improvement to
the report if they could have some guide as to the measurement of concrete piles and the
driving of them.

Mr. A/baa H. Scott, M S.A., who had been prevented from attending the
deliberations of the Committee, was sorry to find himself at cross-purposes with
soaie of the recommendations. He had yet to learn that it was only engineers who had
to deal with designs for reinforced concrete. He ventured to suggest that, in dealing with
concrete roofs, no district surveyor would allow concrete to be worked with only single center-
ing for a slope of over 30 deg. He had never carried out work of this kind with more than
a 25 deg. slope, and too much risk was being run at that ; 18 deg., he thought, was the limit.
It was a pity that they had not asked the opinion of the London Master Builders' Association
and the R.I.B.A. before they issued the report. He suggested that in the L.C.C. Regulations
there were a lot of good definitions for the various terms employed in the work, especially for
centering, and he thought that much of the discussion that evening would have been avoided
if the Committee had adopted the terms used in the L.C.C. definitions.

Mr. R. Graham Keevill, A.M.IMech.B., suggested that pile work should be classified
under two heads, cutting and driving, and moulding. Included in the price for driving should
be given the cost of scantling. Cylinder work did not appear to have been dealt with, and
perhaps the Committee, in elaborating their report, would deal with the question. He
presumed that the form given would take into account the beamless floor, which seemed to be
a thing of the future. Although America appeared to have a monopoly of it at the present
time, there was a possibility of this becoming a standard thing in this country in the future.

Mr. E. Fiander Etchells, F.Pbys.Soc. (Chairman of the Science Standinig Committee,
C.I.), said their one aim was simplicit^^ They would always have difficulties until it was
made clear whether form work included strutting, and whether centering included sheeting.
The\' were building up a terminology for a comparatively new subject, and it was their duty
to buila foundations in such a manner that those who came after them would be able to take
them down.

Centering, using the word in its widest sense, comprised three kinds of timber — sheeting,
battens, and strutting, and they wanted some term to cover the three. After an exhaustive
investigation of all available te.xt-books, it was found that the majority of persons used the
term centering. He thought that there was considerable misapprehension as to the derivation
of the word " centering," many people being of opinion that it was an Americanism. The
word " center " was derived from an old French word, meaning the timber work used for
supporting a structure during its erection. It so happened that structures which most required
supx)ort during erection were arches, some of which had one centre and others three.

The point had been raised as to whether the members of that Institute were professional
engineers or contracting engineers. It was rather a difficult question to answer, but they had
examined themselves and found that five-sixths of them were called professional engineers, and
one-sixth specialist engineers.

Whether they decided in favour of the term "' forin work" or "centering," it would be
advisable to ask the Local Government Hoard to adoj)! that word, as the Regulations had now
left the hands of the County Council, and were now under the consideration of the Board.

Although they were a sjjecialist society, he thought it was advisable that their report
should be recommendatory rather than mandatory, because they were the youngest specialist
institution and ought not to dictate to older societies. It was a (piestion as to whether anyone
was competent to lay down a rule for another autliorily in matters where i)ublic interests were
not concerned; moreover, as there was no penalty aftaclicil, they could not enforce regulations
which they sought to imiK>se.

Mr. Perclval M. Fraser, A.RIBA., agreed with the observations of Mr. Alban Scott.
He knew what the <>i)inion <>\ llic |{uilders' Association would be. An expert estimating clerk
would imt his i)en through all this and a^k for lliicc llc-nis. He strongly deprecated the
reduction of the units from yards cube to feet cube. \vlii(Ii entailed very great labour and
greater risk of error. It was ridiculous to measure pile^ so inu( h per yard cube for the concrete,
including driving.
iHo

y, CONM U'lliriONAl,
« V tN( il N Kl klNd --

STANDARD METHOD OF MEASUREMENT.

Atr. T. J. Carlcss. I'icsidcnl ol ilu' (.)ii.inlit\' Survcxors' Ass<)( iiilion, had /,'rt;it pleasure
m Mipportiii},' (lie rc'pori of the Joint (ommiltee, and ihouKht llial ilir l'ri'si<lenl of the Concrete
Institute would be cpiite willing to accept Mr. Corderoy's suK/^jeslion. Personalis', he was
not alt()f,'ether in accord with the ojjinion. of the majority of the nuMuhers of the Council of
his Associati<Mi. lie did not see the necessity for keeijin^ the work on each floor sejjarate ;
builders wluwn he had consulted did not want it : the\ niij^dil just as well keep the bri(kwf»rk
to ever> floor se|)arate. As an individual, he ihou/^ht that the same unit was not a|)plicable
for all classes of work, although his Institute had af^reed to the foot cube unit. The unit
should suit the work, and the work should not be made to conform to the unit.

Mr. A. a. Cross, F.S.I., said he could not a/,'ree with Mr. Workman's suRgeslion, because,
b>- using a square the tlecimal unit was maintained, but the obje<tion of having loo many
hgures for one column was overcome.

He agreed wnth Mr. Alan Paull that the words, " giving sizes," in connection with bases
and caps for pillars, was superfluous.

Ill reply to a question of Mr. deed's, he thought that keeping the work on each floor
sejiarate cleared up the cpiestion of hoisting, and did not involve the surveyor in very mui h
additional w'ork.

As to Mr. Davis's objection to the measurement of floors by the foot cube, Mr. Cross said
that most of the Committee were of the same opinion, but they eventually came to the conclu-
sion that one unit for the whole w-as desirable, and any other unit for beams and pillars
seemed to be out of the question-
Mr. Alban Scott had asked that the R.I.B.A. should be consulted. They had consulted
the R.I.B.A., and that body had no opinion on the question of a standard system of
measurement.

Mr. Cross concluded by expressing the hope that the final report of the Committee, after
effect had been given to the various suggestions made that night, would be adopted.

1«I

REINFORCED CONCRETE ELECTRIC STATION.

[CQNCBETEJ

Fig. 1.

Reinforced Concrete Roof of Power House
in course of construction.

REINFORCED
CONCRETE
AT THE
CENTRAL ARNO
HYDRO-
ELECTRIC
STATION,
CEDEGOLO,
ITALY.

An interesting instance of reinforced concrete -work in connection -with a hydro-electric
station is that of the Central Arno Station at Cedegolo, erected for Messrs, Adamello,
There are various features in this -work ivhich are ivorthy of study. The ivork ivas carried
out to the designs and under the supervision of Messrs. Damioli Bros., of Milan, to ivhom
'we are indebted for our particulars and illustrations. — ED.

There is some interesting reinforced concrete construction in connection with
the hvdro-electric station recently erected in Italy and known as the Central
Arno Station, and although the methods of design are somewhat different from
those employed in this country, there are several points worthy of notice,
particularly so as regards the design of the retaining wall or dam surrounding
the large reservoir or basin from which the hydraulic power is derived.

The building forming the powder house is over 200 ft. long and about
4S ft. wide, and is a one-story building with outer walls of brick and stone
roofed with reinforced concrete arched trusses. These trusses have
principal rafters 10 in. })y 5 in. reinforced with four bars in the lower
surface and these are inclined in the ordinary way and support panels
of hollow bricks which are put together with a keyed joint and to which the
tiling is attached. A horizontal tie beam, 10 in. by 8 in., reinforced with four
rods in the louer surface and two in the upper, connects the ends of the
rafters, and in addition to this a curved beam is formed which connects with
the same points and rises about S ft. 6 in. above the tie beam. This curved
beam is 12 in. deep b\ 5 in. wide and is reinforced with two bars in ()()th upper
and lower surfaces, w liihr ihe ceiling over the apartment is formed at this level
and follows the same cur\c, this being also (-onstructed with hollow bricks
ha\ing a ke)cd joint. .\n inclined strut coiniecis the rafters and tie beams at
the junction of the lonner with the arched beams and this is 8 in. l)y ^ in.
with one rod in e;i( h corner. The hearing for the trusses is provided by the
mass of reinforced conciele hirniid ;il the junction with the wall, where the
eaves i)roject ;i (lis!;Mi'( of ;ih(;ut j;5 in. from t h,e I'aee of the wall, tiiis portinii
being also in reinloiced ( oncrete, the bars being continued outward from the tie
beams and hooked down. X'arious stirrups and ties are provided al intervals to

all the members and the bars in the rafters are
182

< i.'mked uj) where j^assing over

« V F.NfilNKKRINti — .

REINFORCh:i) CONCRHTB ELECTRIC STATION.

tin- strut to proxicli' cout iiuiit \ . Sonu" idi-.i ol the iii;i«^ nil lulc ol the work Jind
tin- liinhiM-itii^- ri'(|uirt'(l c:in ])c |L;atlu'ic(l Ironi tlu- |)h()t()^r.'i|)Iiic \ic\\s in F/.tf-v.
1 ;iiul J, \\lii(-h wfic taken diiiiui^ j)i()i4 1't'ss, wliiK' the ixlciioi- \ icw of the
conipKlcd hiiiI(HiiL; is sliown in h'tt^. .\.

Fig. 2. Power House in course of construction.
The Central Arno Hvdro-Electric Station at Ckdegolo, Italy.

The water basin has an irregular-shaped plan, with a maximum length of
about 190 ft. and a maximum width of about 150 ft., in addition to the valve
chambers, etc., which are constructed at one end. The total height of the dam
surrounding the basin is about 25 ft., and it is not constructed in the usual
manner with an ordinary single wall, but is built with inner and outer divisions,
which are connected by hoiizontal and vertical slabs and beams, as shown m

183

REINFORCED CONCRETE ELECTRIC STATION. iCONCBET^

ViK- 3. '1 I.I.. -.'- 1 • heel ion >a 1:- mi' n • ■! ' > u- ictc Dam.
TiiK Cknirai. Akno Hydro-Ei.kctric Station at Ckukgoi.o, Italy.

1S4

/v-S^rffSg :^ia Rhinforchd concreth electric station.

tlu' (Iniwin- in F/V. ;,. rii(> (.utsidc width ..f thrsc lu,, dixisioiis is .,l„,ul if, fi.,
.111(1 llir thirkiuss ;,i ilic hasr ..f .arli division is u in., will, ;, ,vd„. li,.n to hin'
lliick .11 tlu- top. R(>inr()i(vm.nt is provided in both inn-.r ;,nd o.itcr sinr;.<i-s

\vi:h stirrups ()r links conncctino- the two sets of rods; wiiile the space between
the two divisions is divided up into three compartments by the horizontal
divisions, and the foundation is formed by a connecting- slab lo in. thick and
beams i6 in. deep, coincident with the vertical stiffeninp- transverse walls.

i8;

REINFORCED CONCRETE ELECTRIC STATION.

[CQNCBETEJ

186

r jN Cr;»N5TVi;tT10NAl
LglF-NrilTMLKPIN(

m H'ilNFURCnn CONCRETE ELECTRIC STATION.

REINFORCED CONCRETE ELECTRIC STATION. [CQNCBETH

The horizontal dixisions arc constructed with rei .forced slabs 4 in. thick and
reinforced concrete beams 10 in. thick, the junction of the slai3 and wall being-
streng-thcned by forming- haunches which extend down to a level with tiie inside
of the beams. The vertical division walls, which also serve to tie the outside
walls together, are spaced at intervals of about 10 ft. 6 in., and semi-circular
headed opening-s are formed in these to connect the whole of the compartments
and allow the water to How through. The interior is communicated with the
basin itself, and consequently the whole of the space between the inner and
outer walls of the dam is filled with water, and the weight of this water is
added to the weight of the dam itself, and serves the purpose of increasing
the resisting moment of the whole structure. It is claimed that a dam of this
design can safely retain a volume of 15 per cent, more water than a masonry
dam occupying the same space, and it certainly forms an efficient and unique
example of construction of its kind. The disposition of the reinforcement
generally can be gathered from the drawing, and need not be further described
here. A view of the work during construction can be seen in Fig. 5, this
showing the two division walls nearly complete and the interior of the basin ;
and the finished basin is shown in Fig. 6, with the water filled into same.
Some idea of the plan can also be gathered from this photograph, and the
valve chambers can be seen in the distance. The top of the wall is filled in
and forms a convenient walking way around the basin.

The example is worthy of study by engineers, as it exhibits a thoroughness
of design to suit the special requirements of the case which is creditaiJie.

188

J, tONMUtHTIONAi:

THE HElMIiACIl SVi^TEM.

THE HEIMBACH SYSTEM OF
COMBINED WOOD AND RE-
INFORCED CONCRETE PILES
AND OF LENGTHENING
WOODEN PILES.

By PROF. DR. SCHONHOFER. Brunswick.

This fourn^l frequently re'vieius interesting technical information as to neiv iniientions,
and the information betna presented as a rule by the in-ventor or his agents is necessarily
ex parte and frequently of a debatable character. It is extremely difficult, in such
statements that are presented, for us to draw the line as to ivhere commercial optimism
ends and general^ technical interest commences. In the following article, presented to us
bv Professor Sch'onhofer, of Brunswick, and dealing 'with an Austrian in'vention, a notable
instance is presented ivhere we think the scientific aspect claims attention, and although
some of the statements contained in this article are not only ex parte but 'ver^ contro'versial,
ive ha've published this contribution as one that may lead to discussion in our columns. — ED.

The wooden pile, used for many centuries, has been largely replaced in recent
times by the reinforced concrete pile. Reinforced concrete piles are every-
where more ad\-antageous — where wooden piles would be destroyed by water,
or where, <:)n account of the great lengths required, they would be too costly
or unobtainable.

Figs. 1 and 2. Figs. 3 and 4.

Showing Method of Constructing Piles.

Mr. Heimbach, of Bregenz, Austria, has ingeniously succeeded, first in
combining the wood and reinforced concrete pile, and next in rigidly
uniting two or more wooden piles. In this way a combined pile has been
constructed, uniting the advantages of both systems, and independent of the
depth of the ground water; whilst, lastly, the difficult problem of the lengthen-

189

PROF. DR. SCHONHOFER.

[CONCBETEJ

in^^ of i1k' wooden pik' has been solved, so that wooden piles may be obtained
of any length.

The combined pile is prepared as follows : A wooden pile, provided with a
broad ring- at the head (Fig. i) is driven in the ordinary w'ay until the head is
about a metre above the surface. The ring is then removed and replaced by
a steel tube, S, made conical below, and forced over the
cylindrical end of the pile. A steel annular wedge with
radial ribs {Fig. 5) is then placed on the pile and driven
home. This expands the upper part of the pile until it
makes a firm and watertight joint with the conical head.
The steel tube is strengthened by one or more protecting
rings, R. Lastly, the steel reinforcement is placed in the
tube, which is then filled with concrete, E. If the thickness
of the tube be suITicient, special reinforcement may be
dispensed with.

In place of the annular wedge a conical w^edge with radial ribs, K', may
be used {Fig. 2). Also a cylindrical steel tube may be used in place of a conical
one, but in that case the protecting rings must be somewhat thicker {Fig. 3).

A wooden pile is lengthened by using, in place of the simple conical tube,
one with two conical ends, placed over the top of the pile {Fig. 4). A double

Fig. 5.

Annular Wedge with

Radial Ribs.

1M(;. (). I'l.AN 01 Buil.DINd Al J.INUAt!

annular wedge K", is then i)hi((Ml on tlu; wood and the second pile, H', with
a cylindrical vn(\, is then driven into the open end of the tube. 'Ihe ramming
causes the wedge to ('nt<:r the ends of bolli the wooden piles, and by fitting
tightly into the tubes to make a liglit joint.

The Heimbach compound piks and ni(lh<Kl oi lengthening have been

iqo

THE H EI M BACH SYSTEM.

(.■in|)li)\ t (1 ill inanv cunslruclions. TIic firm '>(" Ilciinl);i(li .-iiid Scliiu-idLT, ol
Hrt'i^i'ii/ ;in(i l/ind.iii, Iki\i (.■iiij)li)\ id lliciii will) success in in;iny huildinj^s.
Tliis rinn owns I lie piitcnls in all countries. I'i^. ') slious tlic plan of such a
])uil(lins4' at Lindau. Fii:; H is a j^cncral xicw, and I'i^. 7 shows a detail of
tlu' const ruction. I he two new .systems ol j)ilini4' were also exhihiled at the
Internalional Huildini; h.xhihilion in Leiji/.ii^-, attractinj^' much attention and
obtaininj^- the i^old medal ol
the Cily of Lcipzii;.

The combined wtxjd
and reinforced concrete pile
gives all the advantages of
a deep foundation, especi-
ally those of avoiding deep
excavations and costly
dams. The manufacture is
simple, and special pre-
liminary work is unneces-
sary. The costly equip-
ment for the bending- of
reinforcingf rods, erection of
shuttering, etc., necessary
for reinforced concrete
piles, is avoided. Ram-
ming may be begun at once,
and the operation proceeds
rapidly and continuously,

using the ordinary pile-rammer. The special rams and frames used for rein-
forced concrete piles are not required. This is particularly of advantage where
the earth is very soft, as the great weight of special pile-rammers is then a
disadvantage.

The vibration in ramming^ is not excessive, which is an advantage where
the work is near to dwelling-houses or structures the safety of which is
endangered.

The combined wood and reinforced concrete pile is independent of the
level of water or ground-wat^r, provided that the wooden part is at a sufficient
depth. It is also of advantage in soils or waters which destroy concrete. This
is the case with boggy and peaty soils, containing humic acids, with waters
containing calcium sulphate or magnesium salts, sea water, or industrial waste
waters containing acids. Wood is not attacked by any of these substances,
and the concrete is protected by the steel tube, and, on account of the water-
tight connection, cannot be reached by water. The steel tube may be pro-
tected by paint or by a metallic coating.

The load-carrying power of the combined pile is great, and especially
in soft, muddy or peaty ground is large in comparison with reinforced concrete
piles, as the wooden part becomes tightly fixed in the earth and increases in
load-carr\ing powers with time.

The combined pile is specially suited to the foundations of reinforced

191

Fig. 7. Showing Detail of Construction.

PROF. DR. SCHUNHOFER.

ICQNCKETEJ

concrete buildings, as the solt'-plate of such buiidin^^s is naturally much more
easily attached to the reinforced concrete part of such piles than to the heads
of ordinary wooden piles. It is also suited to marine work, as the wood
embedded in the earth is protected from boring molluscs, whilst the concrete
is protected from sea water.

Fig. 8. General Vikw of Building at Lindau.

This system oi piling is cheap, as the embedded portion is of wood, and
only the comparatively short upper part is of the more costly reinforced
concrete.

The Heimbach method of lengthening ])iles has also many advantages,
being axailabic where, <m account of the length required, single wooden piles
\\<;uld b(^ too costly or even unobtainable. This is particularly the case with
marine landing stages, where wcxxlen |)il('s are necessary on account of their
elasticity, whilst they ha\e also to be of gieat length. The union of the
two j)iles is not only rigid, but hi^^hly elastic, so that the combined pile is
fully equivalent to a single pile.

192

' j,lONMkMK-riONAl.

I^WCTORY CONSTJWCTION.

j J8|i1'|l!lfiii!liMiillillillli11llll'^MIll)llill!l!l^

RECENT VIEWS ON

CONCRETE AND REIN.

' FORCED CONCRETE.

THE CONCRETE INSTITUTE.

The method loe are adopting, of di'viding the subjects into sections, is, we belie've, a
neti) departure. — ED.

THE CONCRETE INSTITUTE.

FACTORY CONSTRUCTION.

By PERCIVAL M. FRASER, A.R.I. B.A.

The folloiving is an abstract from a paper read at the Forty-second Ordinary General
Meeting of the Concrete Institute. The lecturer illustrated his paper by numerous
interesting slides.

INTRODUCTION.

It is now generally recognised that a well-equipped series of shops is an absolutely
essential factor in a successful industrial concern.

It cannot be denied that English factory buildings, whether in reinforced concrete
or otherwise, cannot bear comparison with similar buildings abroad, especially in
America. That English factory buildings, even with the most enterprising and
successful firms, are often disgraceful, no one who has had any experience in our great
manufacturing centres can deny.

The attempted adaptation of groups of buildings to a use foreign to that for which
thev were designed is one explanation of the grotesque jumble of nondescript buildings
dignified by the name of industrial buildings which we so often see.

It is also true that in the majority of cases economy could have been effected had
the old buildings been scrapped and an entirely new series of buildings erected. I
seriously suggest that the English factory owner requires educating in such matters as
this, and that he has a great deal to learn from the United States on such points.

The relations of the architect and the engineer who is dealing with the lay-out of
the plan or who is running the process of manufacture should be very close.

Some of the reinforced concrete specialists make a point of preparing complete
designs for factories and other buildings, concerning which they can have absolutely
no experience or knowledge, and this is a further prolific source of ill-designed and
inefticient factory premises.

There is a great deal that is incongruous in our industrial works. A typical English
power plant represents the finest product of human workmanship, and the employees,
from the chief engineer to the humblest stoker, take a pride in keeping it at its highest
jMtch of eflficiency and scrupulously clean, for to their mechanical minds it is a thing of
beauty ; but this is ordinarily housed without scruple in a corrugated iron building,
which is not only an eyesore but totally incapable of efficiently protecting the expensive
machinery it contains.

NOTES ON THE DESIGN OF INDUSTRIAL BUILDINGS.

The governing principle in the design of industrial works is to provide efficient
buildings at the lowest cost. A certain operation takes place in each department, and

E - 193

THE CONCRETE INSTITUTE. (CDNOBETEl

these processes are components of the finished article for the manufacture of whidi the
buildings are erected. Each building unit, therefore, must be designed to allow its
particular j)rocess to be carried out under the best conditions and without restrictions,
and the buildings as a whole must be schemed to allow the various processes to pass
through them in the most direct manner without loss of time or waste in any shape or
form. The difficulties and restrictions of a building site must be courageously dealt
with, and are frequently put to valuable use; such as, for instance, difficulties in the
levels of a building site may be frequently utilised to convey the material by gravitation
through the various departments and thus reduce handling and power consumption,
and again will often enable loading stages to be formed at convenient heights.

The effect of well-constructed, light, and healthy buildings on the health and spirits
of the workpeople is an important factor.

Among the questions which frequently come before an architect in designing
industrial buildings is the following : Whether the building as a whole should be one
storv or more in height. Unless the foundations are likely to prove abnormally
expensive it will generally be found that the one-story building can be constructed the
more cheaply.

A second important detail which practically always arises is the question of
eliminating columns or reducing their number and planning their positions to the best
effect.

Other questions which must infallibly arise are the nature of the lighting, which
must, for many manufactures, be from the roof. In two-story buildings the width of
the building is determined hereby, but it is an advantage to make the upper floor with
roof light. Too much daylight, unlike artificial light, cannot be provided, but the
increase of window space will add to cost and complicate heating and ventilation.
The north or sawtooth roof is always an advantage, but is not always worth the expense,
costing as it does lo per cent, more than an ordinary pitched roof in steel, or 20 per
cent, more than a flat roof in reinforced concrete.

With regard to the clear height of workrooms, a margin should be allowed over
the bare necessity.

The number and disposition of floor beams is often dictated by the needs of
economical design, but frequently one has to provide floorslabs free from beams to
increase headroom or for other reasons.

In dealing with the advantages and disadvantages of reinforced concrete for
factorv construction in comparison with the prevailing methods of construction, the
following points must be considered.

There are, of course, three attributes of every marketable commodity — namely,
goodness, badness, and indifference. A casual examination will show that reinforced
concrete will be adaptable and suitable for factory construction. We have, therefore,
to weigh the special advantages that it possesses with the disadvantages, and decide
whether the advantages are such that it is as good as other methods of construction
at the same or less cost.

Thf* serious comjjetitors of reinforced concrete which are at present before the
building world arc as follows : —

Brick, steel and cast-iron, wood, sheet-iron and metal lathing and plastering,
tiling, tcrra-cotta or similar slabbing and casing, and a number of patent forms of
construction too numerous to mention and most diflicult to classify, most of which,
however, come within the scope of reinforc^'d concrete in one or more respects.

It is exceedingly difficult, if not impossible, to definitely pronounce on the com-
|)arativc ccf)nomifs of the foregoing materials, and we can onlv take specific instances
and endeavour to generalise from tFiese. I am able to give a case where competitive
prices were obtained for a building, which is of a fair size, straightforward, and a
reallv useful one for this comparison. In this case alternative^ schemes were prepared
in the fullest detail and ( onifxtitive prices obtained. The results were as follows : —

1. l''or a steel-frame building with biick walls, corrugated iron roof (two-
thirds north light), wood joists and boards on steel bearers to galleries, and patent
glazing to roofs, the cost was 100 pei- cent.

2. I^'or a reinforced concrete building with roofs as last, ()2 per cent.

3. As last, but with concrete roofs, pari flat, part with north lant(>rn lights,
but with })rick panel walls .S«i per cent.

•94

r »,cx>Nyrk'uc-rioNAL l FACTORY CONSTRUCTION.

4. As No. I, l)ul willi coi I iil;;iI((1 iioii \\;ills, S() pci- (■ciit.
:;. \\lu)ll\ ill I tiiilorcfd concrclc, SS per cciil.
The luiiklint; was ;uMuaIl\ cariiccl out in reinforced conncle, including the gutters,
doAii i)ipis, roofs, walls, foundations, and ev<'rv detail where it was possible for this
material to he used, in this ease iheic were no special cii ( innstances whatsoever in
favtnir of reinforced concrete; indeed, the question of tile supj)ly of a^f^re^ate was a
veiy ilitVicult one, as it had to be broui^ht from twenty-five to thirty miles by rail. The
forej^oini^ lij^ures will apply to all cases of ordinary buildinj^s costing more than, say,
/,2,ooo. A i)uildini.; of less I'osl will, i^enerall\' sjK-akin};, in: found cheaper in some otlier
h)rm of construction, and walls will nearly always be found cheaper in brick panels
than in concMcte slabs.

MA/NTENANCE.

The freedom of concrete from deterioration permits of savings in maintenance
charges. These are exceedingly ^reat in large series of factory buildinj^s, and can never
be shown on pa|)er. Maintenance means more than merely i^uardinj.^ aj^ainsl the ravages
of time. The necessit\ for maintenance implies decay; the maintenance costs are a
d(\ad loss, and maintenance is in itself a thankless job owing to the fact that it is
simj)lv patched-uj) work, nu'rely staving off the inevitable, which every year becomes at
once more onerous and more useless.

Considering the claims of reinforced concrete, without wishing to be unduly
enthusiastic, it may be reasonably asserted that, after a lengthy trial and the closest
scrutinv of our chemists, architects, engineers, and constructors, reinforced concrete is,
practicallv speaking, free from dej)reciation if constructed according to the latest
approved practice.

Concrete constructions carried out during the Roman Empire are completely sound
to-dav after a period of two thousand years entirely without maintenance. As regards
thoroughness of construction and the quality of materials, the Roman constructions
cannot* compare with the modern. This simple truth needs to be emphasised because
the public are apt to draw odious comparisons between the Pyramids of Egypt and the
modern suburban villa, without reflecting that the comparison is wholly unjust and
grotesque.

Even with rigid economv factory construction in concrete is, if conscientiously
carried out, better constructed to-day, and therefore more permanent than any work
constructed by the ancients.

In reinforced concrete we have found one of the few suitable materials for the
prevailing climate of Northern Europe.

FIRE-RESISTING PROPERTIES.

The fire-resisting properties of various forms of construction are of paramount
importance in factory buildings. The effect of fire-resisting construction in reducing
insurance premiums is but a small matter compared with the damage which ensues
to a business owing to the extreme dislocation caused by a tire, which no insurance can
ever cover; for we have to consider the financial loss in the shape of buildings, plant,
and machinerv ruined, the destruction of office documents which cannot be replaced,
and the permanent loss of many skilled workmen who are thrown temporally out of
work, and the occasional terrible loss of life. The output of a firm is, moreover,
temporarilv paralvsed, the normal trend of business is disorganised for a considerable
period, and the eventual effect is that the insurance company will not reinsure at the
same rates.

Timber construction according to English methods is not only rapidly destroyed
bv fire but acts as fuel. .Steel joists and cast-iron structural members are liable to
immediate failure, and owing to the distortion in expansion and contraction will throw-
down walls which with a timber construction would have remained sound and
repairable after the fire.

Steelwork can be effectivelv cased with resj)ect to stanchions and columns, but it
cannot be said that a reallv efficient means of casing beams has yet been found, and in
anv case such protection is expensive and clumsy.

Nothing is, of course, fireproof, but we have to seek for the nearest approach to
this ideal. Ordinarv reinforced concrete construction is as eflficient a fire resister as can
be found. The metal is naturally guarded against by the concrete covering. There is

E 2 195

THE CONCRETE INSTITUTE. [CONQJETE)

nothing combustible about tiic construction; it is not liable to exercise a dangerous
thrusting or overturning action, even when heated and suddenly cooled. It is of course
liable when quenched with a strong shower of cold water to have the covering of slabs
and beams either l^ake off or disintegrate. It is rarely or never found that any of the
concrete, beyond the covering to the reinforcement, suffers any irreparable damage.
Any such covering can be broken away where loose and the building restored after
the conflagration. It can therefore be fairly claimed that for factory construction which
requires a high standard of fire resistance reinforced concrete can rival any other
comparable method of construction.

The fire insurance companies have been quick to recognise the use of reinforced
concrete as a building material for factory construction.

It will be noticed that their rules are very sound and practical. They are framed to
be applied in an honest and liberal manner, and are altogether in great contrast to the
usual official notices of this nature. The only criticism to be offered is, that although
they allow floor slabs to be 5 in. thick, and roof slabs 3 in. thick, they ask for external
wails 6 in., partition walls S in., and party walls 13 in.

The Rules read as follows : —

RULES

AS TO '

FERRO-CO^XRETE OR REINFORCED CONCRETE CONSTRUCTION
Issued by the Fire Office Committee.
" Buildings constructed with concrete, reinforced in every part with embedded metal rods
or bars spaced not more than 12 in. apart, securely connected ot overlapping at least 6 in. at
all abutments and intersections, having also bands or bars across the thickness of the conicrete,
may be deemed as Standard 11. Construction, provided they conform to the above rules for
ordinary brick and steel construction, with the following modifications : —

" Concrete may be composed of sand and gravel that will pass through a |-in. mesh,
or of the other materials mentioned in the Rule (stone, brick or terra-cotta), but in any case
the cement used must be Portland (equal to the British Standard Specification of December,
1904), in the proportion of 6 cwt. o-f cement to each cubic yard of concrete. The Concrete
must be thoroughly mixed both dry and wet, and must be rammed round the metalwork
in position, every part of which must be completely enclosed with solid concrete.

" No external wall to be less than 6 in. thick in any paxt, and no division wall less than
8 in. No party wall to be less than 13 in. thick in an}- part, unless the adjoining building
be of reinforced concrete construction in accordance with Standard Ia, Ib, or II., in which
case 8 in. is allowed.

" Flues may be built of reinforced concrete as described, not less than 4 in. thick,
if lined throughout with fire-clay tubes not less than i^ in. thick. No timber or woodwork
to be in contact with such flue.

" Floors must be constructed of reinforced concrete as described, not less than 5 in.
thick in any part without woodwork embedded therein, supported on beams and columns
of similar reinforced concrete.

" Roofs must be constructed in a similar manner to floors, the concrete in no part to be
less than 3 in. thick.

"All structural metalwork must be embedded in solid concrete, sO' that no part of any
rod or bar shall be nearer the face of the concrete than doul^le its diameter ; such thickness
of concrete musit be in no cas€ less than i in., ])ut need not be more than 2 in.

" Enclosure to staircase and hoist, if of reinforced concrete as described, may be
6 in. in thickness.

" Fireproof compartments in connection with reinforced concrete structures must also
be of reinforced concrete as described with walls not less than 8 in., and floors not less
than 5 in. in thickness."

// YGIKNIC PROPERTIES.

T(j ((jmjdy will) th(! spirit (jf the ilome Oflicc rc(|uirements a constructional
material for factory buildings should be sik li as will not absorb dust or dirt in an\'
form, which can be cl(;an(td or kept clean with liltle elforl, and which offers a fairlv
even surface. Th(! other tyfjes of factory construction -aw matnly of brick walls and
wood and ste/;l-joist fioors, and steel or iron columns, <'ilh(T cased or unprotected. It
cannot be said that reinforcx^d concret<' offers any extraordinary advantages over the
materials named. It is certainly better than brickwcH'k ; and in order to comj)lv with
the Home Office requirements it is more economical to lime-white than to ])aint, so
that it may be considered to have an advantage over metal construction; "nd it is

196

i, coNyrpiK'noNAi^

AK-N(i1NKI,RIN(i '^.

FACTORY CONSTRUCTION.

uiidouhtcclh' nunc .KK-.tiitai^coiis to h.iNc laii^c lloor spans of concrrtc wilhoiit sulisidiary
beams to obtain unbroken suifaces wbicb can be kept s('iuj>uloiisl\' clean and white and,
incidentalK , w bii b rellect daybi^iit or aiiiriciai ilhiniination in a most elTicient manner.
Iherelore, on I be whole, (Vom a bxi^ienic standjx)inl reinforced concrete has in the
aggrej^ate (.|iiablie> whiib no olber material possesses in an equal degree.

SAV/.Va /N SrACE.

A further consideration which aj)plies mainly to warehouse buildings is the im-
portance of affording the utmost llooi' spac(^ foi- the storage of goods. (Jonslruclion
in London is exceeding!}' onerous in this resjxcl. Matters have been matle considerably
easier by the steel-frame amendment of the London lUiilding Act, but it cannot be
deni(^d that a considerable encroachment on lloor s])ace can be avoided by the use of
reinforced concrete walls and supi)orts.

The objection to reinforced concrete, as compared with steel and cast iron, in
resi)ect to posts and columns is that the lloor sjjace occupied is considerably more. This
is imdoubtedly the case, but, excej)ting in <'Xtreme circumstances, such as cotton or
spinning mills, etc., the bulk of tlie concrete sujjport is not a serious objection.

It should be remembered that if a steel stanchion is insulated against fire, it would
be practically as great in sectional area as the concrete column.

VIBRATION.

An im})ortant consideration in all factories where machinery is em|:)loyed is the
aggregate vibration, which is often very considerable. The nearest approach to such
solidity is to construct factories of reinforced concrete, which, while being of mono-
lithic construction and free from joints as ordinarily understood in building construction,
is an effective absorber of vibration. With this in view the use of slender columns and
comparativeh' narrow beams are to be deprecated.

ADAPTABILITY.

Perhaps the unique merit of reinforced concrete lies in its extraordinary adapt-
ability. 'Inhere is no other building material which can be put to such extraordinarily
diverse uses without unwarrantable eccentricity or expense. The value of a material
which can be used for practically any purpose which may arise in the construction of the
wide variety of buildings comprised in industrial works need hardly be dilated upon.
The practical econom}' of such a material is also evident. Provided there are no
insurmountable difficulties in getting on to the site steel rods, timber, gravel, and
cement, we have at hand constituents which are capable of being moulded into any
shape and resisting any strain and fulfil purposes which collectively would require the
use of a large number of different materials. In the ingredients of reinforced concrete
there is nothing w'hich cannot be readilv obtained in the most remote locality of the
kingdom. In places ten or more miles from the nearest station, concrete w^ork always
can comj:)ete in point of economv with anv other permanent form of construction, and
wherever eccentric designs are to be carried out, a plastic material will always hold its
own with a material which has to be wrought into shape.

SPEED OF EXECUTION.

Following on the adaptabilitv of reinforced concrete is the speed with which
construction can go forward. If a contractor will lav down a well-considered and
efficient plant, the rapidity with which a concrete job can go forward is remarkable.
A larger number of workmen (mostly unskilled labour) can be usefully employed, and
the building as a whole can be proceeded with uniformlv and in a manner which
simplifies supervision. Should it be found desirable in a steel or iron construction to
make alteration, time is lost in waiting for the various revised members to be delivered.
With reinforced concrete such deviations can readily be made.

Another point in favour of reinforced concrete against steel construction is that
minute variations in stress can be met without undulv wasting material.

ARTISTIC DESIGN.

An objection which is often urged against concrete buildings, which does not apply
to brickwork or the usual form of construction, is that it is by nature unsightly. If
appearance is an object in a reinforced concrete building a very agreeable effect can be

19:

THE COSCRETE INSTITUTE. [CQNCEETEJ

obtained bv perfectly leoitimate and economical means. Those interested in the possi-
bilities of beauty in'reinforced concrete will do well to read Professor Beresford Pite's
j)aper published in the " Transactions of ihc Institute," \ ol. III.

ALTERAT/OXS TO FINISHED BUILDINGS.

Another objection wiiich mav be held against reinforced concrete, especially for
factory construction, is the great 'difficulty of making alterations which may be found
necessary for various reasons such as an extension of business; but, assuming the
building' has to be altered owing to circumstances which could not have been foreseen,
such extensions and alterations are not impossible. Even if the expense is abnormal,
it is one of those factors which every shrewd business man will be prepared for.

In this connection the American will frequently tell you that if he builds a factory
which will last without undue maintenance a couple of generations, he has more than
done his duty bv r)osterity. We, personally, can hardly appreciate this point of view,
but that the American is' certainly willing to raze to the ground any building which he
considers is out of date is evidenc'ed bv the fact that one of the New York skyscrapers is
being taken down because after a few years' existence it is found to be inconvenient.

h cannot be denied that concrete, when it has settled down, is an exceedingly tough
material, but the great strength to which this material attains should hardly be urged
as an objection to its use.

STRENGTH OF REINFORCED CONCRETE.

The inherent strength of a building constructed entirely of reinforced concrete
compares favourably with a building in any other material or combination of materials.
Much has been said about the monolithic nature of reinforced concrete. We should not,
however, forget that although a building is monolithic it is not monoferric (if such a
word be allowable)— that is to say, that the steelwork consists of a multitude of small
members held together by the concrete, but the external adhesion of concrete to steel-
work makes a well-designed structure in practice a jointless one. Thus, an eccentric
load on one portion of the building is disseminated over a large area of the surrounding
structural members, and the local tendency of a building to spread or settle is resisted,
not by the members locally affected but by the structure as a whole. In addition we
have only to find the strength required in any portion and we can build up our structure
to meet' the stresses induced, where such stresses occur, and without wasteful
extravagance such as is often necessary in comj^romising with steel construction in
certain peculiar conditions.

BUILDING BY-LAWS.

An objection to reinforced concrete construction, which will die out in course of time,
is the antipatln- to a novel method of construction which is characteristic of the
Englishman. I find, however, that individual building owners are easily converted if
one honesth' points out to them the limitations and the advantages of concrete. The
most formidable objection lies in the present attitude of the official world, who, in
spite of the s[jlendid example which has been set by II.M. Office of Works in developing
the use of this material in permanent and often monumental public buildings, have not
been affected thereby to the extent of amending their by-laws. We have at present an
eminently suitable material for the construction of |)ermanent buildings with which it is
difficult \() sntisfv local authorities who, on llie other hand, will readily sanction a
construction of light steel stanchions and roof trusses covered with corrugated sheeting.
Fortunalelv, there appe.-irs to be nothing in local building by-laws which empowers
the local survesor to rejeci buildings in reinforced concrete, and if an architect can
Tjersuade his client lo go forward \\\h his building I do not belie\'e that he can be
prevented.

DAM!' KhSISlANCE.

\ iiiinoi- advantage of reinfoicc-d cone i*le l)nildings is Ihat no d.'mip-j)roof course is
needed, ;nid when one re.dises that 50 per c<rit. of the danii)-pro()f courses which are
used with ihe apprr)val of lo(aI .lulhorities are worse ih.m us<i(ss this advantage is one
which, though unimportant, is nevertheless real.

A further minor ;idvanlag<' over steel construci ion is ihe obviating of nuisanci-s

19H

r /, ct::/N.vrpucTiONAii

FACTORY CONSTRUCTION.

raiiNcd in ctrl.iin |)r()C(ssis 1)\ londcns.it ion. ()fl(n condensation is un.'i\f)i(lal)lc, and
the results of sMinie ar<' often dangerous, hainiful to the nianufacliin s, or ohjeclionahN-
in other respei'ls. With reinforced concrete condensation is reduced to a mininiuni.

/;('//.'/'(/' WOh'K

In nian\ cases it is found convenient or desirable to construct the I)uildinj4 of units
in a similar manner to ordinar\' steel construction, and this can be satisfactorily
aicomplished in reinforcinl concrete. The chief advantaj^e of this is that a \irv'.\\ de.al of
cenlrinj4 and struttinj^ is saved, and tlie work can be lianded over in a much shorter
space of lime than if the concrete had to set in the usual way. At the same time, it
must be admitted that this form of construction is in princi|)le open to objection, the
monolithic nature of the huildinj^s is destroyed, and it is certainly not so economical
as castinj^ the work in the ordinary manner. Its use is chiefly confined to floor slabs
and walls, where it often offers very considerable advantai^es and ( conomy.

FIXING PLANT.

The one j^reat advanta^^e of structural steel in factory construction is the ease with
which machinery can be fixed to the steel members. 'J'hat this use is often turned into
abuse is beside the point, but en<^ineers state that they prefer steel to reinforced concrete
for this reason. A little foresii^ht will enable an architect to meet this objection with
satisfaction to the factory owner.

The bulk of a concrete member is so comparatively large in relation to a rolled
steel member of equivalent strength, that the resulting damage of cutting into such
member is proportionately reduced. Comparing the members, the sectional areas of the
steel joist and of the concrete beam are in the proportion of i to 7 for equivalent
strengths. Therefore the concrete member will stand much more mutilation without
jeopardising its strength than the steel joist.

A simple means of providing for light fixings is obtained by casting a groove in the
beams and columns so that a fixing can be obtained with the greatest ease without in
anv way having to go into the concrete. For gas or water pipes and mains or cables of
anv description, this fixing is very simple, and a good engineering job; again, the
indiscriminate fixing of shafting to walls is accompanied with greater safety on rein-
forced concrete slabs than on brickwork, which is liable to give along the joints, and
the weight, of course, is not so evenly distributed.

ROOF CONSTRUCTION.

The low thermal conductivity of concrete gives it an advantage over the ordinary
forms of roofing, apart from other considerations. The usual precautions taken are to
construct a roof of timber with thick boarding overlaid with felt, upon which are placed
battens and counter-battens and thick slating. This forms a fairly effective insulation,
but the construction is at least as expensive as a concrete flat asphalted. For flat roofs
and in all places where exposed to damp or water pressure concrete can be made, with
due care, absolutely waterproof, and a very valuable and convenient arrangement which
is now often adopted is to construct concrete roois with high parapet walls and utilise
them for w^ater storage. This has a further advaniage that the water is generally at a
convenient height to be drawn ofT under pressure.

VARIOUS APPLICATIONS OF REINFORCED CONCRETE TO
FACTORY CONSTRUCTION.

ENGINE FOUNDATIONS.

Engine foundations are often exceedingly complicated, and for this reason it is
impossible to construct them with plain concrete, so that it is common and often
necessary to emplov steel joists in order to avoid an excessive amount of concrete. It
is obviously better to use a regular system of reinforcement wherever feasible. It
enables the mass of concrete to be reduced to a minimum, and where, as is rnost
frequently the case, the engine is to be set and a large proportion of concrete deposited
after an interval, it is a great advantage to have some means of binding the mass of
concrete together.

199

THE CONCRETE INSTITUTE. CDNCBET E]

BOILER FOUNDATIONS.

With regard to setting the boilers, practically the only efficient manner for the
Lancashire type of boiler, which is perhaps most common in this country, and also for
the water-tube boilers of ordinary type, is to construct a concrete raft so as to offer
a clear working space for the boiler-setters, and for this purpose reinforced concrete
construction is the best possible. Raft foundations are constructed as floor slabs
supported on piles owing to the uncertain nature of the subsoil. It is particularly
recommended that piles tor this purpose should be constructed of reinforced concrete,
as it has frequently been found that where wooden piles are used the heat generated
in certain portions of the flues is so great as to actually char aw^ay the head of the
wooden pile and so cause settlement. The effect of heat on concrete is likely to cause
failure unless a considerable period has been allowed to lapse after the construction
before the heat is applied. In cases where a new boiler is installed and put into use
immediately the setting is completed serious damage may be done to the concrete
owing to the fact that it has not been allowed to dry off naturally. This damage w^ould,
of course, accrue to plain as well as to reinforced concrete, and in the case of the
former, where the practice is often to make the concrete slabs several feet in thickness,
the resulting damage (where the subsoil is good) is not appreciable ; but in case of
reinforced concrete, the slabs being thin, they may be entirely disintegrated.

BOILER SHAFTS.

It is only of recent years that chimney shafts have been constructed with true
economy and efficiency in reinforced concrete, and all interested in this subject should
read a paper delivered before the Institute by Mr. Matthews and published in the
" Transactions," Vol. II., Part i. This session a further paper is announced dealing
with steel and reinforced concrete chimneys. Experience has recently shown the com-
parative cost of reinforced concrete chimneys, which, in one particular instance, show^ed
a saving of 35 per cent, over a brick construction and a saving of 4 per cent, over steel-
plate construction.

An objection to concrete cliimneys is the unsightly aj)pearance, chiefly owing to the
fact that it is unduly expensive to form a side taper, but this difficulty has been over-
come in 2 simple and ingenious w^ay in some instances, and the system employed, so
far from adding to the cost, is decidedly economical. In the cases in mind, the base
of the chimney is quatrefoil in shape on j)lan, and the whole chimney constructed with
one band of centring about 3 ft. high, which is raised, a batten taken out from each
loop, and the centring correspondingly reduced in perimeter until it emerges into
a circle at the summit of the shaft. The actual appearance is distinctly pleasing, and
the insulation is good between the firebrick and the concrete. A certain amount of
play is possible in expansion and contraction owing to the j^eculiar shape of the shaft,
which is in effect equivalent to an expansion ])ij)e on steam tubing.

SILOS AND BUNKERS.

The construction of silos and bunkers, which have hitherto consisted of iron or
steel, has been found in the last few years to be considerably cheaper and equally
efficient in reinforced concrete, and some most imjjortant works have been constructed
in this material. The grain silos which have been constructed in various parts of the
world afford a few typical examjjles. 1 1 is useless to ])ress the claims of reinforced
concrete in this conn<-ction, as so much work has l)een done in this country that it
may be said that ste<'l (xr iron construction is now out of date.

FOINDATIONS.

Many serious (Jinicullics (onncclcd with f(jun<lalions on bad subsoils have been
economically overromcj by a discreet use of leinforccd concret(^ It is a fact that a large
percentage of our factcjries arc; situated by rivers, canals, etc., and for this reason the
foundations are generally expensive. This «x|)(n(lil me on foundations frequently results
in land otherwise chf-ay) proving in the end to be very expensive, as all such expcMiditure
sh(Hdd properly be aclded to the cost cjf building land.

There is practically no form of fonndalioii \\hi<Ii (annol he efficientlv constructed
in reinforced concrete. A coininon, ertiiieDi, ;md ecoiioniicd form is the formation

200

^^^r^SlK^g I'^^CrOh'Y CONSTRUCTION.

of a rail on which ronc-cntratcd ami disliihutcd loads of a huildinjf are equally S|)rf'ad,
so that the unit load is rcducrtl cvcivwhcrc within the liniils of the hcariiij^ {•a|)acily
of the soil.

PiU's and shci^t piles in r(infor(((l coiutcIc have hern used in thousands, and its
usf in ictainin^ walls has been able to oiler the most cxlraordinai y economies.

liRIDGKS.

1 1 is fi'eL]uentl\ found to be a threat conxcnieiice to connect various departments
above i^round b\ means of j^anj^way bridj^es, and as the\ are nearly always inaccessii)le,
it is i^enerallv better to construct these of material for which maintenance is reduced
to a minimum. Hrid^es are usefid to cross public footways, and concrete has an
advatUai>'e over brickwork or stone construction in ol)viatinif an excessive rise, and
also in the saving of massive abutments.

CONCLUSION.

In conclusion, factory buildings are liable to be L^rossly overloaded, the costs are
always reduced to the utmost farthint^, and the buildinjfs are not usually treated with
such care as domestic or i)ublic buildin<^s, and are liable to be severely mutilated and
subjected to the deleterious elTects of steam, vajiours, fumes, acids, oils, and undue
vibration, etc. ; and, consequently, the factor of safety in design should never be
reduced below four. It is also advisable to construct certain portions with even an
increased factor, as, for instance, flat roofs which will with certainty be used for storage,
and walls, beams, slabs, and columns, which are generally subjected to the suspension
of shafting, motors, and other live loads without consideration of the |)uri)Ose for which
they have been actually designed.

In view of the enormous extent in which reinforced concrete has been used for
buildings of this class during the past few years, it has been comparatively immune
from failure.

DISCUSSION.

Mr. H. C. Johnson, of the Engineering Department of Universit}- College, Cork, forwarded
a communication on the Paper, which was read, in the course v"f which he stated that it was
wortii while to visit America in order properly to understand why the Americans were able to
build in reinforced concrete more cheaply than could be done on this side of the Atlaptic.
The reason that they were able to turn out more work per man was mainly due to new, well-
lighted buildings, the great proportion of which were in reinforced concrete. It was possible
in reinforced concrete construction to obtain a glass area equal to 80 per cent, of the total
area of the building front, and run the glass to within three or four inches of the ceiling
line. A large contract had been given to a reinforced concrete firm on their being able to prove
that, including 12 years' maintenance, a concrete structure by them would cost less than if
built in steelwork, the concrete first cost being higher. A saving of 15 per cent, on form work
meant 5 per cent, more profit or less cost on the buildings. Another advantage of using
reinforced concrete for buildings was that the greater part of the materials could be obtained
locally, thereby keei)ing the money in the district.

Mr. Leslie H. Allen ( Vberthaw Construction Co., Bostoai, Massachusetts, U.S.A.), also
wrote that concrete was the only structural material which was made on the site of the buildings,
and therefore there was a need of much more careful inspection of the work, and that the
work itself should only be entrusted to those who had a thorough experience in the execution
of it. Money was wasted or saved in reinforced concrete in the form work or centering, and
everything that could be done to simplify that was of great advantage. The reduction of
vibration was one of the points wdiich appealed to owners of buildings having high-speed
machinery or having a rocking or reciprocating motion, which was distracting to the people in
the building and caused a rapid deterioration of the structure and the machines. Although
there had been several failures in the last two or three years in America, not one of them had
bee;i after the building had been completed and taken over. They had all occurred in the
course of construction, and they had been due to poor sand, faulty designing, or freezing the
concrete before it set, overlapping greeii concrete, or removing the forms too soon, all these
beiui,^ the results of inexperience rather than any inherent defect in the material.

Mr. W. G. Perkins (District Surveyor for Holborn) thought it would have been more
economical to have erected factory buildings to a height of three storeys. If brickwork were
properly executed in Portland cement and solidly bedded up to the steel there was no danger
of the steel rusting. That was the method prescribed by the Building Act, iSgg. If it were

201

THE COSCRETB INSTITUTE. ICQNCBETEJ

not for the fact that the cement did protect the steel they should not be able to use reinforced
concrete in their works to-day. Mr. Fraser, rather unfortunately, seemed to recommend that
people should set by-laws aside, and put up reinforced concrete buildings whether the Local
Authority liked it or not; but if they did not make their buildings in conformity with by-
laws the Local Authority might proceed against them, and perhaps they might have an Order
made for the demolition of the buildings after they were put up.

Mr. Allan Graham, A.R.I.B.A., remarked that anyone looking at the average type of work
that was erected in reinforced concrete was quite satisfied with the lines, but the features that
they placed into the work, and the lack of artistic grace precluded it from an architect's
point of view entirely. They must try and interest the architects in reinforced cO'nicrete work
in order that they might attempt to give a little artistic effect to the designs. Some of the
Ameri'an buildings, in South America especially, seemed to him to be much better designed.
In centering he saw the only future to enable them to reduce the cost of reinforced concrete
suffi(ientl\- that almost ever.\- factor)- in the country could be built of it.

Mr. Ole Svendsen, M.Soc. Danish C.E., did not see why a well-built brick chimney should
be better than a well-built conjcrete chimney. With regard to maintenance, he believed that
concrete chimneys would easily be able to compete with brick chimneys.

Mr. R. Graham Keevlll, A.M.l.Mech.E., regretted that it was the cheapest building that
was freciuently put up. According to Mr. Eraser's paper, reinforced concrete had come out
very favourably. The design of buiUlings was largely in the hands of specialist firms who were
not at liberty to let the cost be known. If the cost of buildings were more generally known,
that would be a large factor in helping forward the construction of concrete buildings, not
only for factories, but for other purposes.

Mrs. Margaret Williamson Morris, who had had very nearly 30 years' experience of work-
shops and factories, api)ealt(l to architects for their assistance in combating dirt and darkness,
and the want of air and light in such buildings as these, which contributed very largely to the
spread of consumption amongst the working people.

The President referred to the increase of strength in conc'rete spread over, say, ten years.
A lot of experiments were being conducted as to the strengths of different cements with all
degrees of grinding, and there was no doubt that with coarse grinding it took very much
longer to obtain its ultimate strength than with the finely ground. It was very much better to
construct a factory of entirely reinforced concrete in the country, as architectural features, as
a rule, were aiot studied to such an extent as they were in towns. In towns it would be a
mistake, o^^ing to the enormous amount of smoke, and the dirty appearance that it got, and
the fact that the surface was alwa\s being attacked by the sulphuric anhydride in the
atmosphere, which gradually caused it to crumble away. From the fire-resisting point of view,
even if concrete cost more, the saving in premiums and insurance was very considerable.
Vibration was very little felt in a reinforced concrete structure where it had been properly
designed. In conclusion, the President referred to several serious cases of electrolysis which
had occurred in the driving of piles in the I^ast End of London.

MR. PERCIVAL ERASER'S REPLY.

In reply, Mr. Fraser said that in America they had very many buildings in reinforced
concrete, and although its use had been artificially stimulated by the fact that the local building
authorities were not so " pig-headed " as they were in this coimtry, they could show more work
and better work in this country than he had s.een at all evonts in the United States. He
reiterated his opinion that factory buildings, generally speaking, were cheaper when con-
structed in one storey than with two or more storeys. II is statement was founded on very
many years' experience of factory <:onst ruction, and although he had been attacked from all
quarters in regard to it, lie had heard no constructive criticisms, merely statements that he was
wrong. He was careful in his i)aper not to mention district surveyors. In his opinion they
were a most excellent bodv of men. It was tlic i)r<)vin( ial local authorities that put the
extinguisher on a scheme bee ause it was outside the by-laws. Those were the people they should
defy. He agreed that brick j»anels were better than concrete panels for walls, for reasons of
economy and l>ecause concrete slabs cra<ked. As to the cost of steel work, he was not aware
that the prices un which he basc<i )iis calculations were so wild. He denied that no building
had eve;- been known f) fall ihrough rust, and instanced Ihe case of ("haring Ooss Railway
station. In his short experienci- of r liinmcjs, he had replaced two steel chimneys with
reinforced concrete chimneys, and both harl lasted u or 13 \ears. Alluding to the remarks
of Mrs. Morris, he- said they had in rcinforcc-d (oiMrclc- a i)art i( iilarly suitable material, its
inherent cjualitics, and the manner in which it (oiiM Ik- put lordlier, affording large window
space. The steam trouble had beaten better un n ih m he, and no salisfactor\- s\stem had \et
been evolved to deal with it.

202

4r CtJNM UUCTiaNAl^
^ KN(ilNKF.PlN(. — J

RHINFORCFD CONCRETE ROOF CONSTRUCTION.

NEW WORKS IN CONCRETE

AT HOME AND ABROAD.

Undtr this heading relUble information rulll be presented of neiv 'works in course of
construction or completed, and the examples selected tuill be from Ml parts of the -world.
It is not the intention to describe these -works in detail, but rather to indicate their existence
and illustrate their primary features, at the most explaining the idea -which served as a basin
for the design.— ED.

REINFORCED CONCRETE ROOF CONSTRUCTION AT LIVERPOOL

CATHEDRAL.

ALTHOroii reinforced concrete did not enter lar<^ely into the construction of this buiidinj^,
some interesting^ work is to be noted in connection with the roof construction. This
worlv comprises the chapter house and choir roofs and some flat roofs over the small

towers. . 1 r r

These latter are octagonal on plan and are finished by stone turrets m the form ot

pyramids, which are carried by the reinforced roofin<,^ The clear width of the towers is

risic

CT-forv o/v /./f^c C

Section Reinforced Concrete Chapter House Roof.
Liverpool Cathedral.

about II ft. 3 in., and each is spanned by four beams, running in pairs at right angles,
and interlacing one another about 15 in. from the wall face. Small beams having
similar dimensions are carried diagonallv across the corners of the square thus formed.
These beams carrv the stone turrets, and the enclosed octagon is left open.

203

NEW WORKS IN CONCRETE.

ICQNCBE TEJ

b: <

p: J

The roof over the choir has
a clear span of 50 ft. 4 in., with
a somewhat shallow pitch, the
inclination from the horizontal
being 26 deg. The total length is
136 ft. 6 in., and the whole forms
an external roof above the choir
vaulting. The system of construc-
tion adopted is similar, on a larger
scale, to that usually employed in
ordinarv timber roofs. The roof
space is divided longitudinally into
three compartments by transverse
walls 2 ft. 3 in. thick, each com-
partment having a clear length
of about 38 ft. At the east end
there is a smaller compartment
14 ft. 7I in. in the clear. The
transverse walls take the place of
principals, and the intermediate
spans are bridged by ridge and
purlin beams. These carry the
smaller rafter beams, which have a
span of about 14 ft., are spaced
8 ft. apart, and in turn support the
general roof slab. The whole
forms in reality an ordinary beam
floor construction, arranged in two
inclined ])lanes. The ridge and
purlin beams were designed as
continuous over three spans, their
depth being 3 ft. 3 in. at the
suj)ports and 2 ft. 3 in. at the
centre of {he spans. The small
bay at the east end is constructed
with a single system of purlin
beams spaced 7 ft. apart. The
ends of all the main reinforcing
bars are hooked over to ensure a
good anchorage, and the web
tension bars are carried completelv
around the main reinforcements
■.[n(] turned down into the centre
of the beam at th(> top. Where no
top metal is required for com-
|)ressi()nal strength, constructional
bars h in. in diauK'ter are provided.
The centring to the imderside was
wrought, and the surface will be
left without any further finish.
The exiernal suiface has been pre-
|)ared to receive copper sheeting,
hardwood slips being built into the
slopes to |)r()\'i(l<' fixing.

'i'he most interesting roof is
thai wliicli covers the circular
eliapler housi'. This building
li.is a ch'ar dianieler of 31 ft.
al llie roof springing, and the
walls are i ft. 9 in. thick.

204

(&^SMiiS!3 Rh:iNFORCED CONCRETE ROOF CONSTRUCTION.

An inlcnial nIoiic i^.illcry ciuiirlcs it jiisl below the rool, siipijorlcd by ;ir(hcs
s|)i iiii^iiii; lioni ilic walls hciicilli. Althoii^^h of ;ini|)le strcnj^th to withstand the llirust
thus |)Ul upon ihcni, it was considered best that the walls should be relieved of all
])ossible iliance of additional thiusl from llu- roof above. The internal doni(,' has a

radius of i6 ft. and rises ii ft. above the sprin^ini^, being 30 ft. 6 in. in diameter at that
level. The height externally from the springing to the apex of the cone is 22 ft. 6 in.
To provide against the possibility of thrust, the roof is encircled at the base with four
series of s-in. diameter bars, each in five lengths, for convenience in handling, with

20.

NEW WORKS IN CONCRETE.

(CDNCBKrilJ

lapped joints of sufficien. ,cn,th .o develop '•-';',;' ';;-f^4'^;^;; "^ theiT ^ho.:
securitv the ends are hooked and he U,p. ^f "''■^.^^^'^d '"fitht to assist the walls

Longitudinal Section.

View of lUiildinU during Consirudiun.
Dbsamparados Station. Lima, \'\:kv.

p,ovid,.d wi,h h. -in.n .n. !,.„■ .lips for Una,.-,- se.uriu. This ,„of will he Hnished wilh

coppf-r. . , ,, , , in(l(l)i((l lo Mr. (i. (iilbort Scott, the

a Jt^roT^h: buiiL;:r::; :.u:';;a;:i:.:,,::,. ..,..1 ,1,.. d,.,..w;„.s whi,. 1,,. umdiv piac a.

our disposal.
206

/o, cx5Nyrunc-rioNAii

' C i FNGITMLE-klNt'. '

R}^:iNr()RCIiD CONCRETE RAILWAY STATION,

REINFORCED CONCRETE AT THE NEW DESAMPARADOS STATION.

