Structural Details in Concrete Bangash

M.Y.H. Bangash

Structural Details in Concrete



M.Y.H. Bangash

OXFORD

BLACKWELL SCIENTIFIC PUBLICATIONS

LONDON EDINBURGH BOSTON

MELBOURNE PARIS BERLIN VIENNA

Copyright© M.Y.H. Bangash 1992

Blackwell Scientific Publications Editorial Offices: Osney Mead, Oxford OX2 OEL 25 John Street, London WC1N 2BL 23 Ainslie Place, Edinburgh EH3 6AJ 3 Cambridge Center, Cambridge,

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All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise without the prior permission of the publisher.

First published 1992

Set by Best-set Typesetter Ltd., Hong Kong Printed and bound in Great Britain by Hartnolls Ltd, Bodmin, Cornwall

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Marston Book Services Ltd PO Box 87 Oxford OX2 ODT (Orders: Tel: 0865 791155

Fax: 0865 791927 Telex: 837515)

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617 225-0401)

Canada Oxford University Press 70 Wynford Drive Don Mills Ontario M3C 1J9 (Orders: Tel: 416 441-2941)

Australia Blackwell Scientific Publications (Australia) Pty Ltd 54 University Street Carlton, Victoria 3053 (Orders: Tel: 03 347-0300)

British Library Cataloguing in Publication Data Bangash, M.Y.H.

Structural Details in Concrete I. Title 693

ISBN 0-632-02853-X

Library of Congress Cataloging in Publication Data Bangash, M.Y.H.

Structural details in concrcte/M.Y.H. Bangash. p. cm.

Includes bibliographical references and index. ISBN 0-632-02853-X 1. Concrete construction—Details. I. Title.

TA681.5.B36 1992 624. Г834—dc20 92-2868

CIP

Contents

Preface vii Acknowledgements ix Conversion Factors xi

I General Requirements for Structural Detailing in Concrete 1 II Reinforced Concrete Beams and Slabs 41 III Stairs and Staircases 59 IV Columns, Frames and Walls 71 V Prestressed Concrete 85 VI Composite Construction, Precast Concrete Elements, Joints

and Connections 107 VII Concrete Foundations and Earth-Retaining Structures 127 VIII Special Structures 151

VIII. 1 Bridges 152 VIII.2 Concrete Shells 179 VIII.3 Water Retaining Structures and Silos 207 VIII.4 Nuclear Shelter 219 VIII.5 Nuclear, Oil and Gas Containments 222 VIII.6 Hydro-Electric and Irrigation/Hydraulic Structures 234

Bibliography Index

257 259

Preface

A number of books on various aspects of concrete design and detailing have been published but this is believed to be the first comprehensive detailing manual. The aim of this book is to cover a wide range of topics, so simplifying and reducing the work required to prepare structural drawings and details in reinforced, prestressed, precast and composite concrete.

The book initially provides a list of extracts from relevant codes and current practices. Where drawings are carried out using imperial units, a conversion table is provided to change them into SI units.

The book is divided into eight sections: Section I deals with the general requirements for structural detailing in concrete, basic drafting criteria and the properties of materials. Section II is devoted entirely to the structural detailing of beams and slabs. Section III covers reinforced concrete detailing of stairs and staircases. A comprehensive description is given of the detailing of reinforced concrete columns, frames and walls in Section IV. The reader is also referred for more information to the later section on integrated structures.

Section V covers prestressed concrete systems with some basic structural detailing of beams and anchorages. Again the reader is referred to other sections, in particular Section VIII regarding the use of prestressed tendon elements in integrated structures. Section VI presents structural detailing in composite construction, precast concrete elements, joints and connections.

Section VII includes basic structural detailing of reinforced concrete foundations and earth-retaining structures. An effort is made to include a number of foundation drawings so that the reader can appreciate the quality and design required for a specific job.

Students of civil and structural engineering who have worked through to this part of the book will have acquired the background necessary to draw the majority of reinforced, prestressed, precast and composite concrete structures commonly encountered in professional practice. To assist the reader in his/her completion of drawings, an unusually large number of drawings have been incorporated into the text since they are generally the principal communication between the structural engineer/designer, architect, builder and client.

Case studies in Section VIII which include the structural detailing of the following special structures in concrete:

• reinforced concrete beam/slab bridge deck, • culvert bridge super and substructures,

viii Preface

• continuous RC girder deck, • reinforced concrete box bridge deck, • open spandrel arch bridge - reinforced and prestressed, • reinforced concrete rigid frame bridge details, • composite/steel - concrete bridge deck, • reinforced concrete rigid frame bridge, • bridge bearings and substructural layouts, • samples of reinforced concrete cylindrical shells, hyperbolic

shells: groin type hyperbolic paraboloid shells and domes, water retaining structures and silos with elevated towers, nuclear shelter, pressure and containment vessels for nuclear power plants, gas and

oil installations and cells for offshore platforms, hydroelectric and irrigation/hydraulics structures, spillways, piers,

intakes, switch yard foundations, electric manholes, chutes, gates, tunnels and culverts.

An increasing emphasis has been placed on the role of the designer in planning reinforcement and structural details so that the detailer can do his/her work thoroughly without having to complete the design himself. Improved methods and standards presented in the text should result in better construction and reduced costs.

The book will serve as a useful text for teachers preparing a syllabus for technician and graduate courses. Each major section has been fully explained to permit the book to be used by practising engineers and postgraduate students, particularly those facing the formidable task of having to design/detail complicated structures for specific contracts and research assignments. Contractors will also find this book useful in the preparation of construction drawings.

M.Y.H. Bangash April 1992

I

Acknowledgements The author wishes to express his appreciation to friends, colleagues and some students who have assisted in the early developments of this book by suggesting relevant changes. The author has received a great deal of assistance, encouragement and inspiration from practising engineers and contractors, particularly those for whom he has acted as consultant. The author is indebted to all those people and organizations who are referred to in this book and to the following, in particular, for making this book a reality:

Indian Concrete Journal, Delhi, India The Indian Road Congress, Delhi, India The Public Works Departments, Delhi and Mahrashtra, India The Governments of Ivory Coast and Ghana The Institution of Civil Engineering Library, London, UK Kaiser Engineers and Contractors, California, USA Bechtel Engineering, California, USA Chatterjee, Polkes, Consulting Architects, Delhi, India Dr F. Garas, Taylor Woodrow Construction Ltd, Southall, UK United States Bureau of Reclamation, Washington DC, USA Pakistan Engineering Congress, Lahore, Pakistan West Pakistan Water and Power Development Authority (WAPDA),

Pakistan Punjab Public Works (PWD) Department, Lahore, Pakistan Gammons (India) Ltd, Delhi, Bombay, India Mott McDonald, Croydon, Surrey, UK Birkenhead Project on Silo, Australia The Atomic Power Construction Ltd, Sutton, UK The former Central Electricity Generating Board, UK TVA Tennessee Valley Authority, Tennessee, USA The United States Nuclear Regulatory Commission, USA The International Association of Shell Structures, Spain British Standards, London, UK American Concrete Institute, Detroit, USA

The Offshore Technology Conference Center, Houston, Texas, USA The UK Atomic Energy, Winfrith, Dorset, UK

A number of original drawings have been modified to comply with the current drafting codes and requirements.

The undertaking could never have been achieved without the patience, encouragement and understanding of the author's family.

Acknowledgements

Artwork Acknowledgements III.6,7,8,9 Birchwood Concrete Products V.4 PSC Equipment Ltd V.5,6,7,8,9,10,11 BBRV, Simon Carves V. 13,14 Cabco VIII. 1.19 Overseas Proj ects Corporation of Victoria, Australia VIII.2.3.a,2.16 S. Eggwertz, Consulting Engineer VIII.2.6,7,8 Perkins and Will, Chicago VIII.2.10 S.D. Castillo VIII.6.3,4,5 Kaiser Engineers and Constructors Inc.

Conversion Factors Length 1 inch = 25.4 mm 1 foot = 0.3048 m

Area l foot 2 = 0.0929 m2

1 inch2 = 645.2 mm2

Mass l ib = 0.454 kg

Force llbf = 4.448 N lkip = 4.448 kN 1 kip/ft = 14.594 kN/m

Density lib/ft3 = 16.018 kg/m3

Pressure 1 lb/m2 = 6.895 kPa (N/m2) lib/ft2 = 47.880 Pa 1 kip/in2 = 6.895 MPa (MN/m2) 1 kip/ft2 = 47.880 kPa

Prefixes in SI units G = giga 109

M = Mega 106

к = kilo 103

m = milli 10~3

Pa = Pascal

Section I

General Requirements for Structural Detailing in Concrete

1.1 Introduction

This section gives general requirements for structural detailing in concrete. A slight departure from these requirements can be expected because each project is different. Individual structural engineers and designer detailers also influence the style of working drawings and schedules. Moreover, structural detailing in concrete can vary since it can be considerably affected by external requirements including those of authorities such as gas, electricity, water, municipal, etc.

1.2 Drawings

Full drawings are prepared by structural engineers acting as consultants as part of the tender documentation. The architects are involved in the preparation of the site and other general arrangement plans. The main contractors are involved in preparation of temporary work drawings, including shoring and formwork. During the contract, drawings are sometimes modified by minor amendments and additional details. These drawings are generally updated as the projects progress. The drawings, which are distributed to other engineers including those providing services and to contractors, are prints taken from the original drawings made on tracing paper, called negatives. These negatives are provided with thick borders as a precaution against tearing. Plastic film on the other hand gives a smooth hard wearing surface. Almost all drawings are done in ink. A typical drawing sheet contains the following data in the panel on the right-hand side of the drawing.

Starting from the top Example NOTES Specification etc. REVISION . . . 751/10 Rev D (details of amendments) NAME OF THE ENGINEER Bangash Consultants NAME OF THE CLIENT/ Bangash Family Estate ARCHITECT DRAWING TITLE . . .

SCALES/DRAWN BY/DATE . . .

DRAWING NUMBER

BANGASH ESTATE CENTRE FOUNDATION LAYOUT 1:20, 1:50, 1:100/Y. Bangash/13 July 1992 Underneath the name of the person and the date The drawing numbers may run in sequence such as 751 or 1, 2, 3 or 100, 101, etc.

The International Standard Organisation (ISO) recommends A or В ranges for paper sizes and most common are Al (594 x 841 mm) and Bl (707 x 1000mm), for structural

4 General Requirements

detailing in concrete A2 (420 x 594 mm) size is recommended. For small sketches and detailing and specifications, design teams and contractors use A4-sized (210 x 297 mm) sheets. All major drawings and site plans carry the north sign.

1.2.1 Drawing instruments

The most general instruments required for good drawings are: a drawing board, woodcase pencils, clutch pencils, automatic pencils, technical drawing pens, erasers, scales, set squares, templates and stencils. A description of these is excluded from this text as they are well known.

1.2.2 Linework and dimensioning

Drawings consist of plan, elevation and section. The structure is viewed 'square on' to give a series of plans, elevations and sections. The two basic types are: first-angle projection and third-angle projection. Dimensioning varies from country to country. Some examples are given later on in this section and in other sections of the book.

1.2.2.1 Line thickness

The following line thicknesses (based on ISO line thickness) are recommended for concrete drawings:

General arrangement drawings Concrete outlines on reinforcement drawings Main reinforcing bars Links/stirrups Dimension lines and centre lines

0.35 mm 0.35 mm 0.70 mm 0.35-0.70 mm 0.25 mm

Colour code Yellow Yellow Blue — White

The line thickness increases in the ratio 1: V2, for example, 0.25 V2 = 0.35 etc.

1.2.2.2 Dimensioning

As stated in Section 1.2.2.1, dimension lines of 0.25 mm thickness are shown in several ways. Some are given below. A gap is necessary between the dimension line and the structural grid. Dimensions are given in different ways. In SI units, dimensions are given as follows in various countries:

Britain (BS 1192) Codes: Sweden Switzerland Italy Japan Germany

All major dimensions shown, say, 1700 for 1700 mm

1700 mm rather than 1700 1.700 m 1700 1.7 m and 1700 1.7m

^

f -U.

General Requirements 5

USA Major dimensions in ft (feet), smaller dimensions in inches Pakistan/India Same as USA on some projects in metres and millimetres.

1.2.3 Grids and levels

A point on the drawing can be located by a grid reference. A grid is a series of vertical and horizontal lines on the plan of the structure. They are sometimes called building grids. They may not have identical spacings but it is preferable that the spacing is constant in the same row between the grid lines. The grid lines are identified by letters and numbers. On sections and elevations, various levels are marked. Typical examples are shown in Sheet No. 1.1 for grids and levels and a proper notation is shown for reference beams and columns.


GRIDS AND LEVELS (a) Levels on section and elevation

SHEET NO. 1.1

zrz:

л

£ **0 FF.L. S.F.L ^ 10000

LEVELS ON PLAN

JL П о 445 ]

FF.L. j 10335

S.F.L. 10000

(b) Grid lines and reference system

:A) гв

d> 3A2 3B2 3C2

©-

со CNI

2A2

LO CO CNI

no CO СЧ1

2B4

2B2

i_j rsj

2C2

1A2 1B2 1C2

(c) Columns and grid lines (d) Stepped levels о u-il

2>--£3—

®г-0

-1 mill

140-000 7ГТ

i col. 'tbose

140050

' ^ 1 4 5 ° SPLAY | | UNDER


1.2.4 Sections and elevation marker

The exact style cannot easily be determined as it varies from countiy to country. In a way, it is not important what style is used, as long as it is simple and clear. The markers are located on the plane of the section or elevation with indicators pointing in the direction of the view. The section markers must be shown in the correct direction and the letters must read from the bottom of the drawing. Some of them are shown later on various drawings and details in this book either with horizontal and vertical thick lines

i ~l ~I

or arrow heads of the types shown. In some important cases two thick lines are shown. Where sections are indicated they are marked as shown below.

x-x A-A

Similar markers can be seen on different drawings. The author has deliberately changed these markers on drawings to give the reader a choice of any marker that he or she wishes to adopt.

1.2.5 Symbols and abbreviations

aggregate bitumen blockwork brickwork building column concrete damp proof course/ membrane diameter drawing elevation foundation full size setting out point setting out line near face far face each face each way

agg bit blk bwk bldg col cone dpc/dpm

dia, 0 drg EL fdn FS SOP SOL NF FF EF EW

centres centre to centre centre line finished floor level structural floor level average external figure internal holes radius inside/outside dia sheet horizontal/vertical not to scale bottom top existing level (plan) x 100000 section S , I I (KK)

crs c/c L FFL SFL av ext FIG or fig int his or HOLES rad id/od sh hor/vert NTS or nts В o r b T o r t


HOLES, RECESSES, NIBS AND KERBS

SHEET NO. 1.2

(a) Holes in concrete structures

(b) Pockets and recesses

PKT. 30 DEEP

1 1 u^n.

/

44-i "ttv

, < !<• 7

4No. PKT "90 DEEP

(c) Nibs and kerbs on beams

BEAM- >< 7<-

NIB '200 DEEP

PT 1 1 — >

h^L ч KERB 150 HIGH


square right hand sketch number approximately specifications pockets kerb nib

With reference to reinforcement far face outer layer Fl far face second layer F2 near face outer layer N1 near face second layer N2 bottom/top face outer layer Bl /Tl or b l / t l bottom/top face second layer B2/T2 or b2/t2

sq rh sk no or NO approx spec PKT KERB NIB

metre millimetre minimum

m mm min

1.2.6 Holes, pockets, recesses, nibs and kerbs (curbs)

They are either shown as thin cross-lines or single diagonal lines with appropriate symbols. A typical example is shown on Sheet No. 1.2.


1.2.7 Reinforcement size

A standard range of bars and sizes is available for use in reinforced concrete. They may be hot-rolled (mild steel, high yield steel) or cold-worked (high yield steel). Bars are made in a range of diameters from 8 to 40 mm. Special sizes of 6 and 50 mm are seldom available. The specification for steel covers chemical composition, tensile strength, ductility, bond strength, weldability and cross-sectional area. It is important to compare these bars with the American system bars. It is useful in case the drawings are done using American steels.

Bars

Britain, Europe, Japan, Russia: Bar types (mm) 8 10 12 16 20 25 32 40

USA, Canada, S. America: Bar types (mm) denoted by # or no. #3 #4 #5 #6 #7 #8 #9 #10 #11 #14 #18

(22 mm) (29 mm) (35 mm) (43 mm) (57 mm)

Area (mm-) 50 78 113 201 314 387 491 645 804 1006 1257 1452 2581

1,2.7.1 Spacing and arrangement of bars

Bars are spaced on the basis of a number of factors which include beam sizes, aggregate sizes, spacers, concrete cover and many others including requirements imposed by other services. Sheet No. 1.3 gives a summary of spacing and arrangement of bars. Both single and group bars are shown. A number of other combinations are possible. When bars of different diameters are used, they tend to be grouped in similar sizes. Some of them are:

10,12,16; 16,20; 20,25; 16,20,25; 20,25,32.

1.2.8 Fabric

Fabric reinforcement is manufactured to BS 4483 and to STM requirements. There are four types of fabric, made from hard drawn mild steel wire of fy = 485N/mm2 or from cold-worked high yield bars:

(a) Square mesh fabric regular bars of lightweight (A Type). They are used in walls and slabs.

(b) Structural fabric main wires 100 mm crs (B Type), cross-wires 200mm crs. (c) Long mesh fabric main wires 100mm crs (C Type), cross-wires 400mm crs. (d) Wrapping fabric lightweight square mesh (D Type) encased conditions for

fire resistance mainwire cross-sectional area 252 mm2; fy = 250N/mm2.


The following chart gives the parameters for fabric reinforcement:

Mesh type

1. Square mesh (200 x 200) A393 A252 A193 A142 A98

2. Structural fabric (100 x 200) B1131 B785 B503 B386 B283 В196

3. Long mesh fabric (100 x 400) C785 C636 C503 C385 C283

4. Wrapping fabric D49 (100 x 100) D98 (200 x 200)

Size of wires (mm)

Main Cross

10 8 7 6 5

12 10 8 7 6 5

10 9 8 7 6

2.5 5.0

10 8 7 6 5

8 8 8 7 7 7

6 6 5 5 5

2.5 5.0

Area (mm2)

Main Cross

1131 785 503 385 283 196

785 636 503 385 283

49 98

393 252 193 147 98

252 252 252 193 193 193.

70.8 70.8 49.0 49.0 49.0

49 98

Weight (kg/m2)

6.16 3.95 3.02 2.22 1.54

10.90 8.14 5.93 4.53 3.73 3.05

6.72 5.55 4.34 3.41 2.61

0.76 1.54

1.2.9 Cover to reinforcement

The distance between the outermost bars and the concrete face is termed the cover. The cover provides protection against corrosion, fire and other accidental loads. For the bond to be effective an effective cover is needed. Various concrete codes allow grouping or bundling of bars and in such a case the perimeter around a bundle determines the equivalent area of a 'single bar'. The cover also depends on the grade of concrete and the full range of exposure conditions.

The table overleaf gives the nominal cover for such conditions. For concrete against water and earth faces, the cover shall be at least 75 mm.

1.2.10 Dimensional tolerance and spacers

Dimensional tolerance should be allowed at several stages in reinforced concrete detailing, e.g. bar bending, provision of shutter and fixing of reinforcement.

On-site minimum cover = Nominal cover — Tolerance of 5 mm.

Spacers as shown in Sheet No. 1.3 are needed to achieve the required cover between bars and the shutter. They are cast into the concrete. There are different types of


SPACING AND ARRANGEMENT OF BARS (a) Spacing of bars

SHEET NO. 1.3

INDIVIDUAL

b

a a

Ь>Кя

TWINNED

a

b

a

b > h „ + 5mm

b

t t t la 1 a 1

b > § h 6 agg

a > < 2 e a n d a > h a g g + 5mm haggIS THE MAX SIZE OF THE COARSE AGGREGATE

BUNDLED

A A A b s e n

a a

b > h +15mm agg

a > 0 e and

Q > h a g g + 1 5 m m

(b) Bar arrangements

(i) hQcyf5 BAR SIZE

GAPS VERTICALLY IN LINE

44«: s П П П

(ii)

i ^SPACER,

it—*—w

10 30 ft

16 16

30

(iii)

• • • •

(iv)

Л 75 L 7 5 _ J*—*L


20 35 — — — 0.60

20** 30 40 50+ — 0.55

20** 25 30 4Q***

60*** 0.50

20** 20 25 30 50 0.45

Conditions of exposure Nominal cover* (mm)

Mild 25 Moderate — Severe — Very severe — Extreme — Water/cement ratio 0.65 Concrete grade c30 c35 c40 c45 c50

* All values in the table are for hagg maximum aggregate size of 20 mm. **To be reduced to 15 mm provided hagg >15mm. ***Air-entrainment should be used when concrete is subject to freezing.

spacers. They are normally plastic or concrete, but spacers in the form of steel chairs are also used. They serve to support the steel. All spacers must prevent the dislodge-ment of the reinforcement cage. They can be used for vertical bars in walls and columns and are clipped into the bars.


SHAPE CODE SHEET NO. 1.4

SHAPE CODE

METHOD OF MEASUREMENT OF BENDING DIMENSIONS

TOTAL LENGTH OF BAR (L) MEASURED ALONG CENTRELINE

SKETCH & DIMENSIONS TO BE GIVEN IN SCHEDULE

20 STRAIGHT

32 A+h

U A d

33 A + 2 h

•H

34 P * —

A + n

35 A + 2n

37 A v4 A+ В -1 /2R- *

38

OR

A

i_ k A + B + C - R - 2 0

J_ — A-

B >r A + B + C - R - 2 *

~Г|-с^

41 г, rB^hz£zd • X

-A—I

WHERE D IS AT LEAST 20 A + B + C

A+ В + С - Г - 2 Ф IF THE ANGLE TO THE

HORIZONTAL - 4 5 ° to


1.2.11 Bar shape codes

The standard shapes for the bending of reinforcing bars are generally given specific numbers called shape codes. They are listed on Sheet Nos. 1.4 to 1.8. Where construction demands a special shape not available in these sheets, a special shape code 99 of any form should be used.


SHAPE CODE (CONTINUED) SHEET NO. 1.5 1

SHAPE CODE


TOTAL LENGTH OF BAR (L) MEASURED ALONG CENTRE UNE


At h — С — |

42 /

\—A—-\

IF ANGLE WITH HORIZONTAL IS 45° OR LESS

A+B+ C + n IF THE ANGLE- 45° А+2В + С+Е-2Г-4Ф

J-H D

H A X 43

/\!Ef": В г В Д t

i

IF ANGLE WITH HORIZONTAL IS 45° OR LESS

A+2B+C + E К С Ч

45 гтто A+ В* C - V 2 r - « к \

D

\

В

1

D* J ^ 48 D

T"

1 С

5T A+B + C

-A—HVC AT

49 IF ANGLE WITH HORIZONTAL

IS 45° OR LESS A+B + C

D

Г Г

51 :

T A ,r(N0N STANDARD) A + B - V 2 r - Ф

(SEE SHAPE 37) 4L

52 ff В

Li

hA1

^ li A+B + C + D - 1 1 / 2 r - ЗФ

• c - H T

- A -

B v ' ^

A + B + C * D - l V 2 r - 30


SHAPE CODE (CONTINUED) SHEET NO. 1.6

SHAPE CODE


TOTAL LENGTH OF BAR (L) MEASURED ALONG CENTRE LINE


zLlh ^ E 53

D

1 A + B+C+D+E

- 2 r - 4 Ф

T' В

h-c-H

54 ^

I

в ~CT А + В + С - Г - 2 Ф

55

OR

A | —

D B A+ B + C+ D+E

- 2 г - 4 0

C — I

r | _ E - A+B+C+D+E - 2 r - 4 0

60

( I V ff • A —

Lb 2 ( А + В ) + 20Ф

62 *

k-c—jV" ^3 IF ANGLE WITH HORIZONTAL

IS 45° OR LESS A + С

,_L

г (NON STANDARD]

65

72 B— A 2 A * B + 25 0 n n



SHAPE CODE.


TOTAL LENGTH OF BAR(L) MEASURED ALONG CENTRE LINE

SKETCH & DIMEMSIONS TO BE GIVEN IN SCHEDULE

73 -BH

г 2A+B+C + 1O0

C.i.d

A

В

74 2A+3B+2O0

75 K-E_

S\

- JD

^-1—4^ t A+B + C + 2D + E + 1O0

A.id.

в с

— -E

D

81 h c^m 2A+3B+220

Aid.

D

83 <7

1ье

A + 2B+C+D - 2 г - 4 Ф

B(o.d.)

BEND UP

В (ad.)

BEND DOWN

85 ± it A + B+0.57C+D - ' / 2 Г - 2 . 5 7 Ф

NON STANDARD

о

I — = s r <

86

WHERE В IS NOT GREATER THAN A/5

g i r ( A + d ) + 8 0 I (MAX) 12m

HELIX A = INTERNAL 0 (mm) В = PITCH OF HELIX (mm) С = OVERALL HEIGHT (mm)


REINFORCEMENT, ANCHORAGE, LAP LENGTHS AND LINKS

SHEET NO. 1.9

ANCHORAGE (BS8110 CLAUSE 3-12-8) (a) Equivalent straight anchorage lengths

of standard hooks and bends (mm) ANCHORAGE

TYPE

HOOK ^ f 4 0

EQUIVALENT LENGTH BE NU k^jn-

1 \ EQUIVALENT LENGTH L = h.

VALUE

16*

240

8Ф

120

N/mm2

2 50

460

250

460

8

128

192

64

96

10

160

240

80

120

12

192

288

96

144

BAR SIZE, mm 16 20 25

256

384

128

192

320

480

160

240

400

600

200

300

32

512

768 '

256

384

40

640

960

320

480

(b) Minimum overall depth of various U-bars (mm)

SHAPE CODE

(HOOK) (HAIRPIN]

В

С

-I

rROMBONE)

R1A<*I

£

(-•urfr

B

6*

80

100

100

120

140

г

20

30 40 20 30 40

N/mm2

250 460 460 250 460

460

8

50 65 -

80 100 -

10

60 80 -

100 120 -

12

75 100 -

120 145 -

16

100 130 -

160 195 -

20

120 160 -

200 240

-

25

150 -

250 250 -

350

32

195 -

320 320 -

450

40

240 -

400 400 -

560



99 ALL OTHER SHAPES- TYPICAL DETAILS SHOWN BELOW.

99 ^ A H

k-c

IF ANGLE WITH HORIZONTAL IS 45° OR LESS & г IS 120 OR LESS. А + В + С + 2П OR E * 2 n + B-^/B2 -D*

A i°

T

99

IF ANGLE WITH HORIZONTAL IS 45° OR LESS A + B + C - 2 ( r + 0 ) IF ANGLE IS GREATER THAN 45° & r EXCEEDS 12 0 LENGTH TO BE CALCULATED. (SEE NOTE 3)

99 m A + B+11/3C

h^ s В

99 4A+ 20 0

99

-A H

ЧЕ к I CALCULATE

^ ' """ General Requirements 21

Sheet No. 1.9 gives data for the reinforcement anchorages, lap lengths and links for various bar sizes and for various yield strengths of steel.


BARS, COUPLERS AND CONSTRUCTION JOINTS

SHEET NO. 1.10

SLEEVE ^ v* REDUCER

'INSERT

(ii)

REINFORCING BAR

(V)

WEDGE

(iv)

Ф BAR DIAMETER Фо OUTSIDE DIAMETER L LENGTH P PITCH L t THREADED LENGTH OF

EACH BAR

COUPLER

4> (mm) 20 25 32 40

Ф (mm) 35 43 50 60

L (mm) 55 75 100 125

P (mm) 1581

1-814 2117 2-540

(mm) 40 45

65

SLEEVE S-] (mm) 140 150 192 240

WEDGE S2

(mm) 200 210 292 340

(vi) LEVEL 5 Ж

тНтг

ZZ

LEVEL 4

Construction joints

^ L A P

]JLAP

4P

(vii) LEVEL 5

^

LEVEL 4 • .

-4-

7M

3_^p ?

ueneral Requirements 23

1.2.12 Anchorage length and reinforcement joints

Both cases and mats of reinforcement are assembled from individual bars of manageable lengths and weights. In order to maintain continuity of the reinforcement for large components, reinforcing bars are coupled by using bar couplers. The joints can be in tension or compression. A simple tension joint is formed with a single sleeve which is compressed onto the bar using a hydraulic press. Couplers can be developed using a combination of a threaded sleeve and a stud. The object is that the tensile strength of such an arrangement must at least be equal to the strength of the bar. Sheet No. 1.10 gives couplers with specifications and construction joints where they can be used.

The minimum lap length for bars T12 and T25 can generally be taken as 300 mm and 350mm respectively.

The American Concrete Institute (ACI Clause 11.5.5.3) Code 318-77 gives useful comparison. The tensile lap length (ld) in SI units is given by:

ld = 0.019 AbyVfc\ ld < 0.058 dbfy,

where db = 0 is the bar diameter; fc' = cylindrical strength of concrete; fy = yield strength of steel; Ab = area of the bar.

The lap length of the compression steel is specified as:

ld = 0.24fydb/Vfc' for SI units; ld < 0.044fydb.

On Sheet No. 1.9, Tables (a) (b), the hook details are given. They are mostly in agreement with ACI code 318-77 except for the following:

4db or 40 or 4d are relevant for bars #3 to 8, 5db or 50 or 5d are relevant for bars #9 to 11, 6db or 60 or 6d are relevant for bars #14 to 18.

Hence while following the American practice they must be included. The value of В in Table 1.9.2 is taken to be 12db. For minimum laps of compression bars in unwelded splices for bars less than 32 mm, the Russian recommendation is 20 to 30 times the diameter of the bar.

Local Bond. Sometimes the reinforcement details may be influenced by the effects of local bond stress. For minimum lap of compression a suitable length of 20 times the bar size is provided.


INTERCONNECTED BEAMS SHEET NO. 1.11

(a) Beam grid (0 PRIMARY

BEAM SECONDARY Mi } BEAMS M2 PRIMARY BEAM

SECONDARY BEAM

(ii)

2T20-03T

27R10-13 -200 M2 2T25-02B SPACER

3T25-01B

PRIMARY; |" BEAM у

SECONDARY BEAM PRIMARY 2T20-06T T BEAM' 2T20-04T

22R10-11-200S 27R10- 12-200M1

2T25-05B

2T25-07B

(b) Beam monolithic with tEND SUPPORT

—HtO-11 orUSi>[

X T 4

(d) Holes in a beam (i) REINFORCEMENT

450 иъФ

As NOT LESS THAN 1/2 As

(c) Cantilever beams

As i -BEAM AS2<f V2AS-,

\r к 4:0-51 or 450-*

(e) Shear resistance of bent-up bars

(i) (ii)

6T20-02T v '- 30T12-04-200 LINKS

2T20-01B

Asb = AREA OF BENT-UP BARS


Sheet No. 1.11 shows some details of interconnected beams with and without holes and shear bars.

(a) Beam grid (Sheet No. 1.11) Cases (i) and (ii) show the layout and a typical detailing of primary and secondary beams. Main reinforcement, shear links or stirrups and connecting U-bars are clearly indicated.

(b) Beam monolithic with a wall When a beam is monolithic with a wall, the minimum lap or bond length of a hook shall be 0.1 x beam length or 45 times the diameter of the bar. The total steel area of the top bars with hooks shall not be less than half of the total area of main steel. This is shown in case (b) on Sheet No. 1.11.

(c) Cantilever beams A cantilever beam shall be reinforced in a manner shown in case (c), on Sheet No. 1.11. Again, the top hooked bars of total steel area As shall have a bond length not less than half of the effective span length. Where bars are extended beyond 0.5 x length or 45 times diameter, the area of steel shall not be less than half the steel area As.

(d) Holes in a beam There are several ways of reinforcing holes in a beam. The most well known are the square and the orthogonal layouts which are shown in case (d) on Sheet No. 1.11. In all cases the bond length beyond the hole shall not be less than 45 times the diameter of the bar.

(e) Bent-up bars Sometimes shear links and their shear amount cannot resist enormous shear faces. The bent-up bars are introduced to resist these shear forces. A typical layout is shown in case (e) on Sheet No. 1.11.


CURTAILMENT OF BARS IN BEAMS SHEET NO. 1.12 (a) Continuous beams without bent bars with hooks

CEND SUPPORT С INTERIOR SUPPORT

+0-251 or450 for 450;

L L T J с г n ca с

-|12*-*M>-0-08l —»tHM5l WITH FREE SUPPORT

(b) Continuous beams with straight bars and end anchorage NOTE: C<US0 C= 0-251


1.2.13 Curtailment of bars in beams

Bending moments and other loading effects vary from one section of the span to the other. Where maximum effects are achieved, a correct amount of reinforcement is provided. As the maximum effects are reduced, economy of reinforcement is achieved by stopping-off or curtailing bars (BS 8110 or any others). The codes generally give clear-cut rules for curtailment in different elements of structures. Cases given on Sheet No. 1.12 are based on BS 8110. Where other codes are involved, the bibliography should be consulted and the drawings modified and prepared accordingly.


BENT BARS AND COLUMN LINKS SHEET NO. 1.13

(a) Bent bars in deep beams

(i)

(ii)

Neutral

(b) Transverse reinforcement and vertical spacing of links

(i) (ii)

LINKS FOR THE FULL LAP LENGTH

-LONGITUDINAL-BARS

-Л-

PITCH

LINKS

LATERAL "DIMENSION

(iii)

PITCH

CONTINUOUS LINK

(iv) Isometric

""— General Requirements 29

1.2.14 Bent bars and column links

Case (a) on Sheet No. 1.13 gives bent bars as recommended by the European Code on Concrete (UC3). This case is similar to the structural detailing of bent-up bars adopted for many years in France and Germany.

Case (b) on Sheet No. 1.13 refers to column links. Longitudinal bars are the main steel, and links which contain the main steel are provided to prevent the main steel from bursting through the sides of the column. Where column lengths are such that bar splices are required they should have adequate lap lengths. The links can be of a square or a continuous helix type. A square cage is shown in the isometric view. In order to achieve continuity in the column-foundation system, starter bars of adequate length from the foundations are produced and are lapped with the main longitudinal reinforcement of the column. Details of these are fully described later on in this book.


SLAB REINFORCEMENT (a) Isometric view

(i)

SHEET NO. 1.14

(ii) Wall support MAIN STEEL

DISTRIBUTION STEEL

SPAN

30 FOR R BARS 40FORTBARS UP TO 20T 500 FOR T BARS OVER 20T

STD BEND PAST ([

STD BEND + d/2

SUPPORT WALL (b) Simple end

I 777 -v

on MAX -7'

40% As MIN L-As

f (c) Restrained end

support , 0-151 « i

[= SPAN • - » •

UNLESS SPECIFIED 5 0 % As MIN

END ANCHORAGE

(d) Continuous internal support 0-31N

X MIN. X

50% AsTOP^

0-15l*x MIN ->'

As TCP

0 3l"x

015 l*x -X

MIN ftslggger

MIN

50% • fAsTOP

T COLUMN

Ix = GREATER OF ADJACENT SPANS I or 11 >r

0-21 MAX

(e) Cantilever slab

4 0 % As MIN

-COLUMN

И

50%AsTOP-

X

As TOP 0 5k » MIN У

,<-

UNLESS SPECIFIED 1-5 к * or 0-3L 0-75k* or ,

- > •

0-151 - 5 0 % As TOP

NOMINAL USE MIN-TENSION 0-2 I

MAX ->'

40 % As "MIN -As

« or 450 WHICHEVER IS THE GREATER

SPAN (CANTILEVER)


1.2.15 Slab reinforcement and method of detailing

Sheet No. 1.14, case (a), item (i) gives an isometric view of the main steel and distribution steel in a simply-supported concrete slab. A specification based on BS 8110 is given when the wall support is given to this slab. For different end restraints cases (b) to (d) on Sheet No. 1.14 show the reinforcement arrangement and anchorages. The specifications indicated are based on the requirements of BS 8110. This sheet can be modified for other codes.

Sheet No. 1.14, case (a) shows various types of restrained ends which can be adopted for slabs. Case (b) on Sheet No. 1.14 indicates the procedure for bar curtailment in a slab recommended by BS 8110. A typical bar arrangement is shown in cases (c) and (e) on Sheet No. 1.14.


FLAT SLABS WITH DROP PANELS SHEET NO. 1.15

(i) Slab division

i COLUMN STRIP^ MIDDLE STRIP ^COLUMN STRIP,

(iii) Discontinuous edge ' 0- ?5l*av. .AT COL. STRIP

AT OTHER STRIPS

r-VARIES

T As (STRIP) 4 0 % As (STRIP) MIN

OH MAX

(ii) Section through flat floor slab ^ L

l/5 - l/4

I • L. • • • • » l '• Uf ' fc *""i»"#JH|

^ • f t 4 b i t M l

ALTERNATE BARS REVERSED

I ^ DROP PANELS


1.2.16 Flat slab

A flat slab is a reinforced concrete slab supported directly on and built monolithically with the columns. As shown on Sheet No. 1.15, the flat slab is divided into middle strips and column strips. The size of each strip is defined using specific rules. The slab may be of uniform thickness supported on simple columns. It is more economical to thicken the slab around the columns and to provide columns with flared heads. They are called drops and stiffen the slab over the columns and, in turn, reduce the shear stress and reinforcement. Flat slabs become economical where a number of panels of equal or nearly equal dimensions are required or where, for a limited headroom, large clear floor spaces are required. These flat slabs may be designed as continuous frames. However, they are normally designed using an empirical method governed by specified coefficients for bending moments and other requirements which include the following:

(a) There should be not less than three rectangular bays in both longitudinal and transverse directions.