LIMA. PERU.

Till.- huiUlin- here d.^n ih.d a.v.rs .•.i.i.r<.xim.il.l\ :m .nr.-i of 2,150 ^M- ni., .-.nd consists
of thr sl.-.tion prop* r, on lb.' -round lloor, .md ihr oHics .,1 ihr i.nlway st;dl, on Hi.- Iwo
upper tloors.

•TT??'^' '"ft-^-

The structure is mainlv of reinforced concrete. There are 92 reinforced concrete
columns running through the three stories. The floors and roofs also are composed of
reinforced concrete girders and slabs. All partitions are of hollow bricks, whilst the
front of the building is faced with pressed blocks of cement and sand to imitate sand

stone.

207

NEW WORKS IN CONCRETE.

ICQNCBETEJ

■■■

^Bi

^^^^= b

HI 592

!!!

Niiia

^^JH^^^^^H

Concrete Block Crusher Station, Prestea, West Africa.

CONCRKIK I'l.'K K l.OAOINfi STATION, I^(KSTICA, WkST AlKICA.

CONCRETE BLOCKS IN WEST AFRICA.

A j^Dod idea of llir Ijuildiiij^ will l)c obl.iiiKd fioin Ihc .•ircoiiip.iiiNiii}^ illustrations.

The whole ol ihc work w.is c;ii lit d out in U) nioulhs. The arcliitcct w;js Mr. R;if;i(l

I". M ;irt|uin.i, whiUl the it inlnr(';<l i"on(i(lc work w.is dcsit*nc(l ])\ Mr. M . M. I'.ilo.

W'c .lie iiulchtcii to oJic ol oui' i()rrcs|)()iid( Jil >^, Mi. O. L. Ali.ii^.i, lor our |)]lolo^r.'^|)ll>^

■ iiul paiticuku's.

CONCRETE BLOCKS IN WEST AFRICA.

\\ ini( I csl iui; ;i|)|)lic.".it ion of the use of concrete blocks foi- mine w oi'l< will be seen bom
ibe illustrations on paj^i' 2()<S, >bowini4 some work carried out on the (lold Coast. 'IIk
ilkrslralions sliow a new Loadini; Station and a new Crusher .Station at tlio Prestea
Ciold Mines (Rlock .\). " Winj^et " blocks were used llirouj^hout for tliis work.

The c'ontractors for the woik were .Messrs. I hompson, Moir \- (ialloway, of

J'arquah and Prestea, (iold CoasI, West Africa.

NEW BOOKS.

NEW BOOKS

AT HOME AND ABROAD.

A short summary of some of the leading books ivhtch have appeared during the last feiv months.

"Reinforced Concrete Construction." Vol. II.
By George A. Hool, S.B.

The Hill Publishing Co., Ltd.. 6 and 8 Bouverie
St., Fleet St.. London, E.C. 666 pp. + viii

Contents. — Retaining Walls — Theory of
Stability — Design — Construction —
Buildings— Design — Floors — 1 ypes of
Reinforcement — Roofs — Columns —
Foundations — Walls and Partitions —
Stairs — Elevator .Shafts —Contraction
and Expansion — v-ontinuous Beams —
Eccentric - load Considerations in
Columns--Wind .Stresses — Design of
a Factory Building — Example of a
Building Design, including the Speci-
fications — Construction — Materials
—Forms — Bending and Placing of
Reinforcement — Proportioning, Mix-
ing, and Placing of Concrete — Finish-
ing Concrete Surfaces- — Waterproof-
ing of Concrete — Construction Plant
— Estimating Unit Costs- — Estimating
Quantities — Example of an Estimate
for a Concrete Building.

This is the second volume on reinforced
concrete by this author, and the first
volume, which was reviewed in these
columns in a previous issue, treats of the
fundamental principles, and has been
adopted as a text-book in a number of
technical schools in America. 'I'he pre-
sent book deals with the more advanced
portions of the subject, and should be of
service to engineers in practice, as well as
to the advanced student. The diagrams
throughout the book are excellent, and
these have been prepared for the author by
Mr, Frank C. Thiessen, with the ic'xcei)-
tion of those pertaining to Construction
Plant, the chapter on the latter having
been f)repared by Mr. A. W, Ransome.
The chapters on Estimating have been
written by .Mr, Leslie H. Allen, and these
form a us(;ful [portion of the book.

The theoretical f;arts of the subject ;ire
treated in a very thorough manner, and
the author does not appear to rr)nsider any
f)oint too small or unimj)ortant to be iin
worthy of explanation, 'ihis section is
well arranged, and (he various examj)les,
which are com[)letely worked out, are
given in such a manner that the reader is
able to follow the a[)j)lication of the tlxoiN

and set his mind at rest on any point which
does not appear quite clear at first sight.
The practical portions are illustrated with
numerous photographs of work actuallv
executed or in course of construction, and
these render this section of the volume
ver\' interesting.

The shear and moment considerations
in continuous beams are dealt with very
fully, and great pains are taken to instil
the elementary principles into the mind of
the reader before proceeding to the more
complicated reasoning and formulae. The
English reader may experience a little
difficulty owing to the fact that the nota-
tion is different to that generally employed
in this country, but a study of the book
will well repay the reader.

" A Manual for Masons and Bricklayers."
By J. A. Van der Kloes. Revised and
adapted by Alfred B. Searle.

London : J. & A. Churchill, 7 Great Marlborough Street
W. 235 pp.-»-xii. Price 8/6 net.

Contents. — Physical and Chemical Notes
—Masonry — Bricks and Stones — Raw
Materials used in the Preparation of
Mortar — The Composition, Prepara-
tion, and Use of Mortars — The Com-
position, Preparation, and Use of
Concrete — Other Work Executed by
Masons, Plasterers, etc. — Estimates
and Costs.

This volume has been prepared by Mr.
.Searle to put before English and American
readers the researches of Professor Van
der Kloes, who is the Professor in the
.Science of Materials of Construction in the
L^niversity at Delft, and the particulars
have been modified and adapted to render
them more suitable to the readers in this
country. Great stress is laid on the neces-
sity of using suitable mortar in all kinds
of construct ion.il brick and stone work,
and the pliNsical and chemical notes which
(leal with ihc defects that commonly occur
are interesting and certainly put the
various items in a new manner which is
(•]< ar and convincing.

Shrinkage and e.\|)ansion, watertight-
ness, weathering, wall canccM", and
osmosis are among the points dealt with,
:iU(\ the whole chapter forms a good
iiilrodiiction to the book.

2 lO

. lONMPIR-IIONAlJ
fvLNdlNl i I'INd — J

NEW BOOKS.

Ch'ikimIIv s|)(;ikiiu^, ihc ])r;utir,il notes
art' 111)1 St) j^t)t)cl as tht>S(' clfvt)lttl it) ilii
ihcDii^tiral aspt'ii, and it is from the lain r
that tht' most valuahli- inft)rmation t an \)r
t)btaincd.

Tilt' nolfs t)n it'inftirt'td coiu'itic aif
\r\\ iiitai^it', and lurtlu rmt)rt' do nt)t
fxprt'ss the nature and functit)ns t)f ilic
oom|)t)ntMit i)arts in a satisfactory niannci ,
altlu)uj4li till' author states that thf usf of
the material ensures a security ai^ainsl lire
which is imobtainable in any other \\a\".
There are many points in this section of
the work which will not be accepted by the
majority t)f enifineers, but they are of some
value to the reader nevertheless. Various
suiijjjestions are gi\'(>n for the surface treat-
ment of concrete, but the author is not of
the opinion that a rich architectural treat-
ment can be obtained without the use of
brick or stone facing.

" LocRwood's Builders' and Contractors,
Price Booh for 1914.'

This price book is for the use of
architects and surveyors and those con-
nected with the building trade. It has
been brought carefull)' uj) to date, and due
effect has been given to the rise in prices
of materials and labour in the various
trades.

The first part of the book deals with
every kind of building work, and the prices
and wages tables have been brought up to
date and considerably enlarged. The
section dealing with electric lighting has
also been added to.

Much useful information is given in the
appendices, in which are tables of weights,
areas, etc., solicitors' costs, stamp duties,
tables for the valuation of leases and
estates, legal notes and memoranda, as
well as judicial decisions and Parliamen-
tary enactments.

There is also the form of Building
Contract and Schedule of Conditions
issued by the Royal Institute of British
Architects, as well as a copy of the London
Building Act and its amendments.

* Spon's Architects' and Builders' PocKet
Price BooK."

This well-known price book forms a
valuable reference for all those in anv wav
connected with the building trade.

The book has been brought thoroughly
up to date, and a great many additions
have been made in the various prices, so
that the diarv has had to be omitted to

kftp llif l)t)ok a reaNonable sizt- Itir pocket

UM'.

The usual t)rd(r of tratles is adojjtt d as
in a well-drawti bill t)f t|uantities, antl
I Ik re is a fulls-'lelailed indf.x to the trades,
so ill ii any in'^oriMalion which is required
is (.juiekh ft)und.

''The Maintenanceof Foreshores." By Ernest
Latham. A.M.Inst.C.E , A.M Inst.M.E.

I.iin<iiiii : Cr( shy, I .nckwood vV Smi. 11*1? h4 pp.
Price 21 - nti.

This little book deals with a subject of
great interest and importance, but in a
\'erv incomj)lete manner, being hardly
more than a grouping of detached notes on
certain aspects of the subject. .Some of
these nt)tes are, however, highly sugges-
ti\-e. The Royal Ct)mmission on C'oast
I%rt)sit)n has presented an extensive report
(a sht)rt summary of which is given in this
book), indicating the urgent necessity of
protective works. Legal problems of a
somewhat intricate character present them-
selves in this connection, and the author
deals with these and with the closely
related question of administrative authori-
ties. On turning to the practical means of
protection, however, the reader is disap-
j)ointed, the treatment of this subject being
rather scrappy and of less value than
might be expected from an author of such
experience in the execution of coast pro-
tection works.

It may be noted that groyning, as com-
monly carried out, is considered to do
almost as much harm as good. Favour-
able reference is made to the Dutch svstem
of protective aprons, and the suggestion is
thrown out that such aprons might be im-
l)roved by oblique steppings, at right angles
to the prevailing set of the waves. No
details of the method of construction of
protective works are given, and there are
no illustrations. Some notes on the pre-
paration of concrete are included, but the
account of reinforced concrete only
extends to a page, most of which is occu-
pied by tests of the steel reinforcement.
Exception may be taken to the statement,
referring to reinforced concrete sea walls,
that the system to be adopted is the first
consideration. The principles of construc-
tion of aprons, etc., are now sufficiently
well understood for the competent engineer
to design his reinforcement without slavish
adherence to any patent system.

Colonel Crompton contributes a chapter
on surfaces with bituminous binding for
marine promenades.

21 I

NEW BOOKS.

ICDNCBETE

" Experimenis with Built-in Beams." (Ver-
suche mit Eingespannten BalKen.) By
Dr. Fritz E. von Emperger.

Lepzig & Vienna: Franz Deuticke, 1913. 259 pp.,
250 Illustrations and Plates. Price M. 10.

This memoir contains a full descrii)li()n
of the experiments, an account of which
has already been given in this journal. It
mav be regarded as forming a complete
treatise on the theory and practice of the
subject, and is very fully illustrated by
diagrams and photographs. The principal
conclusions drawn from the very extensive
experiments on a large scale may be re-
capitulated here.

All reinforced beams which have been
erected without special devices to ensure a
free bearing must be regarded as wholly
or partially fixed, and allowance must be
made for the fixing moments. It follows
that the compression zone in beams should
never be entirely without reinforcement.
With sufficiently good union of beam and
bearing, the beam may be computed as
completely fixed, in which case the abut-
ment mav be considered to include an
element of the wall broader than the beam,
to an extent depending on the quality of
the masonry or concrete. It is best to
make the reinforcement of beam and wall
continuous, as in framed construction, but
precautions must be taken against settling.

The book is handsomely produced.

" Technical Studies of Mortar and Cement "
iZement-und MJ5rteltechnische Studien
I.) By Dr. Hans Kvihl.

Berlin : \'fcrlaf< der Tonindustrie-Zeitung, 1913. Price
5 Marks.

Ur. Kijhl is the successor of the late Dr.
W. Michaelis, and his investigations into
the chemistry and technology of cement
have the same originality and interest as
those c)f his distinguished j)redecessor.
This little collection of memoirs and ad-
dresses deals with a variety of subjects,
from the expansion of cement containing
sulphates to the use of gas analysis as a
means of controlling the fuel consum})tion
in rotary kilns. Concerning the first point,
the author produces evidence to show that
it is not the absolute quantity of sulphates
which determines expansion, 1)ut its ratio
to the lime ccmtent. Thus with cements
of hvdraulic mfjdulus 2*30 to 2' 15 the best
result is obtained with 3 per cent, of
gvpsum, whilst n cement low in lime, with
h\(lr;iiilic inrxlulu'' i''*^5, i^ sli'ongesl with

b per cent, of gypsum, and in fact the true
Portland character does not appear in such
cements until the proportion of gypsum is
considerable.

A new test for constancy of volume was
proposed by the author in 1912, consisting
in boiling tests with thin pats of the
German form, but made with mixtures of
cement with very finely ground normal
sand. It is to be noted, however, that
manv cements would pass this test which
fail in the Le Chatelier test. The use of
fluates is recommended for the treatment
of cement and concrete surfaces which are
to be ])ainted with oil paint.

" Silo Construction in Concrete and Rein=>
forced Concrete." (Silobauten in Beton
und Eisenbeton.)

(Heft 4 of Cement - Verarbeitung.) Cement -Verlag
G.m.b.H., Charlottenburg, 1913. Price Pf. 35.

A pamphlet detailing the advantages of
concrete, especially reinforced, for the con-
struction of silos. Descriptions, with many
plans and photographs, are given of silos
which have been erected to contain grain,
coal, ores, cement, wood-shavings, etc.
The methods of reinforcement and of
statical computation are also described.
Rectangular, cylindrical and hexagonal
silos have been used, and the types of
design and construction may be varied
widelv according to circumstances. It is
evident that reinforced concrete is in every
way superior to steel, wood or brickwork
for structures of this kind, the number of
which is increasing rapidly.

" Posts and Masts." (Pfosten und Maste.)

(Heft 3 of Cement -Verarbeitung.) Cement -Vtrlag
G.m.b.H., Charlottenburg, 1913. Price Pf. 30.

Another of these useful little German
monographs, describing the design and
construction of reinforced concrete posts,
telegraj)h poles, tramway .and electric light
standards, etc. The lightness of construc-
tion which is j)ossible with this material is
surprising, and some excellent examples of
really graceful and artistic standards for
lamps, tramways, etc., are reproduced.
The high elasticity is shown by bending
tests, liie masts returning comj)letely to
their original form after a deflection
.'imounting sometimes to as much as a
metre ;il the free end. On account of the
(lillicnlly of construction, these long masts
;iic iisii.ilJN' made by special firms using
[).il<nle(l processes.

2 I 2

7/, tON> IPnCTlONAI.

MEMORANDA

Memoranda and Neivs Items are presented under this heading, with occasional editorial
comment. Authentic neivs will be ivelcome. — ED.

Building By-Laws and Reinforced Concrete.— The C'hiswick Urban District
Council, under their Act of 191 1, obtained powers to relax or modify their by-laws
with respect to new streets and buildinfjs as to buildinj^s of iron, steel, or reinforced
concrete, and have recently made ihe following regulations : —

(i) All future one-storey ferro-concrete structures be considered permanent build-
ings, provided that in the Co-unciTs opinion sufficient strength is allowed for in the
construction of (a) supjxvrting walls, and (h) all flat pitched or horizontal roofs.

(2) That fcrriKconcrcie dwelling houses be considerod jxTmanent buildings, jjrovided
that all floors are calculated to carry a minimum load, including the weight of the
floor, of one-and-a-half hundredweight per foot super, with proportionate strengths
for supporting walls.

(3) That ferro-concrete factories, warehouses, and public buildings of more than
one storey be not approved as permanent buildings, unless an undertaking by the
owner is deposited with the plans, etc., stating that he will not permit or allow the
agreed maximum safe loads as set forth upon all parts of such plans to be increased
in any part thereof without the permission of the council being first obtained,

(4) That the recognised general engineering formulae for beams supported at each
end be utilised for all calculations except in the case of continuous beams over three
or more spans, in which case the external spans must be treated as beams supported
only.

(5) That fully detailed plans, sections, and elevations of all reinforced concrete
buildings must be submitted with a detailed specification, and on such drawings must
be shown the proposed maximum loads, together with the calculations upon which the
strength of all walls, columns, floors, and roofs have been calculated.

Action of Sea Water on Concrete. — More than twenty concrete piers built several
years ago by the Aberthaw Construction Co., and submerged in the United States Navy
Yard at Boston, are again being examined to note the action, both mechanical, due to
frost, and chemical, due to ingredients in the sea water. As this subject is one which
has a large bearing on the permanence of piers, abutments, sea walls, etc., when built
of concrete, these experimental tests are expected to yield some very valuable results.

Wire Ropeway Supports in Concrete and Reinforced Concrete. — Wire ropeway
supports were originally only made of wood or iron. The wooden supports were bedded
into the earth, or they were mounted in the same way as iron supports on masonry
or concrete. The necessity arose occasionallv of throwing hot ashes and slag from the
carrying rope of supports on to a dump, and the supports were gradually buried in.
Danger thus arose of large parts of the dump catching fire, and for this reason neither
wooden nor iron supports were suitable. Means were resorted to to remove the pressure
of the dump material from the supports. These were then built of bricks, or stamped
concrete pillars were set up as raised foundations on which only short iron carrying
heads were fixed. Supports of this kind were made by Messrs. Adolf Bleichert, of
Leipzig, and our second illustration shows such supports erected some 3-ears ago for
the sugar factory of Messrs. Dobrovitz, in Bohemia, by Messrs. Bleichert. Latterly

,**

213

.^'t.g,

^lil^in

CONCKLTEX

rCONSTRUCTIONAJL^

J^.,..^

PILE DRIVING PLANT

WE MAKE PILE DRIVING PLANTS SUITABLE FOR THE
LIGHTEST TIMBER SHEETING OR THE HEAVIEST FERRO-
CONCRETE PILE, FOR STEAM, AIR, OR HAND POWER

STEEL SHEET PILING

*' Universal Joist

''Simplex"

"Simplex"

43 lbs. per super, ft.
27 lbs.
22 lbs.

»5 J»

Wc buy tlie Pilin^^ back at \\\f- v.n\ of the job, making llie cost to ihe user approxlmalely
1/10, 1/4, & 1/- per 8uj)er, foot rcs[)ectively

CATALOC.UIS AND FIRM Qll ITATIONS ON APPLICATION

THE BRITISH STEEL PILING CO.

DOCK HOUSE, BILLITER ST., LONDON, E.C.

Telephone : 5463 Av<;nu'-.

I ilcHrains ; " I Minifdon," I ondon.

2 14

Please mention this Journal ivhen luritinq.

J lONMkMlcriONAl
f-i. KNdlNl-l KMN(. --.

MEMORANDA

aclu.il ri'iiiforccd concrete supports have
been creeled for ceiiKMit factories which
carry the rojxs on cross-beams. These
are seen in the lirst illustration, and
were built for a cement works abroad,
.111(1 were made by the same firm
iiK iilioned above.

Sieving witti Standard Cement
Sieves.' 'ihc Bureau of .Standards,
I .S.A., have recently issued a Paper
(No. 2()), by Messrs. R. J. Wig and
J. (-. Pearson, dcalinj^ with variations
in results of sicvin<4 with standard
cement sieves. We are unable to ^ive
I he report in full, which deals with
\ arious experiments carried out, but we
publish below the conclusions arrived
at, as they may be of interest and prove
useful to many of our readers : —

In reviewinif the results of the
tests made the following conserva-
tive estimates may be given :

I. Emj)lo\ing the present stan-
dard method of sieving, the greatest
attainable accuracy in single fine-
ness determinations of normal
Portland cement on a standard
No. 200 sieve — that is, the greatest
attainable accuracv in checking uniformity of samples— is about o-2 per cent.
2. " Standard'"' No. 200 sieves may differ in their sieving values by consider-
able amounts, such that their corrections to the ideal No. 200 sieve may be at
least as great as 0*7 per cent.

Wire Ropeway Supi'orts in Reinforced Concrete.

Concrete Wire Ropeway Supports.

MEMORANDA, ECT>[CBETE}

3. Errors of at least o-^ pcv cent, may be looked for in sinigle fineness
determinations of normal cements on a standard No. 200 sieve when made in the
usual routine manner.

4. Deviations exist in the sieving values of " standard " No. 100 sieves, of a
magnitude, roughly, one-half the corresponding values for No. 200 sieves as given
above.

5. " Personal equation " appears to be appreciable in hand sieving, as in most
laboratory operations, the observed values being as great as 0-3 per cent.

6. The rating of a sieve by some system of demerits assigned from direct
measurements appears to be an interesting possibility, and worthy of further study.
Should a system be worked out to give reliable indications, say within 0*2 per
cent, or 0*3 per cent, of the observed sieving value of a sieve, it will add greatly
to the value of the certificate now furnished with standard sieves.

It seems e\ident from the foregoing that both sieving tests and the iuiterprota-
tion of measurements on sieves are subject to conisiderable discrepancies, and the
question arises as to whether some other more reliable method of determining
fineness cannot be made available. The sieve at best is a measure of the coarse-
ness of finely ground material rather than the fineness, and experiments now in
progress at the Bureau of Standards indicate that air separation will offer a more
satisfactory means of determining fineness than mechanical sieving.

In conclusion it may be stated that a tolerance of i per cent, from the specifica-
tion should be allowed with the No. 200 sieve and 0*5 per cent, from the
specification with the No. 100 sieve, every care being taken to conduct the test in
strict accordance with standard methods. These tolerances should be considered
as minimum values since they are based upon the results obtained by careful and
experienced observers ; therefore it should be emphasised that greater differences
are possible in ordinary routine testing.

Concrete" Hardening Material. — A material for hardening concrete now being
introduced in the United States contains 95 per cent, of iron dust, which is mixed with
cement for finishing the surface of concrete floors. From 15 lb. to 25 lb. of the material
is mixed with 100 lb. of the cement while dry, and one part of this mixture to two
parts of sand mak<'s the slurr}' for the top coat, which varies from 0*5 to i in. in thick-
ness. It is said to make a hard and durable floor, which is waterproof and not
slippery. The hardening material is used also to make new concrete adhere to old
in repair work.

TRADE NOTICES, CATALOGUES. ETC.

The Kahn System of Reinforced Concrete. — Most of our readers are well
acquainted with this form of reinforced concrete construction, and we have in this
Journal given illustrated articles and descriptions of buildings and other work erected
on this system.

A new catalogue has just been issued bv lire 'i'mssed Concrete Steel Co., and
every endea\'our has been used to produce this juiblication in an attractive manner.
The book is jirinted on the loose-leaf system, so as to enable sections of it to be sent
out to people interested in the respective subjects illustrated.

It contains numerous illustrations of important structures carri<(l out on this
system.

There are also some notes dealing with the siibjccl of reinforced concrete generall\%
and a few pages are also d<'Voted to describing the Kahn sxstem in j)articular.

Those of our readers desiring U)Y fiirllu t iiifonnnlion, or a copy of the catalogue,,
should a[>[jl\' to llir- Trii"«se(l CoiKrcle Steel ("o., of ("axton House, Westminster, S.W.
The Empire Stone Co., Ltd. A new catalogue has just reached us from this
company. This publication contains a luinilxr of iiilcresting examples of buildings
in which reinforced r-oncrele has been ein|)loycd. Not onK are the various woilvs
illustrated, but in each case a short disc ri|)lion is given of ilic reinforced concrete work
carried out by the comjjanw

The examples includr- factorx' const rmt Ion, rclaliiing walls, staircases, bridges^
rafts, etc. Copies of the catalogue may be oblaiiicd on a|)plication to the company at
Thanet House, 231, Siranfl, W'.C., or al tlicii- ofticis in Birmingham: ^\'inchesler
House, Victoria Square, Hirminghani.

2 16

CONCRETE

AND

CONSTRUCTIONAL ENGlNEEmNG

X'olume IX. No. 4. London, Ai'KII., 1914.

EDITORIAL NOTES.

THE CONCRETE INSTITUTE.
The Present Unfortunate Effort to Change Its Objects and Title.

We ha\c from limL' to lime referred to a tendency on the part of certain nu-ni-
bers of \\\<i Concrete Institute towards utilising the Institute for their ])articular
purpjses. The. e members have been very persistent in their tndtavours. It has
thus come about that althoug-h the general membership had not realised it at the
time — and. as a matter of fact, many members of the Institute's Council had not
realised it either — a change of Memorandum was adopted at an Extraordinary
(General Meeting last winter whereby the Institute, instead of remaining an
institute intended for those concerned in works in which concrete and rein-
forced concrete play a part, is apparently to become an institution for those
concerned in structural engineering.

Now we grant that there may be ample rot^m for some institution con-
cerned specificail}" in structural engineering, although our own experience is
that the Institution of Ci\ il Engineers and the several junior engineering
societies have long afforded ample facilities in this direction, and we would
naturally not raise any objection to such an institution being formed if there
were a bona fide dc^mand for its constitution. But for those concerned in struc-
tural engineering to change the entire objects of the Concrete Institute and
subordinate concrete and reinforced concrete to structural engineering would be
a mistake indeed. One has only to remember how unkindly reinforced
concrete was for many years treated in the Institution of Ci\il Engineers to
understand what its position would be in the Concrete In.siilute if the objects
and title of that bod) were changed.

The Concrete Institute was primarily intended for the exchange of experience
between all the various professions and industries concerned in concrete and
reinforced concrete, which included CWi\ Engineers, Architects, Sur\eyors and
Quantity Survexors, Mathematicians, Scientists and Industrial and Cement
Chemists, Manufacturers and Contractors, and last, but not least, the Concrete
Specialist. The Concrete Institute, as it is now apparently the intention to
re-model it, is. however, simply to become an institution of structural engineers,
and thus the architect, the chemist, the scientist, and the mathematician is either
ruled out altogether or is to play a very secondary role as an '' Associate," or
what not.

2 17

THE CONCRETE INSTITUTE. CQNCBETE]

Application to the Courts.

Leg'ishition, liowcxcr, lias fortunately provided that chang-e in the
Memorandum of an incorporated institution of this kind must have the sanction
of the High Court, so that errors may be avoided and the interests of the
members as a whole safeguarded.

From numerous letters we have received, it would appear that the Court is
to be applied to in the near future, but several sections of the professional
members, a group of those concerned in the co'ucrete industry, and one or two
other groups, appear to be org-anising opposition. On the other hand, some
of the municipal surveyors appear to welcome the change, and the steel frame
contractors and their assistants are jubilantly delighted.

Our View.

Our own view on the proposed change is obvious. We have assisted the
Concrete Institute with advice and publicity as a corporation with a specific
purpose. We consider an independent Concrete Institute a necessity and
approve its original objects and constitution. It is our intention to use every
possible legitimate endeavour that those objects be retained. We shall thus
oppose to the best of our power any change that diverts the objects of the
Concrete Institute from its primary purpose, and we shall certainly oppose any
change from its very excellent and concise title.

Apart from the question of the Concrete Institute per se, we think it is
a national question that this country should have a bona fide Concrete Institute
and not lag behind other countries in this direction. The Empire requires some
centre where all professions and vocations concerned can exchange opinions on
the subject, and also some centre that can speak independently as representative
of all the interests concerned in these important days of new developments in
building — both domestic and utilitarian,

A Referendum of our Readers.

l-'or this reason, we propose also sounding the general view of our many
subscribers and readers as far as it is possible on the subject, and we are
enclosing a postcard which we wall thank the recipients to return (stamped or
unstamped), but filled in in such a form as to give us some idea as to the general
\ieus of our supporters on this subject. It is equally importaiit for us to know
tlie views of (jur most junior readers in a far distant colony, as it is to know
that of the great engineer who practises in (it. George Street. It is equally
imprjrtant for us to know the views of individuals and of corporations, and we
trust that the postcard will be replied to b\- a large number of our readers. In
these da\s of "referenda" and polls, it is particularly useful for us to know
what the feeling on llie subject is, seeing that v.vvn the great majority of the
members of the Cxjncrete Institute ha\'e not had an o])j)ortunity of voicing their
views on the- subject, the attendance at meetings being naturally limited to a few
London members.

W^e will u<;lc<jme, apart from tiic icply to lh<; |)ostcard, corresj)ondence on
the subject. Our endeavour is to retain lor tlu- nation a Concrete Institute of
standing that may have the sam<; prestige in respect to contTete in the world as
the prestige of the Iron and Steel Institute for steel, or tlie Institution of Naval
Architects in the matter of ship (()nstru( tion. The reputation must not only be

2lS

THE CONCRETE INSTITUTE.

A national ri'i)ulat ion, hiil an inlii n ilional rc|)ut al ion, and tliis tinkering at the
Memorandum and ArtiiK-s of tlu- C'oiuirlc Inslitulc is latal to tlic standing- ol

lliis l)od\ .

A Possible New Organisation.

W'c think it is oni\ lair to aimouiuc that we ha\c Ixcn approached irom
;;n cnlirrly uncxiici^ti-d and wvy pouciliil source to lorin another institution
solel\ in the interests of concrete and reinforced concrete, shoukl the objects (jf
till' institute or its title reallx he chanj^ed with th.e sanction of the Court. We
think that consideration of this matter is premature, as we have some doubt as
to the Court sanctioning a change of Memorandum opposed by influential
members and, may be, by other corporations and by the public. We have thus
for the j)resent declined even to consider the matter.

Hut the fact that some such idea has been mooted by distinguished men
solely interested in scientific and experimental aspects of the subject and who
are not connected with the Institute should make that body reconsider the
advisability of the chang-e of objects and title so ardently desired by some of its
strenuous members, and also whether it is worth while to fritter time and funds
on interminable strife — within and without — which waste of effort and money
can result in nothing less than the institution's g^radual collapse or supc^rsession.

REINFORCED CONCRETE AND INTERNATIONAL INVESTIGATION.

Whilst at home some people seem to think that investigation relating to
concrete and reinforced concrete is not a sufficiently wide field for a Concrete
Institute, international and foreign bodies continue to set up new organisations
to cope with difi'erent sections of inquiry, for which there is not only a demand
among the professions concerned, but considerable popular interest.

Besides the well-known International Commission on Reinforced Concrete,
formed at the instance of the International Testing Association, to which we
have had occasion to refer from time to time, the Association in question
has also taken the initiative in forming two further International Commissions
that should have an important bearing on reinforced concrete.

Fire Resistance of Reinforced Concrete.

The first of these is an International Commission on the Fire Resistance of
Concrete and Reinforced Concrete. Delegates have been nominated from all
the principal countries in Europe and from the United States of America, and
Mr. Edwin O. Sachs, F. R.S.Ed., Chairman of the British Fire Prevention
Committee, has been elected President of the Commission. The British
delegates, we should here add, are Mr. Ellis Marsland (district surveyor) ; Mr.
W. Kirkcaldy, A.iNI.Inst.C.E., head of the well-known testing laboratory; and
Mr. D. W. Wood, an insurance surveyor.

The American deleg'ates are the following : — Professor Ira H, Woolson,
National Board of Fire Underwriters, U.S.A. ; Mr. Richard L. Humphrey, Pre-
sident American Concrete Institute; Professor Charles L. Norton, Massa-
chusetts School of Technology; and Mr. R. P. Miller, vSuperintendent of Build-
ings, New York.

\\'hi]st amongst other delegates we would specially like to name the
following appointments : — From Germany : Professor Gary, of the Lichterfelde

B Zl9

INTERNATIONAL INVESTIGATION. ICQNCBETEl

Testing Station, and Chief Oflicer Westphalen, of the Hamburg Fire Brigade;
irom Austria : Professor Melan, of the Technical College, Prague, and
Professor SaHger, of the Technical College, \'ienna ; whilst from Denmark
the delegates include Chief Officer Liisberg, of the Copenhagen Fire Brigade.

Reinforced Concrete Accidents.

The other International Commission that has been formed is an Inter-
national Commission on Reinforced Concrete Accidents, and of this Dr. von
Emperger, of \'ienna, has been elected President. The British delegates in this
case arc: — Mr. Edwin O. Sachs, F. R.S.Ed.; the Concrete Institute is repre-
sented bv Mr. H. Kempton Dyson (Secretary) and Mr. S. Bylander. Australia
has in this instance also three delegates, viz., Mr. J. J. Clark, architect (Mel-
b(jurne); Professor \\\ H. Warren, Sydney University, and Professor Robert
Scott, Canterbury College (Christchurch, N.Z.).

The delegates from the United States are : — Mr. Richard L. Humphrey ;
Professor A. X. Talbot, of Illinois University; and Professor F. E. Turneaure,
of Wisconsin Uni\'ersity.

Of other countries the following are distinguished members :— Denmark
has, among her delegates. Professor E. Suenson, of the Copenhagen
Technical School ; France, Professor Mesnager, director of the Laboratory of
Ponts et Chaussees, and Mons. Hennebique ; Germany has Dr. W. Petry, of
the (ierman Concrete Institute; and Switzerland, Professor Schiile,

We here would specially point tO' the interesting feature that Japan has in
this instance also appointed three delegates, viz., the following: — Professor
Tadahiko, of the Imperial University, Kyoto; Dr. Shinzo Kassai-Onoda, of the
Onoda Cement Co. ; and Professor Kaisaku Shibata, of the Imperial University
at T<;kio.

WorK of International Commissions.

International Commissions of this description naturally work very slowly,
and the resolutions they arrive at are rarely unanimous, but their great advan-
tage is, that they generally get together an enormous amount of valuable
informal ion, which, if properly summarised, becomes invaluable as comprising
the reliable- and authentic data of the points at issue.

In Ixjlh the cases of the International Commissions here referred to the
quest i(;n 'jf pre st nling useful data is one of importance, and reliability the great
factor. We (hjubt if the Commissions on Reinfon^'d ConcTete Accidents can
come to an\- other result b(');)nd a i)rescntati;)n of the primary causes of
accidents, but in the case of the Commission on the Tire-Resistance of Concrete
and l\(iii(or(4-rl ('(jiicrc tc it is to Ix; hoped that some standard specification may
be e\rjl\ed rnurji on ihc lines ol \\\i I'iic Insurance Specification we have
referrerl 1o« in a pn \ ions is.sue, and which, in a few short words, indicates on
general lines only what is absohilcl) essential IVom the lire jDoint of view.

A Warning to the International Testing Association.

The Internat ion.il 'Icsting Assix i;i! ion ji.is doiK- much good work in form-
ing these International ( "onimissions, .nid the re|)orts of souk; of the Commis-
si'^)ns in parlicul.ir lia\c bcin ol iinnicisnr.ihlc \;ihic. Tivere is some danger,
however, thai llicy sliould touch on subjects thai nia\- be controversial from

220

rj.fCN.MK'UiriONAl.l
/vt.N(.lNl-l l^NC. --J

SIR HENRY TANNHR.

\hv iii(liislri;il ;is|)r<t, ;iii(l for this riMsoii 1 nlcnialional spt'cilications on such
suhjcH-is as I'orllaiul C\nu nl or on the (iii;ilil ics of Slci'l and other niclals
should 1h' avoided, nioir panic iilarly ;is vii< h suhjecls arc dcpundent ^'•cncrally
or. local rondilioiis and local innu'ial pioihids.

Now ihat a Hrilish section has been propnly orLjaniscd to reprcscnl I^ritish
interests in llu' International Testini;- Assoeialion, it is to he hoped that this
aspect of ihj Association's work will ha\e i)rop-er attention, for there was a
tcndencN — pa.rticuiarly on tlu' ])ari of the multitude of (Jerman members wlio
ratlH'i- strenuously ix-present tlu' interests of their nation on this parti<-ular
ori^anisation to utilise the Inlernat ional C'onnnissions h)r tint (M)nimercial
purposes of their (^ounlry.

We welcome the formation of Research Commissions such as the ones
referred to abov€, but shall be \ er\' wary of .-mythin^- in the way of Commissions
that attempt the international specification of our national products t^enerally
to the disacKantao-e c)f our coimtrv.

SIR HENRY TANNER.

W'h observe that the public Press has announctd that Sir Henry Tanner, C.B,,
has retired from his post as prmcipal architect to H.M. Office of Works, after
some forty-two years' service with that department. His present post he has
held since the retirement of the late Sir John Taylor in i8g8.

Fortunately, however, we are able to announce that His Majesty's Govern-
ment has very wisely retained the services of Sir Henry Tanner in a consultative
capacity, so that although he may not be in that hourly attendance at Storey's
Gate which is almost necessary nowadays for one holding the position of chief
architect, and althoug-h Sir Henry Tanner will be free from that incessant grind
of routine work which is becoming more and more a feature of modern methods
ot administration, the Government and the country will have the great and
inestimable benefit of his continued advice.

Thus it will not be for us, as so many of our contemporaries have done,
to write at this moment of Sir Henry Tanner as having severed his connection
witli public life, but simply to congratulate him upon the conclusion of a term
of public service in which he has been not only a conspicuous figure, but
which he has made memorable by his broad-minded and practical decisions in
many matters of the highest possible technical moment. Xot least among these
decisions was the unique one whereby reinforced concrete was introduced into
Government buildings, regardless of the conservatism — not to^ say opposition —
that prevailed in this matter both in Great George Street and in Conduit Street,
the homes of the Institution of Civil Engineers and the Royal Institute of British
Architects.

Sir Henr\ Tanner is, as far as Government work is concerned, the pioneer
architect in England to undertake any really great enterprise with this form of
construction, but if he was a pioneer in his own department, he was also a
great leader and most tactful and conciliatory adviser on the many committees
with which his name was associated which dealt with reinforced concrete. We
would remind our readers particularly of his chairmanship of the Reinforced
Concrete Committee of the Royal Institute of British Architects, his office as

B 2 221

OUR COMPETITION. [CQNCKETE

president of the Concrete Institute, his seat on the Reinforced Concrete Com-
mittee of the Institution of Civil Engineers.

It is to be hoped that the subjects of concrete and reinforced concrete will
continue to have Sir Henry Tanner's valuable advice and wise advocacy and
support. Perhaps with the lesser ties of time he will even be able to g^ive yet
more time to these subjects in the future than in the past.

OUR CONCRETE COTTAGE COMPETITION.

We desire once more to remind our readers of the Concrete Cottage
Competition which we have organised and in respect to which competition
designs have to reach us by May 15th,

Particulars of the competition are obtainable upon written application, and
we suggest that all directly or indirectly concerned in this important problem
should use their influence to obtain the co-operation, in this competition particu-
larly, of the younger architects, to whom the matter of a successful design and
the publicity that will be accorded it should be of considerable utility.

Probably over 100,000 cottages will be required during the next few years
for our rural population, and it is not improbable that both for practical,
hygienic, economic and local reasons a considerable proportion of these will be
erected m concrete.

The interest that has already been accorded to this competition by great
landowners and their agents, by public authorities and their officials, and by
the public Press, shows us that there is a very great demand for a suitable
design.

The problem is one of the most far-reaching importance, for it affects not
only the well-being of the rural coimmunity and the tilling of the land, but it
affects many of the great industries concerned in the cheaper forms of building
construction, and thus the problem is essentia^./ one of ;^' s. d.

The reasons for our arranging this competition we have already given and
we trust that by the 15th May we shall find that our object has been achieved
by competitors producing designs of real practical utility. As to the prizes we
offer and the arrangements we have made as to assessors, we would refer to
our advertisement columns.

222

r J , CONy n?l JCTION A L
[t^ EJMCilNKt-BlNCi — ^.

CONCRETE MASONRY IN THE PANAMA CANAL.

CONCRETE MASONRY

IN THE

PANAMA CANAL.

(Conclusion.)

By JOHN GEO. LEIGH.

This article is continued from our March issue.— ED.

Ccncrete has entered largely into the construction of the line by which
electrical eneroy will be transmitted from the hydro-electric generating station
at Gatun to load centres at Cristobal, nearer the Atlantic, and Miraflores and

B;il]}oa, on the
Pacific side. The
line runs completely
across the Isthmus,
parallel with the
riglit-of-way of the
i^mama Railroad,
and will be used for
the distribution of
energy for light and
moti\e power at the
terminal docks,
locks, etc. For this
line there will be re-
quired 917 steel
bridges, having- a
span between side
frames of 36 ft., and
spaced on 300 ft.
centres. The stand-
ard concrete foun-
dation, the type of
which has been
carefully studied,
consists of two
pedestals resting
upon a spread slab,
w h i c h latter i s
reinforced by

A. 2,250 K\V. water turbine.

B. 2,000 K\V. generator.

C. Reactance.

D. Generator ins'rument trans'crmers

E. Generator switches.

F. Busl.

G. Bus 2.

H. Circuit switches.

I. Cable vault.

J. Circuit instrument transformers.

L. First gallery (el. + 40-85).

M. Second gallery (e'. + .55"35).

N. Main floor (el. + 33 25)

O. Low water (el. + 7).

P. 30-ton crane.

K. Penstock.

S. Draft tube.

/»-..■ J.

• r^:!-;.:^.

Fig. 9. Section through Hydro-Electric Station.
Concrete Masonry in the Panama Canal.

223

JOHN GEO. LEIGH.

iooNc!iJfc:i'li:i

scrap steel rails. Each leg- of ihe side frame is secured to the pedestal through
lA\o 15-in. anclior bolts, which are clamped at the lower end tO' the steel rails in
the spread shib. Provision for anchoring the foundations is made by extending
downward long reinforcing rods, encased by concrete in a drilled hole, sprung
at the bottom with light charges of dynamite.

Exhaustive studies have been made to
secure at the various locks not only a distri-
bution (^f lig:ht best suited to the conditions,
but also adjuncts calculated to satisfy
aesthetic demands. Finally, after approval
by the Fine Arts Commission, the type of
standard and bracket illustrated in Fig. 10
was adopted for exterior illumination. The
lamp used is a larg-e power tung-stcn bulb (400
watt), set in a concrete hood, the standards
being- alig-ned longitudinally and transversely
and the lamps spaced on from 50 to 60 ft.
centres. Both the pedestal and column con-
tain a large core, which reduces the weight
and furnishes a runway for the electric
wires. About 3J yds. of concrete and 750
lb. of steel reinforcement have been required
in the construction of each of the standards,
and of the latter there have been erected at
Gatun Ivocks 211, at Pedro Miguel 131, and
at Miraflores 160, some having- single and
(jthers double-arm brackets. Each double-
arni bracket, with reflectors, weighs
apjjroximately 1,612 II)., and the solid ball
linial, weighing 750 lb., is used to counter-
balance the weight of the single-arm bracket.

The single bracket standards are used
on the centre walls, where the lamps are
staggered so as \<> illuminate both lock
chamb<:rs, the double brackets being placed
on the side walls, where il is desired lo
throw ihe lighling llux back <jf the chamber
for a considerable dislanc<'. 'J he refleclors
are cast <;f concrete and proxidc^d with
shading hoods, which })rc\(iil llic glare of
the lamj) filament from j^enet rating along
the axis of the Canal. Ihv, entire rcllccloi-,
with lamj) and so<l«;t, is waterproof and
fitted to resist in (-xcry r(,'spr( t !r<)pi(al
deterioration.

The lamps in the oj>eraling tunnels and
machine rooms in the Unk walls arc also

224

\•>^i. 10. Reinforced Concrete Lamp Standard
and bracket.

CoNCKKTK Masonry in thk Panama Canal.

y, CTQN.S runiri lONAl
<iL KNdlNKI-RlNlV —

CONCRHTH MASONRY IN THE PANAMA CANAL.

j)i()\i(K(l Willi spccialK dcsii^nrd (onciclc icllcclois, .ind iccfii! cNpciiiiU'iit s h:i\L'
ijDiH' far to (Icnvonsl rale llic clliciciU'N ol ihc arraiii'Cincnl s wliicli lia\c been
a(l:)|)!t'(l. In llu- liinncl lij^litin^- the j^rralcst trouhlc was orcasioiuci by tlic \u\\
hicad-iooin of ~ It., wliich ma(lt> it din'irult i:) secure unilorm illuininalioii at the
iloor line. This ohstaele has l)e( n oxereonve I)\ pjac in<^' ceiling" lamps on 15-I1.
eenlres alon^ llu* loni^itudinal axis ol the tiuinels, and 1)\- ])r()\ idinj^" them with
rcllecHors of c'omparat i\ elv simple desij^n eonsistinj^- of inclined surfaces at the
four sides. In the machine rooms it was necessary l(^ dej)end u])on side-wall
illumination, for which i)urpose recesses were cast in concrete at alxjut
the level of the eye, and the efforts of the designers were directed towards
shadiuLj' direct rays from the eye without di;triment to the effectixe li^^htin^ of
the machines. The solution armed at, illustrated in hi}X^- 'i ^m^' •-, ^^^'^ t'> set
the lamp socket in the U)\) of a concrete rellector, ^Touted into the wall recess,

isw

^i=^m^^i^^^^^^^m^^^

'^ /■■a^^ii^ :

1 ,1 1 M u I.I i vl'i-i-L Jlitx .■■■•. . :. vi • V * .• • ♦ •« . >, -• ^.' :■• x--^'

vv.'/jp-/-;

■i;:^=:\:fi;i^7^

"V.*-

A. Concrete reflector for ceiling lamps. B. Ktflector for wall
lamps. C Chase for wiring. D. Cylindrical valve machine.

Fig. 11. Operating Tunnel in Lock Walls.

B. Reflector for wall lamps.
C. Chase for wiring.

Fig. 12. Detail of Tunnel Reflectors.

Concrete Masonry in the Panama Canal.

the wires being br;jug;ht to the lamp through a chase in the wall. In front of the
lamp is placed a concrete shade, containing a semi-circular opening at the
bottom, and adjusted in a vertical plane so as to cut off the direct glare of the
filament and permit the lighting flux to penetrate through the opening and flood
the m.achine. There will be altogether 2,041 tunnel reflectors — 952 at Gatun
Locks, 412 at Pedro Miguel, and 677 at Miraflores — and 4,751 machine-room
reflectors, thus distributed — Gatun 1,524, Pedro Miguel 1,126, and MIraflores

CONCRETE ARCHES AND WALLS AT LOCKS.

To the future traveller through the locks few features of the construction
of the latter will appear more pleasing than the arches at the south end of the
chambers, connecting the w alls of the locks proper with the guide and flare walls
of the approach. They are light and graceful in appearance and provide an
agreeable contrast to the necessarily plain and massive walls of the lock
chambers. In each flight the purjx>se of these arches is the same, namely, to
serve as a bridge over which the electric locomotives will pass when towing a

JOHN GEO. LEIGH.

[CQNCBETEJ

ship llirouj^ii 1 he locks. At Pedro Miguel ihe side wall arches, illustrated in Figs.
I :; and 14, make a continuous bridg:e from the main lock walls at elevation 92 ft.
above sea-level to the win^- walls at elevation +67 ft. The upper arch contains
about 1.093 cub. vards of concrete and the lower about 1,021 cub. yards, while the
arch in the centre wall contains about 1,850 cub. yards. There are in each side
wall arch about 27,676 lb. of reinforcing steel — 60 bars i^ in. square and 92
and 82 ft. long, while the centre wall contains reinforcement weighing 47,100 lb.
The width of the arches in the side walls is 31 ft. and in the centre wall 54 ft.,
the length of span of each arch being 79 ft., the minimum thickness of crown
5 ft., the radius of intrados 90 ft., and the rise of arch 9 ft. 2 in.

Owing to the character of the foundation, a portion of one of the southern
guide walls at Gatun locks differs in construction from that of other similar

Fi^^. 13. Pedro .Mit^uel Locks, showint4 Outlet in East Wall and Construction of Lower Main Gates.
CriNCRKi K Masonry in thk Panama Canal.

works along the Canal line. The wall extends into the Lake 1,500 ft. from the
upper guard gates, and the south, or outermost, 850 ft. rest on light earth,
bed rock being al)r>ul \ ^o It. below the surface. This j)()rtion, therefore, is
constructed upon j/iles dri\<n Iroin 35 ft. to 70 ft. into the groimd ; and to
reduce the weight on lliem a., miK h as possible the wall takes the form of
a reinf.'jrced contrvie ( cllular sirndure. The wall is foimded on a concrete slab,
from 4 ft. U) 5 ft. thick, laid o\cr the t<;[)s of tlu; piles, and is 58 ft. wide and
67 ft. above ihe ground, ulii( h is here 1,2 ft. aboxc s<'a-le\'el. The outside shell

226

J, tTON> TDWCTIONAI

COSCRETE MASONRY IN THE PANAMA CANAL.

is ;i itiiilni ci (1 concn-li' wall, j ll. illicit, wilhin wliiili arc l\\o iS-iii. \\ails 17 fl.
a|);n't, runninj^ ihr Iriii^th ol tiu- jliukIc wall, and lill\ walls ol llu,' sainr
tliii^kiu'ss (M'ossiiii^ lioin side lo side at ici^ulai' iiitcr\als of 15 ll. I luis the
iiitt'iioi" consists ol a scries ol cells, 15 It. 1)\ 17 It., separated by i8-in.
partitions. In tlic ccllulai- ])oiiion ol the wall about 35,000 cuIj. yards of

c-oiu'iH'tc ha\'e been jilaecd.

Modifications of the j)revailin^ method of construction have also to be
noted in (M)nnecti()n with the lower apj)roac^hes to the locks. 'liie uj)j)er
apj^roach walls loi' all the locks are of reinforced concrete in cellular structure,
but for the lower walls at (iatun and .Mirailores — with a view to avoiding- any
]).)ssibility ol (\)rrosi<)n ol the steel reinforcH-nient b\- sea water onh- mass

^WWW^"

B. Uin sq. Bars 12 in. cC- F. 12 in. Drain.

D. Cross drain. G. Caisson se.nt.

E. 45° Slope. 11. Lower guard gate sill.

J. Caisson sill,

Fig. 14. Side Wall Arches, Pedro Miguel Locks.
Concrete Masonry in the' Panama Canal.

concrete has been used. At Gatun the desirability of variation was enhanced
by the relatively insecure foundation, for, after excavation had been carried
50 ft. below sea-level, the use of long piles was found necessary to reach rock,
in some places 50 ft. further below. The structure planned to meet these
conditions and replace the heavy U-section, double g-ravity walls at Pedro
Miguel and Miraflores consists of a series of piers, connected by flat spans
above, forming a causeway of successive bridges. To protect them against
transverse sliding, the piles, which are driven on 4-ft. centres, longitudinally
and transversely, and on 3-ft. centres for the outermost 200 ft., are surmounted
by a continuous base of concrete, extending i ft. below the top of the piles.

227

JOHN GEO. LEIGH.

rCQNCBETEJ

This base is 58ft. wide. The l)ott()m is level, but the top is a series of
inverted stepped arches, described on a radius of 42 ft., the haunches between
which form the bases of the piers of the flat-span bridge. At the lowest step of
the arches the thickness of the base is 5 ft. 7 in., but at the springing- line it
is 3 ft. more. Reinforcement in the base consists of twenty continuous
longitudinal rows of 70 lb. rail, resting on the top of piles, and duplicate rows
of similar rail 4 fl. h in. higher up. The side elevation of the base and of a por-
tion of the completed wall is illustrated in Fig. 16.

Fig. 17 is a transverse section of the wall. Each pier, it will be noted,
consists essentially of two piers, connected by a semi-circular arch. The hori-
zontal normal section of each com.ponent is 18 ft. by 10 ft. ; the inner sides are

Fifi. 15. Construction of the North Approach Wall, Pedro Mif^uel Locks ; view showinf^ method of

l)lacinfi concrete.

Concrete Masonry in the Panama Canal.

verlica] f'^r a JKtighl of 22 fl. 5.I in., this point above the base being the spring-
ing line (jj the arch. On tjic oulcr faces ihe piers are vertical from the base,
at ell-Nation — 39'44, to the loj), which is u ft. above sea-level. The piers, twenty
in number, are set 50 ft. a|)art, cen1r<- to centre, the sj)ans (M)nnecting them being
carried bv four 0-ft. and six 4-ft. h-\n. plate girders, encased in (M)ncrete. To
prcN'ent water from surging from one aj)proa(^]i (Oiannel to the other, when a
lo<^k chamber is dis<'harging, the six spans of wall nearest the k)cks are closed
by 26-ft. curtain walls. 'Ihe wall ext<n(ls i,oiO ft. from the line of fender
chains, and contains about 45,(xj(j cub. yards of concri'te.

The corresponding struiture at .Mirailores, extending into the I'acific
entrance channel, takes tlx foi in of two walls, back to ba(^k, with a space of

228

rTTcoNSTiaTri lONAi

CONCRETE MASONRY IN THE PANAMA CANAL.

5 ft. hitwicn hasi's, and witli fares in rontiiuialion of \hv centre wall. The
outer ciuls are joined by a concrete wall, H ft. thick, perj)endicular to the
parallel walls, and ihe si)ace thus en<^lose(l is filled with rock and screenings,
the deckino- hcin.L; laid oxer llu' lop. This striK lure, whicii contains 82,000 cuh.
\ar(ls of concrete, differs fioin tlie lower ai)j)roa(-h wall at I'cdro Miguel in
that the hasi's of the |)arallel walls do not touch and that each of these walls
rests on nx^k, with a toe alon^- the outer side about 10 ft. wide at base laid in
excavation carried to elexation -50 ft. From the ed^^e of the to€ the wall
bailers inward, 1 on j, to a height of 9 ft., and from this i>:)int rises
verlicallv for 54 ft., a few inches at the top battering inward, i on 3, to form
coping. The rear, or inner, sides of the walls are stepped in, at intervals of

6 ft., from a thickness of 26 ft. 6 in. at base to 8 ft. at top. Corbels, supported
on the steps 6 ft. and 12 ft. below the top, project inward to a distance of 14 ft.
from the face of the wall, to support the superincumbent decking and electric
locomotive lowing rails. At Pedro Miguel the wall is of mass concrete for
950 ft. from its juncture with the centre wall, the remaining 250 ft. being of
reinforced concrete.

DETAIL COST PER UNIT OF WORK.

Not the least interesting and valuable record of the activities of the Canal
Commission will be found in the reports of the Cost-Keeping Accountant. The
cost reports compiled prior to January ist, 1910, included comparati\ ely little
detail, except for excavation work, and were not available until five or six weeks
after the close of each month, nor did they contain any charge for plant
and equipment, such expenditures being carried into the accounts in total only.
With the cummencemeni of concreting, however, it became apparent that some
method should be adopted by which the sums expended in developing quarries
and sand pits for the production of material and in providing mixing and other
machinery would be absorbed in the cost of the product, to the end that all
expenditures incurred for preliminary work, machinery, and installation would
be taken up in the cost of the masonry.

Consequent upon recognition of the importance of such measures, a cost-
keeping system was devised which has provided a uniform classification in the
various construction divisions, identical items of expense entering into the cost
of each division for work of like character. A system of arbitraries, revised
semi-arnually when necessary, was also adopted with a view^ to the absorption
into the construction cost of all expenditures for plant and equipment, based
upon the estimated cost and the estimated amount of work to be accomplished,
and wholly ignoring any salvage w^hich might be realised after the completion
of the latter. In order, also, to state the accounts uniformly, the plant
arbitraries were applied to all construction work prior to the date on which the
system became effective.

By means of this system complete control has been obtained over expendi-
ture for labour, material and services. The labour costs have been prepared from
the daily reports of foremen in charge of the gangs, and balanced against the
monthly pay rolls, and the costs for material have been obtained from the orders
drawn on the storehouses, balanced against the chief quartermaster's reports of
the value of material issued. Sand, stone and cement have been priced at the

229

JOHN GEO. LEIGH.

ICaSCWTF]

cost of delivery at the ware-
houses or storag-e piles, the
prices of the two first being
based upon the n-;onthly
output and the expenditure
connected therewith. The
price at which the material
has been charged into the
vv'ork is the average result-
ing from the cost of the
quantity left in storage at
the close of the preceding
month and the cost of pro-
duction during the month.
In the detailed statements
of costs all expenses are in-
cluded other than the pro-
portions representing ex-
penditures for sanitation,
hospitals, civil government,
lands purchased, terminal
docks and wharves, reloca-
tion of the Panama Rail-
road, purchase of steamers,
construction and repair of
buildings and municipal
improvements in Panama,
Colon and the Canal Zone.
The total amount of
concrete laid during the
fiscal year igio-ii was
1,742,928 cu. yd., distri-
buted as follows : — Gatun
Locks, 911,137 cu. yd.;
Gatun wSpillway, 59)^51
cu. yd. ; Central Division,
1,020 cu. yd.; Pedro Mi-
guel Locks, 498,187 cu. yd.
and Mirafiores Locks,
272,933 cu. yd. Taking
into consideration differ-
ences in the length of the
working day, the average
amount of masonry placed
daily in the locks by
the Atlantic Division was
^^^^573 *'-'• yd., and by

230

g^^5^!yl^^^ CONCRETE MASONRY IN THE PANAMA CANAL-

.pMOHMt-I-J^lNti-

llu' Pacilic- l)i\ision j<Srj(j(j cu. yil. I he cost pw cu. }(1. ;il (iatiin Locks
was vS().5()i(), al llic Si)ill\vay $6.7044, al IV'dro Mij^ucl Locks $4.7040, and
al Mirallorcs vS4.()82(). Al (iatuii the use of 7^^,609 cu. yd. of lar^c rock
Resulted ill a sa\in«^- of $o.2(SS.S pvr cu. \(1. of inalcrial j)lacc(i. 'llu; cost of
stone in bins al (iatun was $2.3403 j>cr cu. \(1., and in lli-c storage pile for
llic locks on liio Lacilic side $0.8443 per cu. yd. Crushed stone from Porto
Hello was lransjx)rti\l to (ialun by barges, and unloaded by cableways and
derricks, while from .\ncon c|uarry the crushed rock was carried b\ rail to
storage and dumped from Iresllc^s. '1 he difference of $0.7184 in the cost of
these two methods deducted from the actual cost in storage left $.1.3219 per
cu. yd. as llie unit cost of Porto Bello stone at (iatun. Sand for the locks
on the Pacific side was secured at Chame, in the Bay of Panama, towed tw-enty
miles, unloaded by electric cranes, and delivered in storage at a cost of $1.8565
per cu. vd., while sand for Gatun was brought fn^m Nombre de Dios and
unk>aded by cableways. Omitting the cost of transportation from the sand-
banks to the docks, the cost to the Atlantic Division was $1.3172 per cu. yd.,
and to the Pacific Division $o.(xdi5. Taking into account the various con-
ditions, the year's operations showed a difference in favour of the Miraflores
Locks of $1.7340 in the cost of cement, sand, stone, and large rock; of the
Pedro Miguel Locks in respect of other items which went to make up the cost
of the finished product — e.g., forms, placing-, pumping, power, repairs, plant
arbitrary and division expenses, and of the Atlantic Division in mixing and
reinforcement.

There were placed in the locks and spillways during 1911-12 1,443,570
cu. yd. of masonry. The unit costs of this work were : At Gatun Locks,
$7.7552; at Gatun Spillway, $7.0988; Pedro Mig-uel Lock, $6.4640; and Mira-
flores Locks, $4.7675. Thus, with a decrease of 512,315 cu. yd. laid in
Gatun Locks, the cost of plain concrete rose $0.5398 per cu. yd. as compared
with the previous year. At Pedro Miguel, also, where the amount laid was
less by 363,609 cu. yd., there was an increase in cost of $1.0143 per cu. yd.,
due to forms, placing, mixing and arbitrary. On the other hand, at Miraflores,
where the amount placed was 456,163 cu. yd. greater, the cost of plain concrete
was $0.0959 l^ss. The labour costs for the year per cu. yd. were lowest at
Miraflores, namely. So. 8394, Gatun Locks coming second with $1.3840, Pedro
Miguel Lock third with $1.4733, and Gatun Spillway next with $1.5425. The
difference between the costs in the Atlantic and Pacific divisions mav be attri-
buted mainly to the cost of cement, sand and stone. The cost of stone at the
storage piles at Gatun was $2.4952, as against $0.7996 per cu. \ d. in the
storage piles for the locks on the Pacific slope. If, however, there be deducted
from this dift'erence of $1.6956 the extra expense attached to the Porto Bell'j
stone, represented by the difference ($0.7365) between the costs of towing and
unloading and those of transportation by rail, together with the difference in
plant arbitraries, amounting to $0.4336, it will be found that the net dift'erence
in labour costs in favour of Ancon quarry was actually $0.5255 per cu. yd.
Sand procured from Xombre de Dios and from the Chagres river beds cost
respectively $2.2414 and $1.2850, delivered at the stock piles of the Atlantic

231

JOHN GEO. LEIGH.

ICONCBETEl

Divisi(3n, as compared with So. 7025, the cost per cii. yd. of the sand gathered
at Chame and towed to Balboa.

ANALYSIS OF CONSTRUCTION EXPENDITURES.

The classified expenditures of the Canal Commission to December 31st of
last year amounted to ;^,'(x|,892,io5, of which about ^^40,442,865 was appor-
tioned to the Department of Construction and Engineering, ;^i8, 41 3,000 to
** general items," ^3^479'450 to the Department of Sanitation, and ;6'i,395,ooo
to the Department of Ci\'il Administration. From the latest available state-
ment of details
(that to Septem-
ber 30th) of con-
struction expendi-
tures, amounting-
in the aggregate
to ^.^40,670,000, I
note the following
particulars : —

Excavation and
dredging of Canal
prism : From and
including Gatun to

the sea, 39»9oi.7,53
cu. yd., cost
^^2, 1 18,330; from
Gatun to Pedro
Miguel, 109,624,594
cub. yd., total cost,
including masonry
and ;^,"i 5,600, value
of plant and equip-
m e n t to be ab-
sorbed in construc-
tion costs after
September 30th,
p£, 1 7,r)9o,ooo ; from
and including
Pedro Miguel to
the sea, 45,228,233
cu. yd., total cost
^,3,000,000.
(iaiun Spill\\ay : Excavation and ])ic|)ariiig foundations, 1,588,921 cu. yd.;

masonry, 229,873 cu. yd., cost ^'377>""^^ i">'' <''>^' VS7.954S; ironwork, gates

and <jp<;raling- machinery, ;673, 235 ; lolal cosl, ^.'700,000.
Gatun Dam: 'JV>tal cost, ;^'i ,783,00(3.
Gatun \j)<:ks : Cost of excavation and |)rc|)aiing foundations, iiK hiding

83,670 lin. fl. concrcli piles, ^.'934,800; mass masonry, 2,041,156 cu. V(l.»
232

Viti- 17. Sectional View of Dual Pier.
Conc:kktk Masonkv in tiii-: I'anama Canal.

CONCRETE. MASONRY IN THE PANAMA CANAL.

cost ^>^, I '^q, J 17, unit Ci)s\ $7,451)1 ; iiiiisoniy used in iiist;ill;il ion ol in.iclniUTy,
2^,011 (U. \{1., cost /v'\^,^^57, unit cost ^ij.^Sj.S; total cost, iiu ludiii^ J4:i^<^'^>
fender cli.iins, opnatini; niacliinir\ , etc., ^,5,000,000.

(iaiiiii li\ (Iro-clcct lie station and plant : Cost ^.'J5,000.

Fif4- IS- Laying Concrete, Gatun Upper Locks ; view from a centre wall culvert.
Concrete Masonry in the Panama Canal

Gatun to the sea : Total construction cost, including ;£'58,670, plant to be
absorbed in construction costs, ;^Ji 1,324,000.

Pedro Miguel Dams: 1,567 cu. yd. masonry, unit cost $5.3872; total cost,
i.-'/S'-^oo.

Pedro Miguel Locks : Cost of excavation and preparing foundations
^^311,560; mass masonry, 906,55^ cu. yd., cost ;£!"i ,099,600, unit cost S5.8838;

233

JOHN GEO. LEIGH, [CQNCBETFJ

masonry for machinery installation, 14,576 cu. yd., unit cost $11.9716; total
cost, including- operating machinery, etc., ;^2,4i3,ooo.

Miraflores Dams and Spillway: Excavation, 159,130 cu. yd.; masonry,
yy,92=^ cu. >cl., cost ^.'108,405; total cost ^£^384, 220.

Miraflores Locks : Cost of excavation and preparing foundations, 3,286,800
cu. yd., ^671, 585; mass masonry, 1,479,079 cu. yd., cost £,'1,634,483, unit cost
S5.3596; masonry for machinery installation, 16,984 cu. yd., unit cost
Si 1. 541 1 ; total cost, including iron work, gates, emergency dams, operating
machinery, etc., £"3,45^'330-

Pedro Mig-uel to the sea : Total cost, including- excavation and part con-
struction of the abandoned locks and dams at La Boca, construction of the
Xaos Island breakwater and about £200,000, value of plant and equipment to
be }et absorbed, £"9,800,000.

Terminal facilities at Cristobal : £"18,360.

Terminal facilities at Balboa : Part cost, including £'57,275, value of plant
and equipment to be absorbed, £^667, 470.

Miscellaneous items : Permanent town sites, Balboa, La Boca and Pedro
Miguel, permanent buildings, power transmission line, trans-isthmian oil-pipe
line, and lights and buoys, £202,000.

In the final quarter of the financial year 1912-13 the cost per cu. yd. o^ the
masonry placed in the several locks was as follows : —

Gatun.
$

Concrete 6'i2o8

Administrative and general expense ... '4444

Total cost 6-5652

Reinforced masonry 9'i382

Administrative and general expense ... 1-0252
Total cost 10-1634

The exceptionally high cost of masonry during this quarter was due to
charges for finishing work, clearing the kx:k floors, etc., these special expenses
being proportioned to " Wood forms," " Mixing," and " Placing."

The progress, month by month, of masonry construction at the various
locks is indicated in llie foHowing tables : —

edro Miguel.

Miraflores.

93-4848

7-7140

9-8458

I '4693

103-3306

9'i833

14-4834

9-7500

3 "3 1 65

2'o55i

17-7999

11-8051

Gatl'N (cu. yd.).

1900.

January —

February —

March —

April —

May —

lune —

July —

August 1,298

Se[;temljer 12,294

October 29,378

Movember 3o,2 7(j

December 42,832

igio.

1911.

1912.

1913-

54,136

72,919

34,983

28,085

55,696

72,103

26,664

30,780

60,998

86,884

27,532

48,180

63,227

67,361

11,600

22,732

74,273

67,844

7,746

13,046

8(),40i

55,035

6,095

5,509

84,001

71,046

8,093

3,431

85,686

66,928

6,855

6,258

76,720

57,298

3,162

442

86,949

53,636

3,252

174

75,152

43,907

6,02()

280

80,212

43,590

5.697

120

Total 116,072 886,451 758,821 147,708 159,037

Grand total 2,068,089

11 , CON.S rm K "IION A I .
^KN(.lNKl-klN(. --.

CONCRHTH MASONRY IN THE PANAMA CANAL.

I'KDKO NlKilKI. (cu. \ d.).

j;inuar\'

l'"i'l)ruar\

Marrh ."

April

May —

Juiu'

July

August

SeptemhtT -2,.i70

Ottober ^,310

.\(»vember io,i6q

Uecember 13,007

13.-J18
i8,7()3

20,576
.K'.63i
4i,4()4
5 1, 264
50,702
61,422
64,248
42,834

Kjl I .

38,513
37,011
44,716
28,635

ig,i35
18,243

iy,(jo6
20,736
15,370
25,637
10,622
14,360

Total 33,856 444,047 30i,8o3

(".rand total 023,438

igi 2.

15,003

12,630

0,331

0,460

10,736

10,061

1 1 ,480

5,005

3,030

6,587

7,972

6,958

100,261

I0I3-
4,652

4,204
13,412

2,145
1,144

773
1 ,820
1,884

1,144
412
630

1,162

33,481

MlK

1000.

January
l""ebruar\- .
March ....
April

May

June

July

August

September

October

November

December

Total

Grand total

Fl.OKKS (cu

yd.).

1010.

lOii-

1012.

1913-

24,018

48,416

50,456

146

20,8g6

63,893

34,979

314

31,173

83,706

21,030

38,758

97,735

13,266

36,154

92,005

6,056

1,603

26.536

68,398

3 836

3,672

32,840

66,026

3,810

6,030

57,003

75,388

3,643

18,133

56,083

46,122

1,907

22,159

60,873

54,790

1,152

23,871

41,726

39,874

2,007

21,533

48.772

46,746

1,859

07,501

474,832

783,180

144,901

1,500,525

CONSUMPTION OF CEMENT.

In view of the impending commencement of lock construction work what
is probably the largest single order ever given for furnishing Portland cement
was awarded in January, 1909. This called for the delivery, f.o.b. New York,
of 4,500,000 barrels, at a minim'jm rate of 2,000 barrels and a maximum rate
of 10,000 barrels a day, ullh the right to increase the order 15 per cent. On
this contract the Atlantic Division received 1,343,757 barrels in wood up to May,
191 1, when this method of shipment was changed to bags, as preferred bv the
Pacific Division from the commencement.

During the period of greatest activity in lock construction the delivery of
cement from the United States amounted frequently to 7,000 barrels dailv, and
a stock supply of from 100,000 to 200,000 barrels was maintained on the
Isthmus to provide against delays in shipment. La^er, however, the rate of
delivery was gradually reduced to about 1,500 barrels a day, a reserve being
maintamed of approximately 50,000 barrels. In September, 1912, tenders
were opened for the supply of an additional 1,000,000 barrels, or of 30 to 15 per
cent, more or less at the option of the Commission. The specification also
provided for delivery up to July ist, 1913, of from 2,000 to 5,000 barrels a day.

JOHN GEO. LEIGH. r—

and thereafter until the completion of the contract, of from 500 to ,,000 barrels
Together w.th two tenders from other companies, a letter was ;;ceiveQ from
the former contractors offering to continue deliveries as might be eededto

complete the u<,rl< on ihc Ca,,;,! ,„ Iho pric- ,j. ,,,,„ ,,,, ,,,„,.,.| „^, ,,^,|
earhcr contract; and ,h,s olfc-r w.,. ac,<.pu.,l by Ihc Secretary of War
recommendation of tlic Chainnan „f ihc ( ■ornmissicn.

ing Ihc
on the

^3'^

RECENT BRITISH PATENTS.

RECENT BRITISH PATENTS
RELATING TO CONCRETE.

Wc Pr^wose to present jUritcrvjls pjrttaiUrs of British Pjtents issuea^in connection
^ coru-nTe Inr reinforced concrete. Tt^e Ust article appeared m our tssue of

'With

October, /"/J. ED.

Column Moulds. Su. 5,037/13. Blaw Steel
Conslnation Company. Accepted Sovenibcr 20/13.—
This iuvciiLiou is applicable lo the formation of all
kinds of concrett' structures circular in cross s^-ction,
whether solid or hollow.

The invention refers particularly to moulds in
w hich the shell is composed of a number of segmental
metal body sections adapted to be assembled together
into circular formation, this shell being adjustable
to diameter by varying the number of sections used.
The invention also comprises improved means for
varying the length of the mould, for stiffening the sheet
metal plates employed in the construction, and for
makinii them conform to substantiallv true circular
form.

The form or mould {Fig. 2) consists of two tubular
sections, the lower of which extends from a to b and the
upper from c to d, but of course as many sections as
are necessary may be employed. Either section {Fig.
i) is made up of four segmental plates (i, 2, 3 and 4),
the plate 4 being a filler plate narrower than the others.
The plates are provided at their vertical edges with
outstanding flanges 5, the flange of one plate abutting
against that of the adjacent one. Extending circum-
ferentially of the plates i, 2, 3 and 4 are a number
of stiftening bands, consisting of substantially arcuate
rigid metal plates set edgewise, which serve also to
give true circular shape to the columns. This circular
band is adjustable to diameter.

Fig. 2 shows two stiffening bands, though any

number may be used. As shown {Fig. i) the band is

made up of four sections (6, 7, 8 and 9), though any

number may be used, depending on the size of the

mould and number of plates used. The sections overlap

and extend through slots in the opposing flanges 5,

10 and 1 1 being the overlapping edges of the sections 8

and 9. The overlapping edges of the stiffening ring sections are provided with slots

12 which receive the wedges 13 lying on opposite sides of the vertical flanges 5.

When the wedges are driven downward they apply tensien to the sections 8 and 9 and

Figs 1 & 2. Column Moulds.

e of czf

Figs. 1—4. Connections for Metal Reinforcement

C 2

237

RECENT BRITISH PATENTS.

also press the opposing faces of the

[CQNCBETFJ

Fif^. 5. Connections for Metal Reinforcement.

the number of plates employed the
diameter of the columns formed ma\
be widely varied.

The plates i, 2, 3 and 4 are made
of relatively flexible sheet metal, and
the stiffening numbers 6, 7, 8 and 9
give strength to the mould and also
make it conform to an approximately
true circular cross section when the
stiffening bands are applied. The ten-
sion applied by the wedges forces the
flexible metal to conform itself to the
inner surface of the bands. A set of
stifl'ening bands is provided for each
diameter of column, such bands being
accuratelv formed to the desired radius.
The bands should be divided into as
few sections as is possible without
interfering with the freedom of remov-
ability of the parts.

In manufacturing the form, the
segmental plates are first cut to the
proper dimensions, next the slots are
punched in the edges, the plates are

then rolled to a given curvature and the flanges are then bent back. By this method,
using automatic machinery when possible, the plates will be exactly alike.

When two lengths of tubular section are used together distance pieces 16 of wood
mav be employed if any unusual strain is to be imposed on the upper section; ordinarily
they will not be necessary, as one section
clamps the other securely at the intergaging
telescope ends.

Connections for Metal Reinforcement, —

— No. 2,945/13. G. W. Stokes. Accepted
December 18/13. — I his invention relates to
the method of connecting the metal rods or
bars used in reinforced concrete constructions.

In the usual method adopted, when there
have been two or more rods or bars of iron
or steel running longitudinally through the
concrete beam, either with or without
stirrups, shear members or ties, it has been
ffjund that the dej)Ositing and ramming of
the concrete has displaced the rods in relation
to one another and in relation to the outside
face of the concrete.

In some cases the rods have been bound
together by tying, soldering, clani|)ing, or
other means, but this has reduced the area of
the metal surface available for adhesion to the
concrete, and caused the metal to l)c less
evenlv distributed over the cross section of
the concrete nn-mb^r.

This invention provides an improved
adjustal>l<- and rigid lateral connection be-
tween two or more longitudinal bars in a
r<'inforr<'d concret<' Ixani, which will keej)
them at the correct distance apart and also
at the correct distance from the face of llie
concret(; member, and will also prevent tli( ii-
displacement during the depositing and rannning (jf the concrete.

23«

i?-

I'iiis. 1-3.

Anjrsi Aiii.E Stirkui'S for Ricinforckd Concrete.
Constructions.

J,c16NM^>^)c■naNAl.

< V KNdlNKl-PlNd —

RECENT BRITISH PATENTS.

riif irucntioii c'(»ii>i>l> in [\\n oi moii' links cuh sin roundiiij^ two or more bais,
at rij^lil .iiij^Ics to the direction of their length ;nul at suitable points, and of two or
more wedi^es, each (hixcn between the two bars with or without distanc(; pieces placed
betwcvn the bais. h'-ach loo|) is fornu.'d b\' bendin^^ a iiKtal rod of round or other
suitable section round a }4;roup of two or more lonj^itudinal bars, j)laced in the exact
|)osition whiih they are desij^ned to occupy in the reinforced concrete beam, or bv
bendiiii; the metal rod round a template, the cross section of which is of the shajje
enclosed by a llexible thread j)assed round the outside of the j^roup of bars at rijjfht
aiii^les to the direction of their lenj^th. 'I"he ends of the loops thus formed are con-
nected to«iether by W(ldin<4, twisting, or crossinj^, and may be continued into the
concrete to act as ties, slirrujjs, or shear members; or they may be bent round another
i^roup of i)ars, or the ends of the loop may be continued until they reach the outside
face of the concrete member, to form short struts between the bars and the moulds,
thus retainin<4 tlie bars at the correct distance from the moulds durin<:f the depositing
and rammino of the concrete.

Fig. I is a cross section, Fig. 2 a side elevation, and Fig. 3 a perspective view of
portions of two round longitudinal bars (a) embraced by a loop (b) and spaced bv a
driven wedge (c) which locks the bars and forms the combination into a rigid frame.

In Fig. 4 the loops (6) are bent round, or slipped over the four bars (a), while their
ends (h) are extended or bemt to form short struts restin^^ on or against the timber or
other mould. The distance pieces (J) are short lengths of square bar to fit convenientlv
between the rectangular bars (a). The wedges (c) are short tapering lengths of flat
steel driven diagonally between two of the bars (a).

^'^'- 5 shows an application of the invention to beam reinforcement. Twc

•J ^'--t +:■

\ — r

Figs 1^3. Reinforced Concrete and Similar Structures.

239

RECENT BRITISH PATENTS.

[CQNCKETE

longitudinal bars (a) are rigidly connected and
retained at the required distance apart by
loops (b) and wedges (c) and together form a
unit of two bars. A second pair of bars (a')
form a similar unit and the two units are
rigidly connecti^d by loops {h') and driven
wedges (c') and thus combined form a unit of
four bars.

Adjustable Stirrups for Reinforced
Concrete Constructions.— ^o. 15,667/13.
.1. .1. Storey. Accepted Xovember 27/13.
— This invention relates to an improved
adjustable stirrup which can easily be
threaded on bars with rough ends or (as is
often the case) on bars which vary consider-
ably from the standard sizes.

The stirrups are also locked on the bars
in such a manner as to be practically im-
movable under the rough usage of ramming
the concrete.

The stirrup h, Figs, i and 2, has its legs
formed tapered with a terminal loop en-
circling the main reinforced bar a; clips (c) are
placed on the tapered legs and driven down
tightly, their final position depending on the
size of the bar a, and therefore allowing some
variation in the latter. In Fig. i there are
shown clips in the three positions they would
occupy respectively for bars of standard size
or slightly above or below it.

The loop of the stirrup may be round
or of suitable shape to correspond with the
bar on which it is placed, while the stirrups
themselves may be either straight or bent as
shown in Fig. 3 and used in any desired
combination.

Reinforced Concrete and Similar Struc-
tures. So. 25,140/13. /. R. Givyther.
Accepted November 3/13. — This invention -* '•

relates to reinforced concrete and similar fireproof structuptes in which tiles, blocks or the
like are used to replace shuttering. The invention consists in an improved method of
keving together such tiles, etc. ; they are formed of sections provided with projections,
preferably dovetailed, on the concrete face, such projections engaging with corresponding
ones on the section below.

Fig. I shc)ws the application of the invention to a rectangular column with beams
running .into it. The tik-s or blocks (a) ar<' provid<'d with dovetail projections (c) keying
into the core, and are held together by a metal strap at the vertical joints.

The beams running into the columns consist of moulded channel-shaped tiles (a)
with similar dovetail [)rojertions (c). The invention is aj)j)licable also to the ordinary
fireproof covering of buiU-uj) s1<'el sections. Figs. 2 and 3 show the application to a
concrete buttr<'ss prcjvickd with metal r<'inforc<'ment. Single trough-shaped tiles (a)
with projections (c) ar<' employ<'d at s<'Ctions .s- .v, z — s, two such sections placed mouth
to mouth Ixing eni[)loye(l at the s^'Ctions r— r.

Concrete Tunnel Lininf^s.— No. 21,904/13. E. R. Callhrop. Accepted September
2c^/i3. — -This invention jnovifles an improved method for lining tunnels and like
excavations or borings with concr<te. The tn<thod consists in progressively building
up sections of tubular form by means of shuttering having means whereby the shutters
may be so connected togctther that they are mutually supported without the use of
independent scaffoUling; two inverted cantilevers meeting at the crown of the tunnel are

240

Fif^s. 1—3.
Concrete Tunnel Linings.

(^vFSofNSSiS'^'] RECENT BRITISH PATENTS.

formed to supiiort the concrete in j)()sition, ;iiul the latter is vibrated in situ to obtain
a coni|)Iete tul)ular section in which the tensile and compressive stresses are equally
(lisiril)ut(xl throughout \\li<-n tlu- concrete- is s<'t and tlu- laj^j^in^ r<'mov<d.

("oncicle is laid over the bottom of the tunnel and as far uj) the sides a.s j)iacticable
the concrete heini; mechanically vibrated 1)\ an\ appropriate apparatus to compact IIk-
particles together, thus renderinj^ it waterlimht and |)r(\<nlin^ the suhsecjueni foiiiialion
of hail' cracks oi' fissures.

A middk' or " key " laj^i^inLj or sluitt<r (2) is arranged up(jn th<" concrete and is
exactly Ci-ntr-ed, such as by a pkmib-bol). l'\n'ther l.'ij^j^in^s (<S) ar<' now placed uj)on
ejich side of the " k<'y " (2) beinj^ t<'mporaril\ att^aclu-d thereto and to adjaci-nt la^j^inj^s
bv sta\' rods (c)), lh<' laj^i^ini^s heinj^ c(>nn<'Ct<-(l to <-acii otlK-r h\ suitable UH'ans to prevent
them shiftinj^.

Each ia^i^inj^ is i)r(nid<'d at its <nds with brackets (10, Fig. 2) connected by a bar
(11) to which are pivotally conm^cti'd the two stays or struts (9), th<' free <'nds of which
are so form<d as to enj^a<:^e with the bar (11) of an adjacent la<^j4in^, and so rigidl\
connect the two to<^ether.

The hii^iiinj^s bein<4 connecUd together, as, for instance, by the aforesaid hinjfes, up
tt) the point where the walls begin to curve upwards and inwards, concrete is then filled
in behind them and vibrated as before, and the building up of the section having thus
been proceeded with, each successive lagging is connected as above described to the
one preceding it and concrete placed upon it as indicated at 12 {Vig. 3). The lagging is
then closed up on to the wall of the tunnel and secured in position, and this operation is
repeated till the section is nearly complete. When nearing the roof or crown of the
tunnel the roof is completed h\ filling in concrete from the end of the section after the
lagging is in position.

This is effected by providing light metal tubes of a length corresponding to the
length of the section under construction and filling them with concrete. The tubes
so filled are placed in the cavity and withdiawn against the action of plungers. The
concrete will thus be left in the cavity, but in order to entirely fill the space, rods of
matured concrete are then driven in until the filling is complete.

In order to facilitate removal of the lagging when the concrete is set one or more of
the laggings is made collapsible.

Waterproofing Cement.— y.o. 5,908/13. G. T. Hill and C. G. .Stone. Accepted
December 4 13. — The object of this invention is to strengthen Portland cement and
render it waterproof.

The invention consists in adding magnesium silicate, in the form of soapstone,
steatite, etc. The improved product, when used in the usual manner with certain
proportions of sand or silica and mixed or tempered with water, forms a mortar which
after setting is waterproof, and possesses tensile strength from 40 to 100 per cent, higher
than mortar made from ordinary Portland cement.

The magnesium silicate, which may be added to the cement in the proportion of
from I to 10 per cent, by weight in the form of a fine powder, must be thoroughly
mixed in the cement. In order to ensure this thorough mixing, it will probably be found
the most practical to add it during the process of grinding the cement clinker.

The magnesium silicate can be fed into and ground in the mill together with the
cement clinker, so that its proper incorporation with the cement and also its degree of
fineness may be assured.

The magnesium silicate may of course be ground to the necessarv degree of fineness
by other means, and then mixed in the cement in the desired proportion bv hand or
machine mixing.

24.1

H, KEMPTON DYSON.

[CQNCKETE]

PART II.
By H. KEMPTON DYSON.

The folloiving article has been ivriiten by the Author to further explain the question
of loads on pillars, "which 'was touched upon by him in his articles which appeared in our
journal last year on the London County Council Regulations on Reinforced Concrete,
Part L of this article appeared in our March issue.— ED.

It is frequently assumed that flat-ended struts are in the same condition as fixed-
ended struts, but there may be a considerable difference. With flat ends no tensile stress
can be developed at the ends, because these are merely kept in contact with the bearing
surfaces by pressure. With fixed ends, on the other hand, such tensile resistance can
be developed. With steel we do not need to employ different equations for the condition
when the eccentricity is such as to develop tension on one side of a strut, as we do
in connection with reinforced concrete, in which the concrete is not to be relied upon
to act in tension; but even with steel we should note that when the eccentricity of the
thrust departs from the core section of a fiat ended strut the condition of the ends
quickly approaches the hinged-ended condition. Up to that point, however, flat ends
are as ^ood as fixed ends, and in reinforced concrete, as this analysis only is true on the
supposition that the eccentricity of thrust is never so much as to be likely to cause
tension at any i)art of the section, we may regard flat ends as the same as fixed ends.
In the case where the ends are neither flat between nor monolithic with j^arts of sufficient
rigidity to maintain the axis at the end in the original position, the ends should not
be looked upon as fixed. In f)ractice the ends of pillars are often not so held, the beams
and slabs at their ends being too flexible, to give conijjlete fixity. In such a case of
imperfect fixity W(; might take as an ai)i)roximation U as equal to //3.

In order to distinguish how far we can go before we are likely to get tension on
one side we should need to determine; the core section. In the case of solid rectangular
sections of one material only this is a rhombus having the i)rincipal axes as diagonals,
the corners being set along each axis at one-sixth of each diameter from the centre.

Consequent 1\, if ^ exceeds - we \Mi(\ lo look into matters closely. This, in the case
d U

of round sections, becomes a limit of

exactly by setting off ordinal es along
the X axis, according to th(,' equation

242

The core section mav be found more
the y axis, corr(!sponding to chosen values on

1, trjN.vrkMK-noNAi;

SLENDHR STRUTS.

= _ ^" . -l^' - \- - ^

fiy- ym

Xtn

in wiruli i^ , .iiul i^y .lit' (lie i.ulii of {^M.ilioii .ihoiil llic axes of x aiul v rcsjx'c t ivciv, and
x,„ and r,„ ;"i' tlic maxiinuin (-o-ordinalcs of the liniilinj^ points of zero stress- nanidv,
tliosc points of the section situated farthest from the eentroid of the section.

There is still another condition for /^. that requires to Ix- determined namdv,
the strut havinj^ one end fixed and tlic other hini^ed hut k< pt in its orif^inai lateral
position (see I'ii^. 5).

To keep th(> hini^ed end in its position a lateral force /'" must he applied at the
hiui^e, while at th(> fixed end there is a moment M. Then the moment at a jjoint
distant x from () is —

M, = Py~F(l-x)

and the equation of the elastic curve is —

El'^4 = F{I-x)-Py.
ax'

Integrating, we have —

y=-A cos x\/-l,'-+B sin xV§-,+~{l-x)
hi El P

in which A and B are constants which can be determined bv the '

dv '

conditions that y = when x = and -^^ = when ,r = We find thereby /

ax C

and

B = -V^.

P ' P

Substituting these values, we get —

3' = f(-/cosxV|-, + V'|^ sin;.\/|, + /
P EI P EI

X). Y^

Putting J = for AT = /, we get either F = 0, in which case there is no

Fig. 5.

bending, or

tan Zv/

The angle in radians whose tangent is equal to the angle itself is 4*493 radians
approximately.

/\^r- = 4-493

Therefore
and

Inserting the value for y in the equation for the elastic curve, we have —

P = 20T87^.

Equating —4 to zero we get-
dx'

Elp= -Fl cos x\/f +F^EI_ ^.^ ^y^.
dx EI ^ P ^ EI

tan ^-^^ = 4-493

the solution of which is a- = '30087/, which means that the point of inflexion is situated
'30087/ from the fixed end and '69913/ from the pin end, and that the value of h for
this condition is '34956/.

2*3

H. KEMPTON DYSON.

iCgNCBETB

In the London County Council's second regulations for reinforced concrete the
value of the virtual lent^th v of a pillar in this condition is given as \/2l, the virtual
length being that of a fixed ended pillar of equivalent strength. If this were true, the

value of -v from the pin-end should be -^/=7071/, but as in that case x would have to

equal '2929/ the foregoing equations would not be satisfied. The L.C.C. regulations
ought therefore to give the value of v as 2 X '69913/= 1*4/. approximately.
Collecting the foregoing, we have : —

Condition of End<5.

Value of /c-

Both ends fixed

Both ends imperfectly fixed

One end fixed and one end hinged and restrained from lateral movement
One end fixed and one end hinged and guided into a position where the

lateral movement of the free end is half the total deflection

Both ends hinged

One end fixed and the other end neither hinged, guided, stayed, nor

supported

1/4
say, / 3
•34956Z

1/3

1/2

To determine all the constants in the formulae for struts we still require to
ascertain two properties of sections— namely, g/d and n/d. For the four types of
pillar reinforcement shown at the top of Fig. 6 the following analysis applies :—

Let / = Inertia moment of area of concrete equal to that of the core of the
pillar (as shaded in diagram)
Is = Inertia moment of the steel sections.
A ~ area of core.
4 s =" area of steel sections.
d = diameter of pillar.
r = radius of any bar about centroid.
Is = /, /.
As = A,A.
II A = N/i\

Av = area of one vertical bar.

_ /4

S = diameter of one round bar.

'Av

Iv = inertia moment of one vertical bar.
It does not matter whether we refer dimensions to rectangular or diagonal axes, we

get for Type 1

, _As_A,A
4 4

A^'
4

2,r

•cry

For TyPG 2 — Av =

U = A^r

Aa_A,d'

8 8

27r

244

('a. OON.STUUCnONAL

SLENDER STRUTS

1'\m- I'ype 3

^"~6 24

For Type 4 —

Generally

and

Also

I d' \ d'\
= -7- = t:^ X ^, = — for rectangular sections,

/ ^d' -^ d\ . ^
-—:=y. X ,-. = 77 for circular sections.

/ + (m-l) /s /[l + (m-l) /J

and

i Ar,[l + (m-l)/J

Inserting the forci^oing values, we get : —

For Type 1 — K. _

f2 + ("^-

iM.[(-V^)%^;]

\ + {m-\)A,

For Type 2

For Type 3 —

For Type 4

l + (m-l)A,

l + (m-l)^,

The formulae for various values are plotted on the diagram {Fig. 6). The values
of gjd and njd for homogeneous sections of various shapes are given in the table on
page 45.

The combination of the values of gjd, derived from Fig. 6, with the values of njd
for the various shapes of the four types of reinforcement is performed diagrammatically
in Fig. 7.

We are now in a position to use Figs. 6, 7, and 3 to determine the resistance^ of
slender struts of reinforced concrete. Fig. 3, of course, will serve for any material.

245

H. KEMPTON DYSON.

ICDNCBETEi

Figure.

I = Moinent of Inertia

^> = Radius of Gyration.

iild = KM\o of Distance

between neutral axis and

extreme fibre to Depth.

y , CTON.vrUUCTION A
«i.IJS(klNKIrJ/lN(

SAll

SLENDHR STRUTS.

I he iinincclialc |)ui|)()sc ol this .11 (iclc is to correct the \'.ilu(s lor {alculatin}^ the strength
of struts put forward in the L. (".('. RcLjulations for Reinforced Concrete Buildings
in London.

Type

k..^uM

Only etched core
areci taken.
/^// bars assunned
same s/zg.

■

/\-area of concrete
^g =■ ch sfee/
j4,=arec// ratio /^y^

Eo-=^ modulus of elasticity of concrete
£^- do do. da steet

/-- inertia moment of steel

g= gyration radius
d^dianneter of core

(outside to outsida of longi-
ti/dinals S wfthm bindirxf)

Vblues a^ C,=(m-/)y^,

Values oi C -(m-/)^,

Fig. 6.

[Copyright of H. Kemptun Dyson.]

Let us take first the most adverse case, and see how the L.C.C. regulations
compare with Alexander's and the Gordon-Rankine formula — namely, a pillar of type 2

247

H. KEMPTON DYSON.

lOQNCRETD

able to bend about its transverse axis, and reinforced with i per cent, of vertical steel
bars, and constructed of concrete proportioned i cement, 2 sand, 4 coarse material, whose
ultimate strength, as ascertained by tests on cubes cast in moulds and made with the
material as used on the job, is not less than 2,000 lbs. /ins though the average strength

n^disfanco fhom naufryjl axis to afctreme stfye. g^g^ynation radius. d=diair>etBf of cor-^.

Values o( §§

^^^lll^lllkb[lfl^ll^l!-^

Values ^ ^

l"'i<;. 7. [Copyright of H. Kenit>ton Dyson.\

as realised on cubes cut out of the work would be over 2,400 lbs. /in-. This becomes
further justified by considerations of eccentric loading in conjunction with variation
in the modulus of elasticity of concrete as the stress increases.

Then lie " 000 Uc = 1 ,440,000 and m = ^^^^9^= W>_00 _ 21.

Uc 2,400

Travelling from the vaku; 21 in the; left-hand margin of Vig. 6 until the line for
value of A^, marked 'oi, is met, next vertically upwards to the conjunction of a
horizontal trace from the intersection of the A ^ line marked "oi and the " C, index line
for type 2," the fjarallcl to lli<- lines \()V values of (l^ C„ until we meet the " C\ index
line for squar(;s," now outwards horizontally to meet the vertical trace from the
very first intercejjt derived, we find ^^/<i — "49. The process is shown by the guiding
arrow lines.

Now, going to Fig. 7, we find the value of g/d = '^() in the bottom margin, travel

248

SLENDER STRUTS.

vertically upw auls uiUil tln' line i^ met niaikcd " Sqiiart- on diagonal," next horizontally
to ni(>('t the value of e/ii. an. I I hen verticall\ upwards to the top marginal scale, we

deiixc the value of

11 (•

K ^

'The pioi-ess is ai^ain sjiown hy j^uidinj^ arrow lines.

b'inally, i^oiui^ lo Fii^. \, we ohtain the following; values for a fairly lonj^ coliiinn of
21) ft. in hei'-hl, which, because it is iniperfecliv li.xed, will have a value of l^ = 20x 12^3,
so that c = -oi /^. -^ -oi X 20X i2-i-3=o-8 inch : —

Vai.uks ok Qi'Ai ikikk Q I'oK Impi;kkectlv Fixed Knds.

F^or a Slenderness Ratio of

l/i =
or l,.lg -

.8-2

14
9-5

16
10-9

18
12-2

20
13-6

22
15

24
16-3

17-7

28
19

30
20-4

Value ofe/g =■

•1

•1<.9

•122

•136

•15

•163

•177

•19

•204

•

L.C.C. Regulations

Rankine

.Mexander ...

•833
•876
•9

•625
•856
•895

•458 -375
•84 1 -825
•877' -86

•292
•81

•842

•25
•7«.5

•822

"•208
- -78

•8

•76 -75 j -74
• 8 •7591 ^738

It is necessary to explain that in the foregoing table the values given for the
L.C.C. Regulations are derived from the actual ones therein contained by multiplying
by •833, because the working stress in direct compression is 500 lbs. /in-, whereas the
stress in beams is put at 600 lbs. /in-, the stress thus being reduced to | ='833 times
the ordinary permissible stress.

We see from this that on any basis the values in the Regulations are too extreme
for exceptional cases. On the other hand, in struts w^hich are hinged at one or both
ends, or are fixed at one end, and which are long though bulky and consequently not
verv slender, the accidental eccentricity created in construction might be so great as
to render the L.C.C. values unsafe. Therefore the author thinks it would be much
better to give a table well on the safe side for pillars imperfectly fixed at both ends, so
as to be simple enough for ordinary uses, but to permit engineers as an alternative to
calculate the struts by a formula of the Alexander type with the particular constants
aforesaid.

2 19

H. SCHUERCH.

ICQNCKETFJ

REINFORCED CONCRETE

VIADUCT, LANGWIES,

SWITZERLAND.

By H. bCHUERCH, Chief Engineer of Messrs. Ed. Zueblin & Cie, Strassburg i. Alsace.

The folloivina is a free TransluHon taken from an article ivhich appeared in our
• contemporary, Armierter Beton," and -which lue publish by the courtesy of that

journal. The illustrations ■were placed at our disposal bv Mr, Schuerch, and our translation
has been prepared by Mr. C. Wesemann, Ciziil Engineer.— ED.

The viaduct here described is being- constructed on the route of the new Chur-
Arosa meter gauge electric railway, Switzerland, close to the villag^e of Langwies,
and is necessary for carrying- the permanent way across the valley of Plessur
and Sapuenerbach, where two streams come together on the site, and where
when the snow melts these mountain brooks often carry down enormous
quantities of water and pebbles, for which a free passage is desirable.

The lack of suitable building- material and the difficulty of bring-ing- heavy
steel work on to the site, owing to the bad condition of the roads, as Vv^eli as the
existence of good gravel and sand material on the spot, led to the use of
reinforced concrete for the construction of the viaduct.

Objections were raised in the first instance by the Swiss Railway Depart-
ment (to whom the designs had to be submitted for approval) to the use of
reinforced concrete for a structure of such magnitude. Finally, however, the
contracting firm, Messrs. Ed. Zueblin & Cie, of Strassburg, who had been
at gr«'at pains in the preparation of the design, and had worked out the static
calculations most carefully, succeeded in <jbtaining the necessary consent tO' the
use <jf reinftjrced concrete, the tender being supported by ample guarantees.

The bridge crosses the valley with one main arch of 96 m. clear span
between the abutments, i.e., 100 in. span from centre to centre of the springers
(h'ifj^. i). The theoreti(\'il rise between (X'ntre springer and centre crown of the
;.rch is 42 m. (^n either side of the main arch are a series of four smaller open-
ings, each ha\ing a clear span of i4"7 m. Beyond the end abutments three more
openings were afterwards added, on the side towards Langwies, instead of an
earth embankment, proposed in the first place. Two of these additional openings
have a clear span of 13 m., and the remaining one has a clear span of 10 m.
The nature of the subsoil admitted of the central section of the viaduct being
construcl<'d in form of an elastic or non-hinged arch, whereas the dec^k of the
outer spans was designed with continuous girders, as the great elevation of the
roa-^lwav |>latform above groiiiid nccessilalcd a structure without horizontal
thrust, the liigh and slender pillars being sufficiently elastic to admit of the
dilatation of th<: railroad slab. In addition to this the latter is separated by
means of expansion joints at the top of the siipj)orting double pillars. Owing

2 ^o

^ii, CON.STPIKTIONAI
C\ KN(.INb-l-RlNti ^

RI£INF()RCHI) CONOR ETH VIADUCT.

to its liij;!! aliiliulr (i,J-(^ 'ii- ;il><>\i' sc;i-l('\('l), the viadiuM is exposed lo j^reat
('h;in«'i'S of ti'nij)ci ;iiiii I', .m<l tlirirl')rr tlu' (luislioii of cxij.'insioii :tiul coiil r;t(iion
li;i(l lo 1k' (^irrrully l;ikcn into fonsidiTation.

VUv c-cntial span (■onii)risL'S two st'i)aralt' afchcd rin^s, llu; 1lli(-kn(•s^ of

251

H. SCHUERCH.

ICQNCBETEi

which is 2-IO m. at ihc crown. The width of either rib at the top of the crown
is TOO m., and, beini^" battered lengthwise, it increases reg-ularly from crown
to spring-er. The two arched riiigs are tied together by means of rigid cross-
Ix^ams.

With tlie view of ensuring- greater stabiUty, the whole of the viaduct
(including- the skeleton pillars) is battered upwards {Fig. 9).

l"he road\\a\- is 4 m. wide between the parapets. This dim-ension Includes
070 m. for either side-walk. The railroad consists of a 30 cm. ballast-bed,
\\hich is underlaid by a layer of sand, resting upon the insulated cement floor of
the railroad blab. The latter stretches between transverse g-irders, of which

r\^. 2. \'iew of Arch Ceiureiiif4 in ICarly Stages of Construction.

RkINKURCED CoNCRKIK VlADun. LaNCIWIKS, SWIT/KULANI).

ihose at ihc lop of the j'illars ha\c a greater (le])lh in order to obtain an increased
rigidil\' in liie transverse dirc;clion of tlie slal).

The lonL' iuidiii.'il vi'-ders of the siii)erst ruet ure of the central arch are ron-
tinuous i)eams running ihrouglioiit the foui- spans, and are connected at the
cr.ywn uitli tiie arch itself and al)o\e liie si)ringe)-s with tlve al)utment pylons. As
the connection with the erown ol the aich does not allow of any n-iovement, the
pillars liad to be suflic iently elastic to allow lor the e\])ansi()n and contraction
of loDgitucJiiial deck-gii'ders.

Tlv' main girders of the outer spans are <'ons1ructed in the form of beams
with a \arving moment ol iii'-rlia (I'lg. 7). 'Ihey also run (M)ntinuously over
four :-j\a]is, and <ire <-onne<te(l with iheii' supports in such a manner that a

2 c 2

Tj, CXDN.vrkMR-nONATl
L«VF.N(.1NH I^INt. —J

RHINFORCED CONCRETE VIADUCT.

c'c'rl;ii:i ainouiit of moxomi-iil is ])()ssil)li'. 'Vhv hcarinij" phitcs al the points of
.sui)i)()rl ol llic i)ill;irs of llic :)uU'r s]);iiis h;i\i' Ijccn i educed to :i n.irrou ni.irj^in

Fig 3 \'ievv of Arch Centreini^. showinti part cf finished Concrete Work.

Fi.^. 4, Front \'iew of finished Arch Centremi; show ins Cabla Ropeway.
Reinforced Concrete Viadlct, Langwies, Switzerland.

of area, with the view of ensuring a hinge effect. Regarding the pillars them-
selves, they are constructed in the form of skeleton pillars [Figs. 6 and 9), viz.,

I) 2

253

H. SCHUERCH.

iCQNCBETE l

X 5

two cross-tied uprights,
as the wind forces are
carried along the road-
way slab direct to the
^ respective abutments and
to the huge double
pylons on the other side.
The latter, therefore,
instead of being cross-
tied by single transverse
beams, are braced to-
gether by means of a
solid cross-spandrel wall
{Fig. 6). The inner pair
of uprights is connected
with the roadway slab of
the central span, the
outer pair with the road-
way slab of the approach
openings, in order to
allow either section of
the viaduct to expand or
contract independently.

The construction of
the viaduct has been
designed from the point
of view of ensuiing a
maximum saving of
material and a minimum
as regards actual
stresses. This was ren-
dered more p o s s i b 1 <:
owing to the live load
on the bridge being a
comparatively light one
in proportion to its dead
weight. I'his also ex-
j)lains the application of
two cross-tied arched
ribs instead of a mono-
lithic ring, although tlic
latter form has also
l)een carefully tai<cp into
(M)nsi(leration. 'i'he static
calculation of tlie viadu(i
has b e e n l)a s e d on
the assumption of a

251

fj, cr>N>"n,>MtTic»N(AT|

r1':lvf()rch:d concrete viaduct.

ti'st-load train ihal comiM-iscs iwo loconiolivi'S of O5 Ions scrvirc ueij^lu each
(tin- 1\|)o ol tin- ivliailic Railways), and an unlimited number of adjoininj,^ j^oods
trucks thai are e()ui)led in one direc lion. Willi rej^ard to the static calculation
of the se(H)n(larv ^iiders — viz., the railroad (U'ck and the minor spans — an
addition lo the ahoxx- lixc load of 1;; \wy eenl. has been considered. 'I he addi-
tional forces
thai ha\e been
lakeii into ac-
c o u n 1 com-
prise : —
(i) \ tempera-
ture change

of ± 15
deg. (Cel-
sius) ;

(2) Contraction
due to sett-
i n g- — 20
deg.

(3) Braking
force s —
one-seventh
of the total
weig^ht o f
the loading
train-axles.

(4) \\ ind pres-
sure :

(a) lookg/m-,
when the
bridge is in
superloaded
condition ;
[h) i5okg/m»,
when the
bridge is in
unloaded
condiiion.
The modulus
o f elasticity-
has been as-
sumed :
E = 2,000,000 t/m-.

E steel

The proportion

E concrete

The safe maximal compressive stress of concrete

H. SCHUERCH.

iCQNCB ETE!

providing- the dead weight of the bridge is combined Avith the most
unfa\ourable superload (Hve load);

o-=45 kg/cm,
prcviding all the secondary and additional forces are taken into account,
i.e., temperature, contracting- due to setting, braking-forces and wind-
piessure.

The safe shearing stress of concrete is assumed :

T=4 kg/cm-'.
Safe tensile stress of steel for reinforcement :
= I, GOO kg/ cm-,
provided the dead weight of the bridge is combined with the most unfavour-
able superload (live load) ;

cr= 1,200 kg/cm-.

Finished Beams and Centreinj^ to OpenintJs on the Lanjiwies Side.
Keinforckd Concrete Viaduct, Langwies, Switzerland.

provided all the secondary and additional forces are taken into account.

The ab<)\e figures are based upon the assumption that the concrete (that is
mixed (^n the spot and is daily controlled and tested by a Martens' set registering-
apparatus) shows thi- following minimum standard strength after 28 days of
setting-time :

180 kg/cm-,

when being rammed on the spot in a jjlastic condition (poured concrete);

250 kg/(>m-%

when being ranmicd on the spot in a moist condition.

Th-' Rittcr method was cmployctd in ihc caltmlations of the internal stresses
m all those parls of the const ru<iion that ai-e siibjecM to cM)mpression — I'/.G.,
the cenlr.d ar( li .ind tlic pillars and also loi- the determination of the tensile
bending stress ol tl)c conf rclc (onst riK I ion, whereas the Christophe method
was adopted in (alculaling the inleinal stresses o/f all the other ])arts of the
structure— namely, those j)arls thai are subject to bending forces and foi- the
calculation of the reinforcemeul . The shearing forces were \erv carefully deter-
mined, and s!eel rods in ! lie lorm ol stin-u])s are j)|-o\ ided \\here\er they extx'cd
the safe shearing stress ol concrete- -7;/£;. :

256 T = 4 kg/cm^.

t:N(JT^t-lJ/lN(i —

REINFORCED CONCRETE VIADUCT.

'Vhv ii-sislaiuc at^iiinsl (■(>lhi|)sini4 was talciihilid accordiii"^ lo llic Killir mclliod.
The piu'iiliar art li-cciU rciii;^ (/'"/i,'.v. 2, \ and .]) is well woilli special incniion.
'I he uppi'i -pait ol the falsework has hccn const riiclcd in the lorm ol a fan iaiill nj)
wilh re und linilKT ohlainahlc on live spot in i^reat lcn«4lhs, at a low jjricc and ol
^ood «;|ualit\. This tiinhiT si-alToldinL; is sup|)orlc'd l)\' three reinlorced concrete
towers whiih ha\c ])i'en constructed in the form ol Iraniewoik or skeleton
towers. The reason for these reinforc^i'd concrete lowers was due to the
followiui^' causis. It was not. ad\ isahle to obstruct the \alley loo much by the
falsework, as the sea ff oh linj;- is exj)()se(l to dani^cr (rom Hoods, an<l is thus
liable to damai^e at times when the snow melts and tin- two mountain brooks,
which j(,>in just on the buildiui^ site, carry d(^\\ n enormous masses of water and
pebbles. For this v ery reason the erection of a scalToldinj^ comjjosed of uj)riy;hts

Fig. 8. Reinforced Concrete Towers in course of construction.
Reinforced Concrete Viaduct, Langwies, Switzerland.

was out of the question, and the tower system only was suitable {Fig. 8). Timber-
work towers would have obstructed the passage more than reinforced concrete
towers, and furthermore they would not have possessed the same amount of
stability. The substructure and the foundations would in any case have required
the use of reinforced concrete exen if timber-work towers had been erected,
as the driving- of wooden piles was absolutely impossible on account of the
nature of the subsoil, which is composed of coarse pebbles and is intermixed
with loose blocks.

The total settlement of the main arch had to be reduced to a minimum, and
this also was another reason for using reinforced concrete for these towers.
When the central arch was closed the arch centreing- showed a total settlement
of, roughly, 30 mm., inclusive of 10 mm. which occurred through the head-
pieces of the diagonal struts cutting into the capping-pieces of the stringers.

^57

H. SCHUERCH.

ICQNCKETEI

The erection of the viaduct was beg-un late in 1912, but at the commence-
ment of the work operations had to be confined to foundations of fhe abutments,

winter setting in be-
fore time and causing-
an interruption of the
work for several
months. Not before
April, 1913, could the
work be resumed. Bad
weather during- the
early summer delayed
progress once more,
and especially pro-
tracted the completion
of the falsework of the
central arch. Later on,
however, the weather
chang-ed for the better,
and by the combined
efforts of all those con-
cerned in the work, it
was finally rendered
possible to complete the
arch-centreing for the
most part on Septem-
ber 6th and the con-
crete work of the larg-e
arch — excepting for the
closing- of some joints
— on October 6th In
1913. The last of those
joints, which were kept
open intentionally for a
long time, was closed
on October 27th.

The winter, of
course, has ag-ain inlcrrupKd th-- work. Init Mill, the approach openings on ihe
SKle toward Langwies are now completed (Fz/,r. ^j ; so is the main arch and the
whole of the p.llr.rs of th(^ superstructure above the central section [sec Froniis-
piccc). llu: pill.-irs ol lh(- outer spans on the side toward Arosa are partlv
finished. TlM-n- n n,;,,ns In be . r„nph-tc(l this spring the roadway platform above
the central span and above tin; appro.,, h op.nnigs on the side toward Arosa.

The buIMing of thi.. viadun has called forth a series of rather ample
mvcstigations and tests as to the strength of concrete, steel and timber,
mcluding- tests on the elastic j)ropcrti(s ol concrete.

liti. 'J

■r(:jtioi), and side

Side \iew of Aicl) CeniicinK m coijisc
openiiifjs toward Lanswies.

RkINF JRCED CoNf.KKTK VlADUCT, LaNGWIKS. SwiTZKRI.ANI).

258

r^i-"S,'>ri^V^Ji"S^ CA!.CULATI()NS FOR STEEL-FRAME BUILDINGS.

■ CALCULATIONS AND
DETAILS FOR STEEL-
FRAME BUILDINGS
FROM THE DRAUGHTS
MAN^S STANDPOINT.

ByW CYRIL COCKING. M.C.I.

In xiieiv of the importance and great 'value of this Paper, ivhich ivas read before the
Concrete Institute, ive are qi'vinq an abstract of same as a principal article rather than
under our heading "Recent Vieivs." There ivere numerous tables at the end of the
Paper ivhich are of remarkable excellence, and ivhich ivere referred to in the discussion but
ivhich ive have not been able to reproduce here. Only a short resume of the discussion is
also given. The Institute is to be congratulated upon this Paper. — ED.

The draui^htsman's point of view in the methods of calculation and preparation of
details for mod<'rn steel-frame ])uildin^s is a most im])ortant one and is seldom con-
sidered.

In order to L>ive the draui,^hlsman a fair start it is necessary that certain matters
should be agreed upon between the architect or his deputy and the district surveyor
before the architect's plans are sent out for competitive tenders from constructional
firms.

The district surveyor should be consulted at the very commencement of every job
regarding which he may have any discretionary powers. The matters to be so discussed
and agreed are chiefly the following :—

PARTICULARS OF LOADING, ETC., TO BE AGREED WITH THE

DISTRICT SURVEYOR.

1. Dead and Superloads. — All firms competing should be provided by the architect
with the fullest possible details and particulars of floor construction, roof coverings,
ceilings, casings to beams and pillars, partitions, the proportion of masonry in external
walls — such as heavy cornices and ashlar work — and all special loading, such as lift
gearing, water-tanks, heavy safes, travelling cranes or runways, etc.

2. Foundations. — The maximum pressures allowed upon the soil ; the fullest possible
Information should be given for the design of party-wall foundations; depths and
extreme limit of spread for foundations to j^arty-wall pillars.

3. Eccentric Loading. — The District Survevor's requirements for the treatment of
eccentric loading on pillars.

4. Pillar End Fixing. — The District .Surveyor's decisions as to what shall constitute
a fixed or hinged end for the purposes of preparing the pillar calculations.

5. Form of CaJcidations. — The form in which the District .Surveyor requires the
•calculations and detailed drawings to be prepared for submission to him for his approval.

Provided the above information is given to all the competing firms the competition
would be a fair one, and it is open to engineering firms to combine together and insist
upon the receipt of such information before agreeing to tender.

Other considerations which should be impressed upon architects in general when
agreeing to tender are, firstly, that the engineer should be allowed a reasonable time
in which to prepare his scheme and tender ; and secondly that, should he be successful
in securing the contract, he should have at least two to four weeks' start in advance

259

THE CONCRETE INSTITUTE. [CQNCBETE]

of the builder or ij;eneral contracted- in order to ])repare his working drawin^^s and
settle the exact positions of the pillars, foundations, etc., and the fabrication of the
steelwork required for the first deliveries.

In the past it was the practice to consider the loadin<f on a floor as inclusive —
that is, the loadper square foot upon which the calculations were based was assumed
to include the weii^ht of construction; now, however, it is becoming the practice to
ascertain individually the superloads, dead weights of floors, beams, pillars, beam and
pillar-casings, etc. This is certainly a distinct improvement, and tends towards greater
accuracy and economy in design.

SUBJECTS FOR DISCUSSION.

Eccentric Loading. — What is the effect of eccentric loading? This interesting
and important question is not so easily ansv^ered as one would suppose from a casual
consideration.

Take the case of a pillar composed of a lo in. x 5 in. I at 30 lb. and 2-8 in. x | in.
plates, and which is considered as possessing one end fixed and the other end hinged^
and is capable of supporting a central load of 53*4 tons on a laterally unsupported
length of II ft., according to the stresses allowed by the Act.

Assuming that the stresses allowed by the Act bear a factor of safety of 4, the
central load causing failure would be equal to 213*6 tons.

Xow let us consider the load of 19*95 tons aj)plied to the web of pillar as being
an eccentric load, the connection being made with a well-stiffened seating rivetted to
the web of the pillar. The seating or bracket being stiffened, the load would
undoubtedly be considered by the eccentricity devotee as acting on the extreme edge
of the seating angle.

Assume that this angle for the case under consideration as being an
8 in.X4 in. X I in. angle.

The eccentric arm would therefore be 4 in.+o"i8 in., equals 4*18 in.

Now the eccentricity coefficient from the formula usually adopted, i.e.r

Cc = 1 + .,, is equal to —

4:iA>i4^6-46,
175-

therefore the additional equivalent central load to that already included on the Pillar

Sheet is ef^ual to —

19'95(6'46-r25) = 103"9 tons,

giving a total equivalent central load of —

103'9 + 48"4^=152"3 tons,

thr- maxiiiuiin fibr<- s-tr<-ss being —

also the factor of safct\ being —

152 3 ^iQ.28 tons/in.-'.
14-82

213-6

1-4.

152*3

I<"urtlvr, tin- actu.al stresses induced in ihe ])illar will dejiend to a large extent
upon llif 'Icptli ;uid (l<tl((tion of the Iw-.-ini, the width and monunt of inertia of the
pillar, and the rigidit\- of the (onnection of llu- beams to the i)illar, also chiefly upon
the continuitv of the pillar at the U\*\ of ihc beam connections — factors which the
befor<'-m<-ntioned formula coiispic uoiisl\ ignores.

As soon as \v<- make ihe pillar conlinuous or securcl\' fix the I'lids lh<' stresses are
entirelv altered in their distribution, and the efhcls of {])<■ <((<ntri(ity vary from one
to one-half those com[)Uted by ttie usual formula according lo th<' amount of continuity
and fixture ;it \]v ends.

260

r-TT^STPMCTioNAi.] CALCULAriONS FOR STEEL-FRAME BUILDINGS.

■V\u' ciiH'siinii ni,i\ !>.■ (onsi.l. 1. (1 very siinplv in ihc f()ll()\vin«^ mannrr : 'I'akc, for
<'x;iinpU-, .1 i)ill;ir supporiiii- .i ( .intil.\<T in the ni:inii«T shown in I'i^. i. In its
(1('11(hM((1' fnrni such ;i i)ill.ii wuiKI inihciti' ,m reversal of he ndint^ moment at the ron-
iKH-tion of ihr oantilrv. T to the piliai , the Io\v<r pillar curvin-^ out to th<' left and the
upiHi- pillar i-urvini4 out to th.' li-ht .U'arlv indicalinii that tlw stresses du<- to
(^M-entricitv ar<- distrihut<d both ahov- and Ix'low the point of connection, and not
below onlv as i*( mrallv assumed. The sum of the eccentric stresses in A and li is

approximatelv equal to W-^, and ih.' sum of the total sti-<-sses C and I) is equal to

\\(i~\\ 'Vhc i)illar heini^ continuous the stross<"S would he dislrihuted half abov<^

\ii ^ • • ,

and half helow the connection, th(r<'fore the total eccenlric str<'ss m A in tension and

in H in comi)ression would In- <qual to ^, and similarly the stresses in (' in com-
pression and in 1) in tension would he equal to ^(^-ij, or th<" total stresses, and

similarlv the maximum stresses jx r square inch, are about one-half those comj)Uted m
the usual wa\' b\ tlie formul.a —

W
A

2/>^'

-J

(CCMBt-j)

Ann of Eccentricity. —S^ome engineers hold the opinion that the eccentric load on
a pillar acts at the centre of area of the seatinjf throui^h which the load is transmitted—
that is, at i)oint A on Fig. 2. Aoain, others contend that the eccentric load can be

assumed as acting in the plane of
the external face of the seating—
that is, at point B on Fig. 2.
Yet again other engineers assume
that the eccentric load acts in the
plane of connection of the seating
to the pillar, point C on Fig. 2.

End Fixing of Pillars. —
Another difficult point regarding
which the draughtsman must
exercise his knowledge and expe-
rience is the question of " end
fixing " to pillars. What con-
stitutes a fixed end? What can
be termed a hinged end? Also
what relation does a flat end bear
to either or both of the above?

Ct«mVi)

I: A

Fig. I.

Fig. 2.

The opinion is generally held that the topmost connection of a pillar in the topmost,
storey and the lower connection of a pillar in the bottom storey shall be considered as
hinged ends, though the latter connection or base of the pillar could reasonably be
considered as a " flat " end.

Also it sieems reasonable to assume that the pillars in external walls which only
receive two- or three-wav connections shall be considered as having one end hinged and
the other fixed.

The important question remains, When can a pillar be assumed to possess both'
ends fixed?

Where a pillar is continuous both above and below the connection at two con-
secutive floors, and receives at both floor connections or " ends " a four-way connection.

261

THE CONCRETE INSTITUTE. [CONCRETE ]

In which the heavier or deeper beams are conn-ected to the pillar perpendicular to its
weaker axis, such a pillar shall be considered as having both ends fixed.

These three important questions — -eccentric loading, eccentric arm, and the end

-fixing of pillars — should seriousl}- be considered by the Institute, and the District

Surveyors' Association should be approached with the object of arriving at practical

solutions of these problems.

■X- * * * ^

After a most valuable chapter on Calculations, which it is impossible to deal with
in summary owing to the references to the illustrations and diagrams, most of which are
omitted, the author went on to deal with the following questions : — ■

Deflection. — The question of deflection is not one that need cause us any grave
concern, for Section 22, Clause 7 of the Act clearly indicates that the question of
deflection can be ignored, excq^t in cases where the ratio of span to depth of beam
is greater than 24. When this ratio is exceeded the calculation of the deflection must
be made in order to ensure that the maximum deflection shaill not exceed j^^yth part
•t)f the span.

When it is requir< d to use shallow beams the flange stress must be reduced in
order not to exceed the permissible deflection.

For plate girders, comjjound girders, and lattice girders in which the modulus
of the cross-section is proportioned to the bending moment at various points along
the span, the depth being constant, we may consider such beams as beams of uniform
strength for the purposes of calculating the deflection.

Seeing that the greatest deflection for a beam of uniform section is obtained with
a uniformly distributed load, it is quite suflicient for all practical purposes to treat
a beam which has to support a complex system of loading as if it were loaded with
the equivalent uniformly distriouted load.

Shear.- — The maximum vertical shearing values for webs can be ascertained from
the following formula- —

where .s = maximum vertical shearing value for web in tons,
f = thickness of web in inches,
c/ = total depth of web or I beam in inches,

']'h<- dejith of an unstirf<'ned web must not exceed sixty times the thickness of web.
This is a very liberal ratio, and should be reduced somewhat for very thin webs.