€5 €1 €3 (b) The length of the bay — etc. shall not be greater than — X width —. (c) The length of the adjacent bays should not vary by more than 10%.

Cases (i) and (ii) on Sheet No. 1.15 give a full picture of the panel division system and the reinforcement layout.

The drop panel is 1.25 to 1.50 times thicker than the slab beyond the drop. The minimum slab thickness is 125 mm or €/36 for interior continuous panels without drops and end panels with drops or €/32 for end panels without drops or €/40 for interior continuous panels with drops. The length € is the average length and width of the panel. For some unknown reason, when the last edge of the slab sits on a column, the details of such an edge shall be carried out as shown in case (iii) on Sheet No. 1.15.


LAPS AND BAR CURTAILMENT SHEET NO. 1.16

(a) Restrained ends

(i) U-Bars in top (ii) U-Bars extended (iii) 'Trombone' bars (iv) L-Bars in top

Т а -

С Та —

— \ + Та-

С ^ L^ *—\

LAP

^k Та-

С •i

KEY F=FACE OF VERTICAL BAR IN RESTRAINING MEMBER

Ta= TENSION ANCHORAGE LENGTH

(b) General recommendations for bar curtailment in slabs

-FACE OF SUPPORT

CONSIDER NON-STD RADIUS VERTICAL LEG>80

M SUPPORT

TOP BARS SHOWN

1/2 LAP TO SUIT ^ K R S SHOWN ALTERNATE

INTERNAL SPAN

Td = TENSION ANCHORAGE LENGTH E = EFFECTIVE END ANCHORAGE REQUIRED IF SIMPLE SUPPORT

N = NORMINAL 12* or d (EFFECTIVE . B A D м п м ш л 1 С | 7 С DEPTH) WHICHEVER IS GREATER * = B A R NOMINAL SIZE

BTM= BOTTOM BM,M^BENDING MOMENT

(c) Continuous beam/slab with straight bars

INTERNAL SPAN 11

V4 ^

EXTERNAL SPAN 12

J*M l %

• • • ft Л ft

• ft" ч-w • * a_ —•—r

-ft • • ft r%

B A R S -BEAMS

BARS-


The general layout of the reinforcement is based on both bending moments (in spans) and bending moments in addition to direct loads (on columns). Typical examples are shown in Sheet No. 1.16.


COMPOSITE SECTIONS AND CONNECTOR TYPES

SHEET NO. 1.17

*#sz ' ^ j ^ ^ . ^ s j g ^ *-*4£*Js* ,<'

i и

МФ »-*k «-i t 9

«лл - и — * -

kt: f^\A>h

rLnl jflfc


1.2.17 Composite sections

This book gives a number of cases for detailing composite sections later. The following are the main types:

(a) steel sections encased in concrete; (b) steel beam flanges embedded in concrete; (c) steel studs in concrete welded to flanges of steel beams or any other sections.

Sheet No. 1.17 gives some composite sections.

38 General Requirments

EXAMPLES OF TABULAR METHOD OF DETAILING

SHEET NO. 1.18

(i)

h A2 H

A1

Plan

(ii)

NOTATION COL-COLUMN SECT-SECTIONAL ELEV-ELEVATION DIMS-DIMENSION

Elevation

(iii) COLUMN BASES

BASE No. OFF X Y Z REINFORCEMENT

B1 B2 LEVEL

D

(iv)

LAP LENGTH

JEVEL E^ V ^ ' I

LEVEL D . ^ L _ .

U г

Г 1

t }F

L=*

(vii)

75 KICKER

A - A

(v) (vi)

• •

• ,

*\ *

<

COL NoOFF LEVEL

С D

REINFORCEMENT

E F SECT ELEV

COLUMN DIMS

A В


1.2.18 Reinforcement designation and tabular method of detailing

In this section a comparative study is given for reinforcement designation. Drawings are modified to replace British Reinforcement Designation and others are noted below.

Country Reinforcement designation

Britain 4T25-05-250t or T, В (4 number of 25 mm diameter high tensile bar of No; 5 at 250 mm centres top (t, T) or bottom B)

4R8-06-300 Links

Sweden

Pakistan/India

Germany

Soviet Union (now

France

USA

CIS)

4025 С 250 408 С 300 stirrups

4No. 25 mm 0 250 mm C/C 4No. 8 mm 0 300 mm stirrup spacings

4Bugel (bars) 0 25 Sbu = 25 cm

25 0 (5) 4 NL 25 L . . . (L = length of the bar)

4025 С 250 408 С 300 stirrups

4#8 250 crs # 4 stirrups No. legs 300 mm crs (written in Imperial units)

All bars in slabs and other structures are designated using examples based on the Tabular Method of Detailing which is shown on Sheet No. 1.18.


1.2.19 Structural details and concrete behaviour

The choice of a structural detail can significantly influence the performance of a structure. Bond, anchorage, bearing, fire, corrosion and other properties of concrete have to be taken into consideration individually or in combination in the design and detailing of concrete structures. Where coating, grouts, binders, sealants and patching are needed, epoxy compounds are used or specified with concrete details. Since concrete is weak in tension, it is important that where bond is most important, structural details must ensure the force transfer between steel and concrete. In the case of bearings, structural details must be adequate to transfer forces from one member to another with a limited area of high local stresses. Structural details must cater for thermal expansion and creep where they are expected. The fire endurance of concrete structures is an essential part of a good design. The endurance period is generally taken as one hour plus. For high seismic risk, a certain minimum number of bars must be provided as continuous longitudinal steel for beams. For beams framing into both sides of a column, these bars must extend through the column for at least twice the beam depth without splices. The structural engineer must indicate quantities of reinforcement, cut-off points and length and location of splices to satisfy code requirements. Where concrete structures are subject to impact, reinforcement details must take into account potential zones of spalling, scabbing and cracking. The bars must span these areas.

Section II

Reinforced Concrete Beams and Slabs

II. 1 Reinforced Concrete Beams

Beams are structural elements carrying external loads that cause bending moments, shear forces and torsional moments along their length. The beams can be singly or doubly reinforced and can be simply supported, fixed or continuous. The structural details of such beams must resist bending, diagonal tension, shear and torsion and must be such as to transmit forces through a bond without causing internal cracking. The detailer must be able to optimize the behaviour of the beams under load. He must liaise with the structural engineer on the choice of structural details needed for particular conditions.

The shapes of the beam can be square, rectangular, flanged or tee (T). Although it is more economical to use concrete in compression, it is not always possible to obtain an adequate sectional area of concrete owing to restrictions imposed on the size of the beam (such as restrictive head room). The flexural capacity of the beam is increased by providing compression reinforcement in the compression zone of the beam which acts with tensile reinforcement. It is then called a doubly reinforced concrete beam. As beams usually support slabs, it is possible to make use of the slab as part of a T-beam. In this case the slab is generally not doubly reinforced.

Where beams are carried over a series of supports, they are called continuous beams. A simple beam bends under a load and a maximum positive bending moment exists at the centre of the beam. The bottom of the beam which is in tension is reinforced. The bars are cut off where bending moments and shear forces allow it. This aspect was discussed in Section 1.2.19. In a continuous beam the sag at the centre of the beam is coupled with the hog at the support. A negative bending moment exists at the support. Where a positive moment changes to a negative moment, a point of contraflexure or inflection occurs at which the bending moment is zero. An adequate structural detailing is required to cater for these changes. Again this aspect is discussed in Section I. The reinforcement bars and their cut-off must follow the final shape of the final bending moment diagram.

Where beams, either straight or curved, are subjected to in-plane loading, they are subjected to torsional moments in addition to flexural bending and shear. The shape of such a moment must be carefully studied prior to detailing of reinforcement. The codes including BS 8110 give a comprehensive treatment on the provision of shear reinforcement, namely links and bent bars. Again, whether the beams are simply supported, rigid or continuous the shear force diagram will give a proper assessment of the number and spacing of such bars.

Beams and Slabs 43

In circumstances where the bars are given lap lengths, they must be in line with the provisions of a code. As discussed in Section I, all bars are checked for bond using standard formulae, so that it should be possible to transfer stresses from one material to the other. The structural detailing of reinforcing bars must prevent relative movement or slip between them and the concrete.

As discussed earlier, the increased compressive area of concrete obtained by using a T-beam is not available at the support. Over the support, the compression zone lies below the neutral axis. In order to strengthen the beam at the support a greater depth with a haunch is provided. The beam will have a different section at the support from that at the centre. Special care is needed to design and detail such a beam.

44 Beams and Slabs

BEAMS

Ca) Simply supported rectangular beams

02 02

HI

M 0 A-A

28R10-03-175

SHEET NO. 11.1

(ii) Isometric view

2T12-02

£ 17-500

2T20-01 3

SUPPORT WALL "

TOP STEEL-

LINKS

CONCRETE 'COVER

-MAIN BAR

(iii) 10R10-08-125

175

[

Bl 12R10-07-200

2T16-06

10R10-08-125

.175

05 В 2T20-04 05

17-650

1T12-05 Я 04 05 04 B-B

(b) Simply supported L-Beams

(i) Downstand (ii) Upstand

-2T20-08-

•3T20-10

0LJ6 ПД 06

• p LJr

Щ и X >f * - * - *

3T20-09B -3T20-11

(c) Simply supported doubly reinforced beams

(>) (ii) MAIN COMPRESSION STEEL LINKS STEEL , (> p~

CONCRETE COVER MAIN TENSILE

STEEL [>Д Щ BRICKWALL

04 04 c-c

X Jr

k j j u f

A-A

Beams and Slabs 45

Since beams are reinforced in the longitudinal direction against bending, Sheet No. II. 1.a shows structural detailing of simply supported reinforced concrete beams for light loading (Il.l.a(i)) and for heavy loading (Il.l.a(iii)) together with an isometric view (Il.l.a(ii)) indicating how main bars and links are placed. The reinforcement layouts are self-explanatory, for example under H.l.a(i), 28R10-03-175 means twenty eight numbers of round ten millimetre diameter mild steel bars of identification number 3 are placed at 175 mm centre to centre. All such bar sizes and spacings are determined from the loading and secondary conditions such as fire and corrosion. Where down-stand and upstand beams in construction become necessary, an optimum reinforcement layout should be devised. One such layout is shown in Sheet No. I l . l .b. A typical doubly reinforced concrete beam layout is given in Il.l.c(i) and Il.l.c(ii).

Sheet No. II.2 demonstrates how links and bent bars are placed in relation to main reinforcement. The examples chosen are for rectangular, L and T-beams with a single system of links. A double system of links is specifically included in II.2.b(iv). Straight and inclined bars for resisting shear are detailed under II.2.с

Sheet No. II.3.a gives reinforcement layouts for both inverted and upright T-beams. A composite bending moment diagram is given in II.3.b(i) with cut-off positions along with two types of reinforcement layouts. A single continuous beam is shown in II.3.b(ii). A continuous beam with bent bars in a frame is detailed with several cross-sections in И.З.с. Continuous beams with slabs and columns are detailed separately in Section IV.

46 Beams and Slabs

LINKS AND BENT BARS (a) Links in beams

(i)

} " "!

LINK DETAILS BAR INFORMATION

-"

SHEET NO. 11.2

(iii) lsometricj view

(ii)

J i

•

i LINK r л

BAR INFORMATION

>

(iv) Beam lap

(b) (i) Links in rectangulai^beams (ii) Links in L-Beams r—LINK BENT DOWN

• • • Р-Пгг-f--<t 9

(iii) Links in T-Beams

"—ENDS OF BINDERS SLAB REINFORCEMENT

(iv) Double system of links T O p U N K COMPRESSION REIN-

i FORCEMENT IN BEAM lot ЗЕГЛГГ^:

— SLAB REINFORCEMENT

(c) Straight and inclined bars (!) - Л i

SINGLE LINK IN NARROW RIB

SLAB Ь_Ь_4

DOUBLE H—SYSTEM

OF LINKS

dotane/2 JT щ, r N s=d0/sinfi *\ =0-41 do when >

>when 0 = 45'

= 0 27d е=зо°

= 1-Ai d 0 w h e n 9 - ~ = 2d0 when 0=35°

REINFORCEMENT

(iii) и d° >

9 A a.1

^

(ii)

do /

-s/2=d0/2sin6 (90°-e/2) = 67-5°when 9 =45°

75°when 6= зо° (iv) ••—»*-d0tane/2

j X ' X / V % ^ а

/ '9X-0/2 X / \ . /IX. /

d0 cote • Й M»

do/2sin0ldo/2sine l i

dj2sin9 «

do/2sin9 « •

do6sin& * l 2 В

—-—•>

Beams and Slabs 47

REINFORCEMENT LAYOUTS (a) Simply supported T-beam

SHEET NO. 11.3

(i)

1 Л CM

bv =80 (ii) 2T25

-2T10-16

2T20

150

Cr№ h = 550

R8 AT 100 mm

150

-R10 LINKS

25 20 25

bw = 300

(b) Continuous beams (i) COMPOSITE

BENDING MOMENT DIAGRAM

CUT OFF POSITIONS -OF TOP STEEL OVER

SUPPORT

MAIN STEEL

(i'l) TENSION ZONE КЧ-

.BOND LENGTH

CUT OFF POSITIONS OF BOTTOM STEEL

-BENT UP BAR

(O C_ SUPPORT

Continuous beam in a frame with bent bars (0 -r^TfA f В f С

u S3 (ii) w к к В

тт Ml ' III I'l III

-».i?

4^ A-A

^

I'1

. 1|*- Ii I*; И

Щ i i ' ii w

B-B

У A

TENSION ZONE

\ / \ L

TENSION ZONE

• . <

TENSION ZONE

.

• •

" 7

c-c

48 Beams and Slabs

ONE-WAY SLABS ON WALLS AND BEAMS

(a) One-way simple slab

1

SHEET NO. 11.4

MAIN BAR

DISTRIBUTION BAR

i

1

J •1

1

J 2

PLAN

• • •

SECTION 1-1

I m *—*—• • • ш • a I ^

SPECIFY COVER-^

-BRICKWALL

SECTION 2 - 2

(b) Simple slabs supported on concrete beams 0) (ii)

l/4 -LACER BARS LACER BARS-

*g' * »

• •

I 30° to 45° 1 -i \ и ft

'10

— Beams and Slabs 49

II. 2 Reinforced Concrete Slabs

Slabs are divided into suspended slabs and supported slabs. Suspended slabs may be divided into two groups: (1) slabs supported on edges of beams and walls and (2) slabs supported directly on columns without beams and known us flat slabs. Supported slabs may be one-way slabs (slabs supported on two sides and with main reinforcement in one direction only) and two-way slabs (slabs supported on four sides and reinforced in two directions). In one-way slabs, as shown on Sheet No. II.4.a, the main reinforcement is provided along the shorter span. In order to distribute the load, a distribution steel is necessary and it is placed on the longer side. One-way slabs generally consist of a series of shallow beams of unit width and depth equal to the slab thickness, placed side by side. Such simple slabs can be supported on brick walls and can be supported on reinforced concrete beams in which case lacer bars are used to connect slabs to beams, a typical detailing of this is shown in II.4.b. Bond and anchorage details will be the same as for simple beams. This has been discussed in Section I.

50 Beams and Slabs

TWO WAY SLAB SHEET NO. 11.5 (a) Simply supported two-way slab

(i) 2

X-

(ii)

V

1 T

BAR DETAILS

J 2 PLAN

26T12-150

7 • • 1

BAR DETAILS

//

1 1 1 1 1 1

SECTION 1-1

(iii) -16T12-200 BRICKWALL

V • f t I t t—*-

COVER MIN BARSIZE

SECTION 2-2

• • t . J L - Д

Beams and Slabs 51

Slabs with reinforcement in two directions or two-way slabs bend in two directions. The principal values of bending moments determine the size and number of reinforcement bars in each direction. Most codes give formulae and tables of coefficients for computing bending moments in both directions. A typical layout for a two-way simply supported slab is shown on Sheet No. II.5.

52 Beams and Slabs

BEAM AND SLAB ARRANGEMENT (a) Beam/slab arrangement

SHEET NO. 11.6

°= COLUMNC^)—

A " В С D > — о — — 5 — S|

|_SEC0NDARY BEAMJ J £ ] [ _ _ ^T_ERNAL_ _ J .

• ^f ' ш ! i г . i ! _ j LSECONDARY l E A M j j _ _ _

о ___ __ __ __ о _ _ _ _ _ _ __ __, о ... Mi_ __ о

Г 1 ' | Г 1|Г" • I s:JJ j ] EXTERNAL !

INTERNAL 5 ] Г " • " ' " • - • " " • л 1 DIRECTION Д OF SPAN I OF SLAB T J

< Ш DO

(b) Typical one-way slab detailing —36T16-5-200 T1 —8T12-7-200T1

(i)

150

20T12-6-200B2

600

,(з:

? г —т—>' 450

COLUMN B3

СЁ)

PLAN

1600

+ (5 -4-

40T25-7-150 T1 (STAGGERED)

^_20T12-3-200 T2 (STAGGERED)

1200

10T12-4-200 T2

\ SUPPORTS

T1 TOP COVER =20 B1 BOTTOM

COVER • END= 40

20

-COLUMN C3

(ii) (B)

19T25-1V.200B1 "18T25-2J ALT.

rS

P E: E _ _

©

Г

Beams and Slabs 53

In R.C. building construction, every floor generally has a beam/slab arrangement and consists of fixed or continuous one-way or two-way slabs supported by main and secondary beams. Sheet No. II.6.a shows such an arrangement. The usual arrangement of a slab and beam floor consists of slabs supported on cross-beams or secondary beams parallel to the longer side and with main reinforcement parallel to the shorter side. The secondary beams in turn are supported on main beams or girders extending from column to column. Part of the reinforcement in the continuous slabs is bent up over the support, or straight bars with bond lengths are placed over the support to give negative bending moments. In large slabs separate reinforcement over the support may be necessary. This is also demonstrated in Section I. A typical one-way continuous slab/ beam arrangement is given in Sheet No. II.6.b for the general arrangement given in И.б.а.

54 Beams and Slabs

FLAT SLAB WITHOUT DROP PANELS SHEET NO. 11.7

(i)

12T25-7-200 T2

2br -^

о un C-sl

о LT> ГП

18T16-13-200 Г2"

150 "7Г 12T25-9 -. 12T25-1oJ B 1 d f

&

(2)

. ,500,

(1*2)

h-(14!

* -

- H -

16T16-13-250T2

(2+3) 10

о CNJ

c3l in

+

PLAN

«9

1600 1350

4)

4+ .d

1 -*Pi

12T25-5-200

• 1.

15T20- 6-250 ]T2stg

1250

14).

>-4

о о

-7(-

8T20-11-250i

12T25-12-175 T1stg

-{-

9T16-8-250 T1

U COVER T1 = 30 B1 = 25 END=30 stg = staggered alt = alternative

6T25-2 J 2 0 0 B 2 a l t

10T20-3-, 1 7 5 B 2 a l f

10T2 0-4-1

(ii)

<

8 i i

• i L J 6

6

1 4 И

IF *

• 1 4 ; 9.Ю

. л , „ _ , r „_ f , .