The question of rivets acting in double shear is one that is apt sometimes to be
overlooked, especially when designing pillars and beams where w^eb connections are
made on both sides of the beam. The bearing values for the rivets through the webs
of pillars and beams should always be inquired into, especially when using the lighter
sections, such as 10 in.x5 in. I at 30 lb. and 12 in.x5 ^"- ^ ^*t 32 lb., which have
relativ<'ly thin webs.

Floor loists enclosed in Concrete. — It is generally admitted that steel beams as
lillers or floor joists i-ncased in concr<-te provide a much stronger floor, strength for
•strength, than if the (oncrfle were omitted. Therefore it is onh reasoaable to make
some alicjwance for !lii> addil ioiial sirenglh in design. Al the same time it is iK'cessary
to bear in mind llie restrictions as to slrt-ss and the proportion of depth to si)an
r<'quir^fi by llie Ael. Tlv additional strength can Ik; calculated b\- tin- usually acoe|)ted
f(jrniiila for conipiiiiiig the slrengtli of reinforced concrete l^eams.

In (jrder to ]<(■<■]> within the hiiiits of span to (1( ptli prrscrilx'd l)\' the Act, we are
'justified in assuming that the depth of the heain is from the (o|) of concnte assimied
as acting with the beam lo the underside of I beam.

After s(jnie inieresiing remarks regarding the tpiestion of rivet pilch, grillage bases,
Tnansard work and wind pressure, the author concluded with the following remarks: —

262

, lON.M k>U("T10NAL
tN(ilNbtJ^lN<i::-l

CALCULATIONS I^^OR STEHLFRAMB BUILDINGS.

CONCLUSION.

I would ur_Li<' tli;it .ill runvlriicM lon.ii ciiLiinccrs ;in<l (Ir.iiiLlhNmcn should su])|)ort llic
London I>uildin_i4 Acts i()0() Anit iidnu nl , ;ind ih.it the Concn'lf InstiiuN' should do ;dl
that is in its powxT to fosl<r ihc iMtUr sj)irii of lo-ojnTation for h.irnionious wcjikin^
bi-lwccn I hi- ^-nj^inccr who has \o dvsii^n and erect sliy-l-franK- huildinj^'s and tin- district
surveyor who is appoint<'d to s(<' that th<' rccjuirt nunls of the Act ar<' faithfully obscrvt^d
and conij)rK'd with.

II nia\ be ihoui^ht by some that c<Ttain anicndnicnts to tlu- Act would be d<-sirabl(',
init in this connection no concessions can be oxix'ctcd. or obtained unless all concerned',
w ith th<' workini* of the Act combin<' toi^cthcr to make the very best of it as it is in its
present condition.

As an Act it is both fair and })ractical, and time has already shown that it has
been the means of considerably inijjrovinj^ the j^eneral desij^n of steelwork both from
the standpoints of £^ood practice, economx, and theoretical design.

FoUoivhio upon the paper iJurc uuis an iiiicrcsiiug discussion, of 7i'/n"r// we here
f^ive a sliort ueeoujit : —

DISCUSSION.

Professor Henry Adams, M.Inst .(' .E., who was unable to be present, wrote saying lie
echoed the author's hope that all constructional steelwork might be carried out in accordance
with the London County Council Regulations, whether legally subject to them or not ; also-
that the steel-frame work should be directly under the control of an engineer, while the
architect contnied himself to the architectural features. He did not understand the author's
relief at not being required to make allowance for the eccentric loading of beams. All
competent draughtsmen had always been in the habit of making this allowance, and also both
to provide for the structural load and the superimposed load. He did not agree with his.
statement as to what the eccentricity devotee would take for leverage distance on the pillar.
With regard to the question of submitting calculations to the District Surveyor to enable him
to judge of the sufficiency of the design, he agreed if his duty merely consisted of checking
the arithmetical accuracy of the calculations, but if his desire, as he assumed it to be, was only
to determine the efficiency of the design he should say, judging from his own experience-
in practical w'ork, that the calculations were a hindrance rather than a help, as he found that
the shorter w^ay was to make his ow^n calculations on the basis of the loads to be carried.
Many of the author's approximations were very useful, but he did not agree that the depth of
an unstiffened web might reach sixty times the thickness. He certainly never adopted so-
extreme a ratio. The author's tables of safe loads on standard beams massed in concrete
would be found very useful. He had not seen any published tables of this kind before,
though this method of construction had been largely adopted for the last fifteen oi twenty
years.

Mr. F. E. Wentworth Sheilds, M.Insi.C.E., thought that the interesting Paper fully
justified the action that the Council and the members had taken, in doing their best to en-
courage Papers other than those on concrete and reinforced concrete. It showed how very
closely allied the different branches of structural engineering were ; indeed, that it was almost,
impossible to have a broad and comprehensive view of materials like concrete and reinforced
concrete without some study of steelwork design also, and that the study of one was immensely
advantageous to the study of the other. He agreed that the tables given at the end of the
Paper, in which safe loads for British standard beams encased in concrete were given, were
most useful and interesting. A little while ago he had occasion to consider a case of a floor
which consisted largely of British standard beams encased in concrete, and he found that
although the concrete casing added very considerably to the strength of the steel beam, it
was almost impossible to take advantage of that fact because there was such a very high
friction stress produced by the loading between the flange of the girder and the concrete. In
this particular case the load was unusually high: ten cwts. to the square foot. He did not
gather whether the author had gone into the question of friction stress between the steel and
the concrete in making up these tables. This was a most important matter, because the
concrete casing round a steel beam would only increase the strength of the steel beam provided
that the steel and the concrete worked together, that was provided the beam did not slip-
within the concrete. If the beam slipped, then presumably the concrete casing w-as of little-
or no advantage to it.

263

THE CONCRETE INSTITUTE. ICQNCBET EI

Mr. IF. G. Perkins (District Surveyor for Holborn) thought the author was distinctly
wrong in stating that one was not required by the Act to make any allowance for the eccentric
loading upon beams. What the true eccentric loading was it was difficult to say, but in the
pamphlet published by the District Surveyors there was a formula given for taking into
account the eccentric loading upon pillars, which might be taken as accurate for ordinary
practical purjwses. If the connections were made perfectly, the beams fitted tightly up
against the pillars, and the pillars were continuous, then perhaps the bending moment might
be reduced by 50 per cent., but as the Act allowed pillars being placed upon pillars they did
not get that perfect continuity in the pillars, nor did they get the perfectly fitting joints, and
in that case he thought the formula of the District Surveyors was the proper one to use. It
was not theoretically correct, but they said in the pamphlet, as the buildings should be
sufficiently braced that there should be no material deflection in the pillars the formula had
been adopted in preference to the more complicated one necessary in cases where material
deflection occurred. He should be very glad that the Institute should have a conference with
the District Surveyors. As they generally had to work with architects, he itiought at the
same time they should invite the Royal Institute to send their representatives to such a con-
ference. As Secretary to the Science Committee he would endeavour to do his best to bring
about such a conference. The grillage was not really the foundation, the griuage was the
base of the pillar ; the foundation was defined in the byelaw as being the concrete, and if they
regarded the concrete as the foundation and the pillar bore directly upon a series of grillage-
beams, which were properly stifi"ened and so arranged that the bearing loaa did -not exceed
that allowed by the Building Act, they could then take the grillage as the base of the pillar,
and they would not be bound by the regulation which governed the rivets in the gusset plates.
Referring to wind-pressure, he remarked that the general public were not acquainted with the
failures that took place in and around London. As an old official it had been his lot to see
several buildings which had been blown over in the neighbourhood of London by wind.

Mr. S. Bylander observed that if the Institute would adopt the recommendation of the
author, that a Committee should consider the further regulations which might be required in
order to make the Act for steel-frame buildings smoo-th working, he thought it would be
welcomed by all concerned. Complicated and troublesome work they wished to* avoid ; they
wished to simplify everything. If they knew exactly what to do they would work with
greater pleasure. He would suggest that they should extend this still further, and that the
Committee should recommend to the London County Council that they should supplement or
amend the present Act as far as might be desirable. The author seemed to mix up the engineer
and the contractor. His (Mr. Bylander's) idea was that the contractor would save a great
deal of expense if particulars were provided by the engineer, and he was sure that the con-
tractor would never be able tO' expect very definite and reasonable information and require-
ments unless it had been prepared by an engineer thoroughly conversant with the particular
work. It had been proved to be successful that the quantity surveyor took out the quantities
from one scheme prepared, and these were afterwards submitted to the contractors for tenders.
On the question of eccentric loading for pillars, he for one thoroughly believed in the assump-
tion that the load was applied on the centre of the beam and not on the face of the pillar.
The assumj^tion that the load was applied at tlie outer edge of the angle was thoroughly
wrong. If there was a stifTener underneath it was most likely the load was applied uniformly
over the bracket. He suggested that the allowable stress for pillars should include, say,
20 per cent, of the eccentric loading. This would simplify the calculations very considerably.
His contention was that it did not matter a bit whether there were beams on four or two sides;
the main thing was that the connection between beams, whether two or four, was sufficiently
-Strong to hold the column lateral. He did not believe in the stiffening efl"ect of the beam to
the pillar by means of connections in order to keep the column rigid. As to beams buried in
concrete, he thoroughly agreed that it was the adhesicm between the steel beam and the concrete
that they had to watch ; that was an extremely difficult thing. He did not believe in the
method of steel beams buried in concrete being the same as reinforced concrete. It was a
most dangerous assumption, ills alternative, which lie thought would meet the case, was a
much simpler one. A beam in solid f:oncrete ttvuld carry a much greater load than a beam
not supiKjrted in that manner. If the beam was endK'dded in cone rid' the floor would be
three feet on either side. TIk 11 the>' should be able to allow a nnii h higher stress. He
further suggested that the stress of beams embedded in floors should be increased by, say,
20 or 25 per cent, 'i'liis would give a fair allowance for (he fact that the beam could carry a
heavier loarl if \\<)\ laterally supported. His belief was that before they got any considerable
stress in the concrete they had reached the excessive stress in the bottom flange, and, therefore,
they might at once dismiss the cahadalions of the top flange, and only consider the bottom
flange.

264

^GiiSSI^j CALCULATIONS FOR STH EL-FRAME BUILDINGS.

N(.lMt-I RlNCi^ — J

]\lr. E'iVarl S. Atuirt'ws, />..S\. (/.<>//</.), said there had iilways seemed to liiin :i tremendous
ainoiinl of misunderstandinu; on tlie- i):irl of en|,dneers as to the failure of lualliemat iciaus to
produre suitable formula' for lluiu. 1 1 is own opinion was that dire(tly jjraeticul engineers
sIiowimI uiathemat i( iauN that tlic\ rcallv were interested iu ^;rtliuff a formula which was
accurate llu- luathcuiat i( ians would rise to tlu- occasion and ^'ive them that. 'J"hc whole trouble
was that there seemiMl to hv a dtMuand for halfd)aked formula-, whii h did not satisfv the
mathematician at all, and whi( h looked sulliciently simple to satisfy the engineer. Tliey
seemetl lo be met b\ this call for simpli(it\', which he was sure was a ver\ bad thing. It
was imi)ossible lo rcdme c(uuplicate<I formula- into simplicity. He liad given (onsiderable
thought to the (piestion of etii-ntrii loading, and he was cjuite in agreement with the main
idea of .Mr. Cocking's result. As to halving the ec( entricitx', though, lie did not understand
the mode b\- whi(h he had attained it. 'J'he only wa\" they would ever learn the actual
stresses in the cohnnn was by actually measuring tb.em, and the work that was being done in
America at the i)resent time in that direction was work that they ought to watch with very
great care.

26s

C. \V. BOYNTON & ]. H. LIBBERTON.

ICDNCKETEJ

Sample of Panelled Ceiling Work done with
Sand or Plaster Moulds.

THE DECORATIVE
POSSIBILITIES
OF CONCRETE.

C. W. BOYNTON and

J. H. LIBBERTON.

O-

=o-

the
(Vol,

We give below an abstract of an interesting Paper luhich was read some time ago before
Western Society of Engineers, U,S.A,, and reprinted in that Society's Journal
No. 8, 1913). Ttie Paper was presented by Messrs. C, W. Boynton and

J. H. Libberton, to "whom lue are indebted for our illustrations. The Paper comprised
numerous other illustrations and examples which are notgi-ven in this abstract. — ED.

There is an old maxim to the effect that the desig-ner should ornament his
construction and not construct his ornamentation. This is an admirable saying-,
but should be subordinated to another rule, that he should ornament his
structure only if he lacked the skill to make it beautiful in itself. A structure
of anv kind that is intended to serve a useful end should have the beauty of
appropriateness for the purpose it is to serve.

There is a certain charm about a massive structure almost irrespective of
design. The sight of a p\ramid on the desk would call forth no expression of
interest or enthusiasm, but let this grow in size until it assumes the proportions
of those famous structures of Egypt and many pilgrimages will be made to
\ i':v\ it. Of course the I{g-yptian pyramids are assumed to be the resting place
of kings, and the placing of the l)]()cks required the use of more muscle or
nia<liiner\ than we at present ha\'e an\' knowledge of, but our idea of their
Ixiauty and grandeur obtains ])rimarily from the immensity of the structures.

There is no reason, however, why mass should not be combined with
decoration, j)ro\'ided the design is not made subordinate to the decoration.
This combination has often been used very effectively. The question is, what
medium shall be chosen? At the Unity Churc^h, Oak l^irk (F/.:,'. i), the
building is not only monolithic concrete, but the ornamentation partakes of the
same characteristics, havii^g Ix'cn (^ast at tiie same time and of the same
material. In <i building of this 1n|H", however, nnu^h attempt at dei^oiation
would he fatal, and the unobtrusive style adopted detracts not in the slightest
from the dig-nit\- oi)Iain!(i by large areas and inassixe construction. With a
different style of buildijig, ■ u( ii as llu- Administration i^uilding at Washington
Park {Fi^i;. 2j, the treatm<nt ni.iv ix' entirely different and the (M)ncrete be
called on to assume the most intricate shajjes.

266

•- CON^vryiKHIONAL
Ci. EN(.lNhb.WlNt. — ,

DECORATIVE POSSI EI LIT! ES OE CONCRETE.

liolh of lluM- huildiiii^s show tlx- same siirfnci- finish. Tlic :ir(hitc<iurL'
(Klrnn lus tlu' (Irc-oration. W'ilh coiKhtions reserved and the dcioralions Irans-
l)osi(l liu' elTecM would l)e hidicrous. In huildini^ the monotony of llie form
eonerele has lu'en relieNcd h\ the use of a rathiT (hv surface mixture w liicli

Fig. 1. Detail of Unity Church, Oak Park, Illinois.
The Decorative Possibilities of Concrete.

discloses the nature of the ag"gregate used. In work of this kind particular
attention must be paid to methods of obtaining uniformity of surface and
absence of horizontal joint markings, although the latter blemish is not nearly
so noticeable on work of this character as with the wet mixture.

E 267

C. W. BOYNTON & J. H. LIBBERTON.

LCONCBETEJ

But the question of pleasing effects depends not only on the surfaces and
the surface treatment, but on ^ the combination of design with the surface
texture. When not carried to extremes, the judicious use of a few division
marks relieves the plainness of design and forms a rather interesting frame-
work for what would otherwise be a monotonous surface.

l-'m. 2. JCiitraiice Detail, Administr.itioii liuiMiii;^, W.isliinjiton Park, Cliica^o.

TlIK IJKf;f)KATIVK PoSSIHII-ITIKS OV CONCRKTK.

!)(•( cration howcx'cr, is not an essential of mass (-onslrutiion, as has been
clearly dcmonsl rated bv the Sj);inish in tlie design of tlie a(l()l)e dwellings and
missions. Hut adobe perishes and our interesting relics of former days will
soon be a thing of the past. Noting the i)()ssil)ililies of monolithic^ eoncretc for

268

OON>TI.M ICT1CBM4U

!)HC()RATI\'Ii POSSIBILITIES OF CONCRETE.

j)r( St rxiiii^- this arcliiu-cluif, Mi', l-'iaiik Miller, I'.S.A., has uiKk'i'lakcii Id
j)L'trir\ iiuk'linili'ly, as it wiTi-, soinr ol llu- inosl iiiltTcslin^ details of the

Fifi. 3. Courtvard, Glenwood Inn, Riverside, Cal.

Fig. 4. Glenwood Inn, Riverside, Cal., looking from the street into the Courtyard.
The Decorative Possibilities of Concrete.

mission architecture developed by the Franciscan Fathers in California {Fig. 3).
Thus when the last adobe wall has crumbled we still shall have a replica of the

E 2 269

C. W. BOYNTON & J. H. LIBBERTON.

ICDNCRETB

Campr.nile of San Gabriel (r /i,'. 4) and the imposing arches of San P'ernando,
these having- been duplicated in the Glenwood Inn at Riverside, California.
Little other material than concrete has been employed — except the roof tile,
which undoubtedly lend colour to the scheme and interest to the picture. On
the roof is a famous collection of bells, over 300, dating^ back to 1278.

Of a mission tvpe, also, are the rest or way stations of the Pacific Electric
Railwav, at Pasadena, California. These are fast replacing the old wooden
rouo-h and readv stations, none of which was consistent with the high class

Fif* 5. Porch Detail of a Residence in Soiitli Oranj^e, N.J.
The Decora iivE Possibilities of Concrete.

residential district thrcjugh which the company operated. On both sides a
bench is built into the wall so as always to furnish protection from rain.

Because it inrludcs some ol the most notable sculpture on the coast, the
building of tbc 'I'lirfjop Polytechnic Institute at Los Angeles, Cal., may have
interest. Jl is all of reinforced concrete. J he sc^ulpture was executed in New
York and cast in glue moulds by a local (M)mpan\'. Warm climates seem par-
ticularlv suited to j:lain concrete construction, and its general adoption may
partially be explain'-d by tlic cool appearajice of the plain surface.

Concrete, still in its lormali\c stale of de\ clopment , is a comparatively
/lew architectural material, although structurally it has been proving^ its
perma.nen<:e for man\' \ears. i Ik- particular reason for gratification comes in

270

'y, fON> IPlKTlONAi:
' A t:.N( il N KKk 1 N( I ^ — ;

DECORATIVE POSSIBILITIES OF CONCRETE.

tlu' new (liM«)\ crii s, Ami new uses lo which il is cont iiui;ill\ hciiiiL; put. I^xfry
cl;i\ sonH't hiiii^ new a\\(\ worlhx ol coiisidci;!! ion is (hscoxcrcd.

Mi-. 1' ri'dciiik Si|iiii(S, ol Xcu N'oik City, h.id xit'Ucd uilli rcj^rcl the
j)r(.Sfnt slab ;ind hf ini lloor const lucl ion. Alti-r scvi'r.il \c;irs ol studv, he
d(,\iscd ;i mctliod ol (hi|)lieat iiijL; the most intricate ol cast ceihn<;'.s in .solid
in)ncrc-te, with a decided sa\inLi ol material. Ills scheme eonsists simj^lv in
eir.jilox iiii^ lawerse colfeis of moulder's sand, whi<h are j)laeed on the lorm
l)e!v)i"e the concrete is p;)ui'ed. When the forms are remoxed, the panels are
exposed, the whole heinij' accomplished in one ()|)eration. Tar more pleasing
surfaees are ol)taini'd than wt-re excr piesenled by the old ])laster-of-paris
mcth,)d of ap|)lyini^- j)re\ii)usly east ])anels lo the work.

Fig. 6 Porch Detail of a Reinforced Concrete Residence at Woodbury Falls, N.Y.
The Decoxative Possibilities of Concrete.

A few years ago the theory of applying concrete by means of a hose and
nozzle met with derision, but every day we hear of more work being done by
this method, the machine being designated as the " cement gun " and *^he
concrete "gunite." An interesting piece of work has been accomplished by
the Boston Ele\ated Railroad at the foot of O Street, Boston, where a garden
i^encc has been constructed bx this method. The base and posts are built of
concrete poured into the forms in the usual way, the posts being relieved by
protecting brick quoins. The street face of the panels were shaped by means
of a xxooden form, and each central panel xvas faced \xith steel. The concrete
xvas applied from the rear with the cement gun, making the panels 2^ in. thick
and the styles 4 in. thick. The interesting point in the operation is that the
entire panels are made in one piece and at one operation.

The ver\- fact that concrete is simple in operation has caused many to

271

C. U^ BUYNTON & J. H. LIBBERTON.

ICO^CBETFJ

undertake construction who are in no way fitted to carry it out, but with proper
super\ision even the most unskilled labourer can accomplish pleasing- results.

A building- should be fitted to the country in which it is to be located, and
more and more attention is continually being given to the unity which must
exist between the landscape and the layout of concrete structures which are to be
added as permanent improvements.

An interesting example of concrete for houses is seen in the detail {Fig. 5),
the residence of Mr. Albert Moyer, U.S.A. Liberal use has been made of
exposed aggregates, employing a mixture of Portland cement with limestone
screenings, marble chips, and dark trap rock. Not stopping here, much

I'ijl. 7. Interior View of a Reinforced Concrete Residence, showinfj substitution of Fresco for Lattice Work.

The Decokative Possihilitiks ok Concrete.

dependence has been j)lace(! upon Moravian j^otlery decoration, which har-
monises well with the concrete surface, 'ihe balcony, also, has been worked
out in pottery. I lie dislinguisliing feature lies in the fact that instead ol
being inlaid, the figure comes out in Ijas-relief, and although somewhat serpen-
tine in design, seems fairly consistent with the grape-vine moti\e.

l<"or some time Mr. Alfred llopkins, of New V'ork City, has been a strong
advocate of reinffjiccd concrete lor the fonst ruction ol buildings, and has
added a large amount ol inlorniation I0 our knowledge ol the coiKM'ete ol the
old Romans, leaving in\ estigalcd liiis |)oint jxTsonally and in some detail.
Nevertheless, he has nexcr brought himself to beliex'e that concrete should be

272

aTcoNsfvurndNAL.

(^ KNC.INKFWlNd --;

DECORATIVE POSSllUEl'l lES OE CONCRETE.

usi'd !()!• tlu' orn.iiiii nl.ilioii upon 'Duildini^s ol tlu- s.iinc in;iUii;i!. I'()r this
ini'-posc lu' a(I\()(MU's tciia cotl.i. lie Ikis recently erected :i larj^c r<-sidence at
\\'(>()dl)ur\ h'alls, ^.^ . This hiiihliiiLi is all ol reiiiloiced concrete to the rool,
and part i)l" this has hi'i-n const ructid ol concrete slabs. lUit for the panels
and column c.ipitals teira colta tile has Iveen used. i^'or the average individual,
of course, a detail of this kind would hi' i)i()hil)iti\ t- in cost. Hut with such a
sized undertakini^- as this nianiinolh lesidence, the hi^h indixidual cost of these
panels is small when comi)ared with the total cost of tlu' building. However,
whh the adxances which are being made in the use of coloured aggregates, it
is generalh j)ossi1)le to obtain all the colour variations necessary in the concrete
itself.

tiieplace Detail, Economy Concrete Co., New Haven, Conn.
The Decorative Possibilities of Conxrete.

It is not customary to build reinforced concrete roofs of the pitch type.
In fact, there is no sensible reason for adhering to this construction when
designing reinforced concrete. The ideal concrete house is built with a flat roof,
n'jt only because architecturally the design may be made pleasing, but because
this t\pe is the most economical in cost and space. An attic is of little use
except for the storage of material which, in the majority of instances, will never
be needed again, and when stored away in an attic corner invites spontaneous
combustion. Reinforced concrete has brought with It a new architecture, and
the sooner we appreciate its value the earlier will be the general adoption of

C. \V. BOYNTON & J. H. LIBBERTON. [S3NCBETEJ

reinforced concrete for residences as well as the endless other types of construc-
tion to which it has already been applied.

Lattice work has been utilised on important dwellings in combination with
decoration of moulded concrete, and where some would use terra cotta, as in
the panel inserts, others ha\e used concrete, depending- upon exposed aggregate
to furnish the touch of colour needed. The lattice idea can be shown by simply
stenciling the lines upon the wall, instead of using wood. (See Fig. 7.)

Wood panelling will also break up larg-e areas of concrete surface, and is
entirely in keeping- with the old half-timbered style of architecture, so familiar
to ( ur forefathers.

Stucco finish has found favour when applied to concrete blocks as a back-
ing-, and there are some architects who believe that this is the only satisfactory
means of handling- what has seemed to be in many cases a sad makeshift so
far as a building- material having architectural merit is concerned. This im-
pression has probably grown from the continued manufacture of rock-faced
and inferior blocks by those who are entirely unqualified to undertake this kind
of work.

It has been stated the so-called dry process concrete block is not of concrete
at all. Having- had little acquaintance with water during- its process of manu-
fr.cture, it consequently harbours an unquenchable thirst, and when used in
the outside walls of a building proceeds to make up for lost time, every rain-
storm furnishing- the elements of a " spree " to the detriment of the block and
the appearance of the dwelling. The dry process, however, is not necessary, it
being equally as easy to add enough water to insure excellent concrete. The
possibility of careful inspection during- its manufacture is a strong point in
fa\-our i){ the continued use of this really excellent building material.

'ihe Economy Concrete Company of Newhaven, Conn., have begun to
demonstrate the possibilities of concrete for furnishing the ornamentation for
buildings oi other material. The fireplace here illustrated (Fig. 8) is composed
principally of (^namental concrete stone. The figures above the mantel are
moulded after the various workmen about the plant, with the exception of the
oni'. at the far right, who represents transportation. The other figures repre-
sent in their order (\) the draftsman laying- out the plan, (2) the sculptor working'-
o\'er ihc pattern, (3) the labourer pouring the concrete, and (4) the workman
putting the finishing touches on the sur[a(~(' and correcMing any flaws caused by
removing the forms.

The vvf)rk is all cast in solid and uniformly j)roporli()ned ccjncrete without
special surfacing, using wooden or plaster moulds. Where necessary glue
moulds are employed for tin undcr-cu! w()r]<. This, of course, gi\'es a rather
smooth surface, aiul is the on]\- criiicisin which could be made (jf the j)roduct.
With t)ut slight additional (expense, however, the sui-face can be chiselled so
a.-> to relie\'e what sometimes appeals to be a rather ])utty-likc surface when
fresh from the uMiulds.

Il should make no dillerence whether the stone trimming is artificial or
natural, the end achiexed is tlial upon which wr should j)ass judgment. In
reality, il matters not wiiether the aggregate in the concrele has been bonded
by nature, or by the hand of man with Portland cement as the binding material.

274

y, CTON.vrUUtTIONAU
A L,N(UNLtJ^lNti ^J

DRCORATIVH POSSllil/JTIHS OF CONCRHTH.

So far as |)('rinaiu'iuH' i^ concciiu'd, concri'ti- has alicadx proxi-d l)('\()iul a
(l()ul)t its supiTioiity to many ol the natural sloiics.

T\v'. writrrs, not hcin^; an-hitcrls, ha\<' dealt somewhat si)arin»4ly wiih
the subject ol" ai (■liit«(-t ural and decoralixt' possibilities ol concrete, and lia\e

Fig. 9. Reinforced Concrete Fire Station at Weston, Mass.
The Decorative Possibilities of Concrete.

rather depended upon the illustrations to indicate the purpose of this paper.
After all, architecture and architectural decoration is a peculiar study. On
the one hand there are those who contend for close adherence to the ancient
styles of architecture, and on the other hand we have many brilliant minds

275

C. W, BOYXTON & J. H. LIBBERTON, ICQNCKETE]

who have acliicxed wonderful resuUs and designed some of our most pretentious
structures aloui;- entirely new Hues, yet without voluminous criticism from
those w ho consider them.sehes authorities. However, since this paper has dealt
more particularl}- with the architectural side of concrete, it is, perhaps, fitting-
to close with a quotation from Mr. Oswald Hering", U.S.A., who has made a
study of concrete and its architectural and decorative possibilities :

" Concrete can be easily and rapidly manipulated. It is less expensive
than either clothed steel or masonry construction alone ; it does not deteriorate
with time, and it is practically fire and waterproof. It grows in strength for a
considerable length of time, and after having attained its ultimate strength it
never weakens, consequently by its use lighter, cheaper, and more durable
structures mav Ijc erected than with any other known materials."

Regarding concrete stone he says :

"The time would seem to be not far distant when • concrete will very
largely supplant marble and stone \Ahere castings are practical. These should
not be 'termed ' imitations ' of stone, for the ingredients are largely the same
as are found in real stone. Nature's process of employing time and gravity
has sin-.ply been superseded and accelerated by man's mechanical ingenuity."

27''^

y, CONM PUC-l lONAi:
«v l.NdlNll l/INd ^

COSTRACTION AND EXPANSION.

iimMm:rmmir\MmMmM\m\\\mm^

RECENT VIEWS ON
CONCRETE AND REIN.

L FORCED CONCRETE.

RECENT PAPERS & DISCUSSIONS.

It is our intenfion to publish the Papers and Discussions presented before Technical
Societies on matters relating to Concrete and Reinforced Concrete in a concise form, ana
in such a manner as to be easily available for reference purposes.

The method toe are adopting, of di'viding the subjects into sections, is, ive belie've, a
ne'W departure. — ED.

THE NATIONAL CONFERENCE ON CONCRETE ROAD
CONSTRUCTION, U.SA-

CONTRACTION AND EXPANSION OF CONCRETE

ROADS.

By Messrs. R. J. WIG, N. H. TUNNICLIFF, and W. A. McINTYRE.

An imporiaui Conicrcncc on Concrete Road Construction was held in Chicago m
February, and nu)}ictous interesting Papers iverc read. One of the most important
reports presented, says the " Engineering Xews," luas that of the Coniniittee on
Contraction and Expansion of Concrete Roads. The Chairman of this Committee was
Mr. R. /. Wig, of the Bureau of Standards. Tic give below a short abstract of this
report and also of one on Aggregates for Concrete Roads.

The data presented by this Committee show that the main cause of contraction and
expansion of a concrete road, or for that matter of any concrete exposed to the weather,
is not changes in temperature but changes in moisture conditions. While there has
been more or less discussion of this subject by cement experts, it will come as a new
idea to most engineers that concrete swells and shrinks every time it is wet and dried,
just like a piece of timber, though of course not to the same degree. But it is established
that the swelling and shrinking of concrete with changes in moisture is far greater than
its expansion and contraction with changes in temperature. The Bureau of Standards
has made most careful measurements on the experimental concrete road near New
Village, X.J., and has found that the maximum expansion of the concrete in this road
occurs in April when the road is thoroughly soaked by the winter's rain and snow and
when the temperature has somewhat increased above that of the winter. The road
then begins to shrink, notwithstanding the increasing temperature of summer, and is
shortest in August when it becomes most thoroughlv dried out.

One important lesson from this discovery is the importance of a rich impervious
mixture for concrete road work, so as to make the percentage of water absorption and
consequent expansion as small as possible.

Another very important result of this Committee's work is its recommendation
that the sub-grade of the road on which the concrete is laid be slightly dished instead of
made flat or crowning. This tends to prevent longitudinal cracking of the road, as
gi ivity tends to cause the two longitudinal halves of the road to slide toward the centre,
thus inducing compression in the road. Further, with the sub-grade dished and the
concrete surface crowned, the concrete will be much thicker in the centre than at the
sides, giving it greater strength to resist longitudinal cracking.

2/7

CONCRETE ROAD CONSTRUCTION. [CQNCBET E]

AGGREGATES FOR CONCRETE ROADS.

By Messrs. SANFORD E. THOMPSON, A. N. TALBOT, and W. M. KENNEY.

The successful devel()j)ment of the concrete pavement dejiends ii{)on : (i) Materials,
and (2) Workmanship.

It is not so much a question as to whether concrete is a suitable material for roads
in comparison with other j3avin<4' materials, as it is a comparison between concrete and
concrete. The durability depends upon the character of the concrete.

Examination of letters received by the Chairman of this Committee from a large
number of cities having concrete roads shows general satisfaction with this tvpe of
pavement. Adverse criticism usually comes from cities where the specifications and
description of work indicate either poor materials and incorrect proportions or improper
methods of construction.

AGGREGATE ESSENTIALS.

Simple rules covering the most essential requirements are as follows : —

(i) For fine aggregate, use only sand or other fine aggregate that has been actualh'

tested for mechanical analysis and tensile strength of mortar, and is free from fine

particles.

(2) Use coarse-grained sands or hard stone screenings with dust removed.

(3) Use sand or other fine aggregate that is absolutely clean.

(4) For coarse aggregate, use hard stone, such as granite, trap, gravel, or hard
limestone.

(5) If bank gravel or crushed stone is used, always separate the sand or screenings
and re-mix in the proper proportions.

If local conditions prevent following any one of these rules, adopt some other
material than concrete for your pavement.

Hrieflx taking uj) each one of these j)oints :

(1) Actual laboratory tests are necessary for fine aggregates, because it is impossible
for the most expert builder to always distinguish by appearance between good and
poor sands. .Sand may be coarse, of good colour, well graded, and apparently perfectly
clean, and vet because of a minute quantitv of vegetable matter may show practically
no strength when made into mortar or concrete. Case after case has been found where
good-looking sand had to be rejected on laboratory test or, if used, produced defective
concrete.

(2) Coarse sand is necessary not only for strength and density, but to prevent the
formation, on or near the surface, of a layer of fine material, consisting of a mixture
of dust and cement which has no durability. Mortar made with fine sand or sand having
a large {proportion of fine grains of silt, hardens slowly and is especially objectionable
in cold weather. This prevents it attaining jjroper strength before the road is thrown
open to traffic. A sand having a considerable proportion of fine particles may possibly
show high briquette tests, and yet the mortar not have good resistance to attrition
or wear.

(3) Sand must be absoluteh free from vegetable or organic matter, or it is liable
to harden not at all or too slowK to be serviceable. Frequently, sand may be entirely
satisfactors' in appearance, and yet be worthless for concrete. Defective sand of this
tvpe is apt to be taken from too neai" the surface of the ground, so that it contains a
very small pericntage of vegetable loam. Al least 2 ft. of top soil and loam should be
removed befor<- UNing the sand, and in mam cases it is necessar\' to take off as much
as 4 or 5 ft., while occasionalh no acce|)tal)le sand can be found in the entii'e bank
because of the peneti-;it ion to a great depth of the deleterious vegetable material.

(4) A coarse aggregate of hard qualitv is necessary to resist the wear and abrasion
of hoofs and wheels. h'ailures of concrete roads have been caused simply b\' the
softness of the coarse aggregate. In one instance, for example, shells wer(> used lor the
aggregate, and the ro.ad went to pieces as soon as it was subjected to wear.

;\ll stone, like shale, slale, shells and soft limestone, must be rejected; while trap,
granite and congUnnerale, aic specialh suitable materirds. A hard limestone, such as
that occurring in certain localiliis along the Hudson River, which is sold in New York
as trap rock, is satisfactor\' for concrete loads. A hard limestone cannot be cut with a
k'nife and the specific gra\it\ is high, say, oxer 2"7o.

278

>,cr-N.vrut)c-rioNAU AGC^REGATHS FOR CONCRETE ROADS.

(iravcl il(U's iiol bond t]uiU' so slroni^ly with ccniciil as docs broUcii stone. When
propt-rlv scrcciiccl aiui fric from ilirt, however, and remixed with sand in the |>ro|)(r
proportions, a _i;ood Mirface eaii he made e\<ii for a one-course i)avement.

(5) Manx roads that are now heinj; hiiiU will |)ro\'e worthless because of the use of
sand taken liirecllx from the bank without scrt-eninj;. If ihe j^ravel contains as much as
40 per cent, of stones and very ricii proportions are used, say i pari cement to ^i P'Uts
bank iiravel, a fair concrete can sometimes be produced, but it is always cheaper in such
cases to screen the i^raxcl and remix the sand and stone in j)ro])er projjortions. There
will be, for exampii-, a savinj^ of 4 bbl., or 1 bat^, of cenu nt jxr cub. yd. of concrete by
usini;' projxMtions 1 part cement to 2 parts sand to 3 parts screened j^ravc-l, instead of
usini^ the unscreened bank gravel in i)roi;ortions i : vi- '• ^""'^ di(Terenc<- will more than
j)av for the additional cost of screenini^ the sand and rejectinj^ part of it. At the same
time, the result will be more uniform and the surface more durable because^ of the stones
which take the wear. When an access of sand is used in the mixture, as is the case
with run-of-lhi'-bank j^ravel, the mortar rises to the top when the concrete is i)laced
and the wearinj^ surface is less resistant than a mix that is uniform throuj^houl.

If the rules i^iven above are followed, and at the same time proj)er foundations,
proportions, and workmanship, are obtained, the concrete pavement will prove durable
and will resist ordinary traffic.

Tentative specifications for ai^j^rci^ates are present(d as follows : —

FINE AGGREGATES.

Oualiiy. — Fine a<4i^rei^ate shall consist of sand or screeninj^s from hard, durable
i<ravel granite, traj), or other hard rock. It shall be clean, coarse, hard, free from dust,
loam, vei^etable, or other deleterious matter. Fine aggregate containing frost or lumps
of frozen materials shall not be used.

Satuplcs for Test. — Average samples of line aggregate weighing not less than 10 lb.
shall be taken from the bank or pile and tested, before the acceptance of the material,
for fineness and for tensile strength in mortar. Individual average samples shall be
taken from each bank to be used, and new samples taken in case of a change in the
character of any one bank.

Receptacles for shipment to laboratory shall be such as to retain the natural moisture
in the sand.

Fineness. — The size of the fine aggregate shall be such that the grains pass when
drv a screen having |-in. openings. In the field a |-in. mesh or, in some cases, a ^-in.
mesh screen may be used for this separation.

Not more than 10 per cent, of the grains below the 5-in. size shall pass a sieve
having 50 meshes to the linear inch, and not more than 2 per cent, shall pass a screen
having 100 meshes to the linear inch.

Tensile Strength of Mortar. — Mortars comjjosed of one part Portland cement and
three parts fine aggregate, by weight, when made into briquettes shall show a tensile
strength at least equal to the strength of i : 3 mortar of the same consistency, made at
the same time, and with the same cement and standard Ottawa sand. The sand shall
not be dried before being made into briquettes, since this sometimes improves its quality,
but correction shall be made for moisture when weighing the materials.

Tensile tests may be made at ages of 72 hours, 7 days, and 28 days. At earlv
periods the strength need not attain the full ratio of 100 per cent, to standard sand
mortar, provided this is attained at a later period. In no case, however, shall sand be
accepted for pavement work whose strength in 1:3 mortar at the age of 72 hours is
not at least 80 per cent, of the strength of the standard sand mortar.

Screening.- — If bank gravel or crushed stone is used it must be screened and
remixed in the proper proportions.

If the sand does not fulfil the above requirements for fineness, it shall be washed,
or else screened when dry over a lo-mesh screen placed at such an angle as to remove
the particles finer than a No. 50 sieve.

Washing. — Fine particles may be removed by washing with a large volume of
water in a box provided in the bottom with perforated pipes and arranged for the silt
and water to flow off through a trough from the top of the box and the sand to be
drawn out from below.

279

CONCRETE ROAD CONSTRUCTION. [CONCKETE]

COARSE AGGREGATE.

Oiialiiy. — The coarse ao'ij;rei>ale sliall consist of clean, hard, durable granite, trap,
congTomerate, gravel, or other hard rock, free from dust, loam, vegetable or other
deleterious matter. In no case shall coarse aggregate be used which contains frost or
lumps of frozen material.

Coarse aggregate containing soft particles shall be rejected.

Coarse aggregate shall not contain a large proportion of flat or elongated particles.

Fincfiess. — P'or one-course pavements, the size of the coarse aggregate shall be such
as to pass an inclined or rotary screen having i^-in. circular openings and be retained on
a similar screen having |-in. openings.

For two-course pavements, the size of the coarse aggregate for the bottom course
shall be such as to pass an inclined or rotary screen leaving 2-in. openings and be retained
on a similar screen having |-in. openings.

For the wearing course in a two-course pavement, the coarse aggregate shall be of
a size that will pass an inclined or rotary screen having f-in. circular openings and be
retained on a similar screen having ^-in. openings.

NATURAL MIXED AGGREGATES.

Natural mixed aggregates shall not be used as they come from the bank or crusher,
but shall be screened and remixed in the proper proportions.

ASSOCIATION OF ENGINEERS-IN-CHARGE.

THE STORAGE OF COAL.

With Some Applications of Reinforced Concrete*
By HENRY ADAMS, M.Inst.C.E.

The folloii'ing is a short ahstraci of a Paper read before ihe Association of Engineers-
in-Charge, on March nth, 1914. TJie lecturer illustrated the Paper by niiiuerous
lantern-slides, and quoted luaiiy exaiiiples of the application of concrete for coal storage,
a nu))iber of which have from time to time been given in our Journal.

The author having been professionally concerned with the buiklings, machinery,
and vessels used in the seaborne and inland coal trade for more than half a century, it
occurred to him that it might be interesting to put together a few notes on the storage
of coal in the course of its transmission from the ship to the consumer.

Where open land is available the simplest arrangement for storing a large quantity,
such as a whole cargo of 2,000 tons or more, at one time, is to jirepare the ground by
levelling and then paving it with creosote d fir blocks, or with ranmied chalk. The latter
makes a cheap and suitable bottom for a large storage ground as at Messrs. Wm. Cory
and Sfm's X'icloria Dock Dejjot.

I'he space can be divided into bins for different qiialilies or \arieties of coal by
fences on three sides, composed of old railway sleei)ers let into the ground vertically for
a foot or so, with old rails for longitudes, and oM crane chains to form lies to i)revent
overthrow by pressure

The coal is lifted from the shij)'s hold in buckets containing 15 to 20 cwt. and trans-
ferred into small iron trucks rim b\ hand along an overhead gangway or limber viaduct
to reach the store and ihen tipped, temjjorary rails of irj-in. square iron, attached to
7-in. bv 2-in. fir sleepers, being laid along the heaj) as it i)rogresses. Or, in other cases,
the crane is s(j |>la( ed ilial it can lift from the shij) or barge and deposit at once on the
stacking ground, but in thai case it is generall\' a long-rake electric crane or a steam
crane travelling along a jxrmanent viaduct as at Dowell's Wharf. The most rec<'nt
arrangement is to have long radius cranes with self-acting grabs holding 15 to 25 cwt.
to reduce the manual labour to a njiniinuni.

Th(; storage of coal is ( hielU' required b\ the merchant who sells to the dealers and
to privatf; consumers, and b\ the large corporations for their own us(^ in the production
of light and power.

The coal hoppers used b\ the meichants aie built almost entii'eh' ol timbei' on a
])rick or iron column foundation, while those used l)\' the corj)orations ai'e mostly of
brick.

280

I, CONMUM)C"riONAl.

THE STORAGh: OF COM.

I lu 11' is al\\;i\s a risk of s|)oiilaii('()Us I'Dinhuslioii where a larj^e tjuaiility of coal
is stored, hut althoui^h the author has known of one or two cases, (here is not nuicli
daiii^ei' where it is kepi inuiei eo\(i. In llu' \arious seahoine coal depots there is always
sullicieiit nioveineiil j^oinj; ^n\ l)\ coal .L;oin_;^, out and other coal coniinj^ in to niininii.-,e
the ri-.k. S|)onlanet)Us cond)iistion of iari^e colleclions of coal is more likely to hap])en
when the carj^o has heen standiiij^ in trucks e\|)osed for some time to rainlall, so thai
the coal is more or less damj) throughout, hut the suhjecl i^ somewhat oh^cur<-, and is
well worthy of a sjx'iial Paper.

I he question of the \\('at hei ini.*; of coa.! is of some im])o!lance. It has been est i!)-
li^lud hexond doubt that coal exjjoxd to the weather deteriorates and loses some of its
calorir.c \alue. The Admiraltv made some experiments upon storinj^ coal under watt r,
ami i! was allciii'd at the time that it kept better than when exposed to the air, but
po>sibl\ that result was desired rather than |)ro\(<l. It is often ik C( s>ar\ to store coal
lor some considerable period in order to take ad\anta_<4e of cheap markets, and also to
a\oid stop|)ai4es of work due to strikes in the coal trade; luuh-r these circumslaiic-s
stackini^ to a heii^ht of al)oul O ft. upon the ij;i'ound is usually I'e-orled to, and it i^
likch" tliat a cover of tar|)aulins would hv of adxantaj^e.

The present century has, however, seen the introduction of a new m(xle of buildiui^
which is peculiarly suitable for the construction of coal stores: reference is made, of
course, to reinforced concrete. In this material, comjjosed as it is of steel rods embedded
in concrete, there is the maximum of durabilitx and the minimum cost of maintenance.
Structures of creosote d timber may last for lifty years, with increasinj^' expenditure for
re|)airs after the first fifteen or twenty \ cars ; but in fifty years a reinforced concrete
structure will be in better condition than in the year it was built. It is probable
that in the future this will be the only method of construction adopted for the purjjose.
It seems impossible to conceive of any better material; it has every advantage and no
drawback.

A somewhat fanciful objcciion to the use of reinforced concrete is bein<^ put forward
by certain of the opponents to the employment of this material for structural purposes —
namely, that, in consequence of its monolithic chru'acter a.nu its extreme hardness, th?
work of demolition, where such is needed, ent;nls excessive costs. There is no doubt
that the strength and toughness of buildings in r(>inforced concrete increase with age,
and that in comparison with brick walling or even ashlar stonework, the expense of
removal of the concrete is great, but the imperishable character of the structure and the
small cost of upkeep are really great points in its favour. It is onl\- in rare cases that
new buildings have to be removed shortly after being built.

As an example of coal storage on a large scale, it ma\' be mentiont d that in connec-
tion with the cable way from the port of Savona to San Giuseppe are twentv-four
rectangular storage bins for coal, each of joo tons capaxitv, at Savona, and fortv-eight
cubic bins measuring 5 metres each way, and having a capacity of 100 tons each, at
San Giuseppe,

At the Flossmiihle paper mills on the Continent a coal silo, 87 ft. 3 in. bv q ft. 6 in.,
with a capacity of ij,i26 cub. ft. in five cells, was constructed in reinforced concrete
immediately over the boilers, with a tower at one end in which the hoisting apparatus
was fixed. The concrete piers were j^rottcted from the heat of the boiler fires b\' means
of asbestos felt, but the author's experience is that no j^rottction is needed even against
the actual heat of hot fuel. Reinforced concrete bunkers should app(\al to a large
number of engineers as being at once a very economical method of storing coal for many
minor purposes, such as mechanical stoker feeding, as well as hand stoking. Low m
first cost, and with advantage of a negligible charge for upkeep, it can be safelv said
that for coal storage ])urj)Oses the use of reinforced concrete is bound to b^con^e universal.

281

NEW WORKS IN CONCRETE.

ICDNCBETEJ

NEW WORKS IN CONCRETE

AT HOME AND ABROAD,

Under this heading reliable information 'will be presented of neio tvorks in course or
construction or completed, and the examples selected ivill be from all parts of the ivorld.
It is not the intention to describe these 'works in detail, but rather to indicate their existence
and illustrate their primary features, at the most explaining the idea "which ser'ved as a basis
for the design. — ED.

CONCRETE BLOCKS AT PORT TALBOT.

In connection with the various improvements and extensions that have been made at
Port Talbot and which are at present in hand, it is interesting to note the use of concrete.
blocks by the Port Talbot Railway and Docks Co. for the erection of their new hydraulic
power station buildings. In the accompan\ing illustrations are shown some of the work
which was carried out in hollow slabs. The buildings comprise the following : —

Hydraulic power station 97 ft. long by 57 ft. wide by 30 ft. to eaves.

Boiler house 97 ft. long by 57 ft. wide by 24 ft. to eaves.

Electric engine house 47 ft. long by 31 ft. wide by 19 ft. to eaves.

Economiser building 6g ft. long by 34 ft. wide b.v 17 ft. 6 in. to eaves.

CoNCRETK Block Hlii.ihm;^ 1 ok iiu. I'cjkt Talhot Duck Cu

'i'h(.- bl(;cks and slabs us( d throughout were " Wingel " blocks, made on " Winget "
machines. The centres ol stanchions vary from 10 fi. to 14 ft. The i)anel walls be-
tween the stanchions are built entirely of 4H-in. hollow blocks from groimd to eaves and
ridges, and are of th<' sam<- thickness throughout without anv ste<'l r<'inforc<'nu'nts of
any kind, with the cxC'Cption of the r<inforc<'d concrel<' still carried across the stanchion
foundations to supjjort the walls.

The engineer to the Port Talhol I\ailwa\' and Docks Co., Ltd., is Mr. W. Cleaver»
M. Inst.C.K., under whose su|)ervision this work was carried out.

, CTONMPIK TiaNAl,
LN(iINKLRlNt> ^

CONCRETE BLOCK BUILDINGS.

PLACING OF CONCRETE FOR DOME OF MELBOURNE PUBLIC LIBRARY.

In our l)<"cNinlHr luiinlxr \vr i)ul)lishr(l a short dcsci i|)lioii of th<' donu* for the
M<'ll)OiiriU' Public Lihr.iry. We tur now ;ibl<' to puhlisli ;i few furth<-r j);irti(ulars
re^ardinf^ the new Reading Room, which was opened towards the end of last year.
Our notes have sinvial r<'f(r(ne<' lo ihr placing ol lh<- (■on(r<'te in |)osilion. 'I"h<- nyw
readinLj-rooni, situated on ihc tii>l-lloor level of the building, is 115 fl. across from side
to side of the oetaj^on, i^ivinj^ a lloor ar<-a of io,()57 sq. ft. between the inner walls, with
a ck'ar heij^ht of Soft, from readin^-rooni lloor to lh<- sprin^in«^ line of ihc doni<-. 'I"li<-
clear height from reading-room lloor to ajx'X of donn- is ii()ft., and tli<- li(i<^lit from
basenKMit of buildinij to ajx'x of dom<' 150 fl.

For the i)uri)ose of |)lacin<f the concret<' a platform about 20 ft. squar<' was er<'et<d
above the central lantern li^ht and carrie^d by the timber centerinj^ b<'low. The mate-
rials used for the concrete were 1 ])nrt cement, 2 parts good coars<' sand (specially
sel<x:ted), 3 parts bluestone screeninj^s up to f in. gauj^e. These materials were stored
in basement, so as to have no stoppai^e of work due to shortage of material, and wen*
mixed bv hand in a thorough manner in the baseuK-nt, shovelled into trucks, which

v\'-\a- h-

"•^J«*

9^^

Concrete Block Buildings for the Port Talbot Dock Co.

were immediately wheeled on to the cage of an electric hoist and thus lifted up to the
platform level above the dome. The concrete was dumped from the trucks on to the
platform and immediately shovelled by hand through hoppers in the floor of the plat-
form, discharging into the heads of chutes, by means of which it was conveyed by
gravity to the various positions required on the dome. These chutes were made in
portable lengths of sheet iron with a timber support to bottom thereof, and were 12 in.
wide by 5 in. deep. The sloj>e of the chutes was approximately 30° to the horizontal,
and it was found that the concrete, which was mixed fairly wet, ran down the chutes
evenly and without any segregation of the constituents. The concrete was discharged
directly into the position desired, where it was continuously rammed and spaded into
position round the reinforcing bars. In this way about 8 cub. yd. of concrete was
placed per hour. In placing the concrete the buttresses were done first, followed by
the heavy ring at the springing of the dome, suitable toothings and skewbacks being
left to take the concrete to be placed subsequently. In placing the concrete in the ribs
of the dome the eight main angle ribs were done first ; the diametrically opposed ribs

283

NEW WORKS IN CONCRETE.

ICQNCBETEJ

Concrete Shute.

work, which was kept wet by
the application of water, the
whole of the exterior face of
the dome was cemented with
3 parts siind and i part cement
and finished with a steel
trowelled surface.

The timber centering was
left in position for four month?
after concreting was finished,
and was then gradually eased
by slacking off the wedges on
top of the wood trusses ; these
were slacked off from the
springing, first working to-
wards the centre. It was found
that these wedges came away
easily, apparently carrying
little weight, no doubt due to
the gradual shrinkage of the
timber. The total downward
deflection of the apex of the
dome on the removal of the
centering was ^^ in. This was
measured by taking readings
on a graduated rod sus|Knd<'d
from the apex of the dome by
means of a surveyor's level sta-
tioned on the flat roof over the
annulus. This deflection re-
284

and portions of the adjacent
purlins and slab were carried
up simultaneously from the
springing to within 4 ft. of the
ring at the apex during each
dav. The eight intermediate
ribs were then similarly con-
structed, this bringing all the
ribs up to within 4 ft. of the
ring at the apex. The concrete
to all ribs was stopped with a
face at right angles to the axis
of the rib at that point and
additional rods put in projecting
beyond the face to give addi-
tional bond to the new concrete.

The concrete ring at the
apex was then placed in one
day, special care being taken
to get a good bond with the
upper faces of the ribs by cut-
ting same back and well grout-
ing in cement mortar.

The concreting of the re-
maining portions of the pur-
lins, the dome slab, 6 in. thick,
and the walls of the lantern
light was then proceeded with.

As soon as possible after
the completion of the concrete

\'iew lookinti up at Central Lantern Light, showing Timberin»4 for Dome

MeLBOURNK PlHLIC LiBRAKV.

/^y,CONMl?lJCTION' A Tj
l» V KNCilNt-l-PINd — J

COSCRETE nriLDINGS AT NORWICH.

in.iiiKcl i-oiisi.inl lor llint d.ivs, \\ hrii il w.is found ncccss.uv (o i<ii)()\c the rod. Up
to th<' pii'sint tli<' donu' has stood \\<II.

The contractors for the work were Messrs, Swanson Hrothcrs, master IniildcTS,
who carried out this extensi\e and diflicuh work very satisfactorih', and the structural
work was under th<' su|w'rvision of Mr, ('has, P. Smart, B.C.E., of th<' firm of Hat<'S,
Pcebk's ;uul Smaii, the archit<'Cts for lh<' huikliiii^, and wh- ,ar<' ind<'bt<'d to him for
these additional particulars,

CONCRETE BUILDINGS AT NORWICH.

The accomprmyinLi two ilUisirations show .some small concnte huildinj^s recently
erected at Norwich by Mr, .\rthur Collins, the City Eni^in<'er, to whom w<' are ind<bted
foi our photoj4raj)hs, Th<' buildini^s are useful in >howin_<4 the application of concrete
and reinforced conci'ete for small l)uildini>s.

! in 11 1 1) ]

Concrete Dwelling-House for Foreman Engineer
AT Norwich M.mn Sewage Pl.mping Station.

Reinforced Concrete Urinal at
Norwich.

NEW BOOKS.

ICQNCBETF]

NEW BOOKS

AT HOME AND ABROAD.

A shjrt sjrn-mry of some of the leaiing books 'which hax>e appeared during the last few months.

"Concrete Products" by " Hollie."

London. The An.'^lo-Gerinan Publishing Co., 15 Craven
Street, Strand, W C. 125 p.).

This little volume has much to recom-
mend it on account of the very practical
manner in which it is written, and the
author has imparted a freshness to his
work which is seldom nzei. with, and which
renders the book very interesting to read.

Before dealing with the matters de-
scribed in the book, we should like to draw
the author's attention to a remark made
by him in the preface — viz., " There is not
a single English book dealing with this
branch of industry. All the information a
man interested in concrete can obtain is an
occasional article in one or other of the
building journals." We were under the
impression that our journal dealt very fully
with all kinds of concrete work, and that
we {)ublished more than an occasional
article on this matter, but either we are
mistaken or the author has not studied
the premier journal devoted to his special
subject.

Facts and comparisons are drawn
between concrete bricks and clay bricks,
and although we are advocates of con-
crete, we are afraid that the writer has
somewhat missed the essential points,
especially when dealing with the question
of appearance, as the artistic taste has not
b'-en considered, and the very irregularity
of a clay brick in colour and shape is the
thing which appeals to the architect, and
after all he is the j)erson who adopts and
specifies the material to be used.

We would call the author's altcntion to
the l.'illcr [jirt of page 7, where he sa\s .
*' .Measure and examine it whichever wax
you ccjncretc blocks op|)osile." 'ihcrc is
<vif|(nll\ something wrong liei'e, ;iii(l w (
fail lo see the author's meaning.

( 'oinj)arisons are drawn between nt arh
all classes of concrete i-rtxlucls ;ind llio-e
produced in other materials, and the .-.d-
vantage* o'i concrete are ver'- strongh
stated, but the writer in all eases is reckon-
ing without the ?tsthetic instincts of the
Irue designer. The various materials use, I

286

in the making of concrete are dealt with
in detail, and the plant required for the
production of various commercial forms
of concrete is described and illustrated
with many useful recommendations.

In dealing with partition slabs the
author does not mention the all-important
fact of allowing these to become thor-
oughly seasoned before they are used in
the work. These slabs have become very
unpopular with many architects solely on
account of un. easoned slabs being used,
with the result that contraction takes place
afterwards and cracks appear in the work,
whereas this is not the case with the
various hollow brick partitions. There is
no need for this unpopularity if manufac-
turers will only see that their products are
fit for use when delivered to the site.

The book is well illustrated throughout,
and despite our criticisms we recommend
it to our readers as being well written and
full of interesting information, which is
presented in a style quite different from
that found in most technical works.

Fire Tests with Floors.

A Floor of Reinforced Concrete reinforced with
Triangular Re nforcemsnt and presented for test by
Messrs. Naylor Bros.. Huddersfield. Red Rook, No.
18S of the British Fire Prevention Commitiee.

Published at the offices of the Coneni tee, 8 Waterloo
Place, London, S.W.

At a lime when the question of rein-
forced concrete is largel}- before the
technical professions, and the question of
regulating such structures is receiving the
all<'ntion of the public authorities con-
cerned, a Report issued by The British
V\n- Prevention Committee (as Red Book
No. iSS) dealing with a fire test on a re-
inforced concrete fioor with triangular
lattice reinforcement may be detMiK^d lo be
of special interest.

The |)refatory note to the Re|)ort indi-
cates th.il in c()mj)arison with other fioor
tests, I he inslructi\'e feature of this invesl'-
galion is that granite chip|)ings do not
appear so satisfactory from the fire point of
\i( w as some of the other materials that
ha\c been used in the Committee's tests,
and fiirlher, thai the question of j)rotecting

J, coNM pnc-naNAi>

NEW BOOKS.

tlic solVil of tlic icinforccd CDiicii'lf bi-ains
rcciuiics cMrclul .ittontion.

1 1 s|)i;iks well for ihc syslcin of con-
st luct ion and the form of reinforcement
useil tliat, iCi^ariUess of what appears lo
have been an imsatisfaiioi y concrete
ai^^re^i^ati', the lloor stood up so well and
obtained The Rritish Vwc PicN-ention Com-
milte(>'s classillcation of " b\dl Protectitjn,
(Mass I>," which means a 4-hoiir test willi
lemj)eratures reachinj4 i,SooOI"., followed
b\' th(^ aj)plication of water from a steam
lire enj^ine, and it is obvious that if a
better form of concrete had been used, and
the question of j)rotection had received
more consideration,, an even better result
with less deflection must have been
obtained — i.e., a result that would have
practically left the floor in such a condition
that it need not be taken down for rein-
statement after a severe fire.

The British Fire Prevention Committee
is testini^ one or two large floors every
vear, and, apart from the non-proprietary
svstems of construction that they have
tested, a number of patented systems have
now obtained the highest classification,
which gives them a special claim for em-
ployment by the public authorities and cor-
porations with whom safety from fire is a
matter of importance.

Some ihirts floors h.ive now been tested
l)\ the ( ■onnnittee, of which about half
were proprietai'v floors, ;md half floors in
common use.

"Transactions and Notes of the Concrete
Institute." Vol. v., Part I.

l'iil)lislie<l at Denison House, 296 N'auxhal! lirid^e
Koad. S.W.

This volume in its |)reliminary page's
contains some notes regarding the member-
ship of the Institute and contributions lo
its library. A new feature is the short
review given of new books received. 'I'he
remainder of the volume contains the
papers read at the meetings of the Insti-
tute, together with a verbatim report of
Vhe discussions. The papers here dealt with
refer to the " Settlement of Solids in Water
.and its Bearing on Concrete Work," by
Dr. J. S. Owens; " Steel Frame Buildings
in London," by Mr. S. Byland<'r;
" Economv in Reinforced Concrete
Design," iDy Mr. J. A. Daveni)ort ; "The
Strength of Cement," by Mr. H. C. John-
son; "Props and Beams in Mines," by
Prof. Stephen M. Dixon, and two reports
of the Reinforced Concrete Standing Com-
mittee. All these have been dealt with in
summary, with extracts from our repor)
on the discussion, in our journal.