^ 9.10 3,4

4 I „ 9.10 -

i

1 i

A - A

Beams and Slabs 55

A flat slab, as discussed earlier, if supported directly on and built monolithically with columns, may differ from a two-way slab in that it is not supported on beams. The slab may be of uniform thickness supported on simple columns. Generally the slab around the columns is thickened in order to provide columns with flared heads, known as drops. The drop stiffens the slab over the column and reduces the shear stress and the reinforcement. Codes also recommend the distribution of bending moments between column strips and middle strips as shown in Section I. A great deal of research has been carried out on flat slabs without drops. Flat slabs without drop panels and with drop panels are respectively detailed on Sheet Nos. II.7 and II.8.

Continuous slabs with mesh fabric are given on Sheet No. II.9. Ribbed slab panel with reinforcement details are given in II.9(iii).

Sheet No. 11.10 gives a reinforcement layout for a simple panel under missile impact. In Section IV, additional structural detailing is demonstrated for beam/slab column arrangements.

56 Beams and Slabs

FLOOR SLAB SHEET NO. 11.8

34T12-01-150T1

30T12-05-1SOT2

A

24T12-08-250B2

32T12-07-200T2

36T12-04-150B1 34T12-01-150T1

• *

-B

18T10-03-250T1

-E3-

-EJ-

32T12-02-150B1

32T12-07-200T2

24T10-06-200B2 -H T-

30T12-05-150T2 —1

18Т10-03-250П

FLOOR SLAB PLAN SCALE: 1:50

1,3 5 , ?

6 1Л

гл

9 6 2 , 4 8 6 10 2 Л 6

SECTION A-A SCALE'1:50

Beams and Slabs 57

CONTINUOUS SLAB REINFORCED SHEET NO. 11.9 WITH MESH FABRIC AND RIBBED SLAB PANEL

(i) Flat slab

АЛ 4 ll/9J. 4 » n I * . 11: A

(ii) Waved fabric

10T16-9-T2 2/ЙВ 10T25-5-T2

8T16-4-250T1 u

16R8-10 LINKS

5T20 -5 B2 mm

FABRIC

»

6T10-TI-150B1 „

U V ,T7P

} 1

И

11

DETAILS OF FABRIC HERE

[VL 4

l 2

I, 2T25-3-250 T1

3T25-10-B1

16R10-7-300 UNKS

m 12R8-12-300 LINKS

X 16R8-6-300 UNKS

X 2T25-2-B1 STAGGERED

5T20-6-B2 2/RIB

(iii) Ribbed slab panel

58 Beams and Slabs

R.C. DETAIL OF TARGET SLAB SHEET NO. 11.10

i*- 1625 - f

о о IT»

n

Li

S1U.5-31C/C TOP 5lT6.25-31c/c BOTTOM

47T4.5-31c/c TOP 47T6.25-3U/C BOTTOM

PLAN

51T4.5-3U/C

51T6.25-31C/C

=TT •* rn

. 24U.5-65C/C LINK

SECTION AA

UTA.5-31c/c

47T6.25-31c/c ш

SECTION BB

Section III

Stairs and Staircases

60 Stairs and Staircases

STAIRCASE REINFORCEMENT SHEET NO. 111.1 (a) Straight stairflight supported on brickwork

9500

• J H • • » • • • <rt f t , f f t f d

Ш

# *

125 W\STE

-ЬД (ii)

kk

21T12-05-250B

,

1

.

•

i "

7T16 -02 -150

7T16 6T12-05-250T -01-150B

I

5 ___,.

>'• i

7T16-04-150T В

— щ

7T16-03-150

1

i — '

PLAN (Small scale) (b) Straight stairflight on beam supports

(i) -x-

A-

/EDGE OF FU0OR SLAB V DETAILS OF DISTRIBUTION BARS

13T12-Q5-250T

\ I C I M I l t

4-

4

DETAILS OF MAIN BARS] 7T16-01-150B -4r

( i i i ) BEAM STEEL

- i zi—r • ^

- r

BEAM STEEL

Stairs and Staircases 61

III.l Stairs and their Types

Stairs lead from floor to floor. They are of several types. The common ones are:

(a) a sloping slab spanning from one floor to a landing or another floor; (b) a sloping slab carried on sloping beams from one floor to another or to a landing.

Typical reinforcement details are given for these staircases on Sheet Nos. III.l and III.2. As seen there are several variations in the presentation of the structural detailing of staircases. In all situations the staircases have landings and waste as shown in the key diagram (i) on Sheet No. III.2. The dimensions are established in Ш.З.а and Ш.З.Ь. The rise of the stair does not usually exceed 150 mm and the tread 250 mm including a nosing of about 25 mm beyond the vertical surface of the rise. The load for which these staircases is designed varies with the type of building. In all circumstances, the detailer must check specifications with the structural engineer prior to carrying out reinforcement details.


STAIRCASE WITH SLAB CONSTRUCTION

(i) Key diagram

SHEET NO. 111.2

LANDING

WAIST-SLAB DEPTH

(a) Slab construction (i)

LESSER OF LANDING WIDTH OR 1800mm

(L

CLEAR SPAN

LESSER OF LANDING WIDTH OR 1S00mm

Ы' ( L a '

ELEVATION "Ь2'

(ii) LANDING

V \

\

lAREA iWTTH IFUGHT

AREAV/ITH FLIGHT 2

X EXTERNAL WALL

x FUGHT 1

FLIGHT 2

PLAN

G- GOING N- NOSING P-PITCH R-RISE T-TREAD W-WASTE

(b) Parts of a staircase (i)

/

Г1*1

MJ>

R (iii) -A


STAIRCASE ELEVATION SHEET NO. 111.3

17

6T12-13 + 5T12-24-125

— 2 1 -19 £

к .

n у •-

J6 _ 25

4T 20-19-300

21T10-17-150

3T10-19-3S0

2 + 3 T 1 0 - 1 8

5T10-20-300 6 T10-21-250

10T12-16-150

9T12-25-150

S E C T I O N A - A

SCALE J _ L 5 0

1st

LANDING

G

S T A I R C A S E E LE V A T I O N

SCALE 1*50


STAIRCASE WITH THE BEAM SLAB ARRANGEMENT

SHEET NO. 111.4

® KICKEFf

©-'

СЭ LTI vO m

GH

150,

t— m

(3>

ir

3T12-04 300T

CD 3600

1

К

.ЗД

о i n гп

т о

ГМ <S1

~3f о

CV1

24Т12

f * 1 оо

CD m

^Е 21Т12-06-350Т

05-300В

3600

^Ш^

600

II

тт

12М10-06-350Т

6Т12

Я

_£ £1— о

I04-300J

10Т12-07-300Т

PLAN

For staircase reinforcement details see Sheet Nos. 111.1 and III.2.


The dimensions and other specifications are derived from the general layout of the building or structure where the stairs are to be used. Two typical layouts given on Sheet Nos. III.4 and III.5 show the exact positioning of these staircases with respect to gridwork and floor levels. Sheet No. III.4 gives beam/slab/column reinforcement layouts with respect to a staircase. Sheet No. III.5 gives a beam/slab/column plan on a section showing levels and grid work. These staircases will have the reinforcement details as outlined on Sheet Nos. III. 1 and III.2.

There are a number of other types such as stairs cantilevered from a side wall, spiral stairs with sides cantilevered out from a central column and free-spanning spiral stairs. They can be easily designed and detailed. They are not included as their use is very limited.

Precast concrete staircases have recently become very popular and a number of companies are involved in producing them. In this book Birchwood prestressed concrete staircases are shown on Sheet Nos. III.6 to III.9. Sheet Nos. III.6 and III.7 give sectional elevations and plans of staircase details. The stairs are connected to precast concrete floor units which themselves are connected to cross-landings and bearings. Sheet Nos. III.8 and III.9 show typical reinforcement details for stairs, bearings and landings. Loading and material specifications are given on each drawing. The standard accepts vinyl tiles, sheet or carpet direct. Where any two or more members join, it is recommended to use site-applied screed to the landing. Dimensions and details for the rise and going for these stairs are given below:

Staircase type Rise (max.)

220 190 170 180 190

Goi ing (min.)

220 240 250 250 250

Private - giving single access Common - giving joint or multi-access Disabled Institutional and assembly buildings Any type not described

The above information has been abstracted from Building Regulations Documents K:1985, M:1987 and amendment 1:1988


GENERAL ARRANGEMENT PLAN FOR CONCRETE STRUCTURES

SHEET NO.

KERB 150 HIGH.

сэ [ Л a>

о сэ 1П

О сэ LTl m

SH

150 3850

250 ^1

СЭ о *— т < х с м 0

Ш

ЗА2 500x300

о LP СМ

ЕЕ

сэ т- m < х г^сэ

сэ in

гя Д50

CD 1Г1 CM

150 STEP.

© 4500

; S '

3E2 650x300

^

oo

СЭ СЭ

CD x » - С Э in

- f - 150 STEP

1A2

7 s C3 i n 2C4 450x300

l o Jin ICM

J x

|сэ j o m о о r- m

125 ^ x ^ C N I O

" LTl

SFL -° 110 150

2B2

450x300

150

N

о сэ in

w i n

1A2

сэ| о 1 , _ m | и x

ml vOI

NIB K200

DEEP

-175

COL. 500x 300

о сэ i n

сэ i n

500x 300 см

6 5 0 x 3 0 0

СЭ in

<3f СЭ i n

® SFL

110-150 7

СЭ СЭ

in CM

©

£ 'i 3 СЭ CM

Отэ zn ш

m o

n > n

1Л

О

c

68 Stairs and Staircases TD314A5 DD13flflfl 541

BIRCHWOOD PRECAST CONCRETE SHEET NO. N1.7 STAIRCASE

&

r0>+

\

\

X1

01 5L0\

™ Ф

^ N

• -

чО Ф

£ ф

\ \ \ \ \ \ \ \ ' | ч \ \ 1 \ ч \ \ \ \ \ х -

i92 Hiain iHonj szzi ЕЕ» mam iHonj згг!

ъ z • t f

II

a z

LOAD

I

a LU

О a. 5

ERI

Q . Ю CO

<L>

> '<V и QJ

О

moo

th

-o Ш 1Л

' c

rs fi

CD

k-X J

"О a;

H

^ j

и ^

es d

i

+=

" > 4

. > о

a. re о

re • a

CO

"re ГЧ

E E ^ z о

to

1/1

0)

с о и f N

Q_ <D

О

X i n 1 Л

X m

y) 5 ,9 < и ^r uS

3v. %»


BIRCHWOOD PRECAST CONCRETE SHEET NO. Ill-8 STAIRCASE Reinforcement Details—1

7 TIO 10 l % -

10 MINGS AT 250 • 2500

TIO 3 146 о

STAIRFLIGHT MK; Fl ' ] No. required

Volume of Concrete = I.12 cubic nslres Total Weight of Flight = 2.771 tonnes

~^~

- И R8 1 I 100

100

15

45

150

1 l ЭД

SUPERIMPOSED LOADING = 4kN/m2

1. Treads and risers finished smooth to receive carpet or vinyl tiles direct.

2. Concrete strength 40N/mm2 at 28 days. 3. Baluster pockets 55 x 55 x 140 deep. 4. All laps to be40d. 5. Cover = 20mm.

_ 7 T l 2 20 230 T 7 TIO 21 230 В

95 90

5

"л

LANDING MK: Ll 1 No. required

Volume of Concrete = 0.169 cubic metres Total Weight of Landing = 0.406 tonnes

70 Stairs and Staircases - — ~~ • u I -I I

BIRCHWOOD PRECAST CONCRETE STAIRCASE Reinforcement Details-2

SHEET NO.

in

CD

OS

SZZ\

s u i • 9'BSI iv SH3Sia n OS!

0L

SSZI

Birchwood Concrete Products 1991

CO

01 E

- vJ3

о

01 CO C\J

О c r ' 0)

<c — i— en

01 L. О С о

О CD

СО

се

" • • • 1 1 ] !г*

001

о

ю — 1 ш 15

0

Section IV

Columns, Frames and Walls

72 Columns, Frames and Walls

COLUMN DETAILS AND SCHEDULE SHEET NO. IV.1 (a) Typical arrangement

(i) . . 13 900 (ii)

75 KICKER,

01 01

4 * 4T25-01 D ж_ тот А ж А-А 19R10-02-200

10000

02

(iii) 2R10-08

75 KICKER

EAM

DOWELS - IN POCKETS

(b) Column schedule (c) Column elevations

COLUMN SCHEDULE Column

Reference

R a № ^c^ .

о о <*

IstSFL 4-500 4 ^

4500

GndSFL '

Type С-35 No

-

4T25

-7

J

4T30

-1

1 ° \ • *

г •

m

20R

10-2

- '

A-A

cc L U se: i t :

un

LTl OJ -* M

о

0R1O

-2-3

0

OJ

J

Г

A-A

cc LU *: L_)

75

К

у 1

5B-6B-35No.

CD

СЭ O J

OJ

ON

О O J 1— OJ

m .

8

8-10

- 3

I / cc \ / LO

m

4T25

-

*• 11 J ' . LTV

•J-

2T20

-

OJ

I/O

о 3: »—

sL-зо

о IN

m ,

хэ 1 : I

\ \ oo oo \ \ се 1 l - j-1 П

cc ~*

-

(i) 2 -

(ii) 8 9

• •

• • 10

A-A 8 9

c-c

RoofSFL 8000

COLUMNS 5B.6B

Columns, Frames and Walls 73

IV. 1 Columns

Columns are usually under compression and they are classified as short columns or long and slender columns. Long columns are liable to buckle under axial loads. The length of the column is the distance between supports at its end or between any two floors. The effective length of a column is governed by the condition of fixity at its ends in position and in direction. Codes give the values of the effective length for a number of cases by multiplying the actual length by a factor. Columns may also be loaded eccentrically or there may be a bending moment imposed on them in addition to concentric (axial) and eccentric loads.

Reinforcement in the form of longitudinal bars is provided both in short and long columns. These reinforcements are necessary to withstand both tension and compression loads. The most efficient location of the longitudinal reinforcement is near the faces of the columns. Such locations reduce the possibility of the reinforcement buckling with the resulting inability to take the load for which the column is supposed to be designed. Such buckling is prevented by lateral reinforcement in the form of ties or closely-spaced spirals. Again, codes give detail specifications for their design including sizes, spacings and the strength of concrete. The minimum number of longitudinal bars in a tied column should be four and the minimum diameter of bar is 12 mm. Typical details of columns and ties are given in Section I. They give locations of longitudinal reinforcement in specifically shaped columns and the method of providing ties to stop them buckling in any direction.

In any large job, it is necessary to give elevations to columns with their respective cross-sections and a column bar schedule must be provided to give column reference, column type and elevation and reinforcement details at various elevations. Sheet No. IV.1 gives, in brief, all these requirements for a specific construction. As column design is based on requirements already discussed above, sizes and reinforcement may change but the layout will be identical to the one given on Sheet No. IV. 1.

The reinforcement bars, depending upon a specific construction, may require couplers, provided on the lines suggested in Section I. Care is taken to provide adequate laps where construction joint detailing is needed. Again a reference is made to specific codes and to Section I.


R.C. DETAILS OF SLAB BEAMS AND COLUMNS

SHEET NO. IV.2

CO

_ J О

CO

< UJ CD

CO <

I CO

о

со

< j — LU О

cJ

'

3750

0

oosz. 'I'

7500

<

. I

. 75

00

7500

1

7500

'

Г "

i

r

1

'

osz.e fc

1

s

0SZ.8L

л 0SZ.E . . 0SZ.E . . 0SZE . .

1 1

WV39 AaV

1 1

i !• •

ON0D3S 0 i_ \ \

—' ' \ UJ \ Z \ < \

£09* 0 0 % I — i

.s:

,CQ

x720

0 M

AIN

'

3000

,

0SZ.E .

•

- •

i

or о о

СП LU Q_ Q_

< CJ Q_ > -

< l


In most constructions, carrying out integrated structural detailing in concrete is unavoidable. Generally in framed constructions, slabs, beams and columns are involved. Sheet No. IV.2 gives a general plan for a typical floor showing main and secondary beams, slabs and columns. Sheet Nos. IV.3 to IV.6 give examples of detailing. Various R.C. components needed for the floor are shown on Sheet No. IV.2. All structural details are self-evident and indicate how an integrated structure can be designed and detailed.


R.C. DETAILS OF BEAMS, COLUMNS SHEET NO. IV.3 AND SLAB

-СП < a :z: о L-J UJ O0

о i -

R.C. DETAILS OF SLAB BEAMS & COLUMNS

I *1 i—2T32-12 BARS h 1800 1800

111! I IP ' -4ТЭ2-11 BARS

2R10-13-125 2R10-13-225 --+-- 4-1R10-13-300 LINKS 2R10-13-150 2R10-13-75

-Lfi J

LI

900 7500

HH -U-

2R10-13-75 2R10-13-150

V J 900

7500

MAIN BEAMS

50 COVER 12 U 12 15 12I2J 1S £

50 COVER

Г^*РЧ

l . ' . l 11 14 14 11

40 175 40

40 COVER

Б 40 COVER

T*\

tf 1 1

I H- ' 11 25 150 25

-2T32-15 BARS

-4T25-14 BARS

25 COVER

SECTION 3-3 SECTION 1-1

SECTION 4-4

SHEET No.

5 ? £T 40 COVER

ГфЩ

/ l /

25 150 25

OH

P О LO

25 COVER

SECTION 2-2

> 00 CD ГП >

LO

CO

О < 4^


R.C. DETAILS OF SLAB BEAMS AND COLUMNS

SHEET NO. IV.5

-Лг t

Щ

<

u

IE

о о

tu

u

I NO

LU 0 0

i^L

NO "1

Й

I If

|fcffl.U5Z3-g-ZU£

I I I I I

V

tdOi)SZfg-ZZ-ZLl

1 If I I -

I V li

i i

ffl eyi i i i i;

\

(d01)S22-£2-ZU£

-XI -i—I—I I i

I I

-I—I—H I I.

: Э

Of:-J

T 1

ГИ01)5г^-гг-ги i i ;

шоТ

U-l| CD

lol

.08) S2Z4Z-2U \

^ - + H I I

I I

U -t—н

2

< h-LU О

SO J


R.C. DETAIL OF INTERIOR COLUMN SHEET NO. IV.6

.ROOF

о 1 Л • J -

* ~

г 8

LTI

FT

H

-4T16-33

4~* 1 -TOP FLOOR

° LTI L •250x600

BEAM

8 •R6-32-190

-4T16-31

Г

300x300 COLUMN

T16BARS-

R8LINK-

h 300 , | 33 33

**

—»-

*31 3 1 ^

31 , 31 • • «

1

33 • 33 40 COVER

SECTION 7-7

300 »i

T16 BARS 31 31

>

R8 LINK'

32 о CD

31 f 31 1 40 COVER

SECTION 8-8


STRUCTURAL WALLS (a) Wall reinforcement isometric view

SHEET NO. IV.7

FLOOR SLAB

SECONDARY STEEL S 80T20-06-250 S J MAIN STEEL 80T20-08-250M

STARTER BARS 80T25

KICKER 75

» • !

» «

HORIZONTAL STEEL 80T20

*2 NARROW

5JGAP

80T20 PLAN

(b) Opening and closing corners

LONG BARS SMALL

SHORT BARS SMALL 80T20-250

LARGE STARTER BARS 80T25-25-175

LARGE STARTER BARS 80T25-175

DISTRIBUTION STEEL

7

DETAILS OF WEEP HOLES

U4-4-U \ • :

IHHIHI

I I I \\\ WW ^—4 \ f

IMtHHHHI

I H

H M

BAR 80T20-08-250

BAR 80T20-250

DETAILS OF No.

OF STARTER BARS 80T25-175


IV.2 Reinforced Concrete Walls

Reinforced concrete walls are generally subjected to axial loads. A typical isometric view of the reinforcement mesh is given on Sheet No. IV.7.a. A schedule is prepared for long, short and starter bars and their cut-off lengths together with opening and closing corners. The sizes of these bars depend on a specific construction and loads carried by a wall. Sheet No. IV.8 gives reinforcement details for an integrated structure, beams, slabs and walls (including shear walls and laterally loaded walls). Again codes are consulted for wall specifications and minimum bar diameters and wall thicknesses.

IV.3 Portal and Frames

Sheet No. IV.9 gives reinforcement details for three different types of portals and frames. Again the thicknesses of frames and bar sizes depend on types of load. The general layout will still assume the same shape as indicated on Sheet No. IV. 10. The frame corner reinforced with loops is shown on Sheet No. IV. 10. It is practised in Germany and is widely recommended by the Eurocode on Concrete and by the American Concrete Institute.


STRUCTURAL WALL SHEET NO. IV.8

® ©

i

2T16 - 1 •H

Ф

Л-

1 Л CM CM

in см CM

< CD

о

ao ОС m

12T16 12T16-

LEVEL 4 SF L 185 50

T

1- 325N2 1-325F2

< CD

H

1 N - NEARFACE F- FRONTFACE

LEVEL 3 SFL

14-110

-4-

SEE DRO

Л-4200

WALL'B'

r SEE ORG SEE DRG-

I I £Ш ^

JF* 3 1 3 - * * -

1 3


PORTALS AND FRAMES SHEET NO. IV.9 (a) Rectangular portal with chamfered edges

157 000

_I

U 5-000 \\ I I I I L 157000 •

^7777

(b) Rectangular portal with straight edges

(c) Gable frame Iff500 WK

VT25-Q3T

2T16T

157 000 Ж

145-000

HINGE

C-COLUMN G-GABLE


FRAME CORNERS WITH LOOP SHEET NO. IV.10 REINFORCEMENT (GERMAN PRACTICE)

(With Permission of DIN Deutsches Institut Fur Normung E.V. Berlin, p. 63 DIN 1045)

Bar diameter db r > 5 cm and > 3 ds < 5 cm and < 3 d5

Hooks, bends, loops, links 15 d^8 20 ds d-, and d 2 > 100cm ds = 0 bar diameter in cm

Sections 1-1 and 2 - 2 are required for the design. Transverse reinforcement or links shall be the same as on Sheet Nos. IV.8 and 9.

Section V

Prestressed Concrete

V.l General Introduction

Prestressed concrete has attained worldwide recognition in the development of industrialized construction and design. Prestressing consists of introducing imposed deformations by tensioning prestressing wires, cables or strands and tendons to a high stress which decreases with time due to various losses such as shrinkage, creep, steel relaxation, friction and wobbling effects. The word prestress is associated with the following:

(a) pretensioned concrete; (b) post-tensioned concrete.

In the case of pretensioned concrete structures, the tensioning of the tendon is carried out before concreting. The prestressing force is held temporarily either by a specially-constructed prestressing bed or by a mould or form. When the concrete strength reaches the specified transfer strength, detensioning and stress transfer to such structures can be performed. In practice these structures are prefabricated.

In the case of post-tensioned concrete structures, the tensioning of the tendon is carried out after casting and hardening of the concrete. This method is more effective in the design and construction of high-rise and long-span concrete structures. The design and detailing of such structures are influenced by the serviceability classification, which includes the amount of flexural tensile stresses allowed while carrying out the design/ detailing of such structures. They are then classified into individual classes which are given below:

Class 1: no flexural tensile stresses. Class 2: flexural tensile stresses but no visible cracking. Class 3: flexural tensile stresses but surface width of cracks not exceeding 0.1 mm for

members in very severe environments and not exceeding 0.2 mm for all other members.

The structural detailing of prestressed concrete members must take into consideration durability, fire resistance and stability. The relevant codes include BS 8110 which should strictly be followed for the correct evaluation of design ultimate loads and the characteristic strength of concrete and steel.

Generally high strength concrete is used for prestressed concrete work. The steel used in prestressed concrete is generally of a much higher strength than mild steel. This aspect is discussed later on in the choice and evaluation of prestressing systems.

Prestressed Concrete 87

Material data and prestressing systems are given on Sheet Nos. V.l to V.14. In such the prestressing tendons can be bonded and unbonded. The structural detailing is affected when the prestressed concrete structure is designed with bonded and unbonded tendons. Before the prestressing load is transmitted into various zones of concrete with bonded or unbonded tendons, it is necessary to protect the areas immediately under the anchorages against bursting effects caused by large loads generated by prestressing tendons.

A conventional steel in the form of reinforcing cages or helicals is provided below the anchorages in concrete to take much of the bursting effects. Codes give assistance in the design of such reinforcement, known as the anchorage reinforcement. The end areas where the anchorages rest are known as anchorage or end blocks. The purpose of such reinforcement is to transfer forces from anchorages smoothly into the concrete without causing internal cracks. The prestressing loads are affected by losses, elastic shortening of concrete, shrinkage and creep of concrete, relaxation of steel, anchorage slip and friction and wobbling effects. Again codes are consulted on these losses due to short and long term loads.

In order to sustain effectively the bending moments, deflections and shear, particularly in post-tensional systems, the tendon should be given a profile over its length where parasitic or secondary moments are to be avoided in a continuous structure. The tendon or cable shall then have a concordant profile.

V.2 Prestressing Systems, Tendon Loads and Material Properties

V.2.1 Available systems

(a) Wire/strand directly tensioned. (b) Macalloy System using high tensile bars. (c) Freyssinet System (France). (d) BBRV System (Switzerland). (e) CCL System (Britain). (f) KA System (Germany). (g) VSL System (Switzerland).

The details of the above systems are given below.

Sheet No. V.l gives data for strand characteristics for standard, super and Dyform strands. Sheet No. V.2 is a table giving basic data for Macalloy bars listing tendon sizes, characteristic loads, bearing plates and duct sizes.

Sheet No. V.3 gives further data on cold worked high tensile bars and cold drawn and pre-straightened wire used generally in pretensioned concrete structures. Sheet No. V.4 is a monogroup for a well-known 15/15 mm normal strand system used in the Freyssinet System. A similar monogroup exists for other strand sizes. Sheet No. V.5 gives the BBRV System where a single tendon formed from individual wires is used. Sheet Nos. V.6 to V.9 give comprehensive data on BBRV tendon systems. Data for the small capacity BBRV systems are given on Sheet No. V.10. Sheet No. V.ll shows the large tendon developed by BBRV to initially take up a 1000-tonne prestressing load. This type of tendon is used in the Dungeness В prestressed concrete pressure vessels. The stress-strain curve of this tendon and its basic data are given on Sheet Nos. V.12, Sheet Nos. V.13 and V.14 give structural detailing and data for Cabco prestressing tendons manufactured by Cable Cover Ltd.

88 Prestressed Concrete

STRAND CHARACTERISTICS SHEET NO. V.1

Nominal size

mm

Standard

12.5 15.2

Standard

18.0

Super 7

12.9 15.4

Dyform

12.7 15.2 18.0

Maximum

Nominal Characteristic area strength

'pu

mm2 N/mm2

Characteristic load

Pk

kN

7 - wire (normal and low relaxation) to BS 3617

94.2 1750 165 138.7 1640 227

19 - wire (normal and low relaxation) to BS 4757

210 1760 370

- wire (normal and low relaxation)

100.6 1830 143.2 1750

7 - wire (low relaxation)

112 1870 165 1820 223 1700

relaxation for initial load

Normal relaxation strand Low relaxation strand

184 250

209 300 380

I

0.8 Pk

kN

132 182

296

147 200

167 240 304

0.8 Pk

12% 3.5%

nitial load

0.7 Pk

kN

115 159

259

129 175

146 210 266

0.7 Pk

7% 2.5%

^ ш м U l NJ -J. J> OJ NJ W W - » W W - i W W - i

O O O O U i U i U i W N J N J M C C C O C O U l U I U l N J N J N J O O O

OJ U l о U l

Ul о l / l

3 сю <т>

ю О l / l

3 сгч а>

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W W - i - i - i NJ - i - i - i - ^ W C f i v l O O V C W C n W f T i - i U I W O O ^ O ' v J W s l U l l O f f i ^ W o w u i M « u j ( y \ - f c c o w c t \ - i M O J U i o w c o K J C f \ o o u i w O U I O U U I O U O O O O ^ O ^ O O O O O O O C F I O J O J U I C O

* W W - i Ю - i NJ _i _ i - i - i - i O O O O W № \ I U I 4 ) W m t f O U l W 0 0 J i W m u i M № W O O O O ( J l W ( I M J \ W t l H i O O O O O O O O O C 0 M ( H

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i centre

anchor;

> " ^ » -Cfq О Z3

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5 ^ Z -г, и

О 5 со z -о

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Size beari plal

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x

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СЛ I m m H z p < NJ


COLD WORKED HIGH TENSILE BARS SHEET NO. V.3

Nominal size

mm

20 25 32 40

Nominal area

mm2

314 491 804

1257

Characteristic strength

Гри N/mm2

1035 1020 995 995

Characteristic load

Pk kN

325 500 800

1250

Initial load

0.8 Pk

kN

260 400 640

1000

0.7 Pk

kN

228 350 560 875

COLD DRAWN AND PRE-STRAIGHTENED WIRE (NORMAL AND LOW RELAXATION)

Nominal size

mm

4 5 7

Maximum

Nominal area

mm2

12.6 19.6 38.5

relaxation for

Normal relaxation wire Low relaxation wire

Characteristic strength

Три N/mm2

1720 1570 1570

initial load

Characteristic load

Pk kN

21.7 30.8 60.4

Initial load

0.8 Pk

kN

17.3 24.6 48.3

0.8 Pk

8.5% 3%

0.7 Pk

kN

15.2 21.6 42.3

0.7 Pk

5% 2%

-е — с

гГК

HOLES FORI* «XING SOLTS.

(Г ) « A .

SNROFLEX SHEATH

BEND.NC RADIUS / " > * " " « A N G L " * " ' < » " > \ FOR SMALL ANGLES 4.S m (

REINFORCING SPIRAL

М м ( | } ( ' ) О Д

Son

H >

ANCHORAGE CENTRES

A N D EDGE CLEARANCES

125 mm Mm

NORMAL. END RECESS

SHEATH F I X I N G THREAD

«.MALLEABLE CAST IRON ANCHORAGE GUIDE

H mm (Г) ИА. GROUT HOLE

ч FORGED STEEL ANCHORAGE «LOCK

STRAND JAWS

DESIGN DATA 15 m m ' N ' N O R M A L STRAND 15 mm strand is available f rom manufacturers to many specifications This system

should only be used for strand no t exceeding 250 kN (56,000 lb), guaranteed ul t imate tensile strength which is the l imit of jack capacity For higher strength strands, this anchorage should be used, but w i th the total number of strands reduced to a max imum of 13 STRAND A N D CABLE PROPERTIES (based on 227 kN (51,000 lb.) strand to B.S.3617)

15mm 'N' STRAND

5/15mm 'N' CABLE

Initial Tension (70% U.T.S.) kN Kips 159 35.7

2 384 535 5

UTS.

kN Kips 227 51.0

3 405 765

Sectional Area

mm^ in2

138.7 0215

2 080 3 23

Mass

kg/m lb/ft 1.10 0.74

165 11.1

JACKING LENGTH For at tachment of stressing jack, cable length must be increased as fo l lows : -For single-end stressing: 1.3 m (4 '3") for centre strands; 1.0 m (3 '3") for outside strands. For double-end stressing: 2.3 m (7'6") for centre strands; 1,8 m ( 6 0 " ! for outside strands.

DUCT FRICTION Friction in the duct due to curvaturc : -

Friction in the duct due to unintent ional variat ion f rom the specified profile:—

k - O . 0 0 3 / m { 0 . 0 O 1 / k . )

STRESSING Stress cables w i th M o n o G r o u p S-306 Jack, For space required for jack access see P.S.G- Technical Data Sheet No. 90

О z О о О с -о (Л

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О < 4^


THE BBRV SYSTEM FOR PRESTRESSED CONCRETE

SHEET NO. V.5A

A fixed anchorage for use in conjunction with the Type 'C stressing anchorage. The arrangement of the wires in the basic element and capacity are the same as in the Type 'C anchorage. This type of fixed anchorage enables the full tendon force to be transmitted to the concrete immediately behind the bearing plate.

Vent pipe 3A" 0

Type E anchorage

Steel wire per anchorage,

Type designation

maximum number 7 mm (0.276") dia.

E130

31

mm in

E170

42

mm in

E220

55

mm in

Bearing plate

End-trumpet

Assembly tube

outside diameter thickness length connection, outer dia. minimum length

Length of anchorage

Dp

HP

LT

D,

Lv

235 52

215 60

130 288

9.25 270 10.63 300 11.81 2.05 60 2.36 68 2.68 8.47 245 9.65 265 10.43 2.36 70 2.76 80 3.15 5.12 130 5.12 130 5.12

288 11.34 326 12.84 354 13.94

BBRV SINGLE FIXED ANCHORAGE SYSTEM TYPE SS, SR AND SL

SHEET NO. V.5B


BBRV TENDON SIZES AND SHEET NO. THEIR PROPERTIES

Tendon reference

No. of wires (7 mm dia.)

Characteristic strength using 1570 N/mm2 wire

Jacking force (kN) at 80% of C.S.



Bearing Plate Side length (sq.)

Thickness

Trumpet Outside diameter

Anchor Head Thread diameter

Standard length

Overall diameter

Pull Sleeve Diameter

Standard length

Lock Nut Diameter

Thickness

Chocks Diameter

Min. thickness

Max. anchorage projection (Stnd. comps.)

Sheathing Internal diameter

External diameter

A

В

С

D

E

F

G

H

J

К

L

M

N

О

B16

16

967

773

725

677

178

15

120

100

60

—

—

135

30

67

40

48

B24

24

1450

1160

1088

1015

220

20

133

115

80

—

—

155

40

87

50

58

B34

34

2054

1643

1540

1438

250

25

154

130

90

—

—

180

50

97

60

68

C42

42

2538

2030

1903

1776

280

35

154

90

53

130

118

178

45

118

65

73

C55

55

3323

2659

2492

2326

300

35

165

98

63

144

138

198

53

138

75

83

L73

73

4411

3529

3308

3087

335

45

194

125

110

160

—

—

228

48

205

85

93

L85

85

5136

4109

3852

3595

360

50

219

130

120

165

—

—

250

52

219

95

103

L97

97

5861

4689

4396

4103

385

50

229

145

126

185

—

—

262

55

228

100

108

L109

109

6586

5269

4939

4610

405

60

229

150

134

190

—

—

270

59

240

105

113

L121

121

7311

5849

5483

5118

425

60

245

155

146

200

—

—

288

62

255

110

118

Length of trumpet 'P' ^ Extension + 105 mm (B type anchors) + 120 mm (C type anchors)

(L type anchors) All dimensions are in millimetres.

V.6


BBRV COUPLING ANCHORS SHEET NO. V.7

Movable (unstressed)

Type BUB N I

•>.:•;, .r.v.y ryv^rr-orô-^r

length

' = A + movement of coupler dur ing stressing

L73

L85

L97

335

405

455

160

120

133

154

154 140

180 165

L109

L121

210

220

235

245

255

180

195

205

215

230

130

160 144

195

210

215

235

250

161

174

186

197

208


BBRV COUPLING ANCHORS Fixed (stressed)

SHEET NO. V.8

260

315

350

290

315

120

340

351

368

133

154

135 160

330 150

170

180

195

180

190

D

210

130

144

165

215

205 230

388 215 245

175

190

200

210

Type BSB

, •

•т • С • '

вГ ID. 1 ЬКНУЫ^^^Ъ*^' ••

ш • ; • — А -

Type LSL

г*

-if..

max length

' ^ • * -x ? -.Я.

All dimensions are in mm.


BBRV FIXED ANCHORS SHEET NO. V.9

Type F

Type E

Type S


SMALL CAPACITY TENDONS SHEET NO. V.10 UP TO 2658 kN

# <» -.<? О о4

^ \ 0 * & h Ч

Combined Anchorages bearing plate ^ ^ ^

kN kN No. Type Type Ref. No. mm mm mm mm mm mm

a x b c x d e f xgd ia . h x g dia.

В J

483 387 8 F SR SL

В J

966 773 16 F SR SL

В J

1450 1160 24 F

SR SL

С E

1872 1498 31 SS SR SL

В J

2054 1643 34 F

SR SL

С E

2537 2029 42 SS SR SL

С E

3322 2658 55 SS SR SL

Type A30O-5O0

n—|п#ттг-1— i r -Ц~Щ$£=!= 1L.

..Type E

150x150 138x138 76) 150X150

32 120x120 120x150

30 1524x310 1344x310

60 x 300 J

175x175 171 x171 89) 175x175

64 160X160 }40 1524x310 1344x310 150x220 80 X 400 J

200X200 197X197 108^ 200 x 200

, „ 220x220 1 0 0 220X220

160X300 80 x 560

50 1524x310 1344x310

250x250 235x235 127) 235 dia.

130 260X260 180x360 120x560 J

55 1524x340 1324x340

250x250 235x235 127^ 250 x 250

260X260 260x260 180x360

55 1524x340 1324x340

120x560 J

280X280 241 X 267 152^ 270 dia.

170 300x300 200 x 450 140x650

65 1880 x 440 1580 x 440

300x300 267x305 152) 300 dia.

220 340 x 340 220 x 500 160X700 J

Type A600-800 Type В

ИГ—,, i nWr—1Г-Г-1—r ftii №-* j->— mi^-JU^— щ

•Jype F

№ » -ri Kmr-^ м|

Type J

tt/r, .. Jl r*— •= Н-Ш 1 - "

75 1880x440 1580x440

Type С 4 ft ,

щ5Р= Type SS, Sr, SL


TYPE Г FIXED ANCHORAGE SHEET NO. V.11 A fixed anchorage consisting of a rectangular steel plate drilled to receive the individual button-headed wires seated directly on this plate. A thin cover plate retains the button-heads during fixing.