,"**

287

MEMORANDA.

EaNCKETE'

Memoranda and Neivs Items are presented under this heading, ivith occasional editorial
comment. Authentic neivs ivill be tvelcome. — ED.

The Maachester Building Trades' Exiiibition.—X Building Trades' Exhibition
was held last month in Manchester under the auspices of the various local Building
Associations. The Exhibition was opened by the Lord Mayor of Manchester. There
were manv features of interest, but it would be impossible to make reference to the
manv exhibits shown, and we must therefore confine our reference to just a few which
are of special interest to readers of this journal. Among those who exhibited were : —

Messrs. Bells United Asbestos Co. {Northern Agency), who showed their
" Poilite " asbestos cement tiles and sheets. This material, as is known, can be used for
roofing tiles, for walls, and ceilings, etc. The exhibit in this instance also showed the
roofing material actually as applied to different classes of buildings.

The British Fibro Cement Works, Erith, showed a simple type of building
roofed with their patent " Fibrocement " slates.

The British Portland Ce)nent Manufacturers, Ltd., London, E.G., had a most
interesting stall, which was primarily of an educative description, and the ever-in-
creasing uses for Portland cement were adequately illustrated. The Company showed
reinforced concrete fence posts and fencing, concrete drain pipes, and every kind of
garden ornament such as flower vases, columns, etc. The use of concrete on the farm
and estate was also shown and demonstrated. The exhibits also included briquettes,
cubes, examples of suitable and unsuitable aggregates for mixing Portland cement, and
also apparata for determining the voids in aggregates.

The Cyclops Concrete Equipment Co., Manchester, exhibited their concrete
block and other machines.

Messrs. Ironite, Ltd., London, exhibited their waterj)roofing material for render-
ing waterproof structures such as tanks, reservoirs, tunnels, pits, etc., where there is
heavy water pressure. The material can also be a|)plied to floors, roofs, fencing, etc.

Messrs. Sano, Ltd., of Manchestc'r, exhibited their jointless composite flooring
and wall covering, and which can be laid on every kind of floor.

Messrs. Vulcanite, Ltd., showed the various ways in which their vulcanite water-
proofing material could be used. The principal feature of their exhibit was a model
swimming bath watcrjjroofed with vulcanite lining.

Some New German Regulations Regarding Reinforced Concrete.— New regula-
tions were issued last November by th(; Berlin Police Authority for the construction of
reinforced concrete ribbed floors that is, of floors constructed of reinforced concrete
beams the f>anels between which are composed of bricks, hollow blocks, or specially
devised objects in addition to the ordinary j)anel of reinforced concrete. Such systems
of construction, mainly in patented forms, have come into frequent use in recent years,
and special regulations for their use have thus become necessary. The regulations of
May, 1907, have therefore been modified and extended in some particulars so as to
cover the new conditions.

The use of hollow blocks, etc., cemented together but without the use of a reinforced
concrete panel, is nol (xrinilted. '|"he llii(-kness of llie panel was \]\{'<.\ l)\ the regulations
of 1907 at a mininuim of X cm. (3] in.), but where the filling blocks are rigidly united
by pure cement mortar, it is permissible to reduce this to 6 cm. (2^ in.). 'J'he shearing

288

l^^i^SiS y^ MEMORANDA.

stresses .ire lo he drtennined loi ilic iliiniirsi p.iii (»l ilic 111), .111(1 where ihi^ is so small
that tht eoiuicte imm (inl\ l)f easl, must not txcird j-^; Ui^. (in.-, I)iil w her( thorou^li
raininiiij^ i^^ |)()ssihle, u|) to 4*5 kj^./em.- nia\ l)e allowed.

As a rule, each rih is to he leinhiued with one rod, .and only when I he hre.idlh of
the rih .It the l(\el of the 1 cinfoi i-cinciit exceeds () (in. is .1 greater numher of rods
allowid. When eoin|)utin^ the dist.aiue hetweeii the rods and the lower surface of the
he.ani, the ihiekness of .in\ plate w hieh is attached for the purpose of ^ivinj^ a smooth
und'i- sui f.ice is lo he inclu(led. The rihhed Hoor nuisl heir on the sup|)ortinj4 walls at
least 1 ^ cm. (5', in.), and nuist not he emploxed .as .a stilTenini^ mendxr. The ribs arc
not to he furthei- .ap.ii t th.aii ()o cm. (j ft.) from centre to centre, except where the fijlinj^
material is j4roo\ed hlocks of .1 >peci.il t\|)e, ceuK-nted together, when the distance
ma\- ho extended lo 75 cm. {2 ft. () in.). In dwellinj^ houses, floors with exposed ribs
must leceixe a tinishin<4 coat of cement.

h^loors huill into the walls on each side must he computed with a moment of ^

8
hut in special cases, when the erection of walls and Hoor proceeds simultaneously and

pi-
the lixini; is siiown to he surficieiit, a moment of 'j- ma\- he assumed. In such a case

alternateh" one reinforcing; rod must he ixnt u|) and the other carried on.

Where ribbed tloors are continuous over several spans the same rules apply as with
other reinforced concrete floors, jjrovided that the reinforcement is carried on con-
tinuously. That is, the floor cannot be rej^arded as continuous when carried by steel
beams, but only when carried bv reinforced concrete beams and projjerly constructed.
For such floors, the bendin<> moment is to be calculated on the assumption that one
span is fully loaded and the neighbouring spans unloaded, as long as the working load
is below 1,000 kg. per square metre; with heavier loads the most unfavourable loading
is to be assumed. Negative moments are to be computed as if both spans adjoining
the bearing were fully loaded.

Floors of the Koenen tv])e are to be computed with a constant moment of ^ for

middle spans and ^ for end spans, whether carried bv steel or reinforced concrete

12
beams.

Certain other regulations, referring to special forms of construction, require
drawings for their illustration.

Port Talbot Dock Works. — In connection with the additional coal tipping and
wharfage facilities at the above docks, it is interesting to note that reinforced concrete
will be used largelv. A 900 ft. long reinforced concrete wharf is nearing completion, and
a further wharf of reinforced concrete is under construction. An extension of 100 ft.
is also being made to the Crown Fuel Works Wharf. We hope to give full particulars
and illustrations in a later issue regarding the concrete and reinforced concrete work in
connection with the improvements in hand at these docks.

Reinforced Concrete and Rheumatism. — Our contemporary, the Builder, recently
contained an article under the above heading, llie writer of the article states that :• —

" There are a great many different fungi, which are all produced by spores falling
upon favourable soils in favourable positions. There are a great many different forms
of rheumatism, and they also are all produced by spores or micro-organisms.

" Sunlight and dryness are unfavourable to the growth of the spores either of fungi
or of rheumatism, while darkness and dampness seem to be favourable to the growth of
them all. Therefore it will be wise to see that all human habitations shall at least be
drv and light in order that no spores of any of these plants shall be produced in the
vicinitv of mankind during the hours of leisure and of rest."

He then quotes numerous cases which have come to his notice and attention. He
states that the " modes of preventing the pre-existing enfeeblement of vitality which
conduces to the catching of rheumatism are of course manifold." It is, however, pointed
out that these methods are for the most part beyond the power of the physician to
affect, but that the remedy lies rather with the architects and builders. The writer points

2F9

T^iiiSi;^^

''J<«B

» -^""'^gp^

rY^lM(^I)17^rP j^CONSTRUCTIONAl^

XISGINBERITSTG

*wiL

COMPARE THE COST

OF THAT TIMBER PILING YOU USED FOR YOUR
LAST JOB WITH THE FOLLOWING—

UNIVERSAL JOIST STEEL SHEET PILING

43 lbs. per super foot when interlocked, on hire for your job
at the approximate price of Is. lOd. per super foot.

SIMPLEX STEEL SHEET PILING

In two weights, i.e., 22 & 27 lbs. per super foot when inter-
locked, on hire for your job at the approximate prices of
lid. & Is, 3d. per super foot respectively.

THEN REMEMBER

THAT THE STRENGTH OF YOUR PILING IS THE
STRENGTH OF ITS INTERLOCK — OUR PILING
HAS AN INFINITELY STRONGER INTERLOCK

THAN ANY OTHER.

THE BRITISH STEEL PILING CO.

4 DOCK HOUSE, BILLITER ST.,

Telephone —

Avenue 5463

Telegrams-

Pilingdom, London.

LONDON, E.C.

v^/o/^/< .S.-
ALBION & RAVENSBOURNE WORKS, DEPTFORD

290

Please mention this Journal 'u>hen ivritinq.

J, CON.M kMKTlONAl,

MEMORANDA

!)u( lli.it it is the honn's of llic people wliith nuisi he kept free from the spore-hcirin^
coiulilions. In okIit to clTi'ii this we imisl " produce dw clliiif^s in which the conditions
are inimical to the j^rowih of ^poic-heai iiij^ oij^anisms." The article continues:
" If * the material interests of the suhj<(l races are the tfuidiiii^ principle of Imperial
(ioxt'iiiment/ let the material interests of our |)eo|)le he the j^uidin^ princi|)le of our
municipal authorities. Let the i ich huild of what materials they like; but let every
munici|)alitv see that the woikman's dwcllini^s he im|)<rvious to wet and to cold and to
vermin almost to llood an<l to earthquake and to lire. In fact, it should be built of
ferro-concrete. Is there a ciieajx'i-, cleaner, slron;;4er, healthic r building material known
to man ?

The writer then |)oints out that as " warmth is essential to overcome on<' of tjie
most prevalent ailments of our climate, and if ferro-concrete be a building material most
iikelv to prove prejudicial to s|)ore-bearin^ diseases, but is too rapid a conductor of heat
to make comfortable dwellings for mankind, it is up to the building profession and to
those familiar with the multii)le requirements of the case to erect workmen's dwellinj^s
of a non-porous solid that shall yet be not too quickly affected by atmospheric alterations
of temj)erature, since every virtue has its failinff, and the sharpest knife must be
handled with the j^reatest care. One of the faulty virtues of ferro-concrete is that it
prevents the penetration not only of damp but of air, while those porous materials to
which we have hitherto trusted for the buildinj^ of our homes have literally leaked at
everv pore. We have been accustomed to respire throuj^h wall and ceiling and floor,
while the wallpapers and plaster of our rooms, if not indeed the very bricks of the walls,
have proved veritable filters of germs, letting out indeed noxious gases from our apart-
ments but retaining with certainty (in the absence of visible openings) every germ for
future potency of infection.

" With the use of a non-porous building material all this automatic imperfection of
ventilation must be exchanged for a purposeful system of architectural efficiency.

" As smooth, cold surfaces are not conducive to comfort for leaning against at home,
all ferro-concrete walls in the house should be lined with a porous and washable dado ;
while parquetry flooring should replace the boards to which we have been too long
accustomed.

" Still greater warmth would be secured by double walls w'ith the necessary air
space between, carefully secured from communicating at any point with the interior of
the house; while a roughened surface to the outer w^all and a padded roof would com-
plete the essentials of sanitary dwellings conducive neither to rheumatism nor rheu-
matics."

Scottish National Portrait Gallery. — H.M. Office of W^orks shortly propose re-
constructing the Scottish National Portrait Gallery in Edinburgh, The gallery houses
a very valuable collection, and the object of the scheme is to protect the building as far
as possible from fire. Concrete floors covered with parquetry- will substitute the present
wood flooring, and the roof will be of concrete.

Concrete Electroliers.— A new concrete office building in Los Angeles has secured
a very pleasing effect in its design by combining electroliers as a part of the architec-
tural plan. These are of concrete and rise from the cornice in the building about lo ft.
in height. They terminate in 5-ft. lights which form a cross. — Concrete Cement Age.

A Concrete Village.— \ he Delaware, Lackawanna and Western Coal Co., of
Pennsylvania, L'.S.A., have put up for their employes a model village, to be known as
Concrete City, which forms an interesting example of a settlement of this kind. The
houses are two-story structures, 50 ft. by 25 ft., built of concrete, with flat roofs and
dark-green " trimmings." They are moulded in one piece. Floors, walls, roofs, stair-
ways, even sinks and wash-basins, are said to be made of " poured " concrete. They
are so constructed that, on occasion, the furniture may be all removed and the entire
house thoroughly washed out with a hose. Each house contains seven rooms, and has
stationary wash tubs, a buttery, and a good dry cellar. Wooden strips are embedded
in the floors so that carpets mav be tacked down. Below the French windows, opening
outward, window boxes for flowers are set in the walls.

291

MEMORANDA. [CaNCBETEj

lINQUIRY.J

To the Editor of Cosckkiv. and Constructional Engineering.

I am presenlh- interested in the desion of a block of buildings. It is pro])Osed
to run combined reinforced columns and pilasters up the outside of the building; these
pilasters to be moulded,

I shall be glad to know if you can give me any information as to suitable treatment
of the external face of the pilasters to ensure that they will have evenness of colour and
a smooth and artistic appearance after completion of the building.

As vou are aware, the difficulty is usually to prevent patchy and white discolouration
and also to prevent small surface cracks when the building has been up for some time.

The pilasters, of course, could be washed over with cement grout or plastered with
cement mortar, but it is proposed to discard both of those methods and to treat the
concrete, after striking the boarding, either by rubbing down w^ith a float when the
concrete is green, or by any other method to ensure a good external surface and appear-
ance for the concrete.

If vou can give me any advice as to this I shall be obliged.

Yours faithfully,

Enquirer.

[REPLY.]

If it is definitelv decided that no surface finish such as cement grout or cement and
sand is to be applied, the only method we can suggest for obtaining a smooth surface
is to have the shuttering very carefully and well constructed, with absolutely close joints,
and a planed, clean surface towards the concrete. The latter should be carefully placed
with fine stuff against the forms and no large aggregates should be allowed to get
against the external faces. After the boarding is removed, the surface should be rubbed
down with a steel float if the concrete is sufficiently green, or sandpaper or suitable
stone mav be employed to rub off any projections.

The Interim Report of the Concrete Institute on the Surface Treatment of
Concrete, published in this journal last year, contains some useful information on the
subject, and there are also some suggestions for surface finish in a book recently pub-
lished entitled " Cassell's Reinforced Concrete."

ERRATUM.

We are asked bv Messrs. Edmond Coignet and Co. to say that through an oversight
it was stated in their advertisement on page v. of our February and March issues that the
new Law Courts at Jamaica were executed bv Messrs. Cowlin and Son, whereas this
work was carried out by Messrs. Mais and Sant, of Jamaica.

292

CONCRETE

AND

COMSTRUCTIONAL ENGITSEERING

Volume IX. No. 5. LONDON, May, 1914.

EDITORIAL NOTES.

THE CONCRETE INSTITUTE.
Public Opinion.

Tin- Concrete Institute wns tlie subject of an extensive leadinj^ article in our
last issue, with the result that we have received much correspondence reg-ardin^
its objects, its administration and its work. I<\irther, the " referendum "
post-cards we issued with the April number, with the object of obtaining some
idea as to the views of our readers regarding- the proposed change of the
Institute's title and the change in its objects, have been returned to us in
considerable numbeis, only one reader differing as to its tenor and about a
dozen as to certam portions thereof.

From the post-cards and correspondence, we realise that the general interest
in the Concrete Institute's unfortunate doings is even greater among the public
— i.e., non-members — than we anticipated, and that the broader and national
aspects of its existence or failure appeal to a large section of the professional
world and to a very substantial section of the industries directly and indirectly
concerned.

It thus appears to us, that if a section of the Council of the Concrete Insti-
tute pursues its present course of pressing for a change in the Institute's primary
objects, so that concrete and reinforced concrete only play a secondary part, the
more influential section of the general membership — including practically all the
professional members abroad and many in the provinces — will retire from it at
the end of the current year, whilst even with its present constitution better work
will have to be done in the interests of concrete and reinforced concrete on lines
that do not lay themselves cpen to such frequent and justifiable criticism.

The Institute's Administration.

A change of President is impending through effluxion of time. It is to be
hoped that, whoever the new President may be, he will take of^ce with the full
confidence and good wishes of the Institute's Council as a whole, and not
through any " arrangement " which would undermine confidence and be fatal to
the Institute's prestige. There are rumours that something of this kind is being
attempted. The Institute has had troubles enough without seeking this fresh
one. On the other hand, a popular President of recognised standing and ad-
ministrative ability could do much towards framing the Institute's policy and
obtaining good management and courtesy towards its membership.

Again, some of our provincial correspondents tell us that owing to some
legal quibble they are not to be consulted on any change, present or future, in

B 293

THE CONCRETE INSTITUTE. [CQNCBETEJ

the Institute, unless they happen to be temporarily staying- in London, or can
afford the time and trouble to travel specially to town to record their vote.
Some 250 members resident abroad are apparently to be kept in the same position.
In other words, close on three-fifths of the Institute's membership is to be
permanentl}- disfranchised at the behest of a section of the Council. Nothing-
could be nK)re unwise than to offend the country and the Colonial member, no
matter what the legal aspects of the Institute's rules may be. Why, even in
public trading companies of standing- the member at a distance can generallv
lodge a proxy, or if he cannot do so, is asked by courtesy to record his opinion
in some informal way.

GENERAL CONCRETE USES IN ITALY.

In an earl\- issue of this journal we pointed to the readiness with which the
Italian was using- concrete for every possible purpose. \'isiting- Italy this
vear the traveller would be struck more than ever bv the increasing- use of
Portland cement concrete for everyday requirements in town and country.
Everywhere in Italy the praises of the material are being- sung- with no
uncertain \ oice.

Leaving- aside leg-itimate constructional work, where concrete now plays
the premier role, one marvels at the adaptability of concrete where it is popular.
Every form of sanitary appliance now appears to be made of concrete — the
sewer, the pipe, the trap, the gully, the slop sink, the pantry sink and
draining- "board," etc. It is used for pavement work, both for the
roadway and the footpath, kerbs of every form, corner posts, lamp posts
and tramway poles, refuse boxes and sandholders, electrical control boxes
and fire alarm posts. Every little culvert, open drain, chute, etc., is being
made in concrete. Again, the material is in use for fence posts, kilometre
jX)Sts, and e\en signposts on the high roads, not to speak of seats and benches,
horse troughs and ornamental fountains of excellent taste.

The gardener appears to use it for rockeries, borders, and for all the odd
jobs for which timber is generally the gardener's mainstay at home, such as
props, shed work, frames.

In many cases old iron rods, gas piping, barrel hoops are made use of as a
rough-and-ready reinforcement, and by some intuition and rule of thumb they
are generally placed in fairly suitable positions.

\<> ad\'ocates of concrete, its ready application in town and country in
Ital} is nrjw quite a revelation. We only wish the " handy man " in England
w(Hild realise h(n\- econ(Mnical and jDractical is its application. Much lime and
money would be saved and the wastefulness of constant painting, repairs and
renewals avoided.

294

THE USHER HALL, EDINBURGH.

THE USHER HALL of MUSIC,
EDINBURGH.

The special attention of our readers is called to the folloivinq article on the Edinburgh
Usher Hall, otoing to the eitensi've use ivhich has been made of reinforcea concrete for a
building to be used as a place of public entertainment. We ha've often divelt on the fire-
res'Sting gualities of this form of construction — qualities so essential in a building of this
description^ and ive 'would here like to draiv attention to the fact that the material lends
itself ivell to dignified architectural treatment, as will be seen from a glance at the
illustrations. — ED. .

General Description. — One of the most important features in the
construrlion of the recently opened Usher Hall, Edinburgh, is the extensive
use which has been made of reinforced concrete.

Reinforced concrete has been employed by the architects for the construction
of the whole of the foundations of this structure ; a large portion of the retaining
walls below ground level; the internal pillars supporting the heavy masonry outer
drum wall and dome roof; the Grand Tier gallery in cantilever; the Upper Tier
gallery in cantilexer ; the whole of the floors, beams and lintels ; the horizontal
air ducts ; and the roofs. To such an extent has reinforced concrete been used
in the design of this hall that it may be said that the whole of the interior acts
as one monolithic mass, clothed by the outer architectural walls of stone.

The style of architecture may be termed " English Renaissance " and the
exterior is simple and dignified.

Above the base course, which is of grey Aberdeen granite, the outer walls
are of cream coloured Darney sand stone. A view of the exterior of the hall
is shown in the Frontispiece.

The hall covers an area of approximately 28,500 sq. ft., and is surmounted
by a dome which rises to a total external height above the lower foundation level
of 113 ft. Internally, the apparent height of the auditorium is limited to 60 ft.
by the introduction of a flat plastered panelled ceiling, for acoustic reasons.
The internal diameter of the circle formed by the outer drum wall enclosing the
auditorium is 117 ft. The length from the front of the concert platform to the
back of the Grand Tier gallery on the centre line of the building is 93 ft. and to
the back of the Upper Tier gallery 104 ft. The proscenium opening is 65 ft. wide
and has a depth of 60 ft., in which there is an intake to the concert platform
on each side, making the width of the orchestra at the organ front 48 ft.
Behind that is the organ chamber, 42 ft. by 18 ft. in size.

There are two foyers on the Grand Tier level, each 38 ft. by 22 ft. 6 in.,
and a central crush hall, also 38 ft. by 21, ft. 6 in. The circular corridor, from
which there are Ave large access doors to the auditorium, is 9 ft. in breadth
and has a total length on the circle of 280 ft. At the ends of the corridor —
one at each end — are spacious cloak rooms, each 38 ft. by 15 ft. The foyers

B 2 295

THE USHER HALL, EDINBURGH.

ICQNCBETEJ

Photographer, F. C. Inglis, Edinburgh.]

Fig. 1. Interior of Hall looking towards Organ.

Photographer, I-'. C. Inglis, lidinburgh.i

l-'iU 2. Interior of Hall showing Cantilevered Galleries.
Tin; DsHEK Hali- oi- Music, Edinhuroh.
296

r J, C-ONMU'DC-llONAl.
L<V E,N(.lNht.RlNt. — -.

THE USHER HALL, EDINBURGH.

and (Miish halls arc Hocifil with rcinfoicfd concicti' coxricd uilli niarhlc. The
cloak looins and corridor arc llooicd willi rc"mlor(H'd concrete coscrcd with
|)olislicd oak l)locI< llooiiiii^.

The arranjLjcn-icnl ol the entrance hall, ciiish halls, cloak rooms and corridor
are the same in all i-es|)ects on the j^ronnd l1oor as on the level of the (irand
'\"\cv. On the I'jjpi-r Tier i^allery Icxcl theic are li\i' crush halls, three in the
(\'ntre, loadino- from one to the other, each v^ ft. by j.|. ft., and all lighted by
ir.eans of dome lii^hts from tlu' rool. The crush halls at the ends of the gallery
corridor are each 49 fl. b\- 15 ft., and are similarly lighted.

On each side of the (M)ncert |)latform at the east end of the hall are spacious
retirini*' rooms for singers, instrumentalists, etc.

There is also <i wide circular corridor beneath the raised tiers of scats
in the orchestra, with a stair opening- for artistes leading directly up into the
centre of the concert platform.

On the top Hat there is a large kitchen and scullery accommodation.

Under the concert platform, and separated from the remainder of the
hall by means of a reinforced concrete floor, there is a sunk basement cover-
ing- approximately 6,800 sq. ft., which is (xrcupied as a boiler house in
connection with the heating- apparatus, and as mechanics' workshop, chair
store, and extraction fan house for the ventilation of the hall.

The extraction fan exhausts from a circular underg-round duct con-
structed of reinforced concrete, and running- round the auditorium, into which
the vitiated air from the hall is drawn and exhausted outside into the open.
This duct is 8 ft. 6 in. square internally, and has a total length of 290 ft.
The chamber for the intake, purifying-, and heating- of fresh air for the supplv
of the hall (known as the " Plenum Chamber ") is placed on part of the roof
of the Upper Tier g-ailery crush halls at the Cambridge Street Lane side of
the building-, and the outer walls of this chamber, which is circular in form,
are constructed of heavy masonr}- in keeping- with the remainder of the
building-.

The internal floors and roof of the Plenum Chamber are constructed of
reinforced concrete, and the whole dead load of this structure, which is of
two stories in heig-ht, and including- the heavy masonry walls, the reinforced
concrete floors, roof, and heavy machinery installed therein, are wholly sup-
ported on a system of reinforced concrete beaming at roof level of the
crush halls. It ma} be mentioned that the Plenum Chamber contains two
powerful fans driven by electro motors, and also batteries of radiators for
heating- the air. The air, after being- purified and heated, is driven throug-h
openings in the flat plaster ceiling under the dome into the auditorium. The
crush halls, cloak rooms, and corridors are heated b} means of radiators.

The stairways at the front entrances to the hall are constructed of rein-
forced concrete and covered with marble. The remainder of the various inside
staircases are constructed of Leoch stone, and, where necessary, are supported
by a system of reinforced concrete stringer beams.

In the auditorium the fronts of both the Grand Tier gallery and Upper
1 ler gallery are of horse-shoe design, and are constructed entirely of rein-
forced concrete covered with fibrous plaster.

The reinforced concrete degrees of both cantilever galleries have been
covered with oak flooring. 297

THE USHER HALL, EDINBURGH.

ICQNCKETEJ

The i;:illcries and area are provided with tip-up seats. The floor of the area
has a rake of 4 ft. <i in. from the last row of seats at the back to the
platform.

The level of floors at the back of the area therefore corresponds with
the level of the platform.

In ihe orchestra the seats rise in tiers, arranged in segmental form.
The following is a summary of the seating accommodation: — Area 1,192,
Grand Tier 428, Upper Tier 813, Orchestra 349, Platform 120; total, 2,902.

The foregoing brief description gives an outline of the general arrange-
ments of the hall. The interior of the auditorium, even when filled, gives an

Photographer, F. C. Inglis, Edinburgh.]

Fi'A. 3. View of Main Entrance Hall.
The Usher IIaei. of Music, Edinburgh.

impression of vaslness, due to the fact that the reinforced concrete galleries
have been (onslruded ni cantilever. The adoption of the cantilever principle
in the constructi(jn of the galleries is advantageous, as there is not a single
pillar within the entire auditorium to obstruct the view of the concert platf')rm
and organ from any seat in ih<' liall.

Attention may be dire(Med to the photograj)hs which show the beautiful
decorative effects obtained, showing that the architects have been aided rather
than ham[)ered by the almost ex(lusi\<; use of reinforcx'd concrete in the struc-
tural part of the work.

The following is an appropriate sunnnary of lh( total cost of the hall and
its site: — .Site, ^,36,000; buildings and lurnishings, ;^,"94,ooo ; organ and case,
;^4,ooo. Total cost, ;£^ 134,000.

Reinforced Concrete Work. — The reinforced concrete foundations were
designed to spread the loading so as not to exceed a maximum pressure on the

298

[

J, fONM UUCniaNAl.
C\ LN(,lMhl\yiNti — ,

TUB USHlik HALL, HDINBURGH.

^rouiu' ol j; ions piT s(|uar(' fool, .md tlu- <;ciuTal arraii^cnicnl and rcinforci--
nuMit ()( tlusr fouiulatioiis is as shown on the working detail clrauin^ rcjirocku <-d
in /'/.;:. 5.

li is intiTestint^- l(» noti- tliat owinj^ to tlu- cart-ful <\'ilrulati()n and design
of tlu'si' rcinfori't'd roncrc'ti- loundation> tlu-rc lias not been the slightest si^n
ol" iine(]ual settUmrnt in thr whole of this ■extensixc structure, a matter of
extreme imj-)oiianee to the eantile\er j^alleries in this building'-.

h'rom tlu' loni^iludinal si'ction (F//;''. (^) it will he seen that a reinforced
concrete ri'taininj^- wall has been constructed round the outer circle of the under-
g-round air duct. This ri-inforced concrc'te wall is desi^'-ned to a(M not only
as a retaining; wall but ?ilso as a foundation beam, servinj^" to distribute the
isolated loads carried into it by the reinforced concrete pillars which spring from
it at the level of the tloor o\ er the duct, supporting" the weight of the super-
structure and main dome roof. For this reason a uniform thickness of 24 in.
was adopted for this retaining" wall for its entire length of 290 ft.

The construction of the underground air duct is completed b\- a reinforced
concrete floor, 6 in. in thickness, this floor beings constructed to slope uniformly
at either side with the slope of the internal area of the auditorium. The duct
is 8 ft. 6 in. square internally.

The reinforced concrete pillars on the outer drum wall supporting- the
Grand Tier and Upper Tier cantilever g-alleries and floors, and also the main
dome roof, are artistically clothed in Sienna marble.

On the Grand Tier level the horizontal area of the gallery in cantilever
projecting beyond the supporting inner drum wall is approximate!}' 3,100 sq. ft.,
and is supported by 28 reinforced concrete cantilever beams, the maximum
outhang^ of these cantilever beams on the centre line of the building being-
20 ft. 7 in. beyond the inner surface of the supporting- wall. These cantilever
beams form one of the most interesting- features of the reinforced concrete work.
Fig. 8 shows an elevation of part of a Grand Tier cantilever beam ; the
maximum depth of these beams is 3 ft. 6 in., diminishing to 1 1 in. at the extreme
outhang-.

The web of the back portion of the cantilever beam is pierced by 3 openings,
each I ft. 10 in. in diameter, for the passage of air in the duct under the Grand
Tier corridor.

The cantile\er beams are received into a continuous padstone beam
2 ft. 4J in. in breadth by 5 ft. in depth constructed on the inner drum wall, and
are " anchored " into the outer drum wall by similar padstone beams 2 ft. in
breadth by 4 ft. 9 in. in depth. The cantilever beams are strutted behind the
point of support on the inner drum wall by the air duct, which is formed by
means of a continuous reinforced concrete floor 6 in. in thickness, the air duct
liaving a depth of 2 ft. 8 in. and a breadth of 8 ft. jh in., and a lower con-
tinuous reinforced concrete floor 4 in. in thickness.

The upstand front of the gallery is constructed of reinforced concrete 4 in.
in thickness curved both in the longitudinal direction following the sweep of the
gallery and also vertically, and beneath the upstand front a strutting- beam
6 in. broad by 8 in. deep, also following^ the sweep of the gallery front, is pro-
vided between the extreme points of the cantilever beams.

For further security an additional reinforced concrete strutting beam 6 in.

299

THE USHER HALL, EDINBURGH.

[QQNCBETEJ

by 12 in. is provided between the cantilever beams at the centre of the span of
the outhang- of the cantilevers and at their lower edge.

The horizontal portion of the reinforced concrete degrees of the seated
portion of the Grand Tier gallery is 3 in. in thickness, and the vertical breasts

PJlot<)^ir(lphcl , I'. C Innlis, luliiibitrnlt.\

VnX. }. \'iew of Corridor.
Thk I'siiEK Hai.l uv Misic, Edinburgh.

are 4 in. in tliickness, the lallcr being const rucled as beams and the former
as floor slabs supported between these beams.

The xertical breasts arc also jiuKiioned with the upper portion of the
cantile\er beams in a secure manner, and serve as struts between these beams.

A reference to the longitudinal section, f Z^''. <), will show that ri'inforced
concrete lintels were jjrovided over the doorways giving access to the area of

300

CiONMUMK-nONAl,

THE USflER HALL, EDLVBURGH.

301

THE USHER HALL, EDINBURGH.

ICDNCBETE]

the auditorium,
and as these lintels
had to support the
loading from both
the Grand Tier and
Upper Tier gal-
leries, they had to
be of exceptional
strength. Their
section is 2 ft. 3 in.
broad by 3 ft. in
depth.

A photo-
graphic view of the
underside of the
Grand Tier gallery
showing the canti-
ai lever beams,
g degrees, struttmg
§ 5 beams, and con-
1 ^ tinuous padstone
-^ ^ beam, and lintels
^ s on inner drum wall
i o is shown by Fig. 9.
J 5 This photograph
^ ^ was taken imme-
yj^ X diately after the
removal of the cen-
H tering under the
Grand Tier gallery.
Fig. 10 shows
a photog r a p h i c
view of the center-
ing in position for
the construction of
the Upper Tier
gallery.

There are two
staircases leading
from the main en-
trance hall to the
Grand Tier crush
hall, each 7 ft. 3 in.
in width, and
having the treads
and landings con-
structed in rein-

forced

concrete also covered with marble.
2

J, tONMUlR-nONAi:
£Vt,N( 11 MhKklNt. ^,

THE USHHR HALL, EDINBURGH.

riu' r|)i)(i 1 HI i^alkrv rovers npproxinialcly .'iii area of 4,400 sq. ft., and
is suj)portr{l 1)\- j() i cinforccd coiu rt'tc canlilfxcr iK'anis. 'Iliis ^^allcry has a
maxinuiin lioii/ontal projection in cantilever of 13 ft. H in. beyond the inner
(hum suj)j)oi tiiiL; wall, heinj^ considerably less than that of the Grand Tier
i^allerv l)elo\v, but is carried back on the rake over and beyond ihc inner drum
wall to the outer drum wall, tlius affordini^'- a considerably larger seating*- area
than on the Grand Tier.

Fig. 7. Plan and Section of Roofing over Orchestra.
The Usher Hall of Music, Edinburgh.

The Upper Tier gallery cantilevers are also supported on the inner drum
wall, and are anchored back into a heavy reinforced concrete continuous pad-
stone beam in the outer drum wall, 2 ft. 3 in. bv 3 ft. 9I in.

The reinforced concrete degrees and upstand front are formed in a similar
manner to those on the Grand Tier.

The horizontal landings of entrances to the Grand Tier gallery are
constructed of reinforced concrete 6 in. in thickness, as also are the walls at
either side of the entrances and the lofty "baffle " walls at the back of this
gallery.

303

THE USHER HALL, EDINBURGH.

ICQNCBETH

The stairways at the five entrance doors leachng- from the corridors to this
gallery are also constructed in reinforced concrete.

The floors at the level of the Upper (lallery crush halls and corridors
present several interesting- features. Towards the ends of the corridors at
either side of the hall the outer drum wall changes direction from the pear-

Fig. 8. Typical Grand Tier Cantilever.

I'lti- 'J. View of Grand i ler Gallery from below on removal of centering.

Thk IISHKK HaI.L oh MuSIC, EniNHtlRGH.

shaped f<;rrn of ihc auditorium to a complete (Mrc^ie surmounted by the main
domed vooL lo j)crmil of this change of direction the wall passes across the
9 ft. corridor in a diagonal circled direction approximately 23 ft. in length,
when it arri\es over the heavy brick butts, l)uilt solid from beneath, at the sides
of the proscenium opening.

The j)r<)blt'm j)r(!scntcd was the support of this wall 2 ft. 3 in. thiclv, rising

304

J , tt>NM k»l K -HON A I .

THE USHER HALL, EDINBURGH.

to ;i liiiL;l>t ul ^1 ft. .iliovf tin- conidoi lloor, and of llic reactions from the t1at
anuTiti' and main domed r^ofs takini^" snpjxnt on this wall, without unduly
intcTJcrino- with the lu-adroon in liic main corridor of tlu- (irand Tier l<-vcl
luMuath. This was ilftctrd hv a sjH'cial sxstcm of riinforccnicnt in the corridor
lloor at rj)|)ir I i<r level lor a total length oi 29 ft. on cither side of the hall,
the tt)tal depth of the reinforced concrete lloor supportinj^" the severe loadin^r
thus imposed on it hein^ confineil to iH in., giving 13 ft. of headroom in the
(irand Tier corridor below.

Further interesting' features (»f the reinforced concrete construction at this
level are the lloors over the crush h.all and foyers on the Grand Tier level below.
These floors are formed by flat slabs 38 ft. by 23 ft. 6 in. and 12 in. in thickness
without projecting beams.

The reinforced concrete roofs over the orchestra and organ present unique
features, as will be seen by a reference to Fig. 7, showing the method of
construction of these roofs in plan and also in section.

The roof over the orchestra had to be centred from the level of the base-
ment, an average height of 60 ft.

The construction of these roofs is carried out at three different levels : —

{a) To auditorium side of beam A slab 9 in. in thickness, projecting partly
in cantilever beyond beams A and B trained to follow the circumference
of the main domed roof.

{h) Between beams A and D slab 4 in. in thickness, with a system of
tertiary beams E, and secondary beams C.

It will be noted from the sectional draw'ing that in addition to the ends of
beams A and B being stayed by the padstone beams at both supports, strong
reinforced concrete gusset pieces have been introduced over beams C at their
junction with beam A.

The main beam A, in addition to the reinforced concrete roofs, over a span
of 62 ft. 6 in., supports the solid masonry wall of the dome to a height of
6 ft. 6 in. above the beam, along with a heavy projecting masonry cornice and
four roof principals of the main domed roof.

The roofs over the gallery crush halls are all of special type, as can be
seen by reference to the longitudinal section. Fig. 6.

These roofs are constructed with the reinforced concrete beams above the
roof slabs, the object of this being to avoid any beaming appearing below the
ceiling line.

A reference to the longitudinal section of the building {Fig. 6) will show-
that immediately below the masonry cornice of the outer drum wall a continuous
reinforced concrete beam was constructed.

This beam has a depth of 2 ft. 6 in., and varies in breadth from loi in. to
I ft. 6 in., and is continuous right round the complete circle of the outer drum
wall supporting the main domed roof, and has therefore a total length of 370 ft.

It serves the purpose of (i) forming a complete circular tie round the dome;
(2) spreading the isolated loads on the masonry from the principals of the main
domed roof; and (3) forming lintel beams over the clerestory window openings
into the back of the Upper Tier gallery.

THE USHER HALL, EDINBURGH.

ICDNCBETEJ

In conclusion of this necessarily restricted description, it may be stated
that approximatclv 300 tons of steel and 6,000 tons of concrete were required
for the reinforced concrete constructional work.

Summary. — The interior of the hall has a very attractive aspect. Its
constructive lines are pleasing- and satisfactory, and it is well proportioned in
respect of height, width, and depth.

The scheme of decoration ot the auditorium and orchestra in white and gold
also satisfies by its simplicity and refinement, and the marble and bronze work
of the entrance and crush halls and foyers are in similar excellent taste.

Y'xu.. 10. Temporary Centerinj^ of Upper Tier Gallery in position.
Thk Usher Hall of Music, Edinburgh

The acoustics of the hall have been proved to be perfect, and this is to be
specially noted in view of the extensive use which has been made of reinforced
concrete construction.

The architects for the hall are Messrs. Stockdale Harrison and Sons, and
M. H. Thomson, T". R.I.B.A., Leicester.

\u the (i<;sign of llie reinforced concrete constructional work the architects
ass(x:iated with them .Messrs. F. A. Macdonald and Partners, consulting-
eng-ineers, 135, W(;llington Street, Glasg-ow, and the close co-operation which
has been uniformly maintained between the architects and the reinforced
concrete eng-ineers ever since the first desig-ns were made in September, 1910,
has materially helped in the < lucidation of many complex structural problems.

306

(9. CON.VTkM TC-IION A I :|

RHINFORCHMHNr IN HRAMS,

SHEARING OR DIAGONAL
TENSION REINFORCE-
MENT IN BEAMS,

By CHARLES F MARSH. M.lnst.C.E.

The folloivrng article should be of special interest to engineers and others 'who
study this important question — ED.

GENERAL OBSERVATIONS.

When loiiifitudinal tensile reinforctnnents are bent up it is necessary to ascertain that
the bending moment is sufficiently reduced at the point of bending to allow of the
bending up of the bars.

All bent up bars should be bent over at the top and continued along the upper
surface and finished with a hooked end having an internal radius of at least twice the
diameter of the least side of the bar, or otherwise securely anchored. They are some-
times carried well into the portion of the beam acting in compression and Hnished with a
hooked end, or, better still, hooked over a bar placed near the compressive surface, the
hook fitting against the surface of the anchorage bar. These methods of anchorage
apply also to special inclined or vertical bars. An alternative method of placing these
bars is to hook their ends around the longitudinal tensile reinforcements and make them
continuous through the portion of the beam under compression. This method is the
reversal of the usual practice, but is advisable since it gives a good anchorage in the
compressive portion of the beam.

When longitudinal tensile bars are bent up it is advisable to make the bends with
as large a radius as possible in order that the compression on the concrete at the point
of bending may be reduced as much as possible. The radius of curvature of the bottom
bends and also the top bends, when the bars are continued near the upper surface of the
beams, should be about 12 times the diameter of the least side of the bar. When vertical
reinforcements or stirrups are used to resist diagonal tension, it is usual to make them
of the same sectional area throughout. As these bars are numerous and have to be
bent to small curvatures so as to pass closely around the longitudinals, they should not
exceed | in. diameter, and may well be t^ or | in. diameter, as these sizes are easier to
bend.

All diagonal tensile reinforcements should be securely attached to the longitudinal
bars. This is sometimes effected by indenting the longitudinals to receive the diagonal
tension bars and tying the two tightly together with wire ties, but the stress on the
longitudinal bars must have become sufficiently reduced to admit of the indentations.
It is obvious that any form of reinforcement in which the diagonal tension bars are
rigidly attached to, or are integral with, the longitudinals is greatly to be preferred.

In the design of T-beams it is advisable in every case to place vertical or inclined
reinforcements throughout the whole length of the beam at distances apart not greater
than the lever arm (a) of the couple resisting the bending moment.

As a consequence of this provision, the value of the resistance of the concrete itself
should only be taken into account in the design of rectangular beams.

It is usual to allow a safe tensile working stress on diagonal tension reinforce-
ments of only three-quarters that allowed for direct tension. Consequently for mild
steel the limiting working stress in the steel for these reinforcements is taken as

307

CHARLES F. MARSH.

[CONCBETEJ

i^ ooo lb per ^q. in. When reinforcement is used to resist dia£,^onal tensile stress the
resistance of the concrete nuist not be taken into account, as the concrete must hava
cracked long before the reinforcement is stressed to 12,000 lb., although the cracks are
unnoticeable and too fine to be detrimental.

INCLINED OR BENT-UP BARS.
The difference of the longitudinal tensile stress (where B, is the greater bending
moment, at one extremity of the length Z., and B., is the lesser bending moment, at the

other extremity of the length /.) will he^^^=^ = ^=^^ where S,„ is the mean shearing

ci (I (^

force on the length h and a is the lever arm of the resisting couple.

When the increment in the stress in the tensile reinforcement over any length
I, is to be taken by inclined reinforcements or bent-up bars in tension and by the concrete
of the beam in compression, one-half of this increment in the
stress may be considered as being resisted by the concrete in
compression on such lines as those parallel to a d and c f {Fig. 1)
cutting the longitudinal tensile reinforcement and one-half by the
reinforcement in tension on such lines as c b and e d {Fig. i).
The stresses on the verticals, such as c d and e f, balancing one a
another. .

It is to be noted that this will not be true when the lines such riG.l-

as a d, c b. e f, and e d have flat slopes, since in such a case the
concrete in compression would be over stressed, and consequently we must assume that

* Proof that B^ — B 2 =S is as follows: —

If we consider a length of a beam to the left of the centre between a section (X) at a distance of (x)
from the left support and a section (F) at a distance of (y) from the left support, and use the following

symbols —

i?j;, = reaction at left support,
P^ = any loads to the left of section (Z),
PFi = any loads between the sections (X)'and (F),
(The W's and W^'s being of any intensity,)
^ = the distances of the loads (W) from the section (A'),
and z^ = the distances of the loads {W^) from the section (F),
We have for the shearing force at section (.Y) —

The mean value of the decrease of the shearing force on the length {y—x) between the sections (A')
and (F) will be —

iy-x)
We have therefore for the mean value of the total shearing force on the length (y — x) between the
sections (X) and (F)—

vPF-

(y-x)

The total shearing force on the length (y—^) will therefore l)e—

S=RjJy-x)-^ [ W{y-x) \- - ^{W,z,).

The bending moment at section (X) will be—

B^^-RLX-::i{Wz).

And the bending moment at section (F) will be —

B^^RLy--i:(Wz)-:L\ yviv-x) \ -^iw,z^),

and the increase of the bending moment over the length (y — x) will be—

B,-B,,-R,Jy-x)--^\ W(y-x)\-^{W,z:)^S.

308

y, CTON>TUUCTI<XAn

RniNFORCIi.^JENT IN HE A MS.

if tlu' r<'iiif()ii'<nunls on lines sik h .is (" /) .ind r d Uaw a lesser slope to the horizontal
than soiiK' limifiii'f aiii'U- lhe\ must he oalinilaled as resistinif iiion- than one-half the

/>\ - li.,

S,„L

stress of '*' '*•' or *^"''\ \\'e will tiK lefoie assume thai for an-^les l<ss than 45° to

</ ii

tlu' In)ri/oiital the r<inforreinenls will resist a Liradiially increasin<^ j)ro[)orlion of the
stress until an anj^lc of say 25° is reached, at which they must be assumed as resisting
the whole of the stress. Diaj^ram Fii*,. 2 j4ives the r<'eiprorals of the proportion of the
total str<'ss which must Iw tak<'n uj) by ih<'. inclin<'d r<'inforcem<'nts for angles b<'lw<<'n
45° and 25° lo the liori/.ontal ; for anj^U's l<'ss than 25° the reinforcenunts must be
assumed to take up the whole of the str<'ss.

Since the increment of stress in the longitudinal tensile reinforcement over a length

h is ^ '" \ we therefore get —

AstCosd = ^^Xq {See Fig. 3)
a
1 ^

Cos (^.A,t.

/f//0 OVER
4S

(1)

or <S,„ = -

q Is
Where A, is the sectional area of the inclined bar

t is the safe tensile resistance of th<' steel to

diagonal tension, is the angle of the inclined bar

to the horizontal, and q is the proportion of the

stress taken by the reinforcement. Where the

reinforcement makes an angle with the horizontal

of 45° or over has a value of 2, and for flatter

angles it has the values given in Fig. 2.

The horizontal projection of the bent-up or in-
clined bar between the points where it intersects
the axis of the tensile reinforcement and the centre
of the compressive resistance must be equal to / j.,
and consequently when ^ = 45" /« = a
andS,„= 2 x 0*707 A.^t = r414 A^t
and in all cases

Cos<^

(2)

2£
/)ND USS

Is = aCot

Sin ^

i/^a/ues of '/<^

, f^ ,a.A J Cos Sin 1 , , „.
and S,„ = J. ■ — - — = -. Ast Sm

e (3)

Fig I.

q a Cos d q

VERTICAL REINFORCEMENTS OR STIRRUPS.

In the case of vertical reinforcements resisting
diagonal tension we must consider the beam as

having a web of the X-braced type {Fig. 4), with diagonals sloping
upwards away from the support, such diagonals being under com-
pressive stress. This bracing is replaced in the beam by the fibres
of concrete cutting the longitudinal tensile reinforcement and parallel
to the slope of the imaginary diagonals.

These fibres, together with the vertical reinforcements, take up
the increment of stress in the tensile reinforcement or

By — B.) _ SjJs*
a a

The stress on the vertical reinforcements will therefore be

See note p. 308.

309

REINFORCEMENT IN BEAMS.

but

iCQNCBETEl

Ast= Tan^,

-^=Cot^ and :.Ad = S,

(4)

Fig 4.

This stress is, of course, the same as would occur
in the verticals of an N-braced girder, as shown by
Figs. 5 and 6.

If the sets of stirrups are ph\ced at equal dis-
tances apart their sectional area must consequently
vary in an arithmetical series of i, 3, 5, 7, 9, etc.
It is generally desirable, however, for the sets of stirrups to be of equal sectional

area throughout.

It will be seen from Fig. 4 that a

set of stirrups having a tensile

resistance of Aj = S„, resist a

total longitudinal tensile stress of

Bi -Pg S,„ls.
a a

If, therefore, we reduce or increase

S /
the value of "' "' we must reduce
a

or increase ^.s^ in same ratio, or

S /
4 .si must vary as '" '"

But as Ast is to have a constant
value if S,„ increases or decreases

— must vary inversely as S„,.
a

Therefore for any value of S,„

. , , S,„/s where the value

A>,t must = — ^^-^
a

Fi G. 5.

of Sm varies inversely as the value

of ^-^
a

But in any beam a will be con-
stant, therefore aAj, = S,„ls (H)
Where S,„ and h vary inversely
as one another, or if we make aA^t

constant <S„,/.s must be constant FiG. €>.

and equal to aA^t.

But S„,l, is the area of the shearing force diagram on the length U, Is being the pitch of
the stirrups.

We can ihcr<-U)U' calculaU^ th<' v.-iKh- of dAj for any b<'am and any arc^a of stirrups
and divide up the shearing force diagram into areas <'qual to aAsf, ^"""^l ^^^^ liniitmg
verticals of such areas will give the si)acing of the stirrups.

Table I. gives the vahu-s of A ^1 for various diameter round and square bars with
various numh<r^ of double hranclK's, which may b<' nuillii)lic(l by the value of a lor
any particular Ix'am.

If the load is uniformly distributed the slK-aring forc<' diagram for thc^ half-sj)an
will be a triangle such i\ A, li, C, Fig. 7. Th<' value of A J for the set of stirrui)s
selected can be obfain<'d from 'I\'ibl<- I.

For the first set of stiirups (i.r.. those at the centre of the beam) the value of S ,„
must be equal to A J.
310

^ trasMin/rnoNAi

N(,1NH.PIN(,

REINFORCEMENT IN BEAMS-

■rAiii.i': I.

Dianu'ttT or
side ot bar.

:)
in

l\(JUluls.

Squares. 1

for

Resistance of s

lirnips

les.

for

Resistance of stirrups

les.

various lumibers

of brand

various numbers of brand

593
1390
2352
3672
5304

()

1186
2780
4704
7344
10()08

1482
3475
5880
9180
13260

296

6<)5

1176
1836
2652

889
2085

3528
5508
7956

375

885

1512

2352

3384

650
1770
3024
4704
6768

1025
2^55
4536
7056
10152

1300
35,0
6048
9408
13536

1675

4425

7556

11760

16920

NOTK. Tlu'si- values are calculated for a safe working tensile stress of 12,000 lbs. per sq. in. If
any other stress is used they must be altered proi)ortionately.

Making the value of 5 „, for the portion of the shearing force diagram at the
apex = ^,s^ »t will be seen from Fig. 7 that the length from the centre of the span to

the second set of stirrups = /« = 2. S„,—^ = S„,

AB reaction at support.

Lay off this distance Z, = CD from the centre of the span (Q and erect a perpen-
dicular cutting the beam this will give the position of the second set of stirrups from
the centre of the span.

Now describe a semi-circle on AC.

From C as centre with CD as radius describe an arc cutting the semi-circle at E^
draw E^E vertical cutting AC at E.

Set off along CA distances EF FG -GH ■ HJ • etc., all equal to CE and draw
verticals FF, GG, HH, JJ , etc., cutting the semi-circle at F, G, H, J , etc.

With C as centre and CF, CG, CH, CJ , etc., as radii draw arcs cutting CA at G„
Hn L, J„ etc., verticals from F„ G„ H„ J,„ etc., will divide the triangle ABC into areas
all equal to CDK, and these verticals produced through the beam are the positions
where sets of stirrups are to be placed.

If the resistance of the concrete is to be taken into consideration we must find this
resistance and set up a vertical ordinate equal to its values on the diagram of shearing
forces, and omit all the sets of stirrups between this ordinate and the point of no
shear on the beam except the set nearest the ordinate.

In the case taken for the example {Fig. 7) the span of the beam was 16 ft., the
uniformly distributed load 4,000 lb. per foot run, the width of the beam 10 in., and
the effective depth 24 in. The reinforcement was stressed at 16,000 lb. per sq. in.,
and the maximum stress on the concrete was 600 lb. per sq. in. The value of the lever
arm was therefore 24 x o-88, and the resistance of the concrete of the beam to diagonal
tension was therefore 60 x 10 x (24 x o'88)=: 12,672 lb.

Consequently the sets of stirrups on the verticals from D and F ^^ would be omitted
if the resistance of the concrete was taken into account.

The following example shows a method which may be adopted in calculating the
resistance to diagonal tension in more complicated cases, and when inclined bars are
used as well as stirrups.

Example. — A T-beam span 18 ft. loaded with 16,450 lb. from a column at the
centre of the span, and also two loads 6 ft. from either support of 12,730 lb. from
secondary beams. Thickness of slab 4 in. Beams continuing over several supports.
Assume depth of rib to be 20 in. and width 18 in., weight = 200 lb. per lin. ft.

c 2

REINFORCEMENT IN BEAMS.

iCDN CBETEl

B = 1,207,236 in. lbs. approximately

width of flange acting with T-beam= 15 x 4 = 60 in. ^ = 21,120 giving d = 17 and

^, = 6-72 sq. ins., or. say, 3-li: in. rods in top layer and 3-li in. rods bottom layer.
The depth of the rib will be 17 in., weighing 180 lbs.

The reactions at the supports are

16,450+25,460 + 3,640

= 22,575 lbs., and the

shearing f:ue diagram will he <is shown in Fig. 8. As the shearing force diagram is
the same on both sid<-s of th<- c<nlre of the si)an we need only use th<> l(Tt half.

In Fig. 8 draw the half-elevation of the Ix'am to any scale and plot the shearing
force diagram to scale below the horizontal line intTK .iting the bottom of tlu' Ix'am.

A sufficiently accurate approximation for the lever arm for a T-beam is (i = d- ^'

and therefore in this case a = \7 — 2'" ^^ '^^
312

REINFORCEMHNT IN BEAMS.

'carjn<^ resistec/ Iry Oent-
ars sAoK/n thus ■' —

ecr/^/na res/ste(/ /;y

FiQ 8.

313

REINFORCEMENT IN BEAMS. [CDNQgETE]

If we bend up a bar of the tensile reinforcement 15 in, from the support, and others
30 in., 45 in., 60 in., and 75 in. from the support.

The bending moment at "/^ in. from the support will be approximately

5(22,575 X 75 -180X6-25 X 37-5 -12.730 X 3)- |{ 1,693,125 -(42,187 + 38,190) }

= 1,075,165 in. lbs.,

and assuming the lever arm as 15 in. the sectional area of the tensile reinforcement

required will be

, 1,075,165 ...„

At= -=4 48 sq. m.

16,000X15 ^

The bending moment at 60 in. from the support will be approximately
1(22,575 X 60 - 180 X 5 X 30) = (1,354,500 -27,000)§ = 1,327,500 X i = 885,000

and assuming the lever arm as 15 in. the sectional area of tensile reinforcement required

will be

. 885,000 ^.^„^

At= — 3 686 sq. m.

16,000X15

The bending moment at ^^ in. from the support will be approximately

1(22,575 X45-180X375X22*5) = |(1,015, 875-15, 187) = 1,000,688 Xf = 666, 125 in. lbs.

, , 666,125 ^.„^.

and At= = 2 775 sq. m.

16,000X15 ^

The bending moment at 50 in. from the support will be approximately

§(22,575 X 30- 180 X 2-5 X 15) = ^677,250-6,750) = §(670,500) 447,000 i.i. lbs.

, , 447,000 ..p^

and At= = 7^2 sq. m.

16,000X15 ^

The bending moment at 75 in. from the support will be approximately

§(22,575 X 15-180X1-25 x 0-625) = §(336,938) = 224,625 in. lbs.

, , 224,625 ^.^.^

and At — = 933 sq. m.

16,000X15 ^

If we bend up i — ig-in. rod at 75 in. from the support, i — ig at 60 in., i — ig at
45 in., i^ — I J at 30 in., and i — 15 at 15 in. from the support we have

5*665 sq. in. tensile reinforcement at 75 in. from the support, one outer ig-in.

rod being bent up.
4*667 sq. in. at 60 in. from the support, the central ig-in. rod being bent up.
3*669 sq. in. at 45 in. from the support, the other outer ig-in. rod being bent up.
2*442 sq. in. at 30 in. from the support, one outer i^-in. rod being bent up.
1*215 sq. in. at 15 in. from the support, the other outer 15-in. rod being bent up.
These areas will give ample resistance in all cases. The rods will be bent up at
angles of 45°, special care being taken to form tJic bends with flat curves, in order that
the compression on the concrete at the bends may be reduced as 7}}ucJi as possible. The
radius of curvature for the bottom bends and top bends, if the bars are to be cotitinued
near the surface of the beams, should be about twelve times the diameter of tJie bar.

The sectional area of i ly-in. rod is ()'994 sq. in. and that of i- i:l-in. rod is
1*227 ^Q- ^"•

And as the distance ai)art of the b<nt-uj) rods has been mad<' equal to the lever arm
we have from equation (2) the shearing force resisted by <'ach of the la-in. rods

<S„, = 1-41 4X12,000X0-994 = 16,866 lbs.
and the shearing forces resisted by each of the i:J^-in. rods

S„, = 1*414 X 1 2,000 X 1*227 = 20,720 lbs.

[^^NE ^'iK?^^J /^/i/NFO/^C/iA/yiAfr IN BHAMS.

Now draw :\ luirizont.il litK on the sho.nin^ forot' di.'ij:jram .it a dislancc below the
bottiMii of the beam of -.m),7jo lb. to ibc scaU- of loads and for a distance of 2^ ft. from
tbi' support, and anotlu r borizontai line at a diNlanrc of ir),S6b lb. to the scale of loads
from 2I fl. to <>.', fl. fioni ibe siipixut. Tbe area of lb<' siuarinj^ force diaj^rani enclosed
by tlw'se lines indiial<s ibe slK'ar r<-sist»d b\ tbe bent-up bars, and the j)(M-tion not
enclosed indicates tbe slu ar reniaininj^ and which must be resisted by further rein-
forc<'ments. These portions of the shear will Ix' taken by vertical stirrups, and as
diai^onal tension i rinforcements must be placed throuf^hout the entire sjjan at no greater
distance apart than tbe len<;th of the lever arm, the sj)acinj4 of the stirrups must not
cxceeil this Uiii^th on lh<' portion l)etwe<'n the section b] ft. from the support and the
centr<' of the si)an.

Now if we use -A-in. diameter bars for the stirrups, each stirru]) having two
branch<>s, from Table 1., and with a value of 0=15 wc g<'t

lor two branches <r^,i =^ 1,836 X 15 =27,540 lbs.
,, four „ rr^,^ = 3,672x 15 = 55,080 „

„ six „ rr^.si = 5.508 X 15 = 82,620 „

The mean shearing force on the remaining portion of the shearing force diagram
for a distance of 2^ ft. from the support as scaled is 1,600 lb., and the area of this
portion of the diagram is therefore 1,600x30 = 48,000 lb.

\V<' must therefore insert two stirrups at a distance of 2^ ft, from the support.

By trial and error we find that portion of the diagram between 2^ ft. and 3 ft. 10 in.
from the suj)port =81,760 lb.

Three stirrups will therefore be placed 3 ft. 10 in. from the support. Similarly the
area of the portion of the diagram between 3 ft. 10 in. and 5 ft. 3 in. from the sup-
port =8 1,940 lb.

Three stirrups will therefore be placed 5 ft. 3 in. from the supports.

The central ordinate. of the remaining portion of the diagram up to the load of
12,730 lb. at 6 ft. from the supports is 4,630. The area therefore is 4,630x9 = 41,670 lb.

The remaining shear to be resisted "by the three stirrups will be 82,080 — 41,670 =
40,410 lb.

The shear between 6 ft. from the supports and the section 65 ft. from the support
where the first bar is bent up is resisted by the bent-up bar, therefore an area of the
shearing force diagram of 40,410 is required between a section 65 ft. from the support
and the centre of the span.

The area of the portion between 6\ ft. and 6 ft. 7^ in. from the support is 38,8801b

Three stirrups will therefore be placed 6 ft. 7^ in. from the support.

The area of the portion of the diagram between 6 ft. 7^ in. and 7 ft. 5 in. from the
support = 8i,5io lb.

Three stirrups will be placed 7 ft. 5 in. from the support.

The area of the portion of the diagram between 7 ft. 5 in. and 8 ft. 2^ in. from the
support = 80,085 lb.

Three stirrups will be placed 8 ft. 2^ in. from the support.

A further three stirrups will be placed at the centre of the span.

315

REINFORCED CONCRETE VIADUCT.

toNCRETEl

REINFORCED CONCRETE

VIADUCT, MARTIN'S

CREEK, U.S.A.