With this anchorage, the prestressing force is transferred to the concrete through the plate.

Type 'F' anchorages are normally used in connection with movable anchorages of the Type 'B' series. If there are several tendons in one part of a structure, it is advisable to put half the Type 'F' anchorages at one end and half at the other.

The anchorage is fastened to the formwork with a pipe which serves at the same time as a vent or as a grout connection.

This pipe passes through the plate and should be well-greased prior to fixing to facilitate removal after grouting.

Vent pipe W 0 • Formwork

Wire stop plate Anchorage plate

Type F anchorage Type designation

Steel wires per anchorage, maximum number 7 mm (0.276") dia.

F32

8

mm in

F64

16

mm in

F100

24

mm in

F138

34

mm in

Anchorage side length thickness

End trumpet outer diameter connection, outer dia. length

Helix outer diameter length (approx.)

Distance of centre vent pipe to tendon axis

SP

Dp

DT

D, LT

Ds

Ls

e

120 4.72 160 6.30 220 8.66 260 10.24 15 0.59 25 0.98 40 1.58 50 1.97 87 3.43 112 4.41 128 5.04 148 5.83 35 1.38 45 1.77 55 2.17 60 2.36 200 7.87 250 9.84 300 11.81 350 13.78 120 4.72 160 6.30 220 8.66 260 10.24 250 9.84 250 9.84 250 9.84 250 9.84

00 00 35 1.38 45 1.77

BBRV 163 No/7 mm Tendon


TYPICAL TENSILE LOAD SHEET NO. V.12 EXTENSION GRAPH FOR 7mm DIA. PLAN HIGH TENSILE WIRE

ff\

•it; Э J

3U

45 -

35 -

ca 3 0

О - 1 25 -

20 -

15 -

TO -

5 -

о 0

/

/ /

1

/ / r

/

o.

I ~J_ 7j

/

/

/

1

/

1, 7 /

/

i 1 Nominal Tensile Strength 1570N/mm2,

1670 N/mrn Characteristic Breaking Load 60-4 к N

64-3 kN Nominal Cross Section 385mm2

Nominal Mass 0-3021 kgs/metre

i 2 0A 0.

% EL( 5 08 1.

3NGATI0N 0 1. 1 U


CCL SYSTEM SHEET NO. V.13

CABCO/MULTIFORCE DEAD END (BURIED) ANCHORAGE

2i" ^ i 57 MM WIN

* H - Ю"

CABCO/MULTIFORCE STRESSING ANCHORAGE

2S4MM BEARING PLATE

2" INT. DIA. SHEATHING

POST TENSION GRIPS

4 i DIA. HELIX WELDED CCL. TUBE UNIT TO TUBE UNIT TYPE "T4"

Cabco strand anchorage

GROUT HOLE

BEARING PLATE

POST TENSION GRIPS

TUBE UNIT FIXING HOLES


CABCO PRESTRESSING TENDON MAIN DATA

Anchorage System

U1 Cabco

U2 Cabco

Cabco из

Multiforce

U4 Cabco

Cabco

U5 Multiforce

U6 Multiforce

U7 Multiforce

U8 Multiforce

Strand-force

Tendon* 4/13 STD. 4/13 SUP. 4/13 DYF. 4/15 STD. 4/15 SUP. 4/15 DYF. 7/13 STD. 7/13 SUP. 7/13 DYF. 4/18 STD. 4/18 DYF. 7/15 STD. 7/15 SUP. 7/15 DYF.

12/13 STD. 12/13 SUP. 12/13 STD. 12/13 SUP. 7/18 STD. 7/18 DYF.

12/13 DYF. 12/15 STD. 12/15 SUP. 12/15 DYF. 19/13 STD. 19/13 SUP. 12/15 STD. 12/15 SUP. 12/15 DYF. 25/13 STD. 25/13 SUP. 13/15 DYF. 31/13 STD. 31/13 SUP. 19/15 STD. 19/15 SUP. 19/15 DYF. 19/18 DYF. 5/18 STD. 5/18 DYF.

10/18 STD. 10/18 DYF.

Tendon Forces (kN) Pk 0.8 Pk 0.7 Pk

660.0 736.0 836.0 908.0

1000.0 1200.0 1155.0 1288.0 1453.0 1480.0 1520.0 1589.0 1750.0 2100.0 1980.0 2208.0 1980.0 2208.0 2590.0 2660.0 2508.0 2724.0 3000.0 3600.0 3135.0 3496.0 2724.0 3000.0 3600.0 4125.0 4600.0 3900.0 5115.0 5704.0

528.0 588.8 668.8 726.4 800.0 960.0 924.0

1030.4 1170.4 1184.0 1216.0 1271.2 1400.0 1680.0 1584.0 1766.4 1584.0 1766.4 2072.0 2128.0 2006.4 2179.2 2400.0 2880.0 2508.0 2796.8 2179.2 2400.0 2880.0 3300.0 3680.0 3120.0 4092.0 4563.2

4313.0 3450.0 4750.0 5700.0 7220.0 1776.0 1824.0 3530.0 3648.0

3800.0 4560.0 5776.0 1480.0 1520.0 2960.0 3040.0

462.0 515.2 585.2 635.6 700.0 840.0 808.5 901.6

1024.1 1036.0 1064.0 1112.3 1225.0 1470.0 1386.0 1545.6 1386.0 1545.6 1813.0 1862.0 1755.6 1906.8 2100.0 2520.0 2194.5 2447.2 1906.8 2100.0 2520.0 2887.5 3220.0 2730.0 3580.5 3992.8 3019.1 3325.0 3990.0 5054.0 1295.0 1330.0 2590.0 2660.0

SHEET NO. V.14

Anchorage size mm 130

// //

175 // H

it

" "

175 "

215 II

II

215 215 215 215 245

rr

" и

и

265 II

и

245 245 265 300

II

II

335 " il

ll

и

ll

362 x 89 "

362x171 ;/

Sheath internal dia. mm

42 li

" 51 il

II

il

ll

и

51 li

75 /; 63 81 ll

ll

ll

81 75 75 81 81 81 " " " " " 90 it

84 100

" " " " "

114x25 It

" twin " twin

* STD. Standard SUP. Super Strand DYF. Dyform Strand


TYPICAL CONTINUOUS PRESTRESSED BEAMS

SHEET NO. V.15

PRESTRESSING TENDON

PRESTRESSING TENDON

^PRESTRESSING 'TENDON

f- PRESTRESSING TENDON

PRESTRESSED TIE

TYPICAL CONTINUOUS PRESTRESSED BEAMS


V.3 Structural Detailing of Prestressed Concrete Structures

Prestressed concrete structural detailing of major structures is given later. In this section, the reader is familiarized with basic problems. The first object is to lay out cables. Here many variations exist. Sheet Nos. V.15 and V.16 show the tendon layouts for continuous beams, precast prestressed elements and cast-in-place (CIP) slabs on precast prestressed beams with continuous post-tensioned tendons.

Many variations exist in the design and detailing of prestressed beams. Sheet No. V.17 gives a detailed cross-section of a partially prestressed concrete beam. Sheet No. V.18 gives a typical example of anchorage reinforcement and tendon details of a beam using Freyssinet cone type anchorages.

A number of available texts are mentioned in the references which can be referred to for the design and detailing of pre- and post-tensioned structures.


CONTINUOUS BEAMS OF PRECAST ELEMENTS

SHEET NO. V.16

-LIP JOINT PRECAST BEAM

-CAP CABLES-

CIP JOINT <-OVERLAPPING REINFORCEMENT

CIP JOINT TENDON

<i( чч. t <У -^ Д" NTENDONS ДPRECAST ELEMENT Г JOINTS D

a 7, JOINT Д ft TENDON PRECAST ELEMENT! fl CONTINUOUS PRESTRESSED SLABS

. PRETENSIONED ^.OVERLAPPING REINFORCEMENT | / TENDON

PRECAST OR' CIR BEAMS

Ц7 % ^ PRECAST SLABS

fe CIP SLAB ^ CONTINUOUS POp TENSIONED TENDON

PRECAST BEAMS- SUPPLEMENTARY REINFORCEMENT / КГ — ' - j REINFORCEMENT у I

CIP CONCRETE-

PRECAST BEAMS PRE TENSIONED SLAB

db

Pre stressed Concrete 105

PARTIALLY PRESTRESSED CONCRETE BEAM

i r

о о m

\

/ T 1 2 1300 У f Щ\ %

• , о \

\ \

"-

// / /

SEVEN CABLES^/ /

f о о

»

Ь 4

200

>o<

Ъ

/ /

V/ 200 Л

SHEET NO. V.17

i

J

j 1

fo о

,,Л10 2 LEGGED STIRRUPS

" • —

\ V\

^ 4

О

о о i

C 5 О (SI

О о m

1 500


ANCHORAGE ZONE REINFORCEMENT

SHEET NO. V.18

о о in

С О

>

<v "t5 с о о

CO

о m

OOE OOE QZ*1

l-i.-Jh-1 i r L_|__JL_

oe^ -I

i ia OOE

с О

ч-> О <D to

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Section VI

Composite Construction, Precast Concrete Elements, Joints and Connections

108 Composite Construction

COMPOSITE STEEL-CONCRETE BEAM SLAB

SHEET NO. VI.1

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Composite Construction 109

VI. 1 Composite Construction and Precast Elements

Composite construction consists of a combination of prefabricated unit and cast-in-situ concrete in a structure. The prefabricated unit may be in reinforced concrete, pre-stressed concrete or structural steel. To obtain composite action, shear connectors are placed in the form of studs, channels, spirals etc., projecting from steel units such as steel beams or precast units. Their function is to transfer horizontal shear entirely from one element to another. The shear connectors are welded on to steel beams and concrete is cast in situ around them. In the case of precast concrete elements such as beams and cast-in-situ slabs, a full horizontal shear is effected at the interface between these two elements when the deformation at the upper surface of the beam and the lower surface of the slab are the same.

Precast construction consists of fabrication of various elements of a structure in a factory. Such a construction is commonly used in buildings and bridges. It results in an economy of formwork and scaffolding, economy in concrete, economy resulting from standardization and mass production of various elements and speedier construction. The disadvantages and shortcomings of such a construction are (a) transport costs, (b) the need for highly skilled labour, and (c) a reduction in the monolithic strength of the structure.

Sheet No. VI. 1 shows a sectional elevation and a cross-section of a composite steel-concrete beam slab. The steel beam is encased in concrete. Codes give equations and specifications for designing and detailing such constructions.


BEAM TO BEAM COMPOSITE CONNECTION (BARS WELDED)

SHEET NO. VI.2

(a) Isometric view

(b) Sectional elevation R 10-200 LINKS T25 BARS RIBBED

T 25 BARS RIBBED

R10 BENT BARS ALTERNATIVELY

(c) Cross-section •T25 BARS

R10 LINKS


Sheet No. VI.2 refers to composite connections between two identical precast beam elements. Both the isometric view and the sectional elevation show the two beams with opposite notches or nibs connected by mechanical fastenings or bolts. Shear stresses at the nib are reduced by the introduction of the bent bars. In addition, a bar cast in one end is projected outside to be inserted into the hole left in the other element. The two elements will achieve a monolothic structure of higher efficiency. A similar method is adopted by connecting two precast concrete beam elements by means of high tensile bars as tie rods leaving grooves at the top of the concrete and filling them with a specified filler. At the bottom a steel bar as shown on Sheet No. VI.3 is welded to a steel plate which is then welded to a bearing plate on top of the precast column bonded by a steel bar. Sheet No. VI.4 shows a composite beam connected to the rib floor units using bars either with sleeve joints and links or bent bars welded to each other or a bar loop between the elements. In the later case in Sheet No. VI.4.a the common plates are welded. An isometric detailing in 3D is given for main beams connected to secondary beams using inserted bars in Sheet No. I.3.b Typical cross-sections for VI.4.b are given in VI.4.с


BEAM TO COLUMN CONNECTION USING HIGH TENSILE BARS AS TIE RODS (a) Isometric view

SHEET NO. VI.3

T25 BAR

(b) Sectional elevation

>

HIGH TENSILE (T25 BAR)

BARS AS TIE ROD

(c) Top plan Г-Т25 BAR


SHEET NO. VI.4

(a) Composite beam connected to ribbed floor units with skirted ends

I — R 8 L INKS

R10BENT BARS

•R8 LINKS

•T20 BARS RIBBED

R10LINKS

(b) Composite main beam to secondary beams ,—T20 BARS

R8LINKS

R8LINKS

(c) T-junction cross-sections

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R8 LINKS âLSAPS.

fe__rf ffr I

r-R10 LINKS

- - I •

•R8 LINKS

и Ji -T20 BARS

R8 LINKS -T20 BARS


BEAM TO COLUMN: USING STEEL BEARING PLATES, VERTICAL PLATES AND DOWELS

SHEET NO. VI.5

T16 BEN!

T20 BARS RIBBED

ANCHOR T16 BAR


Precast concrete beams resting on column brackets or corbels are detailed using plates and dowel bars as threaded inserts as shown on Sheet No. VI.5. Where holes are left because of threaded bars, they are filled with an approved mastic. Details shown on Sheet No. VI.5 represent a few methods for connecting precast elements.

Sometimes factory-made column elements are to be connected to make larger columns of specified lengths. Dowel bars as shown on Sheet No. VI.6 are used to erect such columns. Injection holes are left to fill in hollow areas with grout.

Where prestressing is used to connect precast elements such as those shown on Sheet No. VI.5, instead of tie rods a post-tensioned cable or tendon is introduced. This is shown on Sheet No. VI.7. In such circumstances plastic or steel ducts are left with special holes in the top part of columns, and cables are finally pushed through and stressed. The steel plates at corbels are welded afterwards. A nominal weld of 6 mm would in most cases be enough.


COLUMN TO COLUMN SHEET NO. VI.6 CONNECTION USING DOWEL BARS

Dropped

1 = ^ _

-T32 BARS—__

• -R8 LINKS—•

"^T20 BARS-""

5 7 * — " • i


BEAM TO COLUMN: COMPOSITE BEAMS BY POST-TENSIONING SUPPORTED ON CONCRETE CORBELS

(a) Side view

SHEET NO. VI.7

7T-V J 2R8 LINKS

^*&m.

-T32 BARS RIBBED TYPE •R10 LINKS

12.5mm LOW RELAXATION STRANDS

TO BE WELDED AFTER POST TENSIONING

(b) Cross-section

Ш-. as ян \ ODQ 1 ТЫКС L •2R8 LINKS

1—T20 BARS

^

T32 BARS 2R8 LINKS J—LT\0 LJ

ПЖ 12-5mm LOW RELAXATION STRANDS

(c) Side view

METAL SEAL OR RUBBER RING

^ >

T32 BARS

-R10 LINKS

-T32 BARS 12-5mm LOW RELAXATION STRANDS

>

1Щ -R10 LINKS

(d) Cross-section 125mm LOW RELAXATION STRANDS

1= n

< •

IT

< L •zr. a -J*

-T32 BAR

*£=


COLUMN ELEVATION WITH SHEET NO. VI.8 REINFORCEMENT AND SPLICE BARS (i) l-Section

-1

170

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100 M to

160 | 100 « »u •

--COLUMN

Column splice details

(iii) T-Section ^

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(vii)

-SPUCE BARS

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(vii) Flared heads

Й 1 > 40 ram

45° MAX D^t


VI.2 Joints and Connections

A sequence of particular construction causes joints in a structure. Joints can be between old and fresh concrete and can be between two parts of a structure. Construction joints must be so positioned that the strength of a completed member is not affected. The most suitable place for a construction joint in a simple structure is where a bending moment is zero or a shear force is maximum. A construction joint may be at the junction of a rib and slab of a T-beam or a smaller beam at a short distance from the junction of intersecting beams. Joints can also be possible where columns at different floors are to be integrated with slab/beam construction. As shown in Sheet No. VI.8, a number of possibilities exist for lapping and splicing of bars at or around floor levels. They are detailed on column elevations on Sheet No. VI.8.


COLUMN BRACKETS AND CONNECTIONS

SHEET NO. VI.9

(a) Brackets

PROVIDE MINIMUM CLEARANCE OF ONE BAR DIAMETER BETWEEN EDGES OF BEARING AND STAR

d(BSBHO)

OF BEND

MAIN BARS WELDED TO CROSSBAR OR LOOPED

CROSSBAR OF EQUAL DIAMETER CHAMFER OR REBATE CORNER

PROVIDE HORIZONTAL TIES

(b) Column connections

2T16'U'BARS (ii)

SPLAY REINFORCEMENT FOR OPENING CORNERS

' L' BAR

<L 3 0 0 J

500

(iii)

4 .

^

'U'BAR

(iv) STRAIGHT BARS

'LAPPED


As explained in Section VI. 1, beams are connected to columns using different methods. It depends where and at what level a beam (or beams) can be connected where corbels are involved. Their design and detailing as shown on Sheet No. VI.9 must depend upon induced loads and member sizes. Sheet VI.9.a gives a layout of a bracket or corbel showing the main reinforcement (thick bar) and links for shear. Columns can also be connected directly to beams or vice versa. Some of them are given in VI.9.b. Where reinforced concrete ties are required in frames and trusses some possible layouts and structural detailing of them are given on Sheet No. VI. 10. Another important family of joints are the expansion joints in a bridge. Sheet No. VI. 11 shows three different types of expansion joint used in bridges. They are classified on the basis of their movement but their function is common - to stop the creation of deformation in bridge decks or other structures subject to traffic loads and environmental loads. Other types of joint are those needed in walls, columns and floors. They need to be watertight. A family of such joints in concrete are detailed on Sheet No. VI. 12. In such circumstances, it is important to give data on water bars made in rubber or plastics. Sheet No. VI. 13 gives basic data on such water bars.