The following particulars and illustrations of this 'viaduct noio nearing completion
ha've been taken from the ** Engineering Record,"— ED,

Xext to the 7\inkh:inn()ck viaduct the Martni's Creek viaduct is the most im-
portant structure in the 40-mile relocation of the main line tracks of the Dela-
ware, Lackawanna and Western Railroad between Clark Summit and Halstead,
Pa. It is built entirely of concrete, with long- and lofty spans on deep
foundations, carried to solid rock through beds of clay and boulders.

General Description. — The viaduct is a three-tack structure, 1,611 ft. 8 in.
long and 150 ft. high above the creek. It will be 48 ft. 4 in. wide over all at
the arch rings, and will have two full-centred spans of 50 ft., two of too ft., and
seven three-centred spans of 150 ft., with a rise of 59 ft.

Kach span will have two arch ribs 12 ft. apart in the clear. For the 150-ft.
spans these ribs will have a width of 17 J ft. and a thickness at the crown of
6 ft. and will each contain 1,000 vds. of i : 3 : 5 concrete. They will carry solid
transverse spandrel walls 12J ft. apart supporting floor arches and parapet walls.
The west end span is made of two-arch ring segments of loo-ft. span, forming
an abutment. The concrete floor system is carried to the centre or crown of
the abutment arch, with the adjacent fill extending to the end of the floor;
the toe of the slope extends to the centre of the westerly 150-ft. span, the
lOo-ft. arch being entirely covered by the embankment. The east half of the
westerly loo-ft. span carrying the bridge floor is enclosed on both sides, with
spandrel walls reaching to the surface of the slope and giving the appearance
of a solid masonry abutment. At thi- land vnd of this span the tracks are laid
on tlu; f)]].

The c(jmpleted slrucluie will (^ontain about 84,000 yds. of concrete and
w ill involve about 25,000 yds. of foundation excavation.

Delivery of Materials. — Work was commenced in June, 191 2, and a side
track for material was connec^led with the main line. An additional track was
also l>ui]l parallel lo the side liick, j)arlly supported on a wooden trestle, to
provide lor receiving, unloading, and storing cars. I^'rom 400 to 500 cars of
material are received mc^nthly, and about 8,000 yds. of broken stone, 4,000 yds.
of sand, and 4,000 barrels of ci-ment are kept in storage. Sand and stone are
dumped into lu-aps on llie sid'-iiill and are llience delivered by a Mead-Morrison
chimshell bucket lo storage liopjx-rs at the concri'te-mixing j)l;inl. At the
mixing plan! a 2-yd. Carlin ci!l)i("d mixer is mounted about 10 ft. above the

316

[f\ t N( il N M W 1 N< t ^ — ^J

REINFORCED CONCRETE VIADUCT.

'>''*"l^- l"i»>in 11 ((Miciclc is (iiscli.'ii^cd Inlo l)U(I«'l.s .-md delivered over the
service Uacks to tlic work.

REINFORCED CONCRETE VIADUCT. ICQNCBETEl

Concrete is distributed to the pier sites by a 3-ft. gauge surface track which
runs the full length of the viaduct and serves the power plant, shops and storage
vards. There are in all eight switches, all of which are visible at a central
point, where they are operated from an interlocking stand by one man, thus
effecting a considerable saving of time and increasing the safety.

Sawniill. — An important part of the plant is the sawmill, equipped with
a ripsaw, handsaw, cut-oft' saw, planing mill, and moulding machine, all
operated by one 25-h.p. and one 15-h.p, engine. Besides cutting and planing
timber and doing miscellaneous work, the sawmill is of great importance in
sawing the heavy timber into boards. For this contract a large amount of
i2-in. by 12-in. yellow-pine timber was ordered, and most of it was first used
for the construction of towers, trestles, and for the heavy bracing in the deep
foundation pits. As fast as released the timber is sawed up into smaller sizes
and boards and is planed for use in the construction of concrete forms.

Pier Foundations. — About 30,000 yds. of earth were excavated at and near
the pier site by a Marion steam shovel, which made a cut with an average
depth of about 20 ft. parallel to the axis of the viaduct. The spoil was used
to form embankments for the service tracks and to make a fill, on which the
machine shop and concrete plants were located. The soil consists chiefly of
compact water-bearing sand containing many small boulders and considerable
gravel, and overlies hard blue flagstone at a depth of from 18 to 70 ft. below
the surface.

The pier foundations were excavated to sound rock in open cofferdams
made by driving one or two tiers of steel sheet piling with a No. 2 Vulcan
steam hammer operated in 40-ft. leads suspended from a derrick boom. Where
two tiers of sheeting were required the inner tier was driven first and the
outer tier was driven afterward at a 5-ft. distance in order to allow clearance
for excavating the earth between them.

Siiceting, Draining and Concreting. — About $10,000 worth of steel
sheeting was required for the work, and some of it has been pulled and
redriven four or five times, and endures the service so well that about 80 per
cent, of it will eventually be salvaged. The sheeting was driven with care,
and when a pile encountered serious obstruction by a boulder, driving on it was
suspended and adjacent piles were driven down beyond the boulder and excava-
tion made to undermine and move the boulder, or in some cases it was blasted
and removed so that the piles could be driven without further trouble. By this
scheme the sheeting was put down with very little battering.

Although water was encountered, no difficulty was experienced In keeping
the foundations dry by the use of 6 and 8-in. centrlfug-al pumps. Most of the
excavati(jn was done by a li-yd. Williams l)U(kel suspended from a derrick
boom. The sheet piles were covered uitli tar paper to prevent adhesion of
concrete, anrl the cofferdams were filled nearly lo the surface of the ground with
concrete deposited against the ste<.:l sheeting without ihe use of forms. After
the concrete had set \hv. shut piles were pulled in sets of one, two or three by
an eight-part tackle suspended from an A-frame and by a whip line led direct
from the derrick bfX)m to the hc/lsllng- engine.

Pier Construction. — Above the surrae<' of the ground the pier concrete was

318

REINFORCED CONCRETE VIADUCT.

ilh

„,,,,., ,„ „,„„,.„ for.ns ,ra<l. of brgo ,m.h1s ,7 L- '. -- h,«h, Iuum, w, n
';.„., ,,.„,. \n-,- fou, ,-!.. .o.„-s<.s ..f .-..n.-,-,.,.. lK,.l l..-n .l.-pos,,.! ,n ,hc
': , n.l U». l.M >n,„... l,..l M-l scv,.K,l .Inys, .1,,. p.n.ls w.-r.. .„s,„m„,.. ,-d.

were hoisted i6 ft. by the derrick and reassembled in position for concreting
above, and so on. Concrete was distributed to the piers in three-car trains,
each taking two full buckets, with room to receive a third empty bucket.

Pier concrete was laid during the coldest winter weather, care being taken

3^9

REINFORCED CONCRETE VIADUCT. [CQNCBETE]

to heat the water and the piles of sand and stone and to keep the forms warmed
l)y steampipes under protecting tarpauHns. The maximum amount of concrete
deposited in one month was 8,500 yds., working- one ten-hour shift daily.
About 6,000 yds. of this concrete were deposited in forms ; the average haul
Avas 800 ft.

The concrete for each pier was handled by a g-uyed-derrick with a boom
from 80 to go ft. long- operated by a Mead-Morrison three-drum hoisting engine,
of which sixteen arc installed on the work, one for each derrick on the viaduct
and three at the concrete plant. The derricks were at first set up on the surface
of the ground or on timber towers at the pier site, and after the completion of
the piers up to the top of the extensioins for the arch ribs the derricks placed a
g-inpole on top of the pier and the latter lifted first the derrick masts and then
the derrick boom to new position on top of the pier. The derrick then removed
the ginpole and was ifl readiness to erect the steel truss centres for the concrete
arches and to lay concrete upon them.

Arch Construction. — The i5o-ft.-span arch ribs are built on steel truss
centres. The smaller spans have wooden centres. Four steel centres, each
having- five ribs or trusses, have been provided and erected on the piers in
readiness for the construction of one rib of each of four consecutive spans.
After these ribs are completed and the concrete sufficiently set the centres will
be struck and the sets of trusses will be moved as units 29^ ft. transverse to the
axis of the bridg-e into the centre line of the other ribs which will be built on
them, after which the centres will ag-ain be struck, the trusses they temporarily
supported from the finished ribs separated into four pieces each, lowered to the
g-round by tackles suspended in the clearance between ribs, transferred to
adjacent spans, re-erected, and so on until the spans are all completed.

After the concrete has set thirty days the centres are struck by means of
the adjustable members in the crown panels of the trusses. Part of the concrete
for the arch ring-s will be handled by the pier derricks. As these cannot reach
U) complete the spandrel walls and floor arches in the centres of the spans, it
is probable that they will be supplemented by a cableway. Both ribs of each
loo-ft. span are simultaneously concreted on centreing formed of timber trusses,
with horizontal bottom chords supported on the umbrella projections from the
piers and on a pair of eight-post framed centre towers.

Steel Arch Truss Centres. — The trusses, which weigh about 28 tons each,
are erected four pieces each by the derricks on the piers. The end pieces are
pin-conne(Med to the steel g-rillages on the pier copings 11 ft. below the springing
line, and are held in position by anchorage boils passing through the tops of
the concrete umbrella se{ni()ns and })y anchor bolts at the foot of trusses. They
are self-sustaining until the (^rown sections are in turn hoisted by the derricks
and bolted to them and ihe centre pins driven, niaking them self-suppt)rting.
\n each set there are five trusses spaced 3 ft. () in. apart and braced together
with sway frames and lop-and-boltoin lateral X-bracing with bolted c-onnections.

The trusses arc coven^d with lagging, ol which the upjjer surface is dressed
smooth and grea.sed. Bulkheads are built on the sides and j)arallel to the axis
of the arch to divide the ring into sections corresponding to voussoirs. These
are concreted in pairs synnnetrically j)laced on ()j)i)()site sides of the centre, the

3:0

r,.coNMmK-..oNAi. ] RHINFORCHD CONCRETE VIADUCT.

ffv^N^■lN^-^ yiNii — |

w,.ik l.cin- tlunc in the m(|Iuiuc indicated by the niini<r;ds on the aee()nii)anyin^

tlia-iam, so as to maintain hahnv vd loachn-s on llie centreing-. After adjacenl

voussoirs are cast, the bulkheads between them are removed and the narrow
portions of arch ring- between them are concreted, forming keys which lock,
them together.

321

REINFORCED CONCRETE VIADUCT. [CONCCETEl

The desig-n and construction of the viaduct are under the direction of the
engineering- department of the Delaware, Lackawanna and Western Railroad
Company, of which Mr. G. J. Ray is chief engineer, Mr. F. L. Wheaton
engineer of construction for the Martin's Creek cut-oit line, Mr. A. B. Cohen
concrete engineer, and Mr, Walter Lozier resident engineer in charge of the
viaduct. The contract for the viaduct was awarded to the F. M. Talbot
Company, of New '^'ork City.

3Z2

J CONMPIK'IION'AI
V l.NdlM-liflNt. ^

ELECrROI.VSIS IN CONOR llTh.

ELECTROLYSIS IN
CONCRETE.

Report by E. B. ROSA. BURTON
McCOLLUM and O. S. PETEKS.
ol the U.S. Bureau of Standards

The question of Electrolysis in Concrete continually gi^ves rise to discussion, dnj
therefore the folloivinci short resume of some experiments recently carried out by the
U.S. Bureau of Standards may not be ivithout interest.— HD.

l^RKVious work on ih^ danger lo reinforced concrete structures due to elect r<jly sis
l)y stray electric currents has given somewhat contradictory resuUs as regards
llie extent and nature of the possible damage. The question has now been
re-investigated by the Bureau of Standards, and the principal results may be
summarised here.

The experiments were made with cylinders of i : 2| : 4 concrete, 6 inches
in diameter and 8 inches long. The specimens were kept in wet sand for 20
days before use. One electrode was an iron rod, embedded along the axis of
the cylinder; the other was a sheet-iron cylinder, placed in a vessel of water
surrounding the test specimen. The central rod could be made anode or cathode
at will, and the external electro-motive force could be varied within wide limits.

With a high initial potential difference, such as 57 volts, the central rod
being the anode, there was at first a rapid rise of temperature, followed by a
fall, due to an increase of the electrical resistance. The concrete was soon
cracked, and then broke into several pieces. The damage was due entirely to
rusting of the reinforcing rod, causing expansion. There was no disintegration
of the concrete itself, as each broken piece was found to have its original
strength.

With potential differences of 15 volts or less, cracking did not occur, and
with concrete made from normal Portland cements there was practically no
injury, although the total number of ampere hours passed through the specimens
was actually larger than in the high voltage experiments. It therefore appears
that damage due to oxidation at the anode is not likely to occur unless the
leakage of current is abnormally high, and this danger is not a serious one. The
coating of the reinforcement with copper or aluminium has been proposed, but
is of no value, as both of these metals disintegrate readily in contact with
concrete when a current is passed. The bursting pressure exerted by the iron
in rusting was measured, and was found to be as high as 4,700 lb. per square
inch. Even with high potential differences, corrosion was not found to take
place when the temperature was kept low by artificial cooling. The addition of
salt to the concrete increased the corrosion very greatly, owing to the increase
of conductivity and to the destruction of the passivity of the iron.

Contrary to previous obser^■ations, the concrete was observed to soften
considerably in the neighbourhood of the reinforcing rod when the latter was

323

ELECTROLYSIS /.V CONCRETE. {OCJNCKCTEJ

„K,de the cathode. The softening action began at the metal suriace attd sptead
outwards. The softened material regained its hardness on exposure to
but remained brittle and friable. This action proved to be of greater pracucal
i, ;-tance than the corrosion at the a.tode, as it was foun to <;--■ y^ -
well as with high voltages, the action being roughly P^P-''^-^ '"^f^^^Jf ^^^^^^
of potential. The effect has been traced to the presence of alkah salts in tne
concr «. These salts undergo electrolysis, resulting in the formation of ulkaU
hvdroxide near to the cathode metal. At a short distance rom the cathode no
injurv' to the concrete could be observed. Any increase of alkah salts accelerated

'"^ oZ ;:L:ti::a-consequence of this series of experiments is that the sug-
gestion which has been made to protect reinforced concrete buildmgs by apply-
fng an external electro-motive force, making the reinforcement the cathode,
is worse than useless, as this would result in an acceleration of tne d.s.ntegratmg

action

Waterproofing agents were not found to have any marked effect in checktng
electrolvsis It appeared likely, but was not proved, that external waterproof
coatings would be more effective than waterproofing agents used m Ae m'>^"-8:
of the concrete. Painting the reinforcement was of no advantage, and had the
defect of lessening the bond between metal and concrete.

I precautions in actual practice, the authors make the foUown^g recont-
mendations :--All direct current circuits within a reinforced concrete btuldmg
should be kept free from earths, and tests should be made front t,me to tm
with earth detectors. Lead-covered cables should also ^e >-" a'ed The

jreneral earthing of metallic conduits is not to be recommended, and although
ft is advisable to connect all the metal work of a building together as far as
practicable, the connected metal should not be earthed. .

The report contains a large number of quant.talive delerm.nat.ons of
resistance, etc., under various conditions.

3*4

\», CTONMPUrnONA 1 1

REINFORCED CONCRETE v. CAST IRON.

REINFORCED CONCRETE

versus CAST IRON FOR

LIGHTHOUSE CONSTRUCTION.

By C. WESEMANN, Civil Engineer.

From exjimples pre'viously given in our journal, it has been found thai reinforced
concrete can be used advantageously for lighthouse construction, and although' there may be
indi'Vidual instances ivhere a different method is vreferable for one reason or another,
it ivould appear that great economy can be effected by the use of reinforced concrete.— ED.

An adequate comparison between two different forms of construction for light-
houses is almost imjx^ssible, owing to the varying- conditions and kjcal circum-
stances which attend this particular class of building.

Some interesting facts may, however, be ascertained by comparing the
construction of a Dutch lighthouse erected some time ago in reinforced concrete
and some newly built German lighthouses in cast iron. As regards site, size,
transport of materials and available labour, the conditions in both cases were
somewhat similar.

The question naturally arises as to how reinforced concrete compares with
other systems of construction adopted hitherto for lighthouses, when it is a
question only of light structures, as against so-called " heavy-weight " struc-
tures, exposed to the force of the sea waves.

It is proposed, in the first instance, to give some data regarding the general
dimensions and constructional particulars of the Dutch lighthouse — a reinforced
concrete structure — which was erected on the island of Goerree-Flakkee, near
the village of Ouddorp, in Holland. (See Fig. i.)

The building is situated on the top of one of those dunes so typical of
the Dutch coast line. Owing to the peculiar nature of the dune sand, a rela-
tively shallow foundation is permissible, providing always that the necessary
precautions are taken to prevent the sand from being scooped out from below
the foundation slab.

The height of the building, measuring from the top of dune to the platform,
is 141 ft. The form of construction adopted is that of a cavity wall. The width
of the outer shell at the base of the superstructure is 25 ft. ; the corresponding
width at the top is 12 ft. 6 in. The outline of the inverted cooe is battered
approximately i in 20.

The cross section of the concentric outer and inner walls is octagonal in
shape. The two walls are interlaced and tied together at each floor level by
means of girders arranged wheel shape on plan so as to form a monolithic
structure.

The outer wall is strengthened at the corners of the octagon by means of
eight buttresses; this wall extends to the full height of the tower, and this is

" 325

C. WESEMANN.

[CQNCBETFJ

FifJ. 1. Section.
Rkinforckd Concrktk Lighthouse.

I'i(4. 2. Sectional Elevation.
LioHTHOusK or Cast Iron.

326

J, CTONM PMCriCINAl-i
«V F-NdlNhl PlNti^ — ^.|

RIiINFORCED CONCRHTE v. CAST IRON.

br.icvd 1)\ hoi i/.)iil.il i^irdcrs r\Un(lini4 round \hv oclii^on. 'llii- inner wall

whilst loiinini^ pari of ihc consl rud ion also serves as the slaii-casc well.

Allhoiij^h ihis arranL;enicnl intrrfcres somewhat with ihe size of the rooms, ete.,
it is not parlicularlv d<-t limental in this ease, as the areommodation re(|uired

loi' maehinei'}' ecjuip-
menl , slorag'e, a n d
dwelling purposes is
very simple. The light-
house in this inslancx*
merely serves as a
heaeon, and the lighl-
house-keepers li\'e in
adjacent dwelling-
houses.

The writer is of
opinion that, in plan-
n i n g and designing
future lighthouses in
reinforced concrete, the
inner wall might be dis-
pensed with and the
material thus saved
could be employed in
strengthening the outer
w all. A mezzanine
tloor might be con-
structed between two
floors so as to reduce
the height of the stories.
The stairs could
easily wind along the
internal surface of the
wall and be separated
from the remainder of
the building by a par-
tition wall. A light-
house constructed on
these lines would be
very similar to the one
in cast iron illustrated
in Fig. 5.

The cast-iron light-
house illustrated in Fig. 5 is situated on a clayey " flat " outside the sea
dvke, on ground which is rather soft and wet, and is covered with water by
high spring tides. Before the actual building operations were proceeded
with, a platform of solid clay was made in the form of a sea dyke. This
platform carries the tower and two adjacent dwelling-houses for the lighthouse-
keepers. 327
n 2

IS. 3

View showing Reinforced Concrete Lighthouse in course of construction
Lighthouse at Goerree-Flakkee.

C. WESEMAXN. KONCCET Ei

The building- rests on hig-h wooden piling, which was carried down to the
bearing stratum. The height of the lighthouse is 112 ft. The width of the
superstructure at the base is 25 ft. 4 in. and at the top 3 ft. 10 in. The outline
is battered approximately i in 15.

The wall of the superstructure consists of cast-iron plates with horizontal
and vertically planed flanges, bolted together in sections. The wheel-shaped
girder grillage of steel rests loose on a special bearing flange around the inside
circumference of the wall. The groove between the wall and the outer girdle
of the iron grating is filled in with asphalt in order to allow of partial movement
and to ensure a plastic joint. A special staircase well has been arranged along
the inside wall of the inverted cone.

The internal surface of the cast-iron wall has been lined by a plaster
insulating wall with an air space between.

The mean thickness of the cast iron is 22, mm. — viz., 26 mm. at base and
20 mm. at the top. A reinforced-concrete superstructure having the same
average strength would measure about the same in centimetres.

The proportional quantities of the two respective building materials are
1:10, and the proportional weights (on the basis of the specific weights '/'2 and
2'i) are, approximately, i : 3.

The lighter weight of the superstructure naturally admits of a lighter
foundation, but the proportion is smaller than 1:3, as the massive and heavy
substructure of the ground floor is common to both forms of construction.

In comparing- the two methods of buildingf, the following- are perhaps the
most important points to bear in mind :

Where a site is a difficult one, a minimum amount of building material and
lighter foundations may be a consideration.

Then, again, reinforced concrete requires a somewhat complicated and
diflicult scaffolding, which, when exposed to the rough sea weather, is very
liable to damage. The cast-iron structure is easily put together by means of a
simple hoisting plant without running much risk from weather conditions;
and, also, the main portioin of the w<jrk is carried out in the workshop. There
are also instances where the lighter cast-iron structure might be preferable
from the statical point of \iew, as, for instance, in earthquake districts.

In the example here under review, however, reinforced concrete has cer-
tainly j)rov<-(i to be the superior form of construction as reg'ards cost imd
maintenance charges.

The cost of erecting the Dulch lighthouse in reinforced concrete, exclusive
of equipm(*n1, was ;^.3,55,o. 'Jhis sauK; building would have cost ;£!!"5,500 if
constructed in cast iron, in a(X'ordan(x* with Figs. 2, 4 and 5. This shows a
clear saving of one-third.

These figures only a])pl\- 1f> this individual instant^e, but the question of
cost is, of cc;urse, an import anl laclor. In other cases the above saving might
work out somewhat higher, or, in some cases, less, according to local
conditions.

Figs. 2 and 4 sho\^ an insIaiKc where cast iron was used in preference to
reinforced concrete. I lie HljIiI Ih'Um sl.inds on a saindy " flat " in the middle of
the Jade estuary near the naval station of \\'ilhelmsha\'en. The site is

328

REINFORCED CONCRETE v. CAST IRON.

Blmplitie

Caisson.

Fig. 4. Section.

Lighthouse at Wilhelmshaven.

329

C. WESBMANN.

icqncbetf:

moderately exposed, and becomes dry during three hours at every ordinary tide,
the rise and fall of which is ii ft. 6 in. The tower height from sea level
(ordinar)- high water) to the main focal plane is 30 m., or 98^ ft.

'ihe ffnindation consists of a circular caisson, which has been provided with
a permanent uaterliglil hoi torn in iciiilorccd concrete. The caisson was fitted
up and construct(;d uilli its reinforced concrete l)ottom in a dry do<-k on a plat-
f<^)rm whicli had Ix-en specially prepared to ensure an absolutely le\cl bottom

330

tVtlNCilNh-WlNtt —

REINFORCHD CONCRETE v. CAST IRON.

{acv. Vhv caisson \\:is thru lln;itt(l into position and sunk down U|)i)n the piling,
llu- tt)i)s of tlic wooden lilies wrrc splurically sliapt-d, so as to admit of llic
caisson rcstinj^ upon an al)solutcly li\i'l base. 'Ilic suhst ru( 1 urc was tlun huilt
up in inasoin\, in tlic dr\ , and faced with Dulcli c'linkcrs. Hrusli mattress work
lias been jjhiced around llic fountkition as a ])r()t<-cti()n aj^ainst scouring'.

VUv lii^btliousc is litted witli a doubk- set of \2 li.p. Diisel engines, electric
Ikish lii^hts and central
heatinj;-. Vhv usual ac-
ct)mm()dation for dwelling
purposes and storage of
fuel, cooliui^ water (fresh
water), coal, provisions,
etc., has been provided lor.

The cost of this light-
house, complete, including
designs, and supervision of
the building, amounted to
;£,'9,ooo ; ;£^3,ooo of this was
devoted to machinery and
other equipment.

Fig. 6 shows the
machinery equipment of the
two lighthouses.

A few words should be
added regarding the archi-
tectural aspects of the case.

In this article, light-
houses have been dealt with
which were constructed in
the shape of an inverted
cone and with a straight
outline, somew'hat resem-
bling a chimney of wide
circumference.

If the contour line
were arched inwards, with
breaking points in the level
of the floors, the building would present a better and more pleasing appearance.

The author is indebted for the drawing of illustration {Fig. i) to the Dutch
engineers in charge of the supervision of the building, whilst the remaining
photographs shown and the details as to prices, etc., are taken from the writer's
own personal experience.

Fie;. 6. Interior View.
Machinery Equipment.

331

REINFORCED CONCRETE BUILDING IN BRAZIL. [CQNCKETEJ
O _ O O

if|iTrftri

~ illi i i i

i fiff

^|!

REINFORCED

CONCRETE

BUILDING AT

PARA, BRAZIL.

Reinforced concrete is
being used to a great extent
on the neiv structures in
course of erection in South
America. This form of
construction is admirably
suited to the conditions
pre'vailing in that country,
and ive gi%>e beloiv an ex-
ample of a large building
erected there recently. -ED,

The building illustrated by tlie accompanying- photographs and plans has
recently been completed by the Para Construction Company, Ltd., for the
Administration Offices of the Port of Para.

View of Iiit<;riial t oiirt,

Ki:INI ORCKI) CtjNCKKTE Bl ILDING AT PARA, BRAZIL.

The entire work, excepting the walls, was constructed on the Coignet
system of rein forced^ concrete.

The office accommofhilion is disposed around an internal court and the
principal over-all dimensions of the building are 134 ft. long by 81 ft. wide.

332

k'Sri'ihiiiK'^^l Rf'^^^t^(^F^CED CONCRETE BUILDING IN BRAZIL.

A-m

y °

fc n

(fl

( 1

CI.

333

REINFORCED CONCRETE BUILDING IN BRAZIL. [CONCRETE

The heig-ht is 52 ft. to
the top of the flat
roof, and from the
foundation to the top
of the domes is ap-
proximately 70 ft.
The internal court
measures 86 ft. long-
by 34 ft. wide.

The building- was

erected on reinforced

concrete piles of about

14 in. diameter, and

30 ft. long, and

arranged in groups of

two, three and four

connected together by

N means of reinforced

m concrete caps and

2 beams. The piles

o Oh were made on the site

•2 < and were driven

§ 5 through sand and mud

•| ^ to hard ground by

< „ means of a steam pile-

.2 g driver.

^ I As shown in the

§ Q accompanying

building-

plans,

is coni-

a ground

^ ^ the

^ posed of

^ floor, first and second
floors and a flat roof,
and cantilevered bal-
conies 7 ft. wide are
carried around the in-
ternal court to give
access to all the
rooms. The total
area of floors, flat
roof and balconies
amounts to a 1) o u t
38,000 sq. ft.

T li V reinforce-
ment for the pillars,
beams, floors, and other
parts of the reinforced
concrete construction
w a s c o m |) o s ed

334

y,cr>NMm)c-iioNAi l RBINFORCFiD CONCRETE BUILDING IN BRAZIL.

of round slrcl hais. I lu'sc l)ars, tlu' ((imnt, tin- ^lanitc tliips, aiul a certain
ainoiint ol liinlxr wcic tlu' onK malt rials uliuli liad to he sent lr')p.i luij^land
lor llu' crt'it ion ol tlu- work.

As shown in ihc accoinpanx inj; plans, \hv ]iillars were (■omj)os< (1 of a <( rlain
nuinhiT ol lonj^itudinai i)ars of small diamcliT hound lo^cliuT hy means of
a si)iral wire. 1 lu' l)eams were formed l)y a certain numher of straight l)ars
in tile lowcM" and npjier portions of the heam ("onnected to^'-ether hy means of
wire stirrups, and the slahs were composed hy means of a meshwork ol small
hars.

This is another exam])le of the (M)nsideral)le advantages offered i)\ the use

J
1

View of Entrance Hall and Staircase.
Reinforced Concrete Building at Para, Brazil.

of reinforced concrete for work in the Colonies, or in distant countries where
che labour of bending- the bars and putting- them tog-ether must be done by
natives.

It is interesting- to point out that the steel frames of the columns and beams
in the method here employed are all made in advance on the ground level and
hoisted into position in the moulds ready for the concreting- operation. As all
the bars are rigidly connected and tied together no displacement of any member
is possible whilst the concrete is being- rammed in position, and this of course
simplifies considerably the supervision of the work.

The walls of the building are carried by the reinforced concrete framework,

335

REINFORCED CONCRETE BUILDING IN BRAZIL.

ICa^c HETE l

the framework of each floor supporting- its corresponding load of walls, and the
walls are formed of hollow concrete blocks moulded in advance of the work by
a special machine. The three domes were constructed of timber and covered
with copper.

The building- was erected by iMcssrs. W. Cowlin and Sons, contractors, of
Bristol, entirely by native labour under the supervision of a few Europeans.
The architectural plans were prepared by Mr. E. M. 1\ lusher, architect, of

33^

ItV EN(.lNKKklN(i->-^,

RIiINFORCIiI) CONCRHTE BUILDING IN BRAZIL.

^^^^^ ^ <M ------'^,^^>W^

337

REINFORCED CONCRETE BUILDING IN BRAZIL. [CQNCBETE]

London, and the whole of the work was carried out under the instructions and
control of Mr. J. \V. Kitchin, engineer of the Para Construction Co., while the

■.

detailed plans and uorkiiij^ drawings for the; reinforcx-d concrete work were
designed and j)r(r{)arcd by Messrs. iuhnond Coignet, iJd., of 20, Victoria
Street, Westminster.

33«

FORMS FOR CONCRHTIi WORK.

wnnm

T-TT

RECENT VIEWS ON
CONCRETE AND REIN-
FORCED CONCRETE./,

THE CONCRETE INSTITUTE,

// is our intention to publish the Papers and Discussions presented before Technical
Societies on matters relating to Concrete and Reinforced Concrete in a concise form, and
in such a manner as to be easily a'vailable for reference purposes.

The method toe are adopting, of di'viding the subjects into sections, is, ive believe, a
netu departure, — ED.

THE CONCRETE INSTITUTE.

FORMS FOR CONCRETE WORK.

By ALLAN GRAHAM. A.R.I.B.A., M.C.L

Tlie foUoiving is an Abstract of a Paper read before the Concrete Institute at their

forty-eighth ordinary general meeting. The Paper was illustrated by numerous

lantern slides, and was also accompanied by a large nutnber of interesting plates. A

sJiort report of the discussion which followed is also given.

It has been recently stated, with some truth, that we do not often hear of failures
occurring in reinforced concrete buildings after their completion, but generally during
their erection, and although all failures cannou be attributed to defective forms, yet
the forms are to blame in a sufficient number of cases. Although it is not the
practice, in England at any rate, for engineers to design their forms, an engineer,
for his own protection, should at least set out some typical portion of the forms
for the contractor's guidance, thus doing all he can to circumvent failure in this
direction at any rate. Of course, good forms alone will not ensure safety, and we
have to use vigilance likewise in detecting bad work, bad design, and bad material.

The contention that the engineer should prepare the design of formwork has
much to recommend it. It is not merely that a design is required for a specific case
which will safely support a certain volume of concrete, it is rather the problem of
designing a set of forms which can be erected, taken down, and many times re-used
during the progress of the work.

Timber.

The first important consideration is the timber to be used. \\'hite pine, yellow
pine and spruce are all excellent for the purpose and should be free from knots,
and must not be so dry that they will absorb the water from the concrete and so
swell and bulge as to entirely distort the forms. On the other hand, if the timber
be green it will shrink and cause the same trouble. Varieties with hard surfaces
should be chosen in order that forms may be oftener used before dilapidation.

The timber has to resist the weight or pressure when a considerable height of
wet concrete is being poured, as in walls and columns. Many authorities calculate
this pressure as a liquid of half its own weight — namely, 75 lb. per cu. ft. When the
concrete is placed in layers no calculation is necessary, as it has been found in practice
that for beams the bottom boards should be 2 in. to 2h in. thick, with sides
H in. to 2 in. thick. Column sides should be i^ in. to 2 in. thick. For walls
i^-in. boards are used. Of course the thickness of boards can be varied just as
we place the clamps or braces, but it must not be overdone, nor the material made

339

THE CONCRETE INSTITUTE. [CDNQBETEI

too thin. A more solid board will ensure greater economy, from the fact that the
form can be used over and over again. For slab panels i-in. stuff is generally used,
but i-in. boarding requires staying every 2 ft., li-in. boarding requires staying every
3 ft., 2-in. boarding requires staying every 4 ft. to 5 ft. Studs should be of sufficient
size and spaced so as to prevent the boards between them springing.

They mav be 2 in. by 4 in. to 2 in. by 6 in. if not used beyond 2 ft. to 3 ft.
centres; 3 in. by 8 in. may be spaced about 4 ft. 6 in. centres; 4 in. by 10 in. at from
6 ft. to 8 ft. centres ; 6 in. by 12 in. from 8 ft. to 10 ft. centres ; but the spacing of
the supports must be governed by the nature of the weight coming upon the boards.

Camber.

It is also necessary to give to beams a camber of at least ^ in. in 5 ft. — i.e.,^ljjth
of the span. This generally comes out during the ramming and tamping of the
concrete and in the squeezing of the wedges. After the filling, the beams should be
examined to see if the camber has come out during the process of tamping, so that
it mav again be secured by tightening up the wedges before the concrete has set.

In cases where a great deflection was found in the beams, the failure of the
supports to the studs has been the root cause, probably owing to soft ground. For
that reason a little judgment should be used to see that the sole plates under the
supports are sufficiently large to distribute the load safely over a sufficient area.

Measurements,
It should be carefully noted that the measurements are accurate and that the
inside dimensions shown on the plan are secured, for the examination of several
failures showed that the members were actually carried out to smaller dimensions
than designed.

Alignment.

The forms should be carefully examined to see that they are truly vertical and
horizontal and that the joints are closed so that no part of the mixture can escape.

Cracks.

Any cracks found in the boards can be remedied by filling with plaster of Paris
or clay.

Design.

The forms should be so arranged that the slab forms and sides of beam, girder
and cf)lumn forms can be removed first, allowing the bottom boards of the beams and
girders to be supported for a longer time.

Exposed Concrete.
Extra care should be taken with the forms for all exposed concrete, which should
be made of bevelled-edged stuff. Some use tongued and grooved, but this allows no
opportunity to expand, and the boards cannot be used again. Undressed timber may
be used for hacking, hut it must be watertight.

('lamps and Nails.
Clamps should be used to hold the forms together, as the use of nails and spikes
so destroys the timber as to render it unfit for re-use. The pressure of concrete will
generallv hold panel boards in place with scarcely any nailing. Where nails must be
emjjloved thcv should not be driven home but left so that they may be withdrawn by
means of a claw-ham nK-r.

Rkpaik of {""OKMS.

If forms have been left for a time exposed to the weather they should be gone
over again and [^ropfrly aligned, and any open joints repaired.

Economy.

Form work should Ix- const ru(-tefl with a view to economy in taking down, rather
than in cheapness of erection.

Re-use.

Before re-use the forms should be cleaned again, and the sides and ends should
be freshlv jointed, so as to have a j)erfectly smooth finish to the concrete.

340

J, c^Nyrpm"riaNAi

tVLN(iiNhKWlN<. — .

FORMS FOR CONCRETE WORK.

SriTI \ Ol l'\)K.MS.

I lir luiiulx T t)| scis of Idiihn r(c|iiii cd to Ix-^iii with varies with tlx; kind (jf
huikliiii;, tile weather eoiuHlioiis, aiul tlic sjxcd of eoiislriuiion required.

On an aviMai^e \\ sets of forms is a "fair" allowance. With this number
eicetit)!! on the llooi al)o\c ran hei;in while the concrete below is j^reen. Yet
theii' are man^ iirms who use onl\ one set of forms in a building, my matter wiiether
il he J stori<'s or lo stori<'s hij^h, with of course llu' additional timb<'r for ^irdor bottoms
and supports left in. .\ buildinj^ of larj^e lloor area can be done in sections, setting up,
sa\ , one-h.df of the lloor area at a time, so that the forms for only aJ)out three-fourtlis
(^f one lloor ari' needeil with the extra beam Ixjiioms and posts. It will be self-evident
that in a hit;h buildini.i, small in area, two sets of forms will be needed to ^et on fast
<nou>^h.

Cleaning of For.ms.

.\1I forms should be cleared of all sawdust, dirt, and chips before pouring.
Pockets or traps should be left at the bottom of the forms for this purpose. If one
side of a pillar form is brought up board by board as the concrete is filled in, of course
no door or traj) will be necessary.

Wetting at.l Forms.

All forms, if not coated with some oil, should be thoroughly wetted before the
concrete is poured. Some persons whitewash the forms, but it is not really necessary
if the boards are wrought and properly wetted to close the pores before the concrete
is applied.

Sheet Metal.

Some authorities, in order to give a presentable surface to the concrete, line the
inside of the forms with 20 gauge sheet metal, but however carefully this is done the
nail-heads show. It is also liable to become indented and show an imperfect face on
the concrete.

Striking.

If possible, all forms should be left one week, the beam sides being first struck,
the bottom and strutting being left three weeks. If there is frost or continued wet
weather, the period of duration of the frost or rain should be added to that time.

For members of exceptional sizes, the engineer's judgment must be exercised, but
28 days should be allowed before striking.

Floor and Pillar For.ms.

By far the greatest portion of the formwork encountered in building is mortgaged
to pillars, girders, and slaibs, and it is a close and ingenious consideration of the
application of forms to these items that seems to point the way in the direction of
economy.

There is a great similarity between the various types of forms for slabs and
beams, but there are many varieties of the three types of column forms. Forms for
square pillars as a rule are made with three sides complete and one side left open for
tam])ing and for supervision. The fourth side is brought up as the concrete is
deposited. Another method is to build up the whole four sides gradually with hori-
zontal boarding, and the third method is, of course, to have the whole four sides
entirely completed. This method demands a wet mixture, which must be poured in
from the top. Each of these methods have their advocates.

Steel P'orms.

The use of corrugated steel to support floor slabs, both as temporary centering
and to be left in place permanently, represented one of the earliest attempts to
employ steel forms for concrete construction and has continued in use, having been
used as lagging to support concrete floors of flat slab construction in cases where the
corrugations on the ceiling are not considered objectionable. The ease with which
it can be placed and moved on without apjjreciable damage and its cheapness has
caused its adoption in a great deal of factory work, especially where the cost of
ordinary formwork was considered prohibitive.

THE CONCRETE INSTITUTE, \GJNCSETE1

Tall Chimneys.

In America Ransome's system of building chimneys largely obtains; it has made
no progress in England. Its large square scaffold tower, with the outer and inner
moulds suspended from it, does not appeal in this country because of its complicated
construction.

[Here the author threw on the screen an illustration of a chimney at Northfleet.]
The forms or moulds for constructing the chimney consist of two rings of six sections
held together by latches to form a mould. Two outer and two inner sets are used in
erecting the chimnev. These forms, which are 3 ft. high, enable the chimney to be
erected at the rate of 6 ft. per day. As soon as the forms are filled to the top the
bottom form is released and placed on the upper form, the bottom mould being safely
held in position by the frictional resistance of the concrete.

The concrete is tamped round the rods, which are held to their true alignment by
the aid of the spliced wooden guide ring of two |-in. layers placed 6 ft. above the top
of the form, being shifted up as the chimney rises.

Of course the working platform is carried up inside the chimney of scaffolding
built up section by section. The framing of each section consists of four uprights
properly braced, on top of which stout planks are nailed so as to form a square. An
aperture is left in the platform for the hoisting of materials.

Silos.

In order to save timber, forms should be so arranged that they can be struck
easih and moved up as the concrete sets. [Here illustrations were shown of some silos
carried out by Messrs. Bradford.] The form is not only very light, but it has all the
requirements of a good form — namely, ease of handling, economy of material and
labour, and easv re-use. The forms are made in 12-in. heights of boards, with four
angle posts fixed to the boarding, so that the bottom ends project i in. below the
boards and the top ends i in. below, thus enabling one form to fit on to the other.
Each side is obliquely cut at a greater angle than 45 degs., making the form into four
segments, with stays at the four angles. There is a counter-sunk plate at the back of
the form. The ^-in. hold on the concrete is sufficient to keep the forms in position,
and they enable the forms to carry planks on top as a working platform. Three forms
in height are always in position ; they are filled with concrete at the rate of one form
a day, so that by striking the bottom form and placing it on the top every form remains
in position 3 days, giving the concrete good time to set. To strike the form the thumb-
screws should be undone and the corner pieces pulled out. The holes left by the ends
of the thumb-screws are brushed and finished with cement mortar.

In America the latest bin and elevator forms are on the moving principle. The
forms consist of horizontal framing pieces to which vertical sheeting is attached. The
form varies in height from 3 ft. to 5 ft. ; it must extend along both sides of each wa!),
the forms on the two <<ides of the wall being connected by vertical timber or steel yokes:
which are usually attached to the horizontal framing of the form. The boarding is
generallv covered with sheet steel, but wooden sheeting is quite satisfactory if the
raising of the form is carried on rapidly. In order to obtain smooth walls, then, it is
necessary- that the forms be raised continuously, and this is generally done with screw-
jacks, and m.'m\- of the large contracting American firms have solved the problem in
their own way. Hridges.

Thf [progress of concrete ajjplicd lo bridge design reads like a romance. While
twenty years ago there was hardly a concrete arch in the United States, to-day they
can be numbr-red by their tens of thousands. It is the same in Europe. By persistent
efff;rl the advocates of concrete have been able to gradually convince the authorities
that the extra cost of concret<' bridges over steel is money well expended, for the
concrete bridge has met tlu- requirements of the ideal highway, because of its posses-
sion of the following qualifk alions :- -.

1. Permanence, and its increase of strength with age;

2. Simplicity in design and erection; .and

3. What is very important, llic r([)airs and uf)keep are reduced to a minimum.
Therefore special att^-ntion has lM<'n paid to the forms and centering for this class

of work, as it is the author's firm belief that concrete will come more and more into
use for bridges in this country.

fy^c^NMPuc-noNAi,! FORMS FOR CONCRETE WORK.

I'Thf aiilhor ;4;i\'<' luiiucioiis illustr.itioiis of forms for v.irioiis kinds of structures
such ;is culvtiis, concluils, silos, t.iuks, dams, etc. Ihidcr the hcadinj^ of I>omes some
interest iiii; slides were shown of domes erect<'d in recent years in luij^land, Australia,
ami Anu-ric^i. The MCtion " Hridi^*- " was also <'xc<'llently iliustrat^^-d, but we are
unahK> to make reference lo the numerous examples quoted. |

DISCUSSION.

Mr. M. Noel Ridley, M.lnst.C.B., said lie considered the question of the many forms was
ui all en^inwrs cngaRed in reinforced concrete construction certainly one of the most important
tlunfTs they had to deal with. He agreed that the engineer should design the forms as far as
poNsibhs hut »ni fortunately there were great difficulties in the way owing to the amount of
tunher wastctl and the number of bolts lost. One of the greatest troubles they had was the
(juestion <i f centering, and until the\- lould get a system that would obviate the amount of
timber and strutting u]) that they had, he did not think they would overcome the difficulties.
Timber frames were a most expensive item in the cost of reinforced comcrete and a most
unsatisfactory item, and the sooner the.\ devised a satisfactory method of improving it the
better. He iiersonally had, to a certain extent, gone on the lines of reducing the amount of
centering. He had been able to dispense with all centering otherwise than two steel-wire ropes,
and for long span bridges that type of construction, modified in certain respects, would be of
very great use. In ordinary work he us^ed a great deal of dove-tailed, corrugated steel sheeting.
In using that, the sheeting was left in and was not removed afterwards. It was necessary to
id aster the under-side so as to get an architectural effect, and they were able to put in a type
of ornamentation on their columns and beams very simply and very easily. In small domes he
did not use any centering at all. His method of construction was light weight bars only ig in.
by Is in., which he bent as ribs to the dome; he put sheeting in between those, then the
concrete on the top, and rendered on the other side.

Mr. T. A. Watson, Assoc. M.lnst.C.B., thought Mr. Graham might have devoted more time
to the ordinary centering and a little less to the bridge work. In England they very seldom
saw or heard of a bridge of over loo ft. span being constructed. The majority of spans in
England did not exceed 50 ft. For that reason, and because the cost of centering for ordinary
floor was an e.xtremelj- expensive item, he wished that the author had dealt more in detail with
the forms of construction likely to be met with here. One difficulty they were always met
with and always trying to find some way out of as regarded centering, was taking it down.
It was fairly easy to construct it and put it up in place, but it was exceedingly difficult to take
it down. He fully expected the author would have had some suggestions for the easy striking
of centering. Referring to struts generally, poles were a great deal used amongst contractors,
but unfortunately at present there was a dearth of scaffold poles, and tie struts were rather
expensive, so they had to invent a new method of strutting the beam bottoms, and in order to
make the most of the timber at their disposal they had been using recently 6 in. by 2, or 7 by 2,
or even 5 by 2, spaced about 12 to 18 in. apart, and these things formed a sort of steel structure
of a signal post, by which means they got for the largest diameter the excellent width of the
centering. They got less deflection and they were able to put a greater load per square
inch on these props than they would in the ordinary way. It seemed to him that was a fairly
economical way oi propping centering. He did not think the author had made as much as he
might have done of the reinforced concrete centering for bridges.

Mr. Percival M. Fraser, A.R.I.B.A., remarked that what had been said about an engineer
designing his own centering might apply to engineering works, but he hardly thought it applied
to architectural works. It was a matter of contractors' plant, which an architect was well
advised in avoiding taking any responsibility for. An architect should pay much more attentioTj
to his specification and specify a minimum thickness for his centering. He failed to understand
why the word " centering " should be cavilled at. Various authorities placed tne cost of form
work at anything from 20 to 60 per cent, of the cost. That disparity showed that nobody could
possibly lay down or estimate the cost which the centering had to the whole job ; it absolutely
depended on the nature of the work, and it was easily much more than 60 per cent, or less
than 20 per cent. He regretted that Mr. Graham had not given them a really good type of
centering for a circular silo, which was much more economical in cost than the square silo.

Mr. S. Bylaader, M.C.I., supported the use of the word '" form." and remarked that if the
Concrete Institute adopted it, everybody would use it.

Mr. William A. Haskins, M.C.I., as a quantity surveyor, said it was necessary for him to
convey to many minds, by words alone, what they had to put their value upon, and, although

E 2

.H3

THE CONCRETE INSTITUTE. [OGNQ2EJT3

he welcomed the word '"form-work" as indicating the necessary preliminary structure for
reinforced concrete work, he thought it would be altogether inadvisable to depart — in fact,
almost impracticable for a very long period — from the customary terms.

Mr. Cjrll W. Cocking, M.C.I., asked Mr. Graham what his factor of safety was for the
stresses he gave for timber pillars.

The President said he found the relation the cost of centering bore to the cost of the work
varied between lo per cent, and loo per cent. It could, therefore, be easily understood that
where contractors were, as a rule, given the cube of the concrete and had put on the cost of
centering, how lamentably they must be at sea.

Mr. ALLAN GRAHAM'S REPLY.

In replying, the author stated Mr. Watson had adversely criticised the American form of
centering, but that form had been criticised for ten or twelve years, and it was the result of ten
or twelve years' criticism — the accumulation of facts and the accumulation of practice. He
was afraid it was a misnomer to call it the English practice, because there was no practice ;
every job they went on they found a different style adopted. It was that very different style
that enabled joiners to uie their material up for all they were worth. Replying to Mr. Fraser,
though an engineer had no blame whatever for the centering, if an accident happened in a
building for which he was the engineer, the odium would attach to him just the same. That
was the reason he protected himself by saying if they did ^jot do the centering themselves they
should make the contractor submit his idea for approval. With regard to the cost of centering
he had known a difference of as much as 30 per cent, between two different contractors tendering
for the same job, so there must be some standardisation or else they would never get any
further. Circular silos were more generally erected in America, but nearly all the silos in
England, with few exceptions, were square. That was the reason why he gave the two types
of ordinary centering. Referring to Mr. Haskins' observations, he explained that he was not
concerned with the finishing of the building at all, but only with concrete structures as concrete
structures from the surface. In answer to Mr. Cocking, the greater portion of the formula he
used was based on the Rankine formula, but when they got to a certain height he shifted over
to the Euler formula, as being square.

3+4

'a, CONMPl IC-riON A \]

THE METROPOLITAN RAILWAY.

NEW WORKS IN CONCRETE

AT HOME AND ABROAD.

Under this heading reliable information tvill be presented of neiv ivorks in course of
construction or completed, and the examples selected ivill be from all parts of the "world.
It is not the intention to describe these ivorks in detail, but rather to indicate their existence
and illustrate their primary features, at the most explaining the idea "which served as a basts
for the design.— ED.

REINFORCED CONCRETE IN THE NEW OFFICES OF THE
METROPOLITAN RAILWAY.

A iiANDSOMK buildini^ h.is qiiit<' na-ntly lx'<'n i-xecutod, almost ontirely in rcinforcod
concii'to, for th<' acconiniodation of tlu' staff of the .M<'troj)(>litan Railway, so that the
j)r<'vious ortiros which w<M-e scatti'red in various parts of the company's system are now
canc<Mitrat<'d under one roof.

1 iuiii i:,ic\ diii^ili.

Reinforced Concrete in the New Offices of the Metropolitan Railway.

345

NEW WORKS IN CONCRETE.

ICDNCRETD

For reasons of better economy and efficiency, the new offices have been constructed
partly over the various lines of railway. This, however, has necessitated a considerable
amount of forethought in the planning of the structure, in order not to interfere
with either the existing or future traffic.

Various firms of specialist reinforced concrete engineers were invited to compete
for the general scheme in this material, and, after very careful consideration of the
merits of each particular system, the Coignet system was selected for the preparation
of all the plans and technical information required for placing the work in competition
amongst contractors accustomed to reinforced concrete construction, and also for the
preparation of all the working drawings.

Ground I'lan of First Floor.
Keiniokced Concrete in the New Offices of the Metkopolitan Railway.

A certain numbf^r of contractors comjx^ted upon the s<'k'cted scheme, and ullimat<'ly
the ■execution of lh<* work was giv^-n to M<'ssrs. Ik-nry I.ovatt, Ltd.

'J'he reason for adopting this UK-thod of j)r()cedure was in order to obtain the
best j>ossible results, both in cU-sign and in the actual execution of the work. The
plans and the sufK'rvision of tlK' r<'inf()rc<'(l concrcl<' work were entrusted to M<'ssrs.
Rdmond Coignet, Ltd., of 20, Victoria Str<'<'t, \V<'slminst<T.

The photograph which w<' r<'pro(kice shows th<' front ^'Icvation, which was carri<'d
out in brickwork and special fai<n(.c forming a facing to th<' r<Miiforcc(i (■oncr<'l<' work.

The architectural front on this building was d<'sign<'d by th<' ICngini'crs' Archi-
tectural Assistant. It will be notic<'d that some of the dccorativr features —

346

y, CONM yUCTIONAl

THE METROPOLITAN RAILWAY.

n.-muly, th<- hioii/r l»uH<is .iiid coiipliiii^^, \\1m<1s .iikI sij^n.'ils — cl<».arl\' (l<-ii()t<- tlir
associ.ition of ihis huildiiiL!; with tli<' railway.

riu- harU <'l-('\ati()ii, lu)\v<'V<'r, coiistrurt^d ()\<r iail\\a\ liii<-s, lias l><<n (Icsij^iKii
w itli -4i-<at simplii'ily, paitly for tli<' sak<' of <(()iioin\ and parlU' owin^ to IIk- fact that
ihis |)ortioii of llir hiiijdiiii^ is |)ra(ii(all\ liidKUii from \i<-\v 1)\' the roofs ovrr lli<'
j^lat forms.

'I'Ik' total Kni^tli of th<' front <'l<'vation is aboiil 140 ft., and th<- total iKJLilii
(m<'asui'<(l from llu- foundations to the loof) is aj)])ro.\imat<'l\ 90 ft.

Thr hack portion of tlu' huiklinj^ is C()mj)os<'d of two winj^s, nu'asiirin<4 r<'S|X'Ctiv<'l\
111 ft. in U'lij^th by 3S ft. in width, and 100 ft. by 43 ft. for th<' smalk-r winj^. The
latt<r is ronn<'Ct<'d ti> the bookinj^-hall of th<- ik-w station, facinj^ Marvk-bone Road,
bv a st<x'l footbridife. A retainini>' wall in ri-infora'd concrete has been constructed

Section of Board Room Roof.

. <&«' ■Kf J

3^ /.3a.is

1 t ■ fi

tt^^t/aa

—

/^M>»jia

-r

— 1

, . , fl»' Sffe

\ '

—

anmrao

n ^

-t

qoca

i 3 '
i ^''j ,„

^
^

1 ^

Sbr^rsoe

t^ tr* f.x* .>t^5=-=---^=^J'"^«a>«=f«ta^--jnij£:=:jJa3.^_^z^^'

Section.
Reinforced Concrete in the New Offices of the Metropolitan Railway.

along the front on a length of 152 ft. and with a height of 24 ft. This retaining wall
has been provided to form the basement of the structure, and it is arranged so as to
allow the proper lighting and ventilation of the lower portion of the building, below
the upper ground level.

The building comprises a lower basement, basement, booking-hall floor, ground
floor, first, second, .and third floors, and a flat roof. A superload of 150 lb. per sq. ft.
has been allowed up to the first floor level, inclusive.

The upper floors are calculated for a superload of 90 lb. per sq. ft., and the flat
roof for a .superload of 40 lb. per sq. ft.

The total suj^erficial area of the various floors and roofs in reinforced concrete
amounts to approximately 65,000 sq. ft.

3 + 7

NEW WORKS IN CONCRETE.

[CQNOaTEl

The fjround floor at street level is for the accommodation of the principal suites of
offices and the board room, of which a j)hotoora])h is herewith reproduced. This board
room is provided with a dome in reinforced concrete.

It is situated between two committee-rooms, and, by a special arrangement of
disappearing partitions, it can be enlarged to hold the meetings of the company.

These rooms are panelled in hardwood, with double partitions and windows to
s-hut out any noise from the railway below.

The engineer's office is placed in the north wing, so as to get the maximum
amount of light for the drawing-offices.

The two back wings of the building are supported by massive reinforced concrete
pillars and beams over the new platforms.

\'icvv of Board Room.

Kl.INI OKCKD CoN'Cr<ETE IN THE New OmICES OK THE METROPOLITAN RAILWAY.

Th<- low<-st floor of th<' building is on a 1<'V<'1 witli th<> booking-hall of th<' new
station.

']"he h<'ating ch«amber, stor<', and strong-rooms are situalcd al a lower 1<'V<'1 and
alongsid<' a s<'t of rails, to facilitaW- {]]<■ handling of the coal for h<'ating purposes, also
for th<' handling of store's.

'J'h<' staircase's hav<' automatic lifts. The lift on IIh' south sicic is arrangexl to
descend to platform U'V<1 for tin- j)iirj)Os<' of collecting and (l('sj)atching cash, tick<'ts,
and documents.

Th<' north staircase- lift is connected willi lln' accountant's and other <l<'partm<'nts.
Th<- lift (U'sce-nds to th<' strong-rooms in ilic base-UK'nl.

'I"h<- l<it(li<'ns, (lining-r(jonis, and (arctakcr's quarters are all situal<'<l on the toj)
floor.

348

/.'

CONMPlK'nONAl
fcJM(aNhFJJlN(. — .

TIJH MhrPROPOLirAN RAILWAY.

Vhv <'iitir<' huildinj^ is h<;il<(l l)y iiK'.'ins of r.'idiatois with low-pivssinv liol \\;i(<'r.
'\'hv doors .iir (■o\'(r<(l by ni<;ins of woocUn blocks.
'rb<' coinp.tiu \ < iiLjin^H r for llir work was Mr. W. W'illox, M . Insi. ('.!<'., his

assistant, Mr. C. \V. Clark, havino carried out the architectural work, and his resident
engineer being Mr. O. G. C. Drury, A.M.I.C.E.

The lifts installed are those of" Messrs. Wavgoods, Ltd., and Messrs. Beavan and
Sons, Ltd., supplied the radiators.

3+9

NEW WORKS IN CONCRETE.

ICDNCRKIliJ

REINFORCED CONCRETE BRIDGE IN CALIFORNIA.

The bridge here illustrated was built jointly by the City of Pasadena and County of
Los Angeles across the Arroyo Seco. The work of construction was started in June,

View showinf^ Main Span.

View taken lioi.i VVest-cM.i.ot lirid^e lookin>i towards I'asadena.
Rkini'orcki) Conc.kkik Hkidgi-. in Cai.iiornia.

rs! :;:: ^iprV/xi,;;.;:"; $:,.,,„.„. l... ....„ ..,, ,n,lu.,in, n,h,. of way, lK.av,

35°

r J, CTONM PUtTlONAi;
[t\ ENdlNLlrJJlNd — -.

REINFORCHD CONCRETE BRIDGE.

cuts, ami const ructini^ houUv aid 1)\ lh<' County to conm-ct with the west <'n<J of hridj^e,
was $240,000. 'lluK- ar<' 4'l<v<-ii main sj)ans, witli a total k-nj^th of i,467"5 ft.,
IncUuliiiif appiHJai Ihs. IIk'H' is a 3<S-ft. roadway with 5-ft. si(i<-walUs on <<;s'ich .side.
Th<' loni^est span, whicii is din-ctly over th<' h<d of th<' Arroyo, is 223 ft. from c<'ntre
to crnir<' of |)iers, with a h<'i^ht of 150 ft. above the Ix-d of th<* Arroyo. As will be
ni)t< (1 in tJK' acconi|)anyini4 illustrations, the bridge was huill ])arlly on a curv<'. This

View of Bridge looking North,
Reinforced Concrete Bridge in California,

was done in order to obtain the most economical point for crossing the main part of
the Arro}o and avoiding a large expense for ])iers. The bridge was designed by
Messrs. Waddell and Harrington, of Kansas City, Missouri, w^ho also had entire
charge and supervision of the construction. The Mercereau Bridge and Construction
Company of Los Angeles, California, were the contractors for this work. We are
indebted to Mr. Lewis E. Smith, the City Engineer of Pasadena, California, for our
particulars and photographs.

351

NEW BOOKS.

[CDNCBETEJ

NEW BOOKS

AT HOME AND ABROAD.

A short summary of some of the leading books 'which ha-ve appeared during the last feiv months^

"A Text-BooK of Elementary Building Con-
struction." By Arthur K. Sage and
Wm. E. Fretwell.

London. Methuen & Co., Ltd., 36 Essex Strte', W.C
29j pp. + viii. Price, 3/6 net.

Contewts. — Introduction — Brickwork —
Masonry — Iron and Steel — Carpentry
— Slating — Plumber's Work — Joinery
— Joints, etc., in Pipes — Sanitary
Appliances and their Connections —
Board of Education Examinations.

There is a great need for a really good
text-book on Building Construction which
could be given into the hands of a student
with the confidence that he would be able
to do really useful study and acquire
sufficient knowledge to form a ground-
work of sound construction and enable
him to proceed to the more advanced work
almost unaided by personal tuition. Such
a text-book could only be prepared by
someone who had been in actual contact
with students of all kinds, and we are
pleased to note that the authors of this
\T)lume are both lecturers at the Brixton
School of Building, and as such they must
be well acqiiainted with the class of reader
to which their bo<^)k is presented. We are
glad to see that notes on materi.-ils have
been introduced, as these are absolutely
essential, and there is no justification for
leaving this part of the subject out of an
elementary work, as the student must
understand the nature and limitations of
the various materials before he can fullv
appreciate their application to building
problems. 'I'here are various criticisms we
should like lo make, particularly with
regard lo some of the diagrams, hut spnce
will not permit this, and after .ill, it niusl
be admitted that it is easir r to (riticise
than produce a perf-ct work'.

There do not appear to be any notes on
plastering or painting, and this is to be
regretted, as it would have made the
volume more complete. Generally speak-
ing the book is well written and should
appeal to elementary students, while the
price is so small that it should be within
the reach of all readers and thus become
popular as a text-book for class purposes.

"Portland Cement Manufacture" (Die Port-
land - Zement - FabriKation). By Carl
Naske.