*


TIES SHEET NO. VI.10

(a)

sr

6 T 20-100

NOMINAL LINKS R8

TIE FORCE

6 T 20-100 TOP

6 T 20-100 BOTTOM

4 >

(b)

(c)

4T20 INCLINED-

ANCHOR SPLICE

\ , TIE FORCE T 2 5 BARS

TIE FORCE

A TIE FORCE

-./•-

-FILL IN

4T25

i—T20 TOP & BOTTOM


EXPANSION JOINTS FOR BRIDGES SHEET NO. VI.11 C_ OF JOINT

50 I 50 I 50 I 50 100

ABUTMENT

-T18 CSK Rivet

I T20

COMPOSITE GIRDER SPAN

(a) Expansion joint for movement up to 60 mm

WEARING COAT EXTRUDED NE0PRENE SEA EXTRUDED STEEL SECTION

FILLER

(b) Expansion joint for movement up to 75 mm

EXPANSION GAP

FINGER PLATE ~ 1 ~\ \~ , - ^г[_|п ,

CSK SCREW

TRAFFIC

COVER PLATE

-mO О | i=2>

(c) Plan view of onset of finger plates for expansion joint for movement up to 150 mm


WATER JOINTS IN CONCRETE SHEET NO. VI.12

Ш*&вЩЩрьЕ8& тш mm *т& HARDWOOD' STRIPS

COPPER STRIP OR WATERBAR

DESIGN FOR JOINTS IN EXTERNAL WALLS OF BUILDINGS

EXPANSION JOINTS

SEALING COMPOUND ON ONE OR BOTH FACES-

1st STAGE OF CONSTRUCTION

JOINT SEALING COMPOUND ON ONE OR BOTH

2nd STAGE FACES

OUTER FACE WATERPROOFED PAPER

CONCRETE DISCONTINUOUS BUT NO INIT IAL GAP

WATERBAR

VERTICAL JOINT IN A CANTILEVERED RETAINING WALL

NO STEEL CONTINUED THROUGH JOINT

JOINT SEALING COMPOUND

WALL

NO STEEL CONTINUITY

FORMED

CONCRETE DISCONTINUOUS AND NO I N I T I A L GAP

COMPLETE CONTRACTION JOINT IN RESERVOIR WALL

CONCRETE DISCONTIUOUS AND NO I N I T I A L GAP

WATERSTOP-

мтяящ FLOOR "•W45B»- i^NO STEEL

^У^ CONTINUITY

SEALING COMPOUND ON ONE OR BOTH FACES INDUCED CRACK INDUCED CRACK

"7 CENTRAL CRACK INDUCING WATERSTOP

NO STEEL CONTINUITY

INDUCED

WET FORMED OR SAWN SLOT SEALED LATER

WATERSTOP WITH-CRACK INDUCING UPSTAND

200 •1'5mm COPPER STRIP

25mm BITUMINOUS SHEET

EXPANSION JOINT AT COLUMN

COPPER S T R I P _ OR WATERBAR

i-ASPHALT BITUMEN

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DESIGN FOR JOINTS IN FLOOR LAID ON THE GROUND


PLASTIC WATER BARS FOR EXPANSION JOINTS

SHEET NO. VI.13

(a) Plain plastic water bar

(i) (ii)

(iii) (iv)

(v)

(vi)

Section

Width Web thickness Size of edge bulbs Width(int.) of centre bulb

Placing details Minimum radius to which it can be bent on flat Minimum radius to which it can be bent on edge

140 mm - 4.8mm

12.5mm 12mm

8.25 m

75 mm

Size;

190 mm 4.8 mm

19mm 21 mm

14m

150 mm

240 mm 4.8 mm

19mm 21 mm

16m

150 mm

305 mm 4.8 mm

19mm 28 mm

29 m

230 mm

(b) Rubber central bulb water bar

(i) (ii)

(iii) (iv) (v)

(vi)

(vii)

Section

Width Web thickness Edge bulb diameter Centre bulb diameter Centre core diameter

Placing details Minimum radius to which it can be bent on flat

Minimum radius to which it can be bent on edge

115mm 6.4 mm

16mm 29 mm 19mm

3.25m

75 mm

Sizes

150 mm 9.5 mm

19mm 29 mm 16mm

7m

150 mm

230 mm 9.5 mm

25 mm 38mm 19mm

8m

150 mm

305 mm 9.5 mm

25 mm 50 mm 32 mm

8.75 m

230mm

Section VII

Concrete Foundations and Earth - Retaining Structures

128 Concrete Foundations

FOOTINGS SHEET NO. VII.1

COLUMN REF NO OFF

TABULAR

LEVEL

METHOD FOR FOOTINGS

BASE REINFORCEMENT SECTION LINKS STARTERS

PAD TYPE COMBINED FOOTING

RECTANGULAR FOOTING

J*L J J L

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Ч-т-Ь

Cy2 J

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ELEVATION

PLAN

BENDINO MOMENT DIAGRAM

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н ELEVATION

Fmax. PRESSURE DIAGRAM

PLAN

TYPICAL REINFORCEMENT DETAILS

19T2O-05-15OB 2 . 2 T U - 0 4

19T20-

B ZL_

24T20-C

-06-150T

I . a

_ 1-250B

2» 2T16-03

• „ "I

2VT20-02-2S0T

В ^ Д

PLAN

3R10~0?-200 3R10-07-200

4T2S-08

05 04

СЖГЖ13

4T25-08

ft "3

SECTIONAL ELEVATION

Concrete Foundations 129

VII. 1 General Introduction

An essential requirement in foundations is the evaluation of the load which a structure can safely bear. The type of foundation selected for a particular structure is influenced by the following factors:

(a) the strength and compressibility of the various soil strata; (b) the magnitude of the external loads; (c) the position of the water table; (d) the need for a basement; (e) the depth of foundations of adjacent structures.

The types of foundations generally adopted for buildings and structures are spread (pad), strip, balanced and cantilever or combined footings, raft and pile foundations. The foundations for bridges may consist of pad, piles, wells and caissons.

VII.2 Types of Foundations

VII.2.1 Isolated spread foundation and pad footing and combined pad foundations

These are generally supporting columns and may be square or rectangular in plan and in section, they may be of the slab, stepped or sloping type. The stepped footing results in a better distribution of load than a slab footing. A sloped footing is more economical although constructional problems are associated with the sloping surface. The isolated spread footing in plain concrete has the advantage that the column load is transferred to the soil through dispersion in the footing. In reinforced concrete footings, i.e. pads, the slab is treated as an inverted cantilever bearing the soil pressure and supported by the column. Where a two-way footing is provided it must be reinforced in two directions of bending with bars of steel placed in the bottom of the pad parallel to its sides. If clearances permit, two-way square footings are used to reduce the bending moments. Where more than one column is placed on pads (combined footing), their shapes may be rectangular or trapezoidal; the latter produces a more economical design where large differences of magnitude of the column loads exist or where rectangular footings cannot be accommodated. Sheet No. 1.18 gives section and plan together with a tabular method for reinforcement designation and scheduling. Sheet No. VII. 1 gives pad-type combined footings and their behaviour under external loads and bearing pressures; typical reinforcement detailing for two different combined footings in plan and sectional


CANTILEVER, BALANCED AND STRIP FOUNDATIONS

SHEET NO. VII.2

(a) Cantilever and balanced footings

т

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COLUMN 3 5 0 * 3 5 0 Г

BEAM

_ > 2

COLUMN 350 x35Q

P L A N

12 T 20-150 TOP 12 T 20-150 BOTTOM

U к J > «-^-»

REINFORCEMENT LAYOUT - SECTIONAL ELEVATION

(b) Strip footings

3500 CRS. A

I *4 8T20

V 8T20 I

A?n-T20-25C


elevations. The specifications and quantities may change depending on the spread area and the column loads. In order to keep a record of the types of footings in particular areas and the bar schedule, a tabular method given on Sheet No. VII. 1 is recommended using given headings.

VII.2.2 Cantilever, balanced and strip foundations

Foundations under walls or under closely spaced rows of columns sometimes require (because of restrictions in one direction) a specific type of foundation, such as cantilever and balanced footings and strip footings. The principles and reinforcement details are given on Sheet No. VII.2.


CIRCULAR AND HEXAGONAL FOOTINGS

SHEET NO. VII.3

(a) Circular footing T25-0M5OB

DFTAIL OF CORNER BARS

ПРТАТ1 OF MAIN BARS

nFTAII OF MAIN BARS

T10-03-300B

(b) Hexagonal footing 2VT20-02-300 B2

•T10-100 B4

ORTHOGONAL BARS

24T20-01-300B1

*-T20-150B3

SPLICE BARS AS REQUIRED FOR DESIGN OF WALL

T20-01-300 B1 u T20-150 B3


VII.2.3 Circular and hexagonal footings

For specific structures, it is sometimes economical to arrange the footings or foundations to suit their shapes. This applies to many cylindrical structures such as concrete pressure and containment vessels, hoppers/bunkers/silos and cells for offshore gravity platforms etc. Sheet No. VII.3 gives the structural detailing of such foundations.


PILE FOUNDATION SHEET NO. VII.4

(a) Piles and pile caps: general recommendations

-•ф-ь'-ф NO. PILES 2

NO. PILES It

NO. PILES 3

(» • 1)Hp * 300 l /2»»1)Hp*300

Hp DIA OF PILE; a t) DIMENSION OF COLUMN: > SPACING FACTOR OF PILES

NO. PILES 5

(b) General reinforcement layout

BARS PROJECTING INTO CAP FROM PILES

STARTER BARS FOR COLUMN

LINKS FOR STARTER BARS

VERTICAL LINKS

HORIZONTAL LINKS INOT LESS R12-300 CRS.)

MAIN BARS DESIGNED TO RESIST TENSILE FORCE

(c) Two-pile cap reinforcement layout

•T20 STARTER BARS

T20 BARS (TOP I BOTTOM)

-T20 BARS

- R10 LINKS


VII.2.4 Pile foundations

Where the bearing capacity of the soil is poor or the imposed loads are very heavy, piles, which may be square, circular or other shapes are used for foundations. If no soil layer is available, the pile is driven to a depth such that the load is supported through the surface friction of the pile. Sheet No. VII.4 gives the general layout of piles and pile caps and a typical generalized layout of pile and pile-cap reinforcement is shown in VII.4.a and b. Two-pile, three-pile, four-pile and six-pile foundation reinforcement details are given on Sheet Nos. VII.4 to VII.6. For all these pile foundations, the tabular method given on Sheet No. VII.5 is adopted under the recommended headings. These details form part of the drawings to be submitted for the superstructures.



Three-pile cap Four-pile cap

COLUMN STARTER BARS 4T20

Л SECONDARY STEEL T20 BARS

-T25 BARS

. 4T25

Ш 0 BARS '

SECONDARY STEEL T20 BARS

PLAN

MAIN BAR DETAILS T20 BARS

|

T2S BARSH

V

STARTER BAR DETAILS T25 BARS

SECONDARY STEEL DETAIL

4R10LINK

1 J-V-1

ELEVATION

|

T16 BARS

—T25 BARS

PLAN

Tabular method

COLUMN REFERENCE

BASE TYPE

NO'OFF BASE LEVEL CUT OFF LEVEL BASE REINFORCEMENT A В С SECTION LINKS

D STARTER

BARS.



,310

Six-pile cap --770

1770

ternative (a)

-f-525

COLUMN

<x U r=ii^

-л .

\lOT25

40mm COVER

-12ТЭ0

Alternative (b) 10mm BINDING AT 150 CRS. AROUND PILE BARS

V

Ч2ТЭ0

2775

LEAN CONCRETE BLINDING

350x 350 PILES

Л И . - 1075

Xrt

1075 . 31D.

-ft -35

-Д

4U S! p

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М2ТЭ0

Details of pile cap


PRECAST CONCRETE PILES SHEET NO. VII.7

CHAMFER SIZE\

, 1

±

H. HELICAL BINDING

124

^

SIZE

INFORMATION

OF HELIX HERE SECTION D-D

ELEVATION

SECTION A-A

DETAILS OF , LIFTING HOLE MAIN BARS H E R E _ _ X I ~ S I Z E HERE

APPROVED PRESSED STEEL FORKS IN PAIRS

-DETAILS OF LINKS HERE

SECTION B-B

SHOE

(a) Square pile

ELEVATION

SECTION C-C

(b) Octagonal pile


The piles can be precast or cast in situ. One way of cast-in-situ construction is to drive into the soil a hollow tube with the lower end closed with a cast iron shoe or with a concrete plug. After the tube has reached the required depth, a steel reinforcement case is introduced in the pile and it is gradually filled with concrete. In the case of bored piles, a tube is driven into the ground and the soil inside the tube is removed with augers etc. The rest of the procedure for the steel case and concrete is the same as discussed earlier.

Where precast piles are used, they are designed and detailed to:

(a) bear the imposed load; (b) withstand impact load during driving; (c) withstand bending moments caused by self-load during handling.

Numerous empirical formulae exist for the evaluation of the bearing capacity of a pile. Texts and codes relevant to this area can be consulted for a better design of piles and pile caps. Sheet No. VII.7 gives the reinforcement detailing of two types of piles, namely square and octagonal. The nominal pile sections in millimetres are: 300 x 300, 350 x 350, 400 X 400 and 450 X 450. For a 350 x 350 pile section the bar diameter varies from 20 to 32 mm for pile lengths of 9 to 15 m. Sections 400 x 400 and above are provided with bars of diameter 20 to 40 mm for pile lengths of 9 to 15 m. The link spacings are generally 150 mm unless otherwise specified. The loads on piles range from 400 kN to lOOOkN.

At both the head and the foot of the precast concrete pile, the volume of lateral reinforcement shall not be less than 1% for lengths of at least three times the side of the pile. The pile must have at least a safety factory of two.

For minimum bending during handling, the points of suspension may be taken for one-point suspension, 0.29 € from one end and for two-point suspension 0.21 € from two ends where € is the length of the pile.


WELL FOUNDATION SHEET NO. VII.8

1С ?5J

6 O O - 1

о о о

О

;^fa с K E Y ^ •TOP PLUG IN C.CM 100

, D=2200 .

SAND FILLING

R.C.C.WELL 1 CAP

T12-600

- T 1 8 —

STEININGIN' C.CW. 150

KEYy

600

T12 бОО-'-' ^" J ^ С CM 150 L T12

BOTTOM PLUG IN C.C.M. 200

CURB C.C.M.200

С .CM. 200

Well Detail of curb


VII.2.5 Well foundations

These foundations are used for supporting bridge piers and abutments. The well foundation generally consists of steining, bottom plug, sand filling, top plug and well cap. The well cap is described in the next section on bridges.

The structural detailing of such a foundation is shown on Sheet No. VII.8. The well kerb carrying the cutting edge is made up of reinforced concrete. The cutting edge consists of a mild steel angle of 150 mm side. Where boulders are expected, the vertical leg is embedded in steining with the horizontal leg of the angle remaining flush with the bottom of the kerb. The steining consists of either brick masonry or reinforced concrete. The thickness of the steining should not be less than 450 mm nor less than given by the following equation:

t = k(0.01H + 0.1 D),

where: t = minimum thickness of steining, H = full depth to which the well is designed, D = external diameter of the well, К = subsoil constant,

= 1.0 sandy strata, = 1.1 soft clay, = 1.25 hard clay, = 1.30 for hard soil with boulders.

The concrete steining shall be reinforced with longitudinal and hoop bars on both faces of the well. The bottom plug is provided up to a height of 0.3 m for small-diameter and 0.6 m for large-diameter wells. The concrete shall not be less than grade 30. A top plug is provided with a thickness of about 0.3 m beneath the well cap and on top of the compacted sand filling. The space inside the well between the bottom of the plug and top of the bottom plug is usually filled with clean sand. This is needed to provide stability and to prevent the well overturning.


PLAN OF GROUND FLOOR SHEET NO. VII.9


VII.2.6 Raft foundations

When the spread footings occupy more than half the area covered by the structure and where differential settlement on poor soil is likely to occur a raft foundation is found to be more economical. This type of foundation is viewed as the inverse of a one-storey beam, slab and column system. The slab rests on soil carrying the load from the beam/column system which itself transmits the loads from the superstructure.

VII.2.7 Ground and basement floor foundations

Most building constructions have basements. A scheme is presented through drawings on Sheet Nos. VII.9 to VII.13 giving the layout of the plans of the ground and basement floors, a typical sectional elevation of a scheme and reinforcement details of the basement floor slab and the adjacent retaining wall.

In such a scheme, building loads (imposed and dead), soil-bearing pressures, water table, buoyancy and equipment loads are included in the design.

In this scheme, wherever possible, special keys are introduced with pedestals to take the direct column load and to avoid punching failure occurring in adjacent parts of the slab. This may well also be treated as a raft foundation.


PLAN OF BASEMENT FLOOR SHEET NO. VII.10

0001

V

0008 0008 ooor

0001 OSB'i

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BRICK COVER TO COLUMN ,_

ESCAPE HATCHES

///WW-

SPACE FOR ASHPHALTER

3 LAYERS OF ASH PH ALT

II i n « * 1

о О i n

8:.

GROUND FLOOR

BASEMENT

PROTECTIVE CONCRETE 50 DEEP

8000

•J -

s

PROTECTIVE BRICKWORK

Stf

^ = Ш

750 1000

^ P ? "

950 ,

LEAN CONCRETE 75 DEEP

8000

ЧЧУ//У

1 3 = 6 MASS CONCRETE BASES


TYPICAL SECTION THROUGH RETAINING WALL

SHEET NO. VII.12

M D_ =^

SSDVJ Hioa oos-oz-so-ziae


BASEMENT FLOOR SLAB SHEET NO. VII.13

*F

/

/

т*-

148 Concrete Foundation*

CANTILEVER RETAINING WALLS SHEET NO. VII.14 WALL

EARTH FACE

-T25 BARS T12 SPLAY BARS

-T25 BARS

BASE CONNECTION

T12 SPLAY BARS-

T25

BASE CONNECTION

• —T25 BARS

T25 BARS

T12 BARS

-T20 BARS

EARTH FACE

T20 BARS

•PACKED RUBBLE BACKING

j //(•// ЛС-// - ^

T20-200

4250 M°

T25-200

T20-100


VII.2.8 Earth-retaining structures

Walls for retaining earth sustain horizontal pressures exerted by the earth material. Retaining walls without supports may be broadly classified into two types, cantilever and counterfort. The cantilever retaining wall as shown on Sheet No. VII.14 may have its base in front of the wall or at the back. The back-base cantilever retaining wall is generally used to retain stored material. The soil under the front base has to sustain the vertical pressure induced in the base by the horizontal earth pressure on the vertical wall. In addition, the soil has to resist the horizontal sliding force due to the earth pressure on the vertical wall. Several codes exist to give recommendations for the design and detailing of such walls. The reinforcement layout and concrete thickness depend on the applied loads. The details given on Sheet No. VII. 14 are modified while keeping the same optimum layout.

When the height exceeds 5 to 6 m, counterfort retaining walls are more economical. The counterforts extend beyond the vertical wall and the base at intervals of about 5 to 6 m. The vertical wall is designed as a continuous slab spanning between successive counterforts. Most of the time the counterforts act as tension members between the wall and the base. Sheet No. VII. 15 gives the structural detailing of a counterfort retaining wall.

The retaining wall with shelves and sheet pile walls are outside the scope of this book. The former is seldom adopted, the latter is made in corrugated steel or wood.


COUNTERFORT WALLS SHEET NO. VII.15

о

< I- S£Z

b • 1 1 «

SZIS

4

Ш 00

£ CM

Section VIII

Special Structures

152 Special Structures

Section VIII. 1 Bridges

VIII. 1.1 General introduction to types of bridges

A bridge is subdivided into (a) the superstructure, (b) the substructure and (c) the foundation. The bridge deck system is the part of the superstructure directly carrying the vehicular loads. It is furnished with balustrades or parapets, crash barriers, highway surfacing, footpaths, traffic islands, railway tracks on ties, expansion joints and drainage systems. The substructure comprises piers, columns or abutments, capping beams and bearings. The foundations consist of reinforced concrete footings, spread foundations, rafts bearing directly on soil or rock and capping slabs supported on piles, wells and caissons. The superstructure of the bridge deck system can be any one or a combination of the following: slabs, coffered slabs, grids, beams, girders, cantilevers, frames, trusses and arches and cable-stayed.