3rd Edition. 496 pp. and 408 illustrations. 1914. Leipzig'
Theo-d. Thomas. Price M. 22.

This excellent handbook has now reached
a third edition. Its general features are
well known, and have been retained, the
only entirely new^ section being a short one
on the quarrying of the raw materials!
The principal methods of manufacture,
and the machinery and plant employed in
the process, are very clearly described, and
illustrated by means of clear sectional
drawings, the latter being a welcome relief
from the reproductions of photographs
from makers' catalogues which commonly
do duty in works of this kind. The
progress of the industry since iqoSj the
date of the last edition, h.'is been so rapid
as to necessitate the re-casting of several
sections dealing with crushing and grind-
ing, transport and storage, and the
removal of dust. On such subjects as
these the book is a mine of information.

The brief section on testing has received
less attention than the remainder of the
book, and would not be found adequate by
workers in this country. On the other
hand, the official specifications now oecupy
loo pages, and include all those which are
now accessible from Japan to Chili. This
section will be foimd useful bv many.

352

A ENCilNl-l-klNCi — .

CONCRETE PILES

INDUSTRIAL NOTES.

These pages hji>e been rvscn>eJ for the pre sentaiion of articles and notes on proprictjrj
materials or systems of construction put forv.>arJ by firms interested in their application. With
the adi'ent of methods of construction requiring considerable skill in design and supervision,
many firms noivadays command the sen>ices of specialists ivhose iJiexus merit most careful
attention. In these columns such 'viexos ivill often be presented in fa'vcur of different
specialities. They must be read as ex parte statements— ivilh ivhich this journal is in no way
associated, either for or against— but ive ivou Id commend them to our readers as arguments by
parties toho are as a rule thoroughly conversant tuith the particular industry ■with -which thev
are associated. —ED.

CONCRETE PILES.

TiiK sysli'm of makinj4 concix'to j)ik's by cirivin^:^ a lube with a shoe into the jfround,
leavinj^ the shoe behind, fiUinj^ the tube with concrete, and then withdrawing it, as
protected by John Potter in 1864, is well known, and the system her<'in describ<'d has
been devised with the object of obtaining nior<' satisfactory piles by compelling the
concrete to effectually fill the void created by the w^ithdrawal of the tube, and it is
the invention of Mr. T. W. Ridley, of Messrs. Thos. D. Ridley and Sons, Middlesbrough.
The first part of the patent refers to the joint between the preparatory tube and
the shoe, which is a double or trii)licate one made by a quantity of Tuck's or other
like packing and clay on each side of it. This packing is jjut underneath the bottom

Pull Luici indicate
AFparstu^ before
t'ftinf ind
Dotted Lir
position af
opor*»iani

Fig. 1.

of the preparatory tube and in the recess in the shoe, with the clay on each side, as
shown in Fig. i. By very simple arrangements the tube and the shoe can be tempo-
rarily connected together, so that, like an ordinary timber or concrete pile, they form
one piece.

The second part relates to the withdrawal of the tube and the compression of
the concrete at the same time. This is done by a series of links fixed to the top of
the preparatory pile, shown on the drawing in Fig. 2. The apparatus is first lifted
or raised above the driving head of the tube by two links (.4), which are fastened to
the tube by lugs cast on each side. To A are pinned two links (B), and these again
are pinned to each of the two pairs of links (C and D). Between the links D is fixed

353

INDUSTRIAL NOTES. 1 CQNCBETE3

a ramrod, which is in the form of a tubo with a piston on the end. When the lifting
power is applied at the top, where the links C meet, B and C tend to come in a straight
line, and the links D are depressed and so force down the ramrod, which then causes
the concrete to be forced downwards as the tube is lifted. The compressing force
practically equals the resisting power or the suction of the ground or friction on the
tube in withdrawing it ; and as the tube approaches the top it may be necessary to
increase the compressing power by clamping the tube to the piling frame, making the
tube more difficult to draw, but giving the necessary compressing force on the concrete.

For the foundation of a bridge at Seaton Carew, Messrs. Ridley were allowed to
use this pile, on the condition that they satisfied the designers that the concrete
adequately filled the hole made by the withdrawal of the tube. Two piles were driven
and afterwards dug out. The tube used was 13^ in. internal diameter, and in no
case was the column left in the ground less than 15-5 in., while where the foundation
was peatv the column was nearly 20 in. With this system it is claimed that it is also
possible to form a foundation having a reinforced cast concrete column inserted in the
preparatory tube, in which also is placed a quantity of fine liquid concrete ; then by
means of the compressing arrangement this column is forced down into the shoe, and
the liquid concrete will, as the tube is withdrawn, take the place of the metal of the
tube and thoroughly surround the cast concrete column.

The latter method is used in connection with works in water, and in such cases
the shoe and tube are temporarily connected, as previously described, making the
watertight joint, and this shod tube is then driven down to the necessary depth and
the two are disconnected. When this is done, liquid concrete of very fine material is
placed in the tube, and the previously moulded cast concrete column inserted, the
latter having upon it a flange which is an easy fit inside the tube. This column is
forced down by its own weight or other easy means until the liquid concrete has risen
to the underside of the flange. The withdrawal of the tube and compressing will
then be worked in the usual way. The cast concrete column will thus be forced down
into the shoe, and the liquid concrete will follow the tube up to the ground line, and
form a ring or collar of concrete around the cast concrete column, and fill up the hole
in the ground. When the tube has left the ground, the surplus concrete, if any (and
there should be sufficient to form a surplus), will be left close to where the flange is.
In this manner a reinforced concrete pile — reinforced and designed purely and simply
for the load it has to carry- — can be inserted in the ground and made secure without
being damaged in any way by driving, the only difference being that there is a flange
at or about the ground line. The function of this flange is to act as thei ramrod or
the compressing force, causing the liquid concrete to rise out at the bottom of the tube
and up around the column itself as the tube is lifted.

As an example, the following particulars are given for a foundation pile about
30 ft, long, using a 14-in, internal diameter tube, which would eventually leave a
column about 16^ in, diameter, in the centre of which would be a cast concrete
reinforced column 11^ in. diameter. The units are the superficial inches multiplied
by the length in fe<'t. This may be jwrhaps more readily understood than bringing
the figures down lo cubic feet.

Ft. Sq. in. Units.

Finished pile ... ... ... 30 ft. long x 16^ in. diameter =30x213 =6,390

Finished cast concrete rohimn ... 30 ft. long x iii in. diameter =30x104 =3,120

Finished concrete case ... ... 30 ft- long x 16^ in. - 11^ in. diameter = 30 x 213 — 104 = 3,270

Contents of prei)aratory tube ,,, 30 ft. long x 14 in. diameter =30x154 =4,620

Difference between cast fonf:refe

column and f:ontc'nts of tubc

30 ft. each ... ... ... 30 ft. longxi4 in. — ii^ in. diameter = 30 x 154 — 104=1,500

'J'h<'r<'fore 3,270—1,500 will he n<<-d<d to ins<'rt in th<' tulx' before the cast concr<'t<'
column is placed in [Kjsilion; 1,770-^154 gives nearly 12 ft. in length of tube. This
gives practically two-fifths of th<' 1^'ngth of the pik'. Th<' foremrm driving a pile, which
in this case is 3f) ft. long, wcaild know that Ik- has to j)ut into the tube 12 ft, of its
k'ngth of i]u<- liquid concrete.

Th<n \hv cast concrete column would Ix- allowed to s<'ttle by its own weight or
that of the tackle to ^-nsur^- th<! concrete rising up to tli<' piston, which piston can be

.354

CONCRETE PILES.

i'itlur llu' ()r<lin.ir\ |)ivton oi oiK' s|)<ci;illy cast on lli<' column, as in riv<T or \\al<'r
work. If tlur<' \v;is not a >-nirici< ni c|nanlily of liquid concr<t<' to do this, nion- would
ha\c to he inserted until the iLinj^e was reached. Then the ordinary pressing' arran^e-
nu'iit and withdrawal would Ix' s<'t to work, and the conii)r<ssion woidd tak<' |)!ac<'.
A |)ik' ^o ft. liHii^ shoidd onh' ha\<' to Iw forcid 1)\ ih<' conij)r<'ssion ahout u ft. One
of 40 ft. would ha\'<' to Ix' forc<(l ahoul i() fl., whilv ()n<' of 20 ft. would (jid\ n<ed
about S ft. of forcing;. '\']u- oilier |)oilion should sink hy its own wx'ij^ht.

In th<' cas<' of a i-olunm in ii\< r work, wh<'r<' llu' \nU' its<'lf is not to Ix- forc<-d down

Fig. 3.

below the ground, the flancje would have to be made at or about the ground line, and
the liquid concrete all put in, as it could not be passed below the flange after the
column was inserted.

The photograph illustrated in Fig. 3 shows two piles that have been formtd
according to this system, and afterwards excavated; and it will be noticed that the
fine liquid concrete has spread out in the soft strata and increased the diameter of the
pile, thus achieving the inventor's object in compressing the concrete during the
withdrawal of the tube.

355-

MEMORANDA.

[CDNCBETEJ

Memoranda and Neivs Items are presented under this heading, with occasional editorial
comment. Authentic neivs ivill be ivelcome. — ED.

The Iron and Steel Institute, — We are asked to state that the annual meeting
of the Institute will be held, by kind permission, in the new house of the Institution
of Civil Engineers, Great George Street, Westminster, on Thursday and Friday, May
yth and 8th, commencing at 10.30 a.m. each day. Full particulars can be procured
from the Secretary, Mr G. C. Lloyd, 28, Victoria Street, S.W.

Liverpool Architectural Association, — A paper was recently read before the
above Association by Mr. John A. Davenport, M.Sc, on " Concrete and Reinforced
Concrete Don'ts for Architects." After some preliminary remarks dealing with
concrete, centering, and steel, the author went on to deal with the subject of fire
resistance and economical design. In connection with the subject of fire resistance
the author stated that the fighting of fires was the work of municipal authorities, but
appliances should alwavs be available to deal with an outbreak on the spot.

Fireproof walls, roofs, and partitions should be used to prevent spreading, but
these would be of little use if the coverings to window, door, and other openings were
not as strongly resisting as the rest. After localising the fire, attention must be paid
to the protection of all structural members, whether built of steel, wood, or stone,
and the best material to use is concrete. But the protective coat must be of uniform
thickness for best results, and this prohibits the bedding of pipes, ducts, etc., therein.
The object of the coat is the protection of the steel, and therefore there must be no
passage for the heat to flow from the outside to the inside by way of wood plugs,
metal projections, and so on.

Turning to the subject of economy in design, the lecturer said that economy
depends upon cost of materials and cost of labour, which will vary from time to time;
but these mav be taken at present-day values for comparisons. Neglecting all question
of architectural economy, the cost of the engineering structure is affected chiefly by
the lay-out or arrangement, next by the relative amounts of concrete, steel, and timber,
and also bv the shapes of the sections used. The most economical job is given by the
us^^ of thin slabs support^-d by beams of shod span, the whole being reinforced with
steel of perc^entage slightly higher than the theoretically economical percentage.
Uniformitv of sizes makes for economy, as with dissimilar sizes much time is taken
in k-arning to f;ut in the st<-(l .ind concrete expeditiously. OiIkt things of importance
to <x:onomical d<'sign are th<' choici' of suitabk' and ch<'ap aggregat<'s, and the adoption
of ste<l size's which can be purch.'ised ch<'aj)ly and b<' worked and hrmdled easily.

A list of concr<'t<' and r<inf()rc<(i concrete don'ts Ix-ariiig on the points raised in
th<' j)aper was giv^en, and vi<-ws of r<'inforced concr<'t<' failur<'s, lh<' j)ulling-d(>wn of a
reinforced con(T<-te buikling, and th^e < r<'Ction of reinforced concrete buildings were
shown and described. We give below a few of the " Dont's " nuntioned : —
Don't use any cement that does not satisfy lUitish standard si)e(ifirat ion.
Don't use a sand which is coated with clay or contains any nvitcrial which will alTcct the

settinj^ or stren/itli of the f:einent.
Don't use coke breeze, brick, or any olhcr l>()ro^^ auk'rc/^'alc when a waterproof concrete is

wanted.
Don't mix the concrete too dr\- ; a wet mixture is niiK h easier to work.
Don't let any time elajjse Ix-tween the mixing and laying,' of the concrete.
Don't use any batch after it has (ommencefl to ijel.
Don't lay concrete in frosty weather.
D<m't leave bags of unused cement on the /.(round and exposed to llio weather.

3S6 .

(g^^^^ MEMORANDA.

l)<)n'l liavc wimU ri-iitcrin/^.

l)c)n'( lorf^t'l that tlir inoiiMs sliimld Ix- (If.iiud out lu-lort' llii' con ( ret f is laid.

l)<)irt have (tnlcriii^; up x) U>nK that it (ifhi.\s liardi-niiiK-

Don't loif;et to }.;i\r a little cainhcr to hcanis of lon^; span to compensate for deadweij^ht

dellect ion.
Don't construtl fc.rni> for deep work in sin li a w.ix thai the eonerete nnist he jjonred in from

f,'reat heij^ht.

Steel Po>r/s.

Don't use a steel that tloes not comijlv with tlu^ Hritish standard or the jn<l R.l.H.A. Rei)ort

Speeificat ions.

Don't allow steel to be welded.

Don't allow eonerete to be laid before steel has been seen in the moulds and approved.

Don't let steel be displaced when the concrete is rammed.

Don't let steel be exposed to atmospheric or an\ other rusting influences.

Don't allow the steel to be bent or worked hot if it can be avoided.

Fire-resisting Doi'ts.

Don't omit fire-resisting partitions in any building.

Don't leave unprotected openings in walls, windows and roofs.

Don't leave any structural members unprotected.

Don't leave wood plugs in the protective coatings, as these are easily burnt out and expost

the interior.
Don't embed pipes, mains or ducts in the coating.
Don'i allow a thickness of coating of less than i in.*
Don't use a porous concrete without covering the steel with a rust preventive.

Some Tests on Strength of Overwet Concrete. — .Some data have been compiled
by the Committee on .Specifications and Methods of Tests for Concrete Materials, of
the American Concrete Institute, in connection with an extended investigation into
a standardisation of concrete test pieces, ix'oardino the deleterious effect of too much
water in concrete. While the tests were made in an effort to arrive at a proper
proportion of water to use in mixing test pieces, they at the same time went to show
definitely the effect of a variation in water content which must be of similar, although
not necessarily proportionate, importance in field work.

The tests reported were made under the same prescribed conditions of standardisa-
tion and manipulation, but with necessary local variations in material, by three college
laboratories. The concrete was ajjproximately a i : 2 : 4 mix, with coar.se aggregate
of from h in. to f in. in diameter. Each value given is an average of four 6-in.
diam. b\ h-in. cylinders. The amount of water used varied with conditions of sand
and gravel, but the consistency is described as follows in the Committe<''s report : —

Because of the difference in the effect of different sands upon the consistency, it was
impossible to specify a definite percentage of water. Tests made by members of the Committee
indicate that the most uniform degree of consistency can be obtained by adopting the Chapman
consistency test, wdiich consists in filling a slightly tapering cylindrical form with concrete,
immediately inverting this, and by repeated trials finding the amount of water which will
cause the concrete to just begin tO' slump when the form is removed. A dry mix is, of course,
unsatisfactory, while it is almost impossible to describe a very wet mix which will insure
uniformity.

Speaking generally, however, the dry mix is about 8 per cent, water, the normal
about 9 per cent., and the wet 10 per cent. These perc<'ntages, it will be appreciated,
are much lower than those required to give similar consist<'ncies in actual concrete
work, but the comparison is the same.

The accompanying table gives the actual compressive values up to sixty davs and
the curve the average of the three laboratories for the three degrees of consistencv.

* Tn ou/ opinion this minimum is too low.

^ 357

CQNCDE:rE«

«>gri=-d k-=ii=~< N>=^i=c^ W-^i=^ \x..^i;=..i ..=^i=^ l^.=i!=«< ^o=;>o^ ^~=s^ i».=ii==:g

I
1

SIMPLEX

STEEL SHEET PILING

Illustration

shows

Simplex Piling

being driven

under

difficulties

in India.

The only plant

available was a

small drop

hammer.

This is

only one

of the very

many instances

where

Simplex Piling

has been

used to

advantage

in difficult

positions.

OWING TO ri'S LIGHTNESS IT CAN BE
EASILY HANDLED, & IN SHORT LENGTHS
CAN BE DRIVEN WITH A HAND MAUL.

SIMPLEX PILING IS SUPPLIED IN TWO
WEIGHTS, i.e., 22 & 27 LB. PER SUPER FOOT.

Our Piling may be had on hire at the following approximate prices : —

Simplex Piling, 22 lb. ...
Simplex Piling, 27 lb. ...
Universal Joist Piling, 43 lb.

lid. per super foot for the job

1/3

1/10

»>

THE BRITISH STEEL PILING CO.,

4 DOCK HOUSE, BILLITER STREET, LONDON, EX.

Telc()honc AVKNIJI': Slf.l.

:l(t;r;iiiis— " I'lI.INflDOM, LONDON."

^ y>.=^^,=^ ho-=::it:^ k-=4i^=^ h ^^^^^,^^ k>^^^^ cx>^:4^:^ k<^t^ l«>-=^^^^ ^po-^^HP ^ jcxx^^^

358

Please mention this Journal ivhen ivriting.

.CDN.srPUCJIONAl.
KNdlNl 1 RlNti --.

MEMORANDA

I Alii. I. SIK )\\ I \(

I I I ICT ()!■■ WA'I'I.R PKKCl-.NTAC.l'. C)\ ( OMl'KI^SSIVK

xc.rij ()!• (■()\( ui/ii', ()x6-ix. CN Li\i)i-:ks.

Avtr.ifj;c (oinpiH-ssive stn-nj^lh, lb. piT s(i. in.

Mass. Institute

Ihiive
A«r. Dry

- <l;i>s 1751

14 (la\s 2140

.21 (lays -^(isS

28 <lays -2615

2 months 3056

* io'2 ])er cenl.

rsily of

1 llinois.

I'niversitx of \V

isronsin.

<.f

're( hno

ogy-

Norma

. Wet.*

Dry

Normal

. Wet.t

Dry.

.Norma

l.Wet.:

i.?<)o

1 103

1 (k^o

15,80

9>?,i

2047

1740

065

1775

I3.S4

■2 7<).S

I <J05

600

274-2

2320

1372

i8i()

1623

-2450

20(i5

722

2S'J4

23g6

1464

1820

1657

2380

-2430

860

2670

2882

i8y5

.30(13

2410

2485

2340

787

2;6i

30(J2

1830

water.

t I2"0

|)er cent.

water.

+ lo'o per

( ent.

water.

Reinforced Concrete Telegraph Poles versus Wooden Po/es.— The .suixriority
of rt'inforcxxi conci'tU' for ivU'j^raj))! poh's ()\<t th<' ordinary w ooclcn j)()k'.s has eslablish<''d
its^elf in the recent blizzard in N<'\v York. The Engineering Record reports as follows :
" The storm centre was in and about New York City. The wind blew at a velocity
of eii^hty miles per hour, and there was a heavy fall of snow and sleet. As far as
telei^raphic communication was concerned, New York was isolated for several days.
So severe a load did the ice-coated wires impose upon the concrete poles that the
wooden cross-arms on some of them were broken. The poles themselves, however,
remained intact." Photoi^raphs which accompanied the above report show some
wooden poles, after the blizzard, broken ri<4ht throu<^h, whereas an illustration of some
concrete poles shows these quite intact, excepting for the damage above m<'ntioned.

Removal of Concrete Forms. — The committee on reinforced concrete of the
Canadian Society of Civil Engineers has submitted to the society a draft of proposed
standard specifications for plain and reinforced concrete. These specifications contain
a clause entitled " Form Removal," which reads as follows :

"The forms shall not be removed until the times named in the following table
have elapsed after depositing concrete, not counting periods in which the temperature
has been below 35 deg. Fahr."

Port.

Posts under beams and girders

Floor-slab panels ...

Wall forms ...

Column fojms

Sides of beams and girders

All other parts

Minimum 24-hour day.

20
10

-Enc^inecrin^ Record.

Concrete Dwellings House at Norwich. — We are asked to state that the concrete
block dwelling-house at Norwich for the foreman engineer at the Norwich Main
Sewage Pumping Station, and illustrated in our April number (page 285), was built
of " Winget " blocks made on " Winget " machines, installed by the Norwich Corpora-
tion some time ago.

TRADE NOTICES.

Martin's Adjustable Scaffold Brackets. — Our attention has been drawn to some
patent scaffold brackets, of which we give an illustration herewith.

'Jliese brackets, which are made of steel throughout, are largely used in place of
the ordinary scaffolding, built up from the pavement and swing cradles hung from the
roof.

It is claimed that they are extremely light, yet very strong, and can be fitted by
unskilled labour in two or three minutes ; they can be used for any number of jobs, and
when not in use can be stored easily, as each single bracket is only 4 ins. wide.

F 2

359

MEMORANDA.

ICONCBETEJ

Thev are fixed, at any window openinf^, from the inside of the
building^ bv m<'ans of square threaded steel screw and handle, the
wood blocks which clamp ag<ainst the wall bein<4 i)added with thick
felt.

Double brackets, about 2 ft. 6 ins. wide, are made with fixed
wood platform and handrail comjjlete, and are suitable for working
at a fixed position.

Single brackets may be fixed at each window of a building,
and scaffold boards laid from one to the other, thus providing a
continuous platform along the front of same.

It is claimed that these brackets entirely save the cost of expen-
sive scaffolding, cradles, etc., and so easily pay for themselves on the
first work for which they are used.

The sole manufacturers are Messrs. E. A. Reed and Co., Ltd.,
of 14, \'ictoria Street, Westminster, S.W., who will be pleased to
send full particulars and prices upon application.

Asbestos Cement Tiles and Boards. — It is claimed for these
boards that they are extremely useful as permanent centerings in
certain concrete constructions. Once the old-fashioned wood centres
are removed, the work has generally to be faced up with cement and
sand. Where asbestos cement sheets are used the wood centres may be
spaced wide apart, and the asbestos cement sheets put in situ with joints inside the
wood centre, splashed on the back with strongly gauged cement and sand to form a
good key, and the concrete put in behind, so that when the wood centering is removed
a finished surface remains. The boards can also be used for partitions, ceilings,

linings, etc.

Full particulars regarding these sheets, etc., can be obtained from Jos. Robinson
and Co., Ltd., London, agents for the Carlisle Plaster and Cement Co., Ltd., Carlisle
ChamlxTs, 10, Crooms Hill, Greenwich.

EVERY INCH
A MIXER

THE

VICTORIA

CONCRETE MIXER

(That's the way
^^^|to dischargee
concrete

Write for Catalogue
No. 29 and learn how
the mixing is done.

T. L SMITH Co

13 VICTORIA STREET, S.W,

360

Please mention lliis Journal 'when 'writing.

(TJ H

o -^

S H

-A,

CONCRETE

AND

COlSfSTRUCTlONAL ENGmEERlNG

Volume IX. No. 6. LONDON, Jl'NE, 1914.

ED nV RIAL NOTES.

THE CONCRETE INSTITUTE.
The Council's Annual Report, 1913-1914.

TnK C(u;nL'il of the Concrete Institute have presented their Annual Report, and
a summary thereof, witli copious extracts, will be found in another ccjlumn.

The L.C.C. Reinforced Concrete Regulations.

Hie first point to note in the report is a matter of congratulation — namely,
tliat tlie Institute's Council and Committees have devoted a considerable amount
of time to consider thorout^hly questions reg"arding- the London County Council's
(ieneral Powers Bill of 1909 as far as it relates to reinforced concrete. W'hat-
e\er may 1je the outcome of these deliberations there is not the least doubt that
the work lias been done pain>takin^ly with tiie best of possible intentions, and
the recommendations of the Institute ma}" be looked upon as an equitable
compromise between those who wish to over-police reinforced concrete and
those who wish reinforced concrete to ha\e little or no restriction.

Work of Technical Committees.

The second feature of the report is that some of the technical committees of
the Institute have been doing" a fair amount of useful general work, and have
before them further important matters for consideration. We onl}" hope that
the consideration of some of these subjects will be accelerated, as the all too
frequenc postponement of even a provisional solution of an important subject
becomes wearisome.

As to the work of the various committees, we are surprised to find that the
Tests Standing- Committee propose nothing very definite as to tests, for it has
now a small fund to draw upon — namely, a fund that was specifically ear-marked
for testing- purposes and reading-room purposes, comprising money which was
collected from the existing members who chose to increase their subscription
with a view to assisting the Institute in this direction.

The Proposed Examinations.

The third feature is the constitution of an examination board and the
arrangement of examinations. In principle, we are entirely against the Insti-
tute being- recruited by examination and ha\"ing its membership in the future
chiefly based thereon. To our mind, the \'ery last object of the Institute is to
draw hard and fast lines and to have a kind of minor specialist examination
of admittance. The Institute, to our mind, was primarih- intended to bring

361

THE CONCRETE INSTITUTE, [ CQNCBETEJ

together the various chisses of professional men, and those interested in the
great industries concerned who wish mutually to discuss matters appertaining
to concrete and reinforced concrete nncl their constituents, and anything in the
wav of examination at this stage, wilh the object of putting those who have
passed an examination into a kind of superior class and those very useful
members who happen to be at the head of their relative professions or industries

but ha\e not been examined- -into a secondary class is unwise indeed. The

scientist, the chemist, the arciiitect, are, apparently, according to the present
programme of the Institute, to play " second hddle " to the young surveyor or
engineer, who, bv dint of cramming, passes a certain examination, and like-
wise the captains of industry, who have more actual knowledge, gained in the
hard school of experience, than many a so-called professor.

We should have had nothing against an examination for a diploma, indica-
ing knowledge of concrete or reinforced concrete ; or, in other words, we have
nothing against an examination that would encourage students and junior
members of the various professions and industries concerned. But an examina-
tion that is eventually to create a class difference in the Institute is, in our
opinion, a very sad mistake, and entirely uncalled for in a young institution of
this kind. It is no doubt due largely to those who believe in the value of what
we consider are unnecessary initials, and we are afraid the Institute has done
something to encourage a craving for these emblems of class distinction by
so systematically describing its members as M.C.I. 's. Such a policy may bring
in new members and funds, but it is nevertheless to be deprecated.

As to the proposed examination itself, we will deal with that more closely
at a later date. We think it goes too far.

The "Reorganisation Muddle."

The fourth point, conspicuous in the report, is what we would call for short
the Institute's " reorganisation muddle." A party in the Council of the Insti-
tute apparently wish to turn it into a minor institution for structural engineers,
which is entirely divergent from the j3rimary object of this body. Another party
in the Cfiuncil oi the Institute urges a sidtiis quo in the objects of the Institute,
in its Memorandum of Association, and, above all, a retention of its existing
title pure and simple, whilst they are prepared to make gradually progressive
changes in the articles or rules as the needs of the Institute may require.

We have already pointed to the fact that a new memorandum and a new
set of articles uere a(tuall\' " formally" (sic) passed at two extraordinary general
meetings, without the purpose or the scope of these changes being properly
realised b\- the j)rincipal L(jn(l(Mi members and not realised at all by those in the
provinces or :ii)roa(i. Aj)[)arenlly these changes were made in such an extraor-
dinary fashion that lh( y u ( re of no legal \alue, for e\en the resolutions, we see,
according to counsel's opinion (|Uol((l in the re])()rt, were improperly dralted.
To put il fjuite plainlv, malerial clianges were attem])led wliich would have
entirely altered th(; objects of the Instilute and whic^h would have led to the
resignation of nearly half ils nieinbers, and these changes do not excn show
the redeeming feature of being well con.^idei-ed and properl}' brought about in
accordance willi the law of llie land. As to whal the C'ouncil pi-')|)i)ses to do
mav be read in ihe rejiort. The C'ouncil now by w a}- of compromise —

362

j,CONMPtlC"riONAl
'v KNdlNKl.PlNd --

ANNUAL GENERAL MEETING.

SUJ4J4CS1, lliai (illuM- the proposed chani^c of lli<- general scope of
llu' Inslitulv .IS set out h\ the irxiscd Mcinoi'iinduni of .\ss(jci:iti.)n
of .\o\ iMiil)i-i- last 1)1' p.issitl 1)\ luo furtlicr i-xlraordinary <4c-ncial meetings
with sindi additional aim-ndim-nts in the articles as nia\- be recjuisite, or thai
the i'hani^i's atleni])ted in \o\i'nil)cr — whieli, as a matter ol iact, do not le^all)
■" hold water " at tlu> moiiu-iit he foi-mally rescinded. This comj^romise al le.ist
shows that the oi)pi)ni'nts to tlu' chani^v are making- thenisL-hes felt,

Ti) these extraordinary j^c-neral nieelin,^s, of course, the whole ol the
niemhership will hi' called; hut, as the .\nnual Re|)()rl |)lainly slates, quite lu(j-
ihirds of them li\e awa\ from London. 'Ihese members li\in^ out of L(jndon
are, howe\ei-, disfranchised, as ihey have no right to \ote by proxy. The
result will thus be that, e\en il the changes were again adopted by a London
majorit\ , several hundred of the pro\incial and colonial members would oppose
the change in Court, and we are ad\ ised that they would have a very good
prospect of succeeding; in other words, to-day's impasse would be repeated.

We would thus strongly urge the Institute's Council to go warily in press-
ing for the proposed change. The society stands a fair chance of being ruined
if it adopts the proposed Memorandum — there would be a large secession from
its membership and an immediate cessation of its usefulness. On
the other hand, if it will go steadily, quietly, keeping its old memorandum,
objects and title- -only gradually changing the articles as modern require-
ments may necessitate from time to time — it still has possibilities of getting back
the prestige it enjoyed during the presidency of Sir Henr}' Tanner.

\Vg have been in the closest possible touch with the provincial and colonial
members. The\- resent the proposed changes, and they have no desire to be
associated with an institute ha\ing other objects than the original
ones — namely, to elucidate questions relating- to concrete and rein-
forced concrete and their constituents only. They m.ay be interested in steel
frame construction as used in conjunction with concrete, and in concrete as
used in conjunction with steel frame construction ; but steel frame construction
is perfectly well taken care of by that senior of all engineering societies, the
Institution of Civil Engineers, and by its existing junior associations. Should
an institution for structural engineers really be required (and we believe, as a
matter of fact, there is some scheme for one on foot), let those who are desirous
of promoting such an institution work out their own salvation. The Concrete
Institute has a raison d'etre and a wide sex)pe, and this wide scope will sulhce
for the next few decades at least.

Generally.

The last two years of the Institute's work hav-e, as we see from the records,
led to a slight increase in the members. But it would almost seem that the
Institute has been lately marking time in this respect.

We observe there is a new class of Associate Members already given in
the Annual Report, and also a class of Associates, although of course neither of
these classes actually exists at the moment, owing to the impasse referred to
above. In students there has certainly been progress ; and this we attribute to
the educational talent of the Institute's secretary.

363

THE CONCRETE INSTITUTE.

[CDNCBETEl

In l<jctLii"c work the curric uluni of the Institute lias been proHfic and tlie
subjects chosen frequently of considerable interest.

To repeat, ho\\e\er, the leading" feature of the Institute for the last year
was the work done in trying- to get the London Reinforced Concrete Regulations
put on to a sound looting", and certain other Committee work.

Unfortunately, however, the good work has been largely discounted by loss
of prestige, by dissension within the Institute and within its Council.

If the new president can now by great tact and courtesy, by going slow
in a.n\- question of change and by quietly improving" the administration retain what
is to-da\' left of the Institute's prestige, he will do well and merit the thanks of
the membership and of the nation. On the other hand, if he presses any personal
views or predilections as to the subordination of concrete and reinforced concrete
by according- structural engineering a primary position in the Institute, we are
afraid he may have to preside at the Institute's funeral.

We have, however, reason to believe that Professor Adams may be spared
such a misfortune if he hnds it possible to fulfil the assurance he gave at the
annual general meeting — namely, that he would use every endeavour to act
impartially. Further, one of the vice-presidents, who Is so strongly opposed
to the proposed change; in the original objects of the Institute, and who has
some three hundred members with him, threw out a suggestion for com-
promise that may bear fruit, as the President Indicated that he was not dis-
inclined to further such changes In the rules of the Institute as w^ould give the
provincial and the colonial member a sa}' in such important matters as are now
before that b(jdy.

If the opponents of the proposed changes achieve the withdrawal of what
to them is an obnoxious revision of the Memorandum of Association and obtain
a proper franchise for the entire membership, the}-, on their part, ought to be
read}- to assist in llie modernisation of the Articles, for they would then ha\e
achieved their j;rimar}- end of retaining the objects and titlt; of the Institute and
have gl\en ex'ery member a propL'r say in the development of this Institution.

Hut, unfortunate!}', the tension wilhin the Concrete Institute is such, that
if the President repeats the blunder of glxing' offencx' to a large section of the
membership — as he apparently did in his speech at the Institute's recent annual
dinner — he may find an immediate secession of another groujD of members who
strongly resent an}' tendency towards class distinction and may no longer care
to be associated wi'h this body in an\- form. His remarks at this dinner have
opened up fresh sources '.i'i dissension which il will not be eas\- to smooth over.
We trust, however, that this new source of troul)le may also l)e eventually
overcfjme.

OUR CONCRETE COTTAGE COMPETITION.

Every endea\-(jur is being ni.ide b} the Assessors to ccjmplete tlielr work In
judging the drawings s( iil iji lor llie above (M)m])etition, so as to enable us to
announce the resuh of same in our jul\' number.

Xo fewer than 245 designs ha\e been senl in.

364

tt3N."^ri?nc-nc;NAi:

H.M. NEW STATIONERY OFFICE.

H.M. NEW STATIONERY ^
OFFICE.

By ALBERT LAKEMAN, MSA.

' In our /.iniurv issue of last yejr toe ivere able to publish an article on this building in
its earlier stages. The follo'wing article deals mainly ivith the superstructure. — ED.

REINFORCED CONCRETE CONSTRUCTION.

Thk descrij^tiun i;i\(.'n in the previous notes (k';ilt almost entircl}- with llrj
general plan of the building's, the steel gantries which were employed during
the erection of the work, and the foundation details generally. Owing to the
whole of the superstructure being constructed with reinforced concrete, some
notes on this part of the scheme should be of interest, and although there is
naturally a great deal of repetition in such a large structure, there are features
which are somewhat out of the ordinary run of every-day construction. One of
the chief of these is provided by the arched beams which carry the building over

1 I I -L-IV r \ T±

Fig. 1. Cross Section.
H.M. New Stationery Office.

Bazon Street and connect the warehouse and office portions. This connecting
portion is about 40 ft. wide, and the distance between the two main buildings
is 2y ft. 6 in., the height extending for three floors, viz., the first, second, and
third, giving a total of 31 ft. above the first floor level. The external walls are
of concrete, having a minimum thickness of 4 in., and the arched beams occur
under these walls below the first floor level, as shown in the drawing illustrated
in Fig. 2. They have a minimum depth of 2 ft. at the centre, which increases
to 6 ft. at the springing points, the thickness being 12 in. The reinforcement
consists of six rods on the soffit at the centre, and three of these are bent up
towards the top, commencing at a point about 7 ft. from the centre line on
B 36s

ALBERT LAKEMAN.

[CDNCRETEJ

i CONMPIKTIONAU
A usif.lNKtJJiNt. ^J

II. M. NEW STATIONERY OFFICE.

o-u-h side and ihr ir.nainino time rontinuc In :. line rMn.cnlnr with the soll.t,
./„,1 ;„-,. ,-';,nir(l ^^v\\ dou n )nl,. ihc snpi>nnin- nicnilurs ;,1 the ends ol the span.

Stirrups are provided throughout the length at varying distances apart, as

shown on the drawing. A horizontal string course i8 in. deep with a

B2 367

ALBERT LAKEMAN.

[CDNCBETEJ

6 in. projection is formed at the
top of this beam, and this is also
constructed of reinforced con-
crete. The remainder of the
wall is constructed with con-
crete, reinforced with horizontal
and vertical bars, the piers be-
tween the windows acting- as
stiff eners to the horizontal por-
tions, which are designed as
deep wall beams, with twO' rods
in the lower surface. These
wall beams extend below the
floor level for a distance of
about 2 ft. , and as they take the
ends of the floor beams they are
increased tO' 6 in. in thickness
for this portion. Short stirrups

. . are provided with these main
% a reinforcing rods, and in addi-
i^ g tion the vertical rods are bent
^ ^ round them, thus .anchoring

5 5 S them to the mass of concrete

^ o

2 H above. The outer ends of the
» c **
.2 w secondary roof beams are car-

J^ > I ried by wall beams 3 ft. 4 in.

deep, these being formed by
;t 2 carrying up the parapets tO' the
£ external walls for a height of
I ft. 9 in. above the roof level.
Tlicy also ha\e a thickness of
b in., and the reinforcement
consists of two rods in the
lower and one in the upper sur-
face, with vertical rods at 6 in.
centres bent around both sets.
The floors of this con-
necting building are divided up
into three bays by main beams
24 in. deep and 8 in. wide, witli
six bars as reinforcement in tiie
tensional area, and each ol
these lias a compression flange
() ft. wide and 6 in. thick,
whereas tlie remainder of the
slabs are only 3.], in. tliick. The
secondary Ix'ams are spaced at

368

fONMPt)t"riaNAi.

H.M. NEW STATIONERY OFFICE.

Fifi. 5. Detail of Beam Reinforcement.
H.M. New Stationery Office.

5 ft 6 in. centres, .md tlu'si' \va\v a dcptli ol 12 in. and a tliickncss of 4 in.,
willi two bars \\\ ilir lower surfarc as rcinforccnuMil.

I lu' nK)f is carried 1)> a similar syst<'ni, l)ut tlu- l)canis and slabs arc all
rcdnccd in pr<)i)<)ili<)n to the h)ad to be carried, tliese beinj.,^ 100 lb. for the
lloors and 05 lb. i)er stjuare fool for the roof, in addition to the (Ic.'kI weight of
the malerials cmplovi'd. Stirrups are j)ro-
vided in ail the beams, and tlu'se are
kinked to cli]) the main reinlorcinj^ bars
tightly.

The front wall of the main building to
Stamford Street is an excellent examj)]e of
an external reinforced concrete wall, and
here the window openings are about 10 ft.
wide and h ft. high, with piers between
3 ft. 2 in. wide. The minimum thickness
which occurs over the w indow s between the
piers is 6 in., and the reinforcement in these
portions is provided by horizontal bars in
the centre of the thickness and vertical bars
in both outer and inner surfaces. The piers
generally are i ft. 3 in. thick, and they arc

reinforced with six \'ertical rods, one being placed at each corner and <me in
the centre in each surface, with links connecting the whole of the rods. The
ends of the horizontal rods in the w'all slabs are carried well into the pier, and
are lapped for a length of 18 in. Additional rods are also placed around the
window openings, and all bars coming against these at right angles are hooked
over them, and thus the whole of the reinforcement is well tied together. All
projecting mouldings are formed in the concrete, and the reinforcement is varied
to suit this by turning out the bars as required, this occurring more especially
at the top of the building, where a large cornice and the caps to the pilasters
are introduced. There is some interesting work at this point, and the design
of the reinforcement exhibits considerable skill in the manner in which it is
applied to the various members.

As stated in the previous article, the columns are spaced generally in rows
20 ft. 6 in. apart at intervals of 15 ft. 2 in., and thus the main beams have a span of
2oft. 6 in. and the secondary beams a span of 15 ft, 2 in. The size of the columns
varies from 20 in. square to 24 in. square, with eight to twelve lines of vertical
reinforcement well tied in all directions by links spaced at 8 in. centres. The
floors have been calculated to carry a super load of 3 cwt. per square foot on
the ground floor of the warehouse and 2^ cwt. on the upper floors, while in the
office building the allowance is 100 lb. per square foot for all floors, and 65 lb.
for the roofs. The slabs are only 3^ in. thick in the warehouse portion and 3 in.
thick in the oitice portion.

The main floors are desig-ncd as illustrated in Fis^s 5 and 7, which show a
portion of a beam on the ground floor. This has a maximum depth of 2 ft. 2 in.
from the top of the slab and thickness of 7 in., with six bars in the lower surface,
four of which are turned up towards the ends of the spans to take the diagonal

369

ALBERT LAKEMAN.

[CQNCKETEJ

tension, and links arc provided which pass round these main bars and also
around one small rod which is placed in the upper surface. Continuity rods are
also placed in the upper surface where the beams pass over the columns, and
liaunches are formed at the intersections.

I'lil. I). \iew (,i liiiildiii^; (111 Waterloo Koad Side.
II.M. Nkw Stationkry Oi-mce.

The st;condary beams arc sjiaccd at 5-fl. ccnlrcs and these arc buiH up in
a similar manner to the main l)eams. Tivey have a depth of iH in. and a thick-
ness of 4 in. below th(; slab, with six bars as reinforcement in the tension area.

']"he roof beams are spared in a similar m.iniiei- lo those oonstructed in the
floors, but are of slif^htly smaller sections in c<)iise((uence of tlu' lighter k)ads
to be carried. The whole of the reinforcement wIktc possible was l)uih up
into (Y)mplete skeleton ff)rm before bcinj^- |)lac-cd in the moulds to ensure accuracy
and effect economy.

370

' j,ClONMPlK-riaNAl,
At-N(ilNt.t WIN(. -~.

H.M. NEW STATIONIiRY OFFICE.

I lie conci'dc (-1111)11 )\((1 lor the
coluniiis u;is mixed uilli one j);irl oi
I'oit 1.111(1 (-(iiicnl, one j);irt of s.iiul, .iiid
1\\.) |);irls ol h.ill.ist, .iiul it will he seen
lh;il lliis is iihkIi richer lli.in lli.it
usually adopted. Tlu' object ol this
mixture was to he ahlc to allow a
greater stress per square inch on the
material, and thus a less (|uantil\- was
required and it is elaimed that economy
was effected in this wa\'.

The building has points of interest,
inasmuch as it is a complete reinforced
concrete structure throughout and the
policy of H.M. Ofiice of Works in
adopting- this material is commendable,
as the question of fire-resistance is one
of the utmost importance in a building
of this class. The larg^e area and
simplicity of the building- enabled a
great deal of repetition to be made in
the size of the mem.bers and thus the
materials and centering- could be
economically designed and used.

ELECTRICAL INSTALLATION.

The electrical installation includes
the wiring- for lighting purposes and a
separate direct current service for the
lifts and other power requirements.
The system of wiring commences at
the main lighting and power switch-
boards fixed at the east end of the
basement ; and from the lig-hting" main
board separate i9y 14 cables run to a
central distribution board on each floor
of the warehouse block, and from these
7/16 sub-mains to the fuse-boards.
The main cables are all paper insulated
and lead-covered, whilst the sub-mains
are rubber insulated run in galvanised
tubing-. Generally speaking-, the whole
of the distributing system of sub-
circuits is also run in galvanised
tubing-, which is placed on the surface
of the concrete. Fixings are obtained

^71

ALBERT LAKEMAN.

[CDNCBETD

bN- means of iron dowels cemented In, and the cutting- away for these was
executed hv the contractors for the electrical work, who installed a special
motor-driven air-compressor which drives special pneumatic hammers. The
concrete was found to be so hard that hand cutting- would have involved very
considerable expense and labour. The lamps are distributed evenly over the
whole of the warehouse portion, one being- provided for each bay of about
15 ft. by 20 ft. and the boards and switches are g-rouped near the lift wells.

The building- was desig-ned by, and is l)eing carried oul under the super-
vision of, Mr. R. j. Allison, A. R. I. B..\. , one of the prin(-ij)al architects at H.M.
Oliice of Works

The g-eneral contractors for the building- are Messrs. Perry and Co., Ltd.,
of Bow, and th<; uhol<: of the reinforced concrete was <\'irried out on t lie Henne-

y, CTONM VlIC- HON A L

H.M. NEW STATIONERY OFFICE.

hicilR" sNstcni lioin dcsii^ns |)i(|);ir((i 1)\ Messrs. Moiu licl ;in(l l*;irt luis. 'I h<-
slt'clw ork lor tlic j^atitrics w.is supplied .iiid <reet4'd by Messrs. Drew, Hear,
Perks and Co., I. id., lialtersea .Street W'Oil'Cs, and live reinloreiny; steel was
supplied l)\Messrs. Doimaii, Ia>ni^ and Co., Lid., ol M i(ldi<'sl)r()uy h. The ballast
v\as proeuri'd fioin the Mam i\i\ti- (irit Co., Rochester, and llu' <'lectrieal work is
Ikmiij^" executed 1)\ Messrs. In K i- and i'l'eenian, of 20, New iiridf^e Street, i''..C.,
to the spe(Mrieat ion ol the C hiel i'",n<^in<'er to the OHiee of \\ Orks. The heating
installation is heinj^ eanied out 1)\ .Messrs. Berry and .Sons, ol Westminster.
I'he j)hotoi^raj)hs are those of .M'-ssrs- i flla Camera Co.

Fig. 9. Arch and Buildins over j-iazon Street.
H.M. New Stationery Office.

373

THE CONCRETE INSTITUTE.

HDNCBETFJ

ANNUAL GENERAL
MEETING.

The Fifth Annual General Meeting of the Concrete Institute took
place on May 28th at Denison House, Vauxhall Bridge Road, S.W,, ivhen the Annual
Report ivas put forward, Beloiv ive gi've a summary of the Report, — ED.

A SUMMARY OF THE COUNCIL'S REPORT.

Membership. — The Concrete Institute had on May 14th, 1914, 930 members,
28 associate-members, 6 associates, 54 students, 5 special subscribers, and 16 honorary
members, makini^ a total membership of 1,039. Of this total, 360 reside in London and
its environs, 364 reside in the provinces, and 315 abroad.

Classification of Members. — The decision of the Council, that when the total
membership of all classes reached 1,000 an entrance fee of one f^uinea should be
required of members joining thereafter, has been acted upon. Furthermore, at the
beginning of the 19 13-14 session, a number of alterations were made in the Articles
of .Association, with the approval of Extraordinary General Meetings. These
alterations, in brief, extended the classification of the membership by the inclusion
of classes of associate-members, associates, and graduates. No graduates have yet
been admitted, pending the establishment of examinations. At the same time the
subscription fee for full members has been raised to two guineas per annum. Associate-
members and associates are each required to pay an entrance fee of one guinea and
an annual subscription of one guinea. Students will continue to be admitted as at
present, without an <'ntrance fee, though they will be required to pav a transfer fee
of one guinea upon Ix'ing transferred from studentship to associate-membership.

Finances. — In th<' j)revious annual report a surj)lus was reported, and attributed
chiefly to the income- liaxing been increased abnormally by the collection of a number
of subscri|)tions in arr<'ar. 'J'his year the position is reversed, in that a deficit of
/.'i6f K,-. hkI. has been realised.

Meetings. — 'Ihe number of meetings and i-ducational lectures given in the jjrevious
.Session was larg<-r ihan in any (■ar]i<'r .Session.

As the result of a ballol among members of Coimcil, the bionze m<>dal for the
best Pajx-r read in the 1912-13 .Session has been awarded to Mr. .S. l>\lander, for his
Pajx-r enlitUd " St* (I P'rauK- lUiildings in London."

Early Copies of reapers. — It having been n'|)i-esenlc(l thai some members
resident in \\m- prox'inces and abroad, or for otiiri- reasons iinable lo .attend the meetings,
are desirous of receiving copies (jf jjaj)ers read at general meetings in advance
of their publication in the Transaclions, the Council has tUxaded that in
future nienii)ers may I'eceive regularb adwanee co|)ies of |)apers upon |)a\nient of
5s. annually to cov( r the cost of postag-e, <'tc. The |)i'ivilcge of leceix'ing a<l\ance coj)i<'S
will Ix- <',\t<'nd<'d without any ^iieh prixnienl t(; ;ill llios<' members who pa\' the new
rate of >ubscrif)lion in lli^e menih; isliip cl.'is^ namcl\ , ^,'2 2s. |)cr annum.

Meetings of Junior Members. in tln' past Session informal meetings of the
junior m<int>ers of the Institut'C ha\c b<<n iiislilulMl. 'ihe mei'tings ha\'e so far han

374

.,toNMuiK-naN>u1 ANNUAL GENERAL MEETING.

h-(KI tvn P^idav iwiiini^s, llu' lirsl luo t.ikin^ |)l;u<- on April ^^id .md M.i\ ist, i<ji4.
'I'lu' altrndanci- .il lh<s<' iik'^cI iii^s has Ixcii \<i\ <ni()iiraj4inj4, and il is coiifHU-ntly
<xi)<c-lvd ihat llu' in^vliiii^s will Ix- of j^i<'al <chuat ional assistant' to junior nuinlH-rs
of iIk' InsiiiuU'.

The Scope of the Institute. — In former ainuial ifpoiK r(f< r^'ncv has lH<-n nia<i<'
to a " ConnnitU'-c ai)|)oint< il lo consicUr iIk' \\id'cn<<l scop^- of th<' ( 'on{i'<-l<' Instilulo,"
the titlo of this ( 'oiiiniilt<'<' Immmj^ sul)s<'qu<nll\ chanf^id to llu- " lnipr()v<'ni<:'nts
('oniniill<H'." An ahstract of iIk- n-porl of tiu- ConimilU'o was aj)]Mnd<d lo lh<' report
of the ("ounril for the kjii-i^ Session, in which it was stated that the (Committee was
appoinl<d to l.aU<' <'nvri4<'lic strps lo di'vrlo]) tlK- struttuial <ni;in< ■ciin^ side of the
widiMi€d scoix>, and that thi^' ('oniniilt<'0 had di'fmed for the purpose of the Institute
that " Structural Knj4ineerin^ " was that hranch of engincx-'rinj^ which de.alt with the
scientific desii^n, the construction, and the erection of structures of all kinds in any
material. 'J'he Comniitte>e further defined " Structures " as bein<4 those constructions
which are subject princij>ally to the laws of statics as opposed to those constructions
which are subject to the laws of dynamics and kinematics, such as enj;jinos and
machines. The Committee unanimously recomm<nd<d and the Council subsequently
adopted their recommendation — that a sub-title should be add<'d to the Institute, so
that the full title should be: "The Concrete Institute, an Institution for Structural
Eniiineers, Architects, etc."

Examinations for the Institute. — The C'ommittee also recomm<'nd<'d the institu-
tion of examinations in structural i-ns^ineerinj;^. Accordingly, the Council, during the past
Session, appointed an Examination Committee, which was subsequently (in December
last) merged in a nucleus Examination Board. The Examination Board has compiled
a syllabus and rules for the proposed examination, w hich are ajjpended to this rei)ort.
It is proposed to hold the first examination next year.

Alteration of the Institute's Articles. — The alterations to the Articles of
Association, j)reviouslv referred to as having been carried at the Extraordinary General
Meetings at the beginning of the Session, were made and adoj)ted at the suggestion
of the Committee.

Alteration of the Institute's Memorandum of Incorporation. — At the same time,
proj^osals were put forward for the amendment of the Memorandum of Association,
wherebv the enlarged scope would be more clearly defined, although the Committee
had in their original re])ort stated their opinion that Clause 3 (i) of the present
Memorandum did not limit the scope of the Institute to concrete and reinforced concrete,
but that the clause enabled the Institute to deal with iron (including steel), bricks,
gravel, sand, cements, and other structural materials, and their application. The
amendment proposed to Clause 3 (i) was as follows, the words to be added being
shown in black type, and the words to be omitted by italic tyi>e within square brackets :

3. (i) To advance the knowledge of concrete and reinforced concrete and other

materials employed in structural engineering, \thcir constituents,] and

to direct attention to the uses to which these materials can be best

applied.

Consequential alterations were made in other paragraphs defining the objects of the

Institute. Also, in addition, it was proposed to make an alteration consisting of

adding the words " and Associate-Member " to the word " Member " in Clause 7, which

defines the liabilities of the members, this alteration being suggested in view of the

fact that a new class of associate-members was created by the alterations to the

Articles.

Action of the Board of Trade. — When the alterations were duly submitted to
the Board of Trade, after their approval bv the general membership, the Institute was

375

THE CONCRETE INSTITUTE. [CONCBETEi

required to give, and gave, an undertaking to apply to the Court for allowance of the
alterations to the Memorandum. The Board of Trade raised certain objections however;
in particular they objected that the addition of the words " and Associate-Member " was
not an alteration of the objects of the Institute, which was the only alteration permissible
in the Memorandum of Association, and that only with the approval of the Court, The
Institute's counsel has similarly advised the Institute. The Board of Trade raised the
further objection that, as the proposed alterations to the objects appeared to have the
effect of extending the scope, they were of the opinion that the enlarged scope ought
to be shown by an alteration in the title of the Institute. The Institute's counsel has
also expressed the opinion that the resolution which was actually passed did not in
terms refer to any alteration in the Memorandum of Association, the resolution using
the words " New Regulations." Counsel expressed the opinion that the Court
might verv well take this objection and refuse the order.

Differences in the Council.— ^''^^^^^■ences have arisen in the Council as to what
action the members should be recommended to take so as to put the matter in order
before applying to the Court, and the Council has decided to place the following alterna-
tive policies before a General Meeting of the Members before going into Court : —

(a) To rescind the alterations to the Memorandum and revert to the original Memo-
randum of Association with the necessary further alterations to the Articles
to provide for Associate-Membership.
{b) To rescind the alterations to the Memorandum of Association and to repass
the same with such additional alterations as may be required to meet the
objections of the Board of Trade.
In connection with the second of these policies, the Council regret to find that a
misunderstanding has arisen as to the intention of one paragraph out of twenty-five,
namely, Clause 3 (2). If the second policy be agreed to, " concrete and reinforced
concrete " will be specially and specifically mentioned in the aforesaid clause.

Special meetings for the purpose of deciding between these policies will be convened
at the beginning of next Session.

Tlie Institute and the L.C.C. — The Council and Committees have been very
much occupied in the past Session with technical matters. In previous Reports the
action of the Institute has been recorded in respect to the Regulations made under the
provision of Section 23 of the London County Council (General Powers) Act, 1909, with
respect to the construction of buildings wholly or partly of r<'inforced concrete. The
Institute made suggestions upon a draft which was submitted by the London County
Council, and, subsequently made suggestions upon the first set of Regulations when
issued h\- the London C-oiinty Council. These suggestions for (he amendment of the
Regulations were sent to the Local (Government Board, and in June, i()i3, the London
County Council rescinded their first set of Regulations and made new Regulations,
which were the outcome of prolong<'d negotiations between technical advisers of the
Council and the Local Gov<-rnni<-nt Boar<l. The statutory notice of the intention of
th<; London Counly Council to apply to the Local Government Board for allovv^ance
w,-i> duly given to the four Sori<-li<'S named in the Act, nauK-ly, the Royal Institute of
British Architects, {\\<- Institution of ("ivil ICngin^'ers, the Surveyors' Institution, and
the Concrete Institute. 'i"he second (and revised) R<'gulations thus came before the
Societies for consideration with a vi<'vv to submitting furthe'- suggestions for amendment
to the Local Government Board. It was found that, as a result of the n<>gotiations
between the technical advisers of \h<- London County Council and th<' Local (iov<rn-
m<nt Board, many drastic alterations had h<vn made to the first set of R<'gulations,
and as the Building Acts Committ<''e of ihe L.C.C. r<'j)orte(l " in some instances they
render the Regulations som<'what more onerous than lhos<; originally adopt<'d by the
Council." The matt^-r is naturally one of <--xtr<m<- iniporlancy to th<' in<'mb<'rs of this
376

fa-00r«miUCTlCKAa

ANNUAL GENERAL MEETING.

Insliluli', luil iikkIv .is .iririMiiii^ |)r;i(lic-<' in London, hiii Ix'C.'iiis^' \]u- R^t^iilalions, w h<-n
finallv ;i|)|)r()$(l, w ill pi oh.ibly be icfcii cd to l)\ niunici|);ili(i(s in promoting Rcf^ulations
for ih<ii i<Np<(ii\<' lor.iliti<s. Tlu' ("ouniil ;nul tin- Standing C()inniilU'<'s, i.e., lli<-
Siiiiirv Standinj^ ( "oniniitt<v, \hv K<Mnf()rc<d Concn-lt' Praclicv Stan<ling Coniniilt<'<-,
the Pai lianKnlarv ($iniiiitt<'<', :\n(] iIk- 'r<'sts .Standin«4 ('()niniill<'<', liav<', th<'r<.'for<', j^ixy-n
iar<'ful (U^IaiUd consick-ralion to th<' r<'vis<'<l R<_t*ulations.

riu> Institul<''s su}4^<sti()ns as to llu' anKMidnu-nt of the s<'cond s<'l of R<'^iilations
\\<r<' s<Mit to the other t<'clinical soci<'ties, and the Institute has lx*en informed that
thev have be<'n sui)port<(i in larife part by the Royal Institute of British Architects and
bv the Surv<vors' ! n>titiiti()n. Th^' Institution of Civil I'Lnf*ine<:'rs informed the Insti-
tute that thev had not made su,«4i^<'stions for amenduK-nt in detail. The Institute's
sui^tfestions \v<'re finallv subniitt<'d to the L(x:al (iov<'rnnu'nl lioard in I)<-(<'inber last
and are now und<T consideration by the technical advisers of the London County
Council and the Local Government Board.

The Institute's Committees have been so closely occupied with tl e L.C.C. Rcj^ula-
tions that they liave not been able to do much other work, though they have a num!:)er
of subjects in hand for consideration. The details of their work are given below.

New Members of Council.— \n June, 1913, Major H. S. Rogers and Mr. Morgan
E. Y<'atnian wvve co-oj^ted as Members of Council.

President and Vice-Presidents, — In accordance with the Rules of the Institute
one Vice-President has to retire every two years, in order of seniority. Accordingly, Mr.
Edwin O. Sachs retired and was re-elected a Vice-President in November, 1913.

Mr. E. P. Wells's term of office as President expiring in May, Professor Henry
Adams was appointed President for the ensuing two years. The appointment of
Professor Adams as President created a vacancy among the Vice-Presidents — who are
required to number five — which the Council decided to fill by the appointment of Mr,
H. D. Searles-Wood as \'ice-President. This will create a vacancy among the ordinary
Members of Council.

The following Members of Council have resigned during the past year : — Mr. E. J.
Lovegrove and Mr. Henry Tanner. The foregoing vacancies among ordinary Members
of Council have not yet been filled.

The Late Mr. W. G. Kirkaldy. — The Council deeply regret to record the decease
of Mr, William G, Kirkaldy, an esteemed Member of Council, Chairman of the Tests
Standing Committee, and one of the representatives of the Concrete Institute on the
Joint Committee on Reinforced Concrete conducted by the Royal Institute of British
Architects.

Finance and General Purposes Committee. — The Finance and General Purposes
Committee has held regular meetings preliminary to each Council meeting, and the
general results of their deliberations are contained in the foregoing pai ticulars of the
Council's work for the year.

Science Standing Committee. — In addition to considering the L.C.C. Regu-
lations for Reinforced Concrete, the Science Standing Committee has been concerned
with the revision of the Standard Notation for Structural Engineering Calculations, in
view of the criticisms made at the General Meeting when the draft report on the matter
was submitted. The finally revised notation will be issued shortly. In conjunction
with the Reinforced Concrete Practice Standing Committee a Standard Specification
for Reinforced Concrete work has been prepared in draft and will be submitted for
discussion at a General Meeting next Session.

The Science Standing Committee has the following further matters under
consideration : —

1. Standardisation of joints and connections in reinforced coacrete.

2. Advice to Superintendents of reinforced concrete work.

3. Amendment of the Standard Specification for Cement. 377

THE CONCRETE INSTITUTE. [OQNCBETE]

4. Co-ordination of the Standard Specification for structural steel of all kinds.

5. The adhesion of and friction between concrete and steel.

6. Reinforced concrete piles.

7. The effect of sewage upon concrete.

. 8. The effect of oils and fats on concrete.

Reinforced Concrete Practice Standing Committee, — During the past Session
the Reinforced Concrete Practice Standing Committee has met, in conjunction
with the other Standing Committees and the Council, to consider the L.C.C. Regula-
tions for Reinforced Concrete Work. The Committee has held joint meetings also
with delegates of the Quantity Surveyors' Association, and with members of the Concrete
Institute who are Quantity Surveyors by profession. Several meetings were held, as
a result of which a draft report on a Standard Method of Measurement for Reinforced
Concrete was submitted for discussion at a General Meeting. Since this meeting, the
report has been considered by the National Federation of Building Trades Employers
of Great Britain and Ireland and by the Institute of Builders, who have made sugges-
tions for its amendment in certain particulars. Meetings will be subsequently convened
to consider the various criticisms and steps taken to issue a final report in due course.

The Committee has prepared, in conjunction with the Science Committee, a draft
Standard Specification for Reinforced Concrete Work, as recorded above.

The Reinforced Concrete Practice Standing Committee has the following further
matters under consideration : —

1. Advice to clerks of works, inspectors and foremen as to methods of properly executing

concrete and reinforced concrete work and of preventing defects and failures.

2. Regulations, recommendations of Joint Committees, and various methods of calculation

in respect to the design of reinforced concrete and the like

3. Forms and centering for reinforced concrete work.

4. Standard concrete mixtures for general purposes.

5. The use of cinder, ash, clinker, and breeze in concrete.

6. Means of keeping reinforcements in place when concreting.

7. Methods of making concrete watertight and of waterproofing concrete.

Tests Standing Committee and Parliamentary Standing Committee. —
The Tests Standing Committee and the Parliamentary Standing Committee have held
joint meetings with the Council and the other Standing Committees, as previously
mentioned.

The Tests Standing Conimittte has the following matters under consideration : —

1. The effect ui)on steel of the i)resence of sulphur in aggregates.

2. The grading of aggregates.

3. The expansion and deterioration of concrete due to changes of atmospheric temperature.

4. The effect of the use of sodium silicate on the surface of concrete as affecting

reinforcing metal.

5. The erratic results obtaiiu-d by the Vicat needle in ascertaining the initial setting time

of cement.

6. The collection of data regarding the elastic moduli of concrete for stresses within

working limits.
Investigation Committee. — I he Investigation Committee has held meetings

at which have been considered (a) the action of the Local GovernnK'nl Board in r<>s|K'ct
to the periods allowed for th<- repayment of loans sanctioned by them to Local Aulhori-
ti<'S for the construction of works of r<'inf(>rc(d ("oncr<'t<' ; and (h) rej)orts of failure's of
reinforced concrete structures. In conneclion with the l.iller, a Standard Report Form
for the us<' of observers of (k-fects and failtire-s has been diawn up.

Joint Committee on Loads on Highway Bridges. — The Joint Committee
on Loads on llii;li\vay l)ii<lg(s, (onduclcd by the ('oncrele Institute, has been engaged
in the drafting of its rejjort, jnit it is not yet completed. It is expected that it will
be ready for presentation for discussion at a Geiie'ral Mee'ting next Session.

Attache'd to the; Re-jx^rt, in foiin of an Apj)e'ndix, we're' given the' Rtdes anil
.Syllabus of the- proj)Osed Examination, and we- give- below particulars of same, as
follows : —
378

[^'SmNS'im?^] ANNUAL GENERAL MEETING.

APPENDIX.
Rules of the Examination.

TIk.' I*l\;iiiiiii;iti()n is dix'uh*! into two p.irls :

Part I. Sci<ntilic (for ( Ir;i(hi;it<'shi|)), consists of wiitt^n |j;i|)<rs (1< ;ilin^ witli

tli<' scii'mifu- basis of tin- sul)j<'tl.
Pari 11. 'l\rhnical (for .\ssiH'ial<'-M<'nilH rshi|)), consists of \\iiit<n |)a|)4rs and
vivd-vocc examinations, d<'alin<4 with tlu' ti'chnolo^y of tln' sul)j((t.
riu' <'xaniination is lirld lialf-\i'aily in May and Octolwr.

1. Tlio a},H> of till' ( andidalc at the date of examination is not restricted.

2. A candidate n\a\ enter for Part 1. alone, and if successful lit- ma\ take Part II. at a
subsequent I'^xaniinat ion. A candidate is not permitted to i)resent himself for Part II. unless
he has passed Part 1., or one of the Pxaminations (see below) wliiili are accepted by the
Council in lieu of Part 1. ; but a candidate may enter for Parts I. and II. together.

In Part II. a candidate must enter for two at least of the subjects, one of whi(h must be
Structural luigineering. The subject or subje<ts in which he is successful will be
named on the Ortihcate.

.^. The Examination is confined to Students and (iraduates of the Institute.

4. Candidates exempted from Part I. may be registered as Cracluates without passing that
part of the ICxamination, but no Certificate will be issued.

5. Applications to be admitted to either or both parts of the Examination must be made
on the prescribed form, must be received by the Secretary not later than one month before the
date of the Examination, and must be accompanied by the necessary fee.

6. The fee for either part of the Examination taken separately is j^i is. (One Cnunea). If
the two parts are taken at one time the fee for the whole Examination is jCi iis. 6d. (One and
a Half Guineas).

7. Each applicant will be informed wdien he has been accepted as a candidate, after
which the fee will be forfeited if he does not present himself at the Examination for which he
has entered.

8. Every candidate who qualifies in. or is exempted from Part I. of the Examination,
will, on passing Part II., be granted a Certificate of having passed the Associate-Membership
Examination. On passing Part I. a Certificate of having passed the Graduateship Examina-
tion w-ill be granted.

9. The fact of passing the Examination does not exempt a candidate from the other
requirements for election in accordance with the Articles and By-laws of the Institute.

10. Candidates are required to attend at the Examination Room fifteen minutes before the
hour fixed for the first paper to be taken by them.

11. Drawing and mathematical instruments, including slide-rules, may be used. The
use of books will not be allowed in Part I., but in Part II. candidates may bring and use text-
books and note-books.

The following will be exempt from the requirement to sit for Part I. of the Examination.
(a) Bachelor of Science.
(d) Bachelor of Engineering.

(d) Associate Member of the Institution of Mechanical Engineers (by examination).

(e) Associate of the Royal Institute of British Architects (by examination).
(/) The holder of a commission in the Royal Engineers.

ig) The holder of such other degree or qualification as the Council may determine
in specific cases.

Syllabus of the Examination.

Part I. (A) Compulsory .Subjfxts.

I. Principles of Statics and Theory of Structures. — Forces acting on a rigid
body; composition and resolution of forces; couples; moments of forces; conditions of
equilibrium, with application to loaded structures. Graphical and analytical treatment
of the foregoing. Centre of gravity ; specific gravity.

Graphic and analytic methods for the calculation of bending moments, shearing
forces, and the stresses in individual members of framed structures loaded at the joints ;
reciprocal diagrams ; incomplete frames and redundant members ; buckling of struts ;
effect of different end fastenings on their resistance; combined stresses; section
modulus ; methods of dealing with statically indeterminate problems, as beams supported
at three points, etc. ; travelling loads ; rigid and hinged arches ; stresses due to weight
of structures ; theory of earth pressure and of foundations ; stability of masonrv and
brickwork structures.

THE CONCRETE INSTITUTE. KPNQ3E3^

2. Strength and Elasticity of Materials.— Fhyslcn] properties and elastic con-
stants of cast iron, \vroui>ht irt)n, sleM;"!, timber, stone, concrete, cement, and other
materials ; relation of stress and strain ; limit of elasticity ; yield-point ; Young's
modulus ; coefficient of rigidity ; extension and lateral contraction ; resistance within the
elastic limit in tension, compression, shear, and torsion ; strength and deflection in
simple cases of bending; beams of uniform resistance; reinforced concrete beams.

Ultimate strength with different modes of loading; plasticity and permanent set;
working stress ; phenomena in an ordinary tensile test ; stress-strain diagrams ; suddenly
applied and impulsive loads; resilience; fatigue of metals; effects of hardening,
tempering, and annealing.

Forms and arrangements of testing machines for tension, compression, torsion, and
bending tests ; instruments for measuring extension, compression, and twist ; forms of
test-pieces and arrangements for holding them ; methods of ordinary commercial testing ;
percentage of elongation and contraction of area ; test conditions in specifications for
the principal materials of construction.

Part I. (B) Selective Subjects.

Two of the following subjects must be taken in addition to the compulsory
subjects : —

3. Chemistry. — Constitution of matter; chemical elements; Dalton's atomic
theorv ; Newland's law of octaves ; Mendeleeff 's law of periodicity ; modes of chemical
action ; atomicity ; analysis and synthesis ; composition of materials employed in
structural engineering.

4. Physics. (Note : A candidate taking this subject must be prepared to answer
questions in three of the five sections.)

Sound. — Nature of sound; pitch, intensity, and timbre; transmitting media; velocity
of sound; sound waves; vibrating strings, plates, and membranes; resonance; inter-
ference ; reflection and absorption of sound.

Light. — Theories of Light ; transmitting medium ; velocity of light ; solar spectrum ;
laws of reflection ; ])hotometry ; candle-power ; candle-feet ; absorption of light ; colour ;
polarised light ; action of lenses ; telescope and microscope.

Heai.— Sensible and latent heat ; thermometers ; pyrometers ; effect of change of
temperature in solids, liquids, and gases; transfer of heat; radiation; conduction and
convection; relative conductivity; thermal units; Joule's equivalent; thermal capacity;
specific heat; combustion.

Magnetism. — Magnets; magnetic phenomena; magnetic field; polarity; the
mariner's compass; magnetic meridian; deviation and declination of the compass;
inclination or dip; induction; galvanometers.

Electricity. — Static and voltaic electricity; induction; conductors; electro-negative
and electro-positive elements; electrolysis; lightning; system of electrical transmission;
electrical units; measureni<nt of <k'Ctrical work; Ohm's law; principles of arc and
incandescent lighting.

5. Hydraulics. — Pressure on surfaces; centre of pressure; strength and stability
of structur<s supporting water pressure; laws of fluid friction; impact of water on
surfaces ; storage of wat<'r and construction of reservoirs.

6. Geology. — Classification of rocks; succession of strata in aqueous formations;
explanation of geological terms ; glacial drift ; conditions of deposition in fresh and
sea water; denudation; disintegration and chemical decomposition of rocks; method
of dealing with bad ground for <'ngine<'ring works.

7. Geodesy, — 'f'h<- th<'ory, structur<', and a<ljustm<nt of th<' j)rincipal surveying
and levelling instrum<-nts, and the- princij)k's of their <'mj)loym<'nt under various con-
ditions; land surveying; contouring; k-vi-lling and us<' of theodolit<'.

Part II. Tkcmnkai..

Subject S nuist In- t.-ikcn 1)\ all candidat<\s, and at l<-ast one other subject.

8. Structural Engineering (Generally L — M-.avvi'.ih of construction; loads— dead
loads (dislribut<d and con(<ntrat<(i), liv<- loads (rolling and suddenly ap[)li<'d) ; IxMiding
moments; resistance monK-nts; str<'ss<'s and strains; sh<'ar stresses; dell<H-tion ;
secondary stresses; fatigue of metals; safety factors; wind i)r<'ssures ; standard sections
of rolk'd st<-el ; j)rofX'rt)<-s of sections; girders rolhd sections (simpk' and compound),

380

r.^coNM-purrioNAiJ ANNUAL GENERAL MEETING.

plato \v<'l) and laltic<' \\<1), trusMcl fi anu- ; j)illars, colimins, staiuliioiis, |)i<Ts and striils
geiKTallv ; <'(T<Mitric loadini; ; fixity of <ii<ls; ; roofs symnu'trical and iinsynniK-lrical
trusses; connortion of j^arts ; bridf<<'s <4ii(k'r, siisinnsion, rantilov<'r; archos — <'laslic
rib, ri<:jid and briictnl, two and tlir<x> pivot<'<l ; nKthods of oroction ; testinj^ and inspecting
materials of construction; <lT4'Ct of workshop processes on steel; mass retaininj^ walls
and tluMr stabilit\ aj^ainst waUr ])r<ssur<' and <'arth pressure; pressur<-s in silos, bins,
and liopiMMs.

9. Reinforced Concrete Construction.— Cn^nern] principles; .idvant^a^es and dis-
advantai^t>s of r<'inforc<'d concrete; niat<'rials of construction and their testinj^; nature
and propertii's of materials for concrete; mixing concrete by hand and machine; effect
of frost and precautions to obviate damage ; laying concrete ; testing actual concrete
used; testing comj)let<xl structures; failures and causes; conij)arison of cost with other
methods of construction; fir<-r<'sisting projx^rties ; causes affecting expansion and con-
traction; surface finish, durability and maintenance; form work (centering, shuttering,
strutting, moulds, etc.), precautions in fixing, order and periods of removal.

Routine of designing; arrangement of roof and floor slabs, cross beams, main
beams, and pillars; loads on floors; calculation of reinforcement for various parts;
loads on foundations; rough estimates of cost; rules and regulations.

10. Steel Frame Construction. — Order of procedure in designing ; external forces,
wind, snow, etc. ; arrangement of roofs ; loads on floors ; arrangements of main and
cross girders and stanchions ; caps and base plates ; grillages ; junctions ; erection ; brick
and stone panels and casings; protection against fire; painting; rough estimates of
cost ; rules and regulations.

Candidates desirous of being examined in Masonry, Bridgework, or any other
branch of Structural Engineering not specified above may be so examined subject
to the approval of the Examination Board and upon notifying the Secretary at least
six weeks beforehand.

THE ANNUAL GENERAL MEETING.
The Annual General Meeting of the Institute was held at Denison House, Vauxhall
Bridge Road, S.W., with the outgoing President, Mr. E. P. Wells, J. P., in the chair.
Unfortunately, there was only a very small attendance, and the discussion was thus
kept within merely formal limits. We present a summary below of such discussion
as there was, at the same time mentioning that the new President, Professor Henry
Adams, M.Inst.C.E., was installed in the chair and took charge of the conclusion of
the meeting.

A special feature of the proceedings was the presentation of a medal to Mr. S,
Bylander for his excellent paper, entitled " Steel Frame Buildings in London," which
token he certainly merited.

DISCUSSION.

The President, in moving the adoption of the Report and Accounts, referred
specially to the time devoted to the new Regulations upon Reinforced Concrete, which
had occupied many hours. He believed the Regulations would become law in a very
short time, and most of those interested in reinforced concrete, he was afraid, would
find them very stringent indeed. There was a lot of other work to be carried on in
the next 3^ear, which had had to be deferred owing to the amount of time that had
been spent on these Regulations.

Sir Henry Tanner, Kt., I.S.O., seconded the motion. The Council were to be
congratulated on the increased amount of work they had done during the past year,
and the number of papers which had been read must add much to the usefulness of
the Institute.

As to the financial situation, they had had some undue expenditure during the
past year, but he was very glad to hear the President say that he thought, proceeding
as they were, they should be in a better condition at the end of the next financial year.

Mr. Edwin O. Sachs, F. R.S.Ed., did not w^ish to occupy their time on the annual
report at a short formal meeting of that description, with a small quorum present. He

c 381

THE CONCRETE INSTITUTE. [CQNCBETE]

congratulated the Institute on the excellent work w hich it had done in connection with
the London County Council Reinforced Concrete Regulations. The work had been
most studiously and carefully undertaken, and they hoped that there would be a
successful issue to what had been done in that direction. It was a matter for
congratulation that the papers had been more numerous and that some of them had
been so interesting.

The only point of criticism he wished to raise at the moment was in regard to
what he might term the " Reorganisation " scheme. It struck him — and he spoke on
behalf of a large number of members not resident in London — that the Council had
been trying to go too fast, and that much trouble and friction could have been avoided
by going slowly. There had been not only an admitted attempt to materially change
the policy of the Institute, but that change had unfortunately been accompanied by,
what he would term by courtes}', some most unfortunate errors or misunderstandings,
and considerable muddling, which had not conduced to the prestige of the Institute.

They all hoped, he was sure — and he thus emphasised it on behalf of a large
number of country members — that the coming year would find some way out of these
troubles, that compromise might be found to be the suitable way out, and that Professor
Adams in his year of office might not have a troublous, but a pleasant time to look
back upon when he ended the very difficult work of presiding over the meetings of
the Concrete Institute.

Mr. H. D. Searles-Wood, F.R.I.B.A., echoed Mr. Sachs' sentiment, and hoped
there would be a little careful consideration, that they might resume their harmonious
meetings again.

The Chairman put the Resolution to the meeting, and it was unanimously adopted.

The President then presented the bronze medal of the Institute to Mr. S. Bylander
for the best paper that was read in the Session 1912-13. It was a most excellent
paper.

Mr. Bylander, in acknowledging the compliment, said he considered that the
Concrete Institute was doing real good work for the engineering profession at large
and reinforced concrete and steel-vv'ork in particular.

The President said the last important business was for him to vacate the chair,
after being in it for two years, and to instal Professor Henry Adams as the President
for the ensuing two years. He desired to thank all the members for the extreme
kindness they had shown him. In asking Professor Adams to take the chair, he hoped
at the end of his term he would be able to announce an increase in the membership,
and he trusted that the Institute would be more looked up to than it was at the
present time.

ProfeSoOR Adams, NLInst.C.E., then took the chair. He said that during his
term of office he should use his best endeavours to serve them faithfully and impartially
so long as he occupied the chair. Whatever his personal opinions might be upon any
matter that came before the Institute, he should feel in duty bound, not only loyally to
support, but to give effect, to the best of his ability, to the wishes of the majority; and
he hoped that in a very short time they should be able to find some m<>thod by which
the members all over the world would be able to have a voice in the management of
the Institute.

Mr. H. D. Skaki.es- Wood, i^\R.I. B.A., proposed a vote of thanks to the out-
going President.

Mr. E. Morgan Yeatman, M.A., in seconding the vote of thanks, said he hoped
that in the position of past-President Mr. Wells would continiH' to gi\e the Institute
his assistance on th<; Council.

Tlif Resolution was carried by acclamation.

Mr. Weij.s, in r<'liirning thanks, remarked that his best end<'avours would be at
the service; of the Institute.

382

tVF-NCilNh I K'lNCi —

PANAMA-PACIFIC EXPOSITION.

m II I

PANAMA - PACIFIC
EXPOSITION.

REDUCING THE
FIRE HAZARD.

Corner of Market anH Kearny Streets, San Francisco.
PanamaPac'ikic Exposition

By JOHN GEO. LEIGH.

In the folloiving article it is
shown hoiv concrete and rein-
forced concrete ha've entered
into the scheme of building for
this Exhibition, primarily ivith
a ■vietu to protection from fire.
-ED,

\'iHi\G with the marvellous resources of the country tributary to San Francisco

are the advantages which have been conferred upon the city by geographical

position and a splendid

harbour. The commerce of

the port has grown year by

year, ever quickened by the

opening of the Pacific, the

discoveries in Alaska, the

awakening of China and

Japan, the acquisition by

the United States of its

island possessions, and, last \

but not least, by the certain

completion of the Panama

Canal.

To celebrate this great
event, and commemorate,
unofficially, the city's resur-
rection from the overwhelm-
ing catastrophes of 1906,
San Francisco is preparing
a magnificent pageant, by
which, coupled with a
pledge to receive them with
true Californian hospitality,

C2 383

Fig. 1. San Francisco and its Environs.
Panama-Pacihc E.xposition.

JOHN GEO. LEIGH.

lOQNCBETEJ

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it hopes to attract ten millions
of people g-athered from all
quarters of the world. Already
visitors to San Francisco find
it difficult to realise that eight
years ago practically the entire
city — excepting a residential
district on the north-west and
a fringe of houses in another
corner — was little better than a
mass of smouldering ruins.
Hosts of friends rose up to
succour it, giving its people
hope and courage in the great,
though seemingly impossible,
work that lay before them.
The result is a San Francisco
even more beautiful and im-
pressive than that of former
days — a triumph, on the one
hand, of honest wooden struc-
tures and, on the other, of
steel-frame and reinforced
concrete. Rivalling as a
monument to human skill and
industry even the Panama
Canal and International Ex-
position, which, on the day
it opens, will represent an
aggregate expenditure of
;£,' 1 0,000,000, will be the new-
built city.

In view of the proximity
of the latter to large lumber-
producing centres and the
necessarily temporary nature
of exhibition structures, the
r^xposition authorities have
endeavoured to eliminate so
far as possible the general use
of building materials such as
steel, brick, stone and con-
crete. Very conspicuous, how-
ever, in their construction
programme have loomed the
questions of fire prevention
and protection, and it is with

T J, C'ON.M UMKTlONAl.l
(tVt:N(.lNKl.RtN(i — i.

PANAMA-PACIFIC EXPOSITION.

tliis sidr of tlieir aiiivitiis ihal llic j)rcsi'iit arli(le will primarily deal.
iMoin tlu" i^cneral i)laii <^f tin- grounds and l)uil(iin^s {Fi^. 2) it will he seen
tiial llir main exiiibilioii paiaci's are IweKc in number. Of liiesc- eij^lit are
C()inj)iised in a central i^innj), the walls of llu- various huildinj^s l)einj^- treated

Fii

(1) Palace of Machinery. (2) Palace of Horticulture.
Panama-Pacific Exposition.

with colonnades and otlier architectural features serving- as sides of the
connecting- courts and avenues. Here and there, also, are placed
various arches, towers, etc. The four remaining buildings form separatf'
units, the Palaces of Macninery and of Fine Arts flanking- respectively the
eastern and western extremities of the main group, while the Horticulture

385

JOHN GEO. LEIGH.

[CQNCBET E]

Palace and Festival Hall are >et in grardens to the south. In the centre of the
south line ot tJie main yroup, frontino- the main entrance to the Exposition and

Fig. 4. Palace of Fine Arts.

3H6

Fig. 5. The Tower Gate.
l^ANA.M A- Pacific Exi'OSITION.

on the north and south axis,
is the Tower Gate {Fig. 5),
a sculptured mass rising- to
a heig"ht of 435 ft. — leading-
from the Court of the
Universe to the Court of
Honour. That this g-rouping
involves a g-reat fire risk is
suiliciently evident from the
fact that — with the exception
of the Palace of Pine Arts,
the Main Entrance lower,
and the dome and dome
substructure of ihe Palace
of Horticulture — timber is
exclusively employed in the
frames, wall studding-, and
slu-athing- of all the build-
ings. To reduce tliis hazard
the a u t h o r i t i e s have
adopted several extra-
ordinary measures a n d
introduced not a lew
noteworthy innovations in
exhibition ])uilding- c o li-
st met ion. A m o n g" tile
foiincr mav be mentioned a
fine (•(|uij)ment of fire-hg-ht-
iiig- apparatus, su(^h as
motor-driven lire engines,
iiosi' wag-ons, and liook and

J CONyilMKTlONAl.
'v l.NdlNlA.K'INCi —

PANAMA-PACIFIC EXPOSITION.

lacklcr triic'ks; hij^li-pi cssiuc .in<l sccond.-iiy water syslciiis lliroii^lioiil llu'
orounds and huildiiij^s, wilh static |)i cssiii is ol rcsiXMt i\ <-l\ ;^()o 11). aiul z^a 11).
to <H) 11). piT s(|. iiu-li ; autoinatii- s|)i iiiklci s t hi oiii^hoiit llu- inlfiior ol the huild-
inj^s, and open ( orncr spiii>l<K'i- hclxM'fn buildings ami on huildin^'-s facing each
DtluM-; an automatic tiro alarm svslc-m, and such i)r()t<.'ct i\ c dc\ ici-s as wht'cl and
liand chemical c\tiniL;uishcrs. I<:spcciallyvalual)]c, howcxcr, in the event of danger
should he the coiicreti' " the walls " extending- from the ground to the tops

Fif4. 6. Concrete " Fire Wall " —Palace of Education.
Panama-Pacific Exposition.

of the various parapets and — v, ith the object of preventing the spread of fire —
subdividing- the main group of buildings into separate units.

As indicated in Fig. 2, these walls are erected at the ends of structures
connecting two buildings across an intervening court. They are composed of
a 6-in. curtain wall reinforced by h in. sq. steel bars, i8 in. centres in both
directions, and are supported by concrete spandrel beams, which, in turn, are
supported by reinforced concrete columns, resting upon concrete caps supported
on driven wooden piles. These " fire walls " are used in place of the regular con-

387

JOHN CEO. LEIGH.

[QONCBKll IJ

9uiiinj ani -I,

2' . <• ijllilj »«'

sicno* Tfuoaoa csirat

Of BtAII. I

StCTIOI t - t.

tliritTtji :? TYfiotL coLunn
sBOti'z kiiiroHCttfr.

Sotlt HO. " Hi.

mi i StCTIOI SHOtiia otrtii
or rrnciL wtu HKiiroHOtuttt.

Fifi. 7. Typical D<:tails <,f " Fire Wall - Construction.
Panama-Pacific IIxhosition.

388

j,C0NMkMK-I10NAi;
«VEJsl(.lNl-LWlN(. — .

PANAMA-PACIFIC EXPOSITION.

slriu t'u.n of limber coiiuniis, hy hykrill slicilliinj;- (j^rooved \v<j<k1 sheathiii^'^ lalli)
:iiui |)l;islii-. In F/<,'. 7 will In- loiiiul some tyi)i(<'il details of this " fire wall

Concrete " Fire Wall."" view showing form work.
Panama-Pacific Exposition.

construction, Figs. 8 and 9 beings photog-raphs of walls taken during- the progress
of the work.

A careful study of other types of fire-resisting- walls, such as brick self-
supporting- walls and steel
columns and beams with an
8-in. brick or 6-in. concrete
curtain wall, resulted in the
selection of the above-
mentioned type as the most
economical in respect both
of cost and speed of erec-
tion. In this inquiry a con-
crete wall 6 in. thick was
considered equivalent for
fire-resisting- purposes to an
8 in. brick wall. The con-
crete which has been used
is a mixture of cement,
sand, g-ravel, and blue trap
rock, in the proportions of
one part cement to six of
aggreg-ate, the various
parts of the latter being

determined from time to time bv laboratory tests. The average cost of this
wall, including curtain wall, beams and columns, and reinforcing steel and
beams, has been approximately 2s. id. per sq. foot of surface.

389

Fig. 9.

C nciet( " Fire Wall," view showing arrangement of reinforcing
rods in concrete beam.

Panama-Pacific Exposition.

JOHN GEO. LEIGH.

fOGlNCBETEJ

Other fire-resisting- materials are being used in the construction of the
Palace of Fine Arts [Fig. 4). Though isolated from the main g-roup of build-
ing's, and therefore less liable to fire risks, this edifice has called for special
protection, because of the anticipated valuable exhibits for which it has been
prepared. The Fine Arts Palace, consequently, will be constructed with a
steel frame, with walls and roof of cement plaster applied to an expanded metal
lath, known as "Trussit," manufactured by the General Fireproofing- Com-
pany, of New York and
34 and 36, Gresham
Street, London. T h e
roof slab is approxi-
mately 3 in. thick, w-hile
the vertical walls have a
thickness of 2^ in. The
trussit, 24 gauge and
I in. thick, is laid hori-
zontally, and fastened to
the steel frame (see
■^ Fig. 10) by means of
.° special wire clips placed
2 5 in. on centres. The
corrugations of the lath
t, interlock at the ends, and
* are fastened with 16-
gauge tie wires at inter-
; vals of 12 in.
*- The cement plaster

■; used consists of one part
? Portland cement, three
parts sand, and a small
amount of hair, well
tempered with lime mor-
tar to set up hard and
firm. The metal lath is
supported temporarily on
the inside face by
studding, and the first
coat of plaster is ap-
plied to the fabric on the
outside and llcjaled lo an even surface with a depth of at least -y in. over the
extreme projections of the melal. After the first coat has set, the temporary
studding is removeci and ihc ()|)posite si(k' of the melal j)lasteri'd as noted for
the first coat, allouiiig for a total thickness of 2}, in., including the final
plaster coat. I'his gives, in <lTcct, a reinforced wall of minimum thickness.
C(jncrete, it may be explained, was not used, for the simple reason that the
necessarily thicker wall w(>iild have been more costly. The final coat is of

Fiji. 10.

Trussit Wall and Roof Reinforcement.
I^anama-Pacii IC Exposition.

390

PANAMA-PACIFIC EXPOSITION.

hard \\;ill pla.sttT, coloiiri'd .'iiul si ipj^lcd in iinilalion of trav<Ttinc marble —
tin- rliaiactfristir linish siiiracc on all the l'"xposili()ii j)ala(H's.

A wall const iiution similar to that just di'srrilx'd will Ix- usfd for tlu-
Main Iowim (iatc, f\(C|)l thai ihc j)lasUi- wall will he su])))oilcd 1)\ a woodiii
insti'ad of a slci-l frame. in the (l<sis4n of this tower the type of const rud ion
adopted is a steel striieture uhieli supports the timber framework of the lloors
anil walls. This, although cv'rtainly not rirej)roof, ma\ be t<-rmed fire-resistin^'^,
and an api)roaih to what is commonly known as "mill construction." 'I he
jLjeneral frame of the walls i> buill up of h-in. l)y h-in. ])()sts, about Hit. on
ci'ntres, with iiorixontal j^irts lo ft. centres, all with flush outside surfaces. To

't:ficji J.J.

Fig. 11. Typical Details of Transformer Vault Construction.
Panama-Pacific Exposition.

this framework is fastened the metal lath, the ribs of which run horizontally,
and this in turn is attached to the supports with i.^-in. galvanised iron staples

9 g-auge, 6 in. centres. The cement plaster is then applied as in the case of the
Palace of Fine Arts.

Alternate current will be distributed in conduits throughout the Exposition
grounds at 4,000 volts, and will be stepped down, where required, to the
adopted secondary voltages. For this purpose suitable fireproof transformer
vaults, built of reinforced concrete throughout, are placed in all the main
building-s in situations indicated in the g-eneral plan. Fig. 2. These vaults, of
which typical details are shown in Fig. 11, are approximately 10 ft. by 10 ft. by

10 ft. hig-h, having- walls reinforced with |-in. sq. bars, 18 in. on centres hori-

39'

JOHN GEO. LEIGH.

ICDISCBETEi

zontallv and vertically. In Fig. 12 are Illustrated two of the vaults in course of
construction.

Another use of concrete likely to be of interest to many readers may be
noted in connection with the footing g-rillages. These generally, whether for
pile or spread footings on earth, are of timber; elsewhere, however, and con-
spicuously in the case of the Main Tower Gate, they are of concrete, reinforced

li;^. \i. (Concrete- 'J'ransforiiier \aulis.

(1) In the Mines and Mctallnrfiy Falace ; and (2) In the Varied Industries Palace.

I'anama-Pacii'IC Exposition.

with steel bars. The footings of this structure are twelve in number and of
three different sizes, the largest — 14 ft. 6 in. by 17 fl. and 4 ft. 9 in. thick —
capping a cluster of 42 wooden piles and supporting the cast-steel base of a
tower leg. For a building of such magnitude it was deemed advisable to
abandon the use of timber for grillage and adopt either a steel I beam grillage
embedded in concrete or a reinforced concrete slal), and pre fere nee was given
to the latter design because of its marked economy.
392

y^CONMPlK-riaNAl'

PANAMA-PACIFIC EXPOSITION.

raUiiii^ llu' l*'-\j)()slli()n as a whole, llurc can l)c' no (|U(sli()n that ihc firc-
ri'sistinj^ (|uahlit's ol coiKM'ctt', cornljiiu-d willi its strcnj^th and clH-apncss when
compared willi steel and brick const i net ion, ha\c ai)j)ealed with ^reat force to

V\-A. 13. Court of Palms.
Panama-Pacific Exposition.

the authorities, and that in many minor directions also — e.g., as foundation
for the wooden manholes for both the sewer and water systems, as backing

Fig. 14. Court of the Four Seasons.
Panama-Pacific Exposition.

for the electric conduits, as manholes for the high pressure water system, and
as steps and caps for balustrades — the material has been warmly welcomed.

393

JOHN GEO. LEIGH.

CDNCBETEi

Supplementary to the Festival Hall within the Exposition grounds proper,
and for the purpose of accommodating- the various conventions, musical gather-
ing's and other functions of kindred character which are being arranged for the
coming- \ear, the Exposition Company is building at the junction of
\'an Xess A\ enue and Market Street — in what is fitly described as the civic
centre of San Francisco— a fireproof permanent Auditorium. This building,
intended as a gift to the municipality and to form part of the new city planning
scheme, covers an area of 113,438 sq. ft., and will have seating capacity for
10,000 persons. The materials which are being used in construction are steel,
stone, brick, terra cotta and concrete. The foundations and footings are of
mass concrete, one part cemicnt, three parts sand, and four parts broken rock ;
while all retaining and partition walls and corresponding foundations are of
concrete of the proportions i :2 14, the whole being reinforced where required
with deformed bars. The superstructure is a steel frame, fireproofed with
concrete of a similar mix, the columns and steel beams, which are reinforced
with Clinton welded fabric, 5 in. by 9 in. mesh, 12 and 13 wire, being so
covered that there is a minimum of 2 in. of fire-proofing on all parts. The
floors throughout are reinforced concrete slabs, spans up to 6 ft. 8 in. being
3^ in. thick, reinforced with Clinton welded fabric, 3 in. by 16 in. mesh, 3 and
8 wire, gi\ing a net area of "187 per foot of width. Slabs from 6 ft. 8 in. to

8 ft. 8 in. are 4 in. thick,

" " "" "■""•''■'■ and spans greater than

8 ft. 8 in. are 4 in. thick,
both being reinforced with
2^ in. by 16 in. mesh, 3
and 8 wire. The fabric in
all cases is continuous over
the tops of the floor beams.
The basement and main
floors under the Audi-
torium, respectively 5^ in.
and 7 in. thick, are laid
directly upon the ground.
The l)alcony construction,
also of concrete, is banked
up with G-in. walls and
slabs, reinforced with de-
formed bars.

The grounds dedicated
to the j)urposes of the Ex-
position comprise 635 acres,
divided into three sections
and having about two miles
of water front. In the
centre are grouped in a
rectangle, 2,900 ft. by
1,437 ft., eight (A tlie great

Y'lti,. 15. Court of Ahiiiidaiice.
Fanama-Pacii-ic ICxrosiTioN.

39+

(;,,ooN.sTm»cTioNAU PANAMA-PACIFIC EXPOSITION

Ltv l-N(.lNI.l.VlN(i -^ J

exhibition |);ilacH's, uilh ;i ('cnlral Court of lloiioiir, 500 ft. by 900 it., and,
wt'st and (.•a^; ol thi^, \\id<- avt'nucs lorniiniL; sul)sidiarv courts. At one end
ol the i^roup is tlie l'"inc Arts Talacc, a loui; curved building', with an area,
inrhidini^ colonnadi- and iDtwnda, of 2o.:|,j^J5 s(|. ft., uliile at the other extremity
is the .Machineiy P. dare. 'I'lie latter — 307 ft. by c)()7 ft. and 103 ft. in heig'ht —
is probal)ly the lar»;-est tinil)er buildini^' e\er erected. Tlie foundations required
i,(K)o j)iks, the t^irryin^^ capacity beini; taken at 20 tons per pile, and the limber
in the buildinij;- itself amounts to al>out 7,600,000 ft., board measure. Flanking^
this i-< a building;', 250 It. b\ Soo It., intended lor automobile and m(jt(jr-<:ar
exhibits; and westward, on cither side of the main entrance, are the Pakioe of
Horticulture — constructed almost entirely of ^lass, 630 ft. by 300 ft., with a
dome of 152 ft. diameter, risini^- to a heig-ht of 188 ft. — and the Festival Hall,
with an area of 57,400 sq. ft. and seating capacity for about 3,000 persons.
The main buildings ha\ e interior arched aisles, with a dome of 100 ft. at the
centre, their heig^ht, as a general rule, beings 65 ft. to the cornice, 96 ft. to the
ridg-e and 160 ft. to the top of the dome.

East of the building's mentioned above are 65 acres devoted to amusements,
usually known as " side shows," the concessions for which — fewer than 100
out of a total of more than 6,000 applications — have, it is stated, been granted
with " the most rig-id selectiveness," having- satisfied " a hig-h standard of
propriety, g;ood taste and educational value, as well as effective fun-makings
and entertainment." To the west are 65 acres assig^ned for the building's of
foreig^n Governments, 45 acres for those of the States of the Union, 12 acres
for the exhibits of the Federal Government, and larg-e areas for the live stock-
exhibition building-s, racecourse, aviation field, drill gfrounds, etc. The two-
story building- to be occupied by the exhibits of the State of California will be
in what is called the " old mission " style, reminiscent of the Spanish occupa-
tion, and will co\er a.pproximately 3,550 ft. by 675 ft.

A quite unusual system has been adopted for the exterior lig-hting- of the
buildings, the rows of incandescent lamps characteristic of the majority of
recent exhibitions being- replaced by arc lamps and concealed searchlights so
screened and directed as to flood with light the entire fronts. It is intended
to open the Exposition on February 20th, when m.any of us hope to find the
United Kingdom more w orthily represented than appears probable at the present
moment, and to continue it until December 4th — an exceptional period due to
the favourable climatic conditions ordinarily prevalent in the City of the Golden
Gate.

Warm acknowlcdg-ments are due from Coxcrete .and Coxstkuctional
Engineering and the writer personally to the Exposition authorities — and
particularly to Mr. Harris D. H. Connick and Mr. A. H. Markwart, respectively
the Director and Assistant Director of Works — for much invaluable information
and for placing- at their disposal a larg-e and interesting- selection of drawing-s,
etc. ; and also to the H. S. Crocker Co., the official photog-raphers, for a variety
of excellent photographs of San Francisco and its environs and of the
Exposition itself.

395

EWART S. ANDREWS.

[CDNCBETEJ

PROBLEMS IN THE THEORY OF
CONSTRUCTION.

SLAB FORMULA FOR REIN-
FORCED CONCRETE DESIGN.

By EWART S. ANDREWS, B.Sc.Eng.

The question of Slab Formulae for Reinforced Concrete design is one ivhich claims
considerable attention, and the article here published "will doubtless be of interest to those
studying this important question, Folloiving upon this article is also a short article on a
Bending Moment Problem, also by Mr, Andreivs, — ED,

Very many mathematical investigations have been made from time to time by
elasticians to determine the strength of slabs or plates supported along all four
edges ; with the growth of reinforced concrete construction these investigations
have received renewed attention. In the present article we propose to show how
some such formulae can be derived in a simple manner and to compare such
formulae with others which are in common use. The formula which is in most
common use in this country is known as the Grashof-Rankine formula, and is the
result of mathematical reasoning which is very difficult to follow, and experiments
have not, we think, proved this formula to be much superior to others.

Prof. Bach's theory is very much simpler to follow, and we will consider this
first, restricting our consideration to uniformly distributed loads. This theory is,
however, not in very common use because, in accordance with the usual manner
in which its results are expressed, the reinforcement should be placed diagonally.
We shall first show how this theory can be adapted to the ordinary case of
reinforcement parallel to the sides of the slab.

The fundamental assumption in liach's theory is that the reaction pressure
of the slab along the four sides is constant. It is generally thought that this
assumption is not quite correct and that the pressure is rather greater towards the
centre of the sides. We will, therefore, deduce three sets of slab formulaL' based
upon the following assumptions : —

(l). Pressure upon supports uniform.

(2). Pressure variation upon sides in accordance with a parabola.

(3j. Pressure variation upon sides in accordance with a triangle.

Case I. Uniform Pressure.
This is Bach's Theory ; it is usually expressed as follows. Assuming that
the diagonal sections are the weakest, consider the bending moment about the
line AC, Fig. 1.

Let p be the pressure per unit length along the supports and let W be the
total uniformly distributed load and w its intensity per unit area.

'^^^" ^ = 2(l + bj

^96

(1)

^2' CTONM kMK-|10NAl

SLAB h'ORMULAl.

The supporting" foivos oi i (actions niav hv taken as a forrc equal to pb actin^^ at

y and one i^iual lo /»/ aelin^; al A ; the load on the A ABC- and acts at the

centroid C ol tlu> ^.

The iieriiendic-ular distance of A' and V from AC are each - and the

perj^endicular distance of G fioni AC is .

. ' . Taking moments about AC we have :

T^ J- ' r^ pbXc ,pl^c W a
bending moment = £5 = — ~ 1- ^' - ^ '^

2( 2 " 3 ^'
Wa

(2)

\
\

/ /
/G

\
\
\

f 1 N

D'
X

E
X

« —

1 A'

f i

Fig.

Fig. 2.

But

(tXAC = 2 area of A ABC = lb.

lb
• • <^ = ■^'

B =

12AC

Wlb^
l2\7+b''

(3)

397

EWART S. ANDREWS.

C QNCBETEJ

Now this has to be resisted by the section AC, and if ch is the effective
thickness or depth of the slab, we have

B = i^.AC .ds'
where />t. = resistance modulus.
IX depends upon the percentage reinforcement and the working stresses
adopted. For the "economic reinforcement" of '675 per cent, for c = 600 and
^ = 16,000, />i = 95 ; for other percentages and stresses its value may be taken from
the curves which are given in the text-books upon reinforced concrete.

. ■ . In equation (3)

Wlb

\2AC-

Wlb

fx . ds'' =

~\2{t'-\-h')
_ wb'

If we neglected the supports on the short sides we should have :

(4)

where

3 =

B = Moment of Resistance of section YY
= fxds' . I

J 2 Wb wb'

(5)

We could get result (4) from (5) by multiplying by

'^V-'l

being called a slab coefficient, which has the following values : —

— , this quantity

;

Diagonal

slab

coefficient.

•333

1*25

•407

1*5

•461

175

•502

*533

This is the most convenient way of expressing Bach's theory for diagonal
reinforcement. In general, however, the reinforcement is placed parallel to the
two sides of the slab instead of diagonally ; we can therefore proceed as follows :—

Bach Theory applied to Reinforcement Parallel to Sides of Slab.

We can consider in a similar manner the strength of the section XX, Ftg. 2.

1 ^
The reactions on the sides will have reactions at the mid-pomts ccjual to ^

at D and E and pb at Y. The load acts at the i)oint F.
398

i J, C10NM U»K riONAl '

SLAB I^^ORMUL.Ii

Tlierefi^rc, tal<in^^ moincnls about tlu' liiu! A'A' we have

/ \V I

• I PI) •

«-^;"-;-'j-:

= !^{2l \ h)
4

^ Wl{2h + l) _\Vl

8(/ + />) 8

Wbl
8(/ + /))
Neglecting side support on long side, we should have :

\Vl

(6)

B =

.'. Slab coefficient for XX =F/.=

l + b I

(7)

+ 1

Similarly, if we consider the strength of the section YY we should get :

/ 1

Slab coefficient for YY^Fi,^

l + b ^j^h

{-)

These results can be tabulated as follows : —

Slab coefficients

Short section

Long section

F„

•500

V25

•444

•556

1*5

•400

*600

175

'364

'636

•333

•667

Case II. Pressure Variation according to Parabola.

We have previously pointed out that there is reason to believe that in
rectangular slabs the supporting pressure is greater towards the centres of the
sides than towards the corners.

We will now therefore assume the pressure to vary in the form of a parabola
as shown in Fig- 3. We will take, as before, the total pressure on each side
proportional to its length, so that the total pressure on each long side =Pl

and that on each short side = Ps =

2(/ + 6)" ^ ^" ^ ^^^^ ^^ 2{l + b)

The pressure at the centre of each side is therefore 1'5 p, p being the value
given in equation (1). The resultant pressure along AB will act at the point Y,
while that on the half sides AX, BX will be at the centroids of the parabolas — i.e.,

— from X.
16

D 2

399

EWART S. AXDREWS.

ICDNCBETEJ

Therefore, taking moments about XX we have

B=Ps

I , 2Pl 3' U" I

2 2 16 2 4
Wbl , 3Wl- Wl

4(Z + 6) ]6(l-hb) 8

8{l + b)\ 4»

(9)

Fir . 3.

Fig. 4,

Neglecting side support, we have as before

B=^^

.'. Slab coefficient for XX = Fi =

{H h)
I

46
I
b

Similarly, we get for W by reversing / and b

Slab coefficient for YY = Fh
400

l^b

(10)

J, cTONMvnc-ric»N(ATI

SLAB FORMULAE.

/ I
These rcsulls c:u\ be t;ihul;iled ;is follows: —

(11)

Slab coefficients

Short

section

A'X

Long section YY

t',

F„

'375

•375

V25

•306

'444

'250

•500

175

•205

•545

•167

'583

Casi-: III. Pressure Variation according to Triangle.

In this case we will assume the pressures to be even more concentrated at
the centres than in the previous case, and assume the pressure distribution shown
in Fig. 4.

As before, we take total pressure on each long side =Pa= 77477 \ ^^^ ^^^^

on each short side = Ps =

2{l + b)
Taking the side pressures as acting at the centroids of the triangles, we get :

B=P . ^4-2. Pl. I _W,l_
'2 2 6 2*4

Wbl

wi-

^{l^-b) 12(/ + 6) 8
8{l + b)( 3 i

8(/ + 6)

i^-i)

(12)

. Slab coefficient for XX = Fi —

l + b

1 —

1 +

(13)

Similarly, by reversing I and 6, slab coefficient for YY

b 3

= F/,=

14)

401

EWART S. ANDREWS.

ICQNCBOEi

These results can be tabulated as follows : —

Sla

lb coefficients

Short section XX

Long'

section YY

f^i,

"333

•333

1-25

"259

'407

'200

•467

175

•151

•515

•111

•555

The Use of Slab Formulae.

We have, in the foregoing treatment, developed three sets of slab formulae,
according to different assumptions of pressure distribution. Whichever of these
is adopted, -and we think that the parabolic distribution is the best of the three»
it should be remembered that the resulting calculations give only the average
stresses across the section. A very simple rough way of allowing for this would
be to divide the span into three equal parts and to space the rods in the centre
portion twice as close as in the ends. The slab coefficients given by the Grashof-
Rankine rules are, on the other hand, for maximum stresses only and relate
strictly to central strips. If, therefore, we use formulae for average stresses we
should remember that actually the stresses will be greatest at the centre ; as a
rough approximation we might take the stress variation as parabolic. The
reinforcement, therefore, should be spaced closer together at the centre than at
the ends to allow for this variation in stress.

For ease of comparison we will quote the values of the slab coefficients
given by the Grashof-Rankine formulae. They are : —

Slab coefficients

Short section XX

Long

section YY

•500

'500

r25

•291

"709

'164

•836

175

"096

'904

"059

'941

If we use the Grashof-Rankine figures, the calculations give the reinforcement
required at the centre only, so that there is some loss in economy if the same
reinforcement is maintained throughout.

We shall get these points more clear by a numerical example.

Numerical ICxamimJ':. -A rectangular slab, 18 ft. long and 12 ft. wide,
has to carry a uniformly distributed /oad of 200 lb. per sc/. f/ . Treating the
ends as simply supported, and taking the stub as 5 ins. deep to iJic centre of
reinforcement, find a suitable reinforcement in eit/ier direction,

I IS

In this case ' — ' — 15
/; 12

402

n^fASiSr^ ^^^^^ I'ORMULAl.

^ , ,. ,, , _U^/_(200X18X12)X(18X12)
Free bending moinenl lor long span — - —

-1,166,400 in. lb.

, , , Wl (200X18X12)X(12X 12)

I)(i. for short span — =

8 8

= 777,600 in. lb.

(1) Parabolic Formula: F,= 250: F„ = '5Q0.

.". B.M. for short span = 777,600 X '500.

= 388,800 in. lb. (l)

.•. B.M. for long span = 1,166,400 X "250.

--291,600 in. lb. (2)

Now for short span : ft= 18X 12 and (L = 5

^ B ^ 388,800 _

^ bds- 18 X 12X5X5

= 72

Reference to a diagram shows that for ^ = 16,000 lbs. per sq. in., f^=72 for

'5% reinforcement, so thac the necessary amount of steel parallel to the short

., . '5X5X12X18 c-A

side is =5 4 sq. in.

100

5'4

Taking i in. bars of area '196 sq. in., we should require . = 28 say.

196

These could be arranged with the centre 12 at 6 in. centres, and the
remaining 16 at 9 in. centres.

For long span : 6 = 12X 12 and <i.s = 5

.-. f.= ^91,600 _g^
12X12X5X5
From our diagram we see that this is given' by about '57% reinforcement.

. ' . Area of steel required parallel to the long side=

= 4'1 sq. in.

1 41
. ' . Using 2 in. rods of area "196 sq. in., we shall require = 21 rods.

* 196
Say 9 rods at 5 in. centres at the centre, remainder at each side at 8 in. centres.

(2) Grashof-Rankine Formula:

F„ = '836 F; = '164
. ' . B.M. for short span = 777,600 x '836.

= 650,000 in. lb. nearly (3)

.'. B.M. for long span = 1,166,400 x '164.

= 191,000 in. lb. nearly (4)

. r , 650,000 , ^

• • ^°' ^^^°^^ ^P^^ ^ ^18XT2^^T^^120

This requires r42'^o reinforcement; it w^ould really be better to increase the
depth.

.-. Area of steel required = 1^ ^ X 5 X 12 X j8 ^ ^^. .^_

100

• 433

EWART S. ANDREWS. [CDNCBETE]

191,000 ,, .,^,, .„ .

for long span M ^ i2x 12X5X5 ^-^^' -^^^^^ 38% will give this.

. ^ -38 X5X12X12 ^.^
. , Area required = r^r^r —27 sq. m.

It will be seen that the Grashof-Rankine formula makes a greater difference
between the relative reinforcements required in the two directions than does our
suggested parabolic formula.

A BENDING.MOMENT PROBLEM.

" Tlie best position for the prop of a uniformly lo(^ded beam supported at
one end and overhanging the prop at the other.''

In this problem no new principles are advanced, but the problem is not to be
found in the text-books with which we are acquainted, and will probably be of
interest to the students among our readers.

A beam AB on span L is supported at one end A and overhangs the
support C at the other end ; we wish to find, with a uniformly distributed load,
the position of the support C which will be most economical — i.e., give the least
bending-moment.

If the length of the overhanging portion BC is h and the distance AC is Zi, the
B.M. diagram will be as shown shaded in the figure ; the portion BxD is a parabola
tangential at Bi and is the familiar diagram for a cantilever with a uniformly

distributed load ; the portion AGCx is a parabola of height ^, the usual one for

a freely supported span AC ; and A\D is a straight line.

The maximum positive B.M. will be given by KJ , which will be equal to

-^ b her unit length

404

fj, CON.Vl PIK riONAl.
L*Vl.N(.lNl.t.lMN(. — ,

A BENDING-MOMENT PROBLEM.

^ - since llu' H.]\T. iM'lwecn the point 4, and the point /^ of contrallexure

will he llio same as for a freel\' supportcul beam of span A^E, and the maxinuim

negative \akK is given by C\l). Our problem resolves itself into find the

position of C to make .//\ or C|/) the least possible.

Now, if you move tlie jjoint C to the left, C\D will increase and J\J will

decrease, whereas if C moves to the right the converse happens. If, therefore,

C\D = I\J, movement of C will increase one or the other, so that the least \ alue

of either occurs when they are e(|ual.

.p.. . p iU -- a)'- ^-hlr

1 his gives - — —

(S 2

i.e., (ix-af^-Alr
or (/,-a) = 2/, (1)

Again, bv the propertv of the parabola

This can be found by taking the B.M. at E for the span A\C\ ; also by

similar A's.

EF _AxE

CD AiC^

i.e..

^p^^-x^L^ (3

(4)

Combining (2) and (3) we get :

2 ^ ^ 2 h

Ir
or, ci — i-

Putting this result in (l) we get :

i.e., /r-2/, l2-J{ = o (5)

The solutio-n of this quadratic equation gives, taking the positive root :

li 2

••• l + - = ^'^^- = ^ = l + 2"414 = 3'414
t-'i I'l '2

or, /2 = ^^ i.e., h = '293L

3 414 —

In this case the maximum B.M. will be equal to

Pl-f = P^(1293L)- ^ _^

2 2 23*3

It w^ill be of some interest to compare this result with that which would

occur if each end were overhung and the supports were placed so as to give the

least B.M. for this condition.

In this case the best condition is given when the overhang is '207L. This

gives a maximum B.^I. equal to ^ ^ 207L) -^pL_ ^ which is half that

2 46*6 ^^ '

for the previous case.

+05

REINFORCED CONCRETE IN BELGIUM.

[QQNCRETEl

BUILDING FOR THE BELL

TELEPHONE MANUFACTURE

ING COMPANY, AT ANTWERP,

BELGIUM.

:-l'/#///'

An argument often brought forivard against the use of Reinforced Concrete for buildings
ivhere elaborate machinery is needed is, that it is not suitable for this purpose. In the
present example it is shoivn that any difficulties that may present themselves can be ivell
oziercome, — ED,

A LARGE building- was recently erected almost entirely in reinforced concrete for
the Bell Telephone Manufacturing Company at Antwerp.

The site of the new^ building, which is intended for a factory, is situated
at Rue Diercxsens, Antwerp. This building is composed of a principal body
having in plan the shape of a rectangle 72*93 m. in length and 1678 m. in

Interior View of Machinery Room Ijei'ore Installation of Maciiincry.

KlCrNI-OKCI.U CONCRETK BuiLOING TOR THE BkI.I, TkLKI'HONE M-ANi;i-ACTURING Co., AnTVVKIU'.

width (243 ft. by 55 fl. 10 in.). On tlic long side of the Iniilding, lacing
toward tlic (V)urlyard, ihc new building includes also a rectangular portion
which will constitute the Ixgiiniing of a future extension. The dimensions of
this portion are \()'yH m. long b)' X r>^ i^^- wide (35 ft. by 12 It.).

The building is compf)se(l of a ground llooi' ])uilt ox'er a basement, four

406

r>, CONM PllCriONAl .1
^tV KNdlNLl-I^lNd — J

REINFORCED CONCRETE IN BELGIUM,

upprr slorc'vs, ;in(l .1 H.il km.I. Hi.' I1<hmn .nc Mipp.rKd ))> lour lines of j/illars
in ninlorcH'd coiurclc n;inul\ . l\\<. (inlr;il lines, one line f.-iciny tlu- slrcct :.ncl
anollKT line l;i<in- llu- eourt>:ir(i ;il the b;iek ol the building-.

The portion ol the future <-xlension is supported by five pill.-irs constructed
r,uiru-ientl\ slron- lo support tlu' lo;id which will come upon iheni when the
extension is <Tirt<-(l. 'ihe lour i>osts idonj-- the side of th<' adjoinin- building
are also constructed in such a manner as to be stronj^ enough lo support the
load of anv future extension which may take plac<- towards this adjoining

buildini;'.

The various lloors arc accessible by means of two staircases and two lifts.
One of the staircases and one of the lifts is situated on the side of tlu- present

\'iew of Macbinary Room installed.
Reinforced Concrete Building for the Bell Telephone Manifactlring Co., Antwerp.

factory, and the other staircase and lift are situated on the side of the future
extension towards the courtyard.

The pillars are resting- on foundations entirely in reinforced concrete, spread
on the ground in such a manner as to produce a pressure not greater than 2 kg.
per sq. m. (i ton iGh cwt. per sq. ft.)-

It was originally intended to provide ordinary concrete foundations spread-
ing the weight of the pillars over the ground at the rate of 3 kg. per sq. m.
(2 tons 15 cwt. per sq. ft.]. After the g^round was excavated, however, to the
level of the foundations, it was found that the subsoil was composed of fine
sand mixed with clay, and the presence of water at this level had the effect of
transforming the subsoil into more or less liquid mud. The difficult problem

407

REINFORCED CONCRETE IN BELGIUM.

[CQNCCETEl

of spreading heavy loads coming froni the pillars on to this very bad ground
was salisfactorilv sohcd b\- the adoption of spread foundations in reinforced
concrete. To facilitate the construction of these foundations it was necessary
to surround them by means of wooden sheet piles, in order that the reinforced
concrete work should be executed in the dry. These sheet piles were withdrawn
after the foundation work was completed.

The ground lloor is calculated for a superload of 2,200 kg. per sq. m. for
the slab (4 cwt. per sq. ft.). The beams, however, are calculated for a super-
load of 1,100 kg. per sq. m. (2 cwt. per sq. ft.). This different rate of loading
on the beams and slabs was necessitated by the fact that the machinery is liable
to be shifted to any portion of the floor slab, thereby creating concentrated

J'^xterior View.
Keisforcid Concrkte Building i-or the Bell Telephone Manufacturing Co.. Antwerp

loads, 'ihc first, second, lliird, and fourth Hoors are all calculated for a suj>er-
load of S50 kg. per sr|. m. (174 lb. per sc|. fl.). The flat roof has l)een calcu-
lated \'>r a supcrlfjad of joo k'g. per sf|. m. (44 lb. |)er sq, ft.). Oxer and above
the superloads indif ah d, ihc (l;\i(l weight of ihc constru(Mion and c-oinposition
flofM'ing, weighing S4 kg. per s(|. m., lias been tal^cn into account b)r ihe
grfjund, lirs!, sc( ond, lliird, and lourlh floors, and a la\'er of asphall weighing
20 kg. per scj. rn. has 1)( ( n piMxidcd lor llic rool.

Rivr r sand and hard br:)kcn slonc were used for ihc making of live con-
crete. The malcrials wci'c mixed in ihe pi'opoil ions ol ;;oo k'g. ol ("cmcnt,
'400 cu. m. of sand and '.Scjfj cii. m. ol gra\cl (ap|)i'oxima1cl\- 1, 2, 4 in parls).
Concrth; tesl (aibes made wilh llicsc malcrials and wilh lliis mixture gave
exc('ll( n1 results < )\ over 2,_|oo lb. per s(|. in. alter 1 w cut \-eighl da)'S.

40S

^^SKSSIS ^ REINFORCIiI) CONCRJiTH IN BELGIUM.

Tlu' .stti'lw ;ii k is <nliril\ ci iinp: )sc(l ol inimd hars nl mild sled.
Tlu' wall ol tlir IKml I'lcxalion lacing; \\\v slrccl and 11m- wall ol tlic hack
i'U-\ati()n taciiii; llic lOiirlNard were const nictcd in brickwork, liaxiiii^ a lliick-
iH'Ss of I it. () in. Iioni llic liist llo'nr lo lIic roof, and i ll. lo in. Ironi llic
foundation'- to the lii st IIodi-. Tlic back wall o\ cilookinj; the court is laced
with while enamelUd biicks for the i-ellcclion of lii^ht. '1 hcse brick walls are
supported at each lloor b\ reiidoiced concr<'le lintels spreadiiii^ the loads on
to the pillais. The walls at ea(di lloor, therefore, do not carr\ an\ load, and
their thickni'ss is in accordance with the lU'li^ian regulations.

/''>• ^ shows a i^eneial view of the elevation, which lias been desig-ned by
the an-hiticl with the objet t of formiui^- a suitable continuation of the existing
buildiui^'s. The two other \ iews show one of the floors previous to the fixing"
of shaftini;- and niachiner\- and after the nia(-hiner\ has b'jen j)lace(l in position.
/''/_<,'". 2 shows that there is no particular dilliculty in adapting ehiborate
machinery to the fle)ors and pillars of a reinforced concrete factory, and, in
spite of the heavy \ibration due to this machiner}-, scarcely any vibration is
perceptible on the lluors themselves. Some of the launching machines resting
directly upon the groimd floor weigh oxer nine tons each.

A special method of fastening the machinery to the floor was adopted in
order to prevent cutting holes in the composition floor and in the concrete.
This process consisted in fastening the machines to the floor by means of pieces
of felt about | in. thick dipped in a special c^ompound, which securely sticks the
felt to the foot of the macliine and to the floor. Whilst this process does
undoubtedly prevent, to a certain extent, the vibration of the machines from
being transmitted to the floor, it was not adopted with this idea in view, and,
apart from this, no other precautions, such as india-rubber sheeting or other
material, have been taken to reduce the vibration. Needless to say, as usual
in most factories, any of the machines are liable to be shifted from one place to
another. This, however, can be done without any difticultv.

The work was carried out under the supervision of Mr. G. A. Pennock,
plant engineer. The general plans of the building were prepared by Mr. J. L.
Hasse, architect of Antwerp, and the plans for the reinforced concrete work
were executed by Messrs. Edmond Coignet, Ltd., of 20, \*ictoria Street,
London, S.\\\, the entire contract being- carried out bv Messrs. G. Hargot and
R. S'omers, of Antw erp.

409

THE CONCRETE INSTITUTE.

[CONCRETE)

S'teiifc^-iB

j RECENT VIEWS ON
I CONCRETE AND REIN-
FORCED CONCRETE. II