Deck surface members may be classified into the three groups which may be of precast, cast-ш situ and composite construction. They may be of conventional reinforcement, partially or fully prestressed or composite construction. The following classified system lists fully the types of bridges constructed in reinforced, prestressed and composite materials.

(a) Slabs (i) solid slabs 1 Supported directly on piers, with or without haunches or drop (ii) void slabs J heads;

(iii) coffered slabs - they act like a grid; (iv) above with beams of reinforced concrete and prestressed concrete (precast or in

situ beams).

(b) Beams* (i) longitudinal stringed beams with webs spaced apart and integral with the deck

slab; (ii) longitudinal and transverse beams forming a grid system integral with the deck

slab; (iii) inverted longitudinal beams, trusses, and girders, fully or partially integral with

the deck; (iv) a single central longitudinal spine beam, T-beam; truss and girder composite or

monolithic with deck.

*Note: T-beams (precast beam slab deck) (a) T-beam with in situ concrete topping; (b) 'tophat' beams with in situ concrete topping; (c) continuous beams.

Special Structures 153

Span range for: (a) precast post-tensioned I-beam 20-35 m; (b) precast post-tensioned T-beam ranges up to 45 m.

(c) Boxes (i) A single longitudinal box beam or several box beams with and without cantilevered

top flanges comprised of: (a) a double webbed single unicellular box; (b) twin or multiple unicellular boxes with or without cross-beams or diaphragms.

(d) Frames (with or without struts) They may have members in one or more plane. They may be portal frames (single or multiple), vierendeel girders trestle piers, spill through abutments and towers for cable-stayed or suspension bridges.

(e) Arches They are classified as:

(i) solid arches; (ii) open spandrel arches;

(iii) solid spandrel arches; (iv) tied arches; (v) funicular arches;

(vi) strut-frame with inclined legs.

(f) Suspension and cable-stayed bridges Suspension bridges with draped cables and vertical or triangulated suspender hangers are adopted for spans exceeding 300 m. Cable-stayed bridges are economical over the span range of the order of 100 to 700 m with concrete deck, pylons and frames. For cable-stayed the elevational and transverse arrangements are given below. (i) Elevational arrangement:

single, radiating, harp, fan, star and combination. (ii) Transverse arrangement:

single plane (vertical - central or eccentric); ) No cables single, double, double plane (vertical or sloping). J triple, multiple or combined.

VIII. 1.2 Types of loads acting on bridges

They are classified as follows.

(i) Permanent and long term loads: dead; superimposed; earth pressure and water pressure of excluded or retained water.

(ii) Transient and variable loads (primary type): vehicular loading; railway loading; footway loading and cycle loading.

(iii) Short term load: erection loads; dynamic and impact loads.

(iv) Transient forces: braking and traction forces; forces due to accidental skidding and vehicle collision with parapet or with bridge supports.

(v) Lurching and nosing by trains.

Short-span bridges over > highways or rivers or flyovers

over freeways.


(vi) Transient forces due to natural causes: wind action; flood action and seismic forces.

(vii) Environmental effects: loads generated due to creep, shrinkage of concrete; prestress parasitic moments or reactions and prestrain and temperature range or gradient.

Relevant codes are consulted for the application of these loads on bridge structures.

VIII. 1.3 Substructures supporting deck structures

The deck structures are supported directly on:

(a) mass concrete or masonry gravity abutments;

(b) closed-end abutments with solid or void walls such as cantilevers, struts or diaphragms;

(c) counterforted or buttressed walls or combinations; (d) open-end or spill-through abutments with trestle beams supported on columns.

The intermediate piers can be of the following type:

(a) solid or void walls with or without capping beams; (b) single solid or void columns with or without caps; (c) trestles and bents; (d) specially shaped columns, e.g., V-shaped or fork shaped etc.

In most cases bridge bearings are needed to transmit deck loads to substructures and to allow the deck to respond to environmental and vehicle loads.

VIII. 1.4 Structural details

Bridge engineering is a vast field and based on site and other requirements no two bridges can be totally the same. Here the reader is given examples of some reinforced, composite and prestressed concrete bridges with simplified structural details.

Sheet No. VIII. 1.1 shows a reinforced slab culvert layout with sectional elevation and plan. VIII. 1.1.a shows a reinforced concrete beam/slab bridge on skew. VIII. 1.2 shows a reinforced concrete T-beam bridge superstructure in cross-section,

the longitudinal section of a central beam and a plan for a reinforced concrete deck slab integral with main beams.

VIII. 1.3 and VIII.1.4 VIII. 1.5 shows a reinforced concrete twin-box bridge deck with parapets. VIII. 1.6 shows a composite steel beam concrete deck bridge with a typical longi

tudinal elevation and cross-section with shear connectors. VI11.1.7 shows structural details of a reinforced concrete rigid frame with footings.

The road surface rests on this frame. VIII. 1.8 shows a reinforced concrete bow-string bridge showing arches and sus

penders with their reinforcement details. Cross-beams and cross-sections of the bow-string at various zones are fully detailed.

VIII. 1.9 shows typical bridge decks with post-tensioned girders and pretensioned

show deck and girder details of a continuous reinforced concrete girder bridge.


beams. They are shown in relation to their respective reinforced concrete decks.

VIII. 1.10 shows additional bridge decks with post-tensioned girders and also gives an articulated prestressed concrete balanced cantilever bridge. For the arrangement of prestressing and the tendon profile see Section V.

VIII. 1.11 1 show elevations and cross-sections of an open spandrel arch bridge scheme to \ and relevant structural details of parts where prestressing and conventional VIII.1.15 J steel are recommended. VIII. 1.16 shows a choice of bridge substructure comprising piers and bed blocks. VIII 1 17 ]

, I show reinforcement details of a typical pier bent and well cap for a pier \ „ [ consisting of several wells. V l l l . l . l o j


REINFORCED CONCRETE SLAB CULVERT LAYOUT

SHEET NO. VIII.1.1

PARAPET-

ROAD LEVEL-,

SECTION ABCD

HALF PLAN AT BOTTOM HALF PLAN AT TOP

PLAN


REINFORCED CONCRETE BEAM/SLAB BRIDGE DECK

SHEET NO. Vlll.1.1.a

Ui <t

!i<

f t . —4 *

* I I

« *

Л * 4

J Щ % .

p 'P

*;°

•л о: 0

* g

I

JSS IS P S


T-BEAM BRIDGE SUPERSTRUCTURE

SHEET NO. VIII.1.2

(a) Cross-section

T12-200

(b) Longitudinal section of central beam

80i

'TtO ^ H y 3 ™ • • / / У " 2 П 6 у ^ 2 Т 3 6 /lU(> / -3 T 'g Hangers ** f Kl У ^' " K ' ' • • ' ' • • * ' • ' • ' Ш

\ \

\ 4

Kf к 4

s f\

' I - 500 \—; 2000- "-'•aca—i-'

5 S 5

"000—*—Ю00—*—T500-

-i2!.0-

-isco-

-u«o

-3500-

600

4T36 12Ш)

T"^C-WG0

(c) Detail of deck slab

—<• r — — — ' I T : I-+- ' ! i | | ' | | I

' > ••г г- i—' - — - I - 1 — 1 — — t - -" fv -1 - i . -"Tf

i i ! ' H r r - t - r - ^ - r - r - T f - г - г г г г •>• • • • •' |Û|,[-:--i .4ll j-i^^>--iU' ; ' ; ; ' •"; : : ;h ' гт-р ii—гт.-т -п-ттТ 1гтт^-ctt =t - ny••"• 1 -" 1—J—t—t ;•. .it—i i i ; t - r J - : r - j -T r -F '44 T - r - - ~H i ' - -Г^Т'Я—гтттт r r JT i i r r r t - x l t J -: —i—•—t ~» l i t i I i -i—r- '—'r— b-rr-H " t ' i . - ! - • "* — i • i i ' ' i i ' i i • i i M ' *' r i. < l

' i ' I ' M ' T i - t —t - 1 — i — >—I—I— > т T T — r I t - ! - • • • -

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M i l l

Ft ! ..

-T16-2U)

•T16-2t0

L


CONTINUOUS R.C. GIRDER BRIDGE

SHEET NO. VIII.1.3

(a) Reinforcement details in central span в

8ТЗБ 12T36

РЧ. 3000

B' 3000 3000

a 36

3000 3000,

\

c: 12T36

V A t . J

500

:::i -ТЮ

-T10-200

t T10-300 - *

18T-40 4 (3 rows)

4ТЗБ

!T

1

> <

• •

» •

• • • «

-?

<

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^ 1

500

250

'.

750

•

SECTION C-C

5T36

SECTION B-B (b) Reinforcement details in end span

-4ТЭ6

J tOOO

(c) Deck reinforcement

EÛ12

? \ / T10-150

150 x 150 R С Posts at 1-500mm interval

kerb 600 x 300

fi—«T12 , -T12-100

* ' A • ' 7 7 T10-150

V— 800 T10-150

—^/J-7-r. Л f *c T12-1D0 • N

580

T12-100 » • • щ • f

7

(d) Reinforcement details on both sides of the suspended part

c o n ^ O OH m 2

ic П О 73 О m 73

о

f CO

on

О <


TWIN-BOX BRIDGE SHEET NO. VIII.1.5

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Special Structures

COMPOSITE STEEL BEAM CONCRETE DECK BRIDGE

SHEET NO. VIII.1.6 1000

•h 7500 1000

{ WC 50mm

300mm R.C.SLAB

ГГ MAIN GIRDER

CROSS GIRDER

^ r: тт

750 | 2000 2000 2000 2000 I 750

(a) Cross-section of deck slab

T12-U0 T10- 2»0 SHEAR CONNECTORS l 8 0 m m W t

ZZL ~^r

Ф Ф Ф Ф 30 DIA. STUDS

300 mm R.C. SLAB

Й i» Й

100 250 i 250 250 250 250

200

.BEARING STIFFENER 180x15

--[>-5 т 10° |WELD

200 30mm BOTTOM FLANGE PLATE

250

INTERMEDIATE STIFFENER 8 0 0 x 8 0 0 SPACING

^ 5mm CONTINUOUS WELO

ABUTMENT •BEARING PLATE 25mm

(b) Longitudinal elevation DECK

SHEAR CONNECTORS

b I ^?y4? i I I I I

L

10 _ _

100 ; 100 | 100

I

• г г

30

I

-^ ^> -e 100 i 100 , 100

- 4 — 1

4 - -ф- <h -Ц

(c) Detail of shear connector

т 250

L


R.C. RIGID FRAME BRIDGE SHEET NO. VIII.1.7

(a) Longitudinal section of a rigid frame

T25-60

4ГТ2 5-120

T12-300

7500

(b) Reinforcement details in footings

T25-180T

T12-250 1550


BOW-STRING BRIDGE WITH TYPICAL REINFORCEMENT DETAILS

SHEET NO. VIII.1.8


TYPICAL BRIDGF DECKS WITH POST-TENSIONED GIRDERS (a) Cast-in-situ prestressed concrete deck

SHEET NO. VIII.1.9

(b) Bridge with precast prestressed girders

(c) Deck with composite construction

(d) Deck with composite construction

P V) О О О О О О СТ

PIER


TYPICAL BRIDGE DECKS WITH SHEET NO. VIII.1.10 POST-TENSIONED GIRDERS (CONT.)

(e) Pretensioned inverted T-beam

(f) Hollow cored pretensioned deck —* • • • • • t

lot of ofol (g) Pretensioned beam with top decking

. — . —. . . . ... . . — i

(h) Schematic diagram of balanced cantilever bridge

GIRDER WITH TWO iSUSPENDEQ GIRDER WITH ONE

CANTILEVER

(i) Articulation

о -о

>А

10000 10000

50000

ELEVATION OF HALF SPAN OF BRIDGE

SCALE 1:200

T2000

I

4

CO

>

и 70

> 70 Г) I CD 70 a о m

ел

О <

£ <% л

!

-a


OPEN SPANDREL ARCH BRIDGE SHEET NO. VIII.1.12

ь 6800

1260

425 x 425 Columns

300x700 Bracing ZL

• \ -

"fc

<&

2520

Л"

&..„-•1У&

600 - 6 0 0 _

2520

* * t

.600

SECTION A-A SCALE 1:50

о

425

-v

Shear keys 125 long x 200 wide x 30 deep at 250 crs

9950

> < •

R20 bars as end Suggested tendon profiles, each post-tensioned tendon block reinforcement contains 16 no 17 mm 0 wires and has an initial prestress = 733 kN

10000

SECTION С С SCALE 130

- V

>

о

>

П I CO

a о LO

m m H z p 



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о

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-2R20-80

END SECTION OF POST TENSIONED

BEAM SHOWING END BLOCK REINFORCEMENT

| 175

END SECTION OF POST TENSIONED

BEAM SHOWING BEARING PLATE

. 1 2 2 . . 122

R 8-300 Links

122 122 56

э о о с 1631163 1 1631

~D О IT ^

D О О С

3 о о о

| - 600 , |

SCALE 1:20

56 163 163 163 56

L A

О

-300 Links —

Til Э О

О О

D О О С

[, 600 „|

SECTION D-D SECTION БЕ

NOTE : A l l longitudinal s teel in parabolic arches to be 32 dia,


PIERS AND BED BLOCK SHEET NO. VIII.1.16

(a) Solid pier of masonry Typical framed piers

CUT WATER

GIRDER л JOINT.

I 1/ STRAIGHT PORTION

(b) Cellular R.C. pier

r~

GIRDER SLAB JQINT

J

Bl

(c) Trestle R.C. pier

BENTCAP ~^

-COLUMN-

(d) Hammerhead type

Typical shape of piers

Typical details of bed block over piers

t T12-150 d 280

400

T12-180e /—T12-1S0Q /-T12-150c

Л- 4= LT1

^ • * * • *

• 4 *

-T12-180a 75 LT12-150c

8100/2 -840-LON&ITUDINAL SECTION

ZL

I—T12-180a 75 -T12-150c

PLAN


DETAILS OF PIER BENT SHEET NO. VIII.1.17

9T32 BARS (TOP) 50 COVER

Ф T12-125 —= 2

3 n / **ms

T32 BARS(BOT) T32BARS^:

T12-300—+ **•

•TOP BEAM

T168 LEGGED STIRRUP

18T32 COLUMN BARS

- R10 SPIRAL

- 915 DIA. R.C. COLUMN

T16 8 LEGGED STIRRUP

6R8-150 STIRRUP-

T

T32-150(TOP) A1 to A5 Type-

-A1 — A2 A3 A4

A5 B6

IBS vw B3 62 ^B l - l

I—835

T30T32 150 BARS (ВОТ) Bl to B6 Type

3275 ——-»


WELL CAP FOR PIER SHEET NO. VIII.1.18

i n CM

L. i n CM CM

к

о CO

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EL

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\

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T <

i n CM CM

0052

< a.


As stated earlier, in order to protect vehicles from accidents, and the pedestrians while crossing the main bridge, typical details are given for hand-rails forming the bal-lustrades on Sheet No. VIII.1.19.

Sheet Nos. VIII.1.20 and VIII.1.21 give different types of bridge bearings. Structural engineers working on bridges and codes of practice are consulted on the use of any one of these on a specific job. The manufacturers can provide loads and specifications for individual types of bearings.


DETAILS OF HAND-RAILS SHEET NO. VIII.1.19

091-

"55

ьТЗ> 1ГПГ

I/)

< Г

4L 091 061

тггз—гг*

09L 061

081 Ж"

1 <

-L os»

3

< ' l —

о и > с о

о о. о и

I > О о СП

•е о и


TYPICAL ROCKER BEARING FOR SHEET NO. VIII.1.20 COMPOSITE STRUCTURES

I

I

GIRDER

i ~N

j L

D/2, 4"l

LEG* N

! " " •

I

400

ROCKER

ROCKER PIN

1 30

4 b-50

•50 ROCKER

BED PLATES CONCRETE END BLOCK

800 R.C. ROCKER BEARING

150

I . 2 5 0 . ,

3T10<

\

\

Ч5Т

1 Л

тю-Н- • T10-

•

• •

SECTION A-A О i n

250

T10 A * l

>| P о

*

Ь й_

p ff p.

T6 HELICAL LINKS

SECTIONAL PLAN


ROCKER BEARING SHEET NO. VIII.1.21

i Ft 75M.S. PLATE 47575

T 29°

CROSS BEAM •T-BEAM L_375 .

•—25 EXPANSION JOINT BETWEEN SLAB

-*—!b f . A — '

K-200H

LEAD SHEET 200x20

CROSS BEAM

•200-4—375 - T-BEAM T л MS PLATE 325x375x25

.1640- 50 m ш Л \

COURSED RUBBLE MASONRY

Ar

DRAIN PIPE\ 1540

i Tf

RSF

r L

K—375"

PLAN OF ROCKER

V DETAILS OF ROCKER BEARING

LUGS ENGAGING WITH HOLES IN BEARING PLATEgsSf t jg^ fo^ f l

CAST STEEL PLATE

*Li2

R.C ROCKER

ROCKER BEARING

Section VIII.2

Concrete Shells

VIII.2.1 General introduction

Various concrete shell roofs in reinforced concrete have been designed to provide for large uninterrupted roof spans for industrial and other buildings. Various attempts have been made to classify the types of shells. The most popular classification is based on Gaussian curvature and is given below:

(a) Shells of Positive Gaussian Curvature (Synclastic Shells) Here the surface curves are away from a tangent plane at any point on the surface. They lie completely on one side of the plane. Examples are: spherical dome and elliptic paraboloids. (b) Shells of Negative Gaussian Curvature (Anticlastic Shells) They are formed by two families of curves which are opposite in direction. Examples are: hyperbolic paraboloids, conoidal shells and hyperbolas of revolution. (c) Shells of Zero Gaussian Curvature (Singly Curved Shells) They lie between positive and negative Gaussian curvature. Examples are: cylindrical shells, cylinders and cones.

In addition to the above classification, shells are classified on the basis of shells of rotation and shells of translation. The shells of rotation are domes (spherical, elliptical, conoidal) and the shells of translation are hyperbolic paraboloids, elliptical paraboloids, etc. Sheet Nos. VIII.2.1 and VIII.2.2 give some of these examples.


CYLINDRICAL SHELL SHEET NO. Vlll.2.1

FEATHER EDGE SHELL SHELL WITH VALLEY BEAM

снояо BARREL VAULT

SHELL WITH EDGE BEAM

SYNCLASTIC OR ELLIPTICAL SURFACE ANTICLASTIC OR HYPERBOLIC SURFACE

CONOID HYPERBOLOID


HYPERBOLIC PARABOLOIDS SHEET NO. Vlll.2.2

0)


THIN CYLINDRICAL SHELL AT HELSINKI, FINLAND

SHEET NO. Vlll.2.3

(Courtesy of S. Eggwertz, Consulting Engineer)

R8-200

6T10-100 •- 6T10-7S

• 6T12-100


VIII.2.2 Shells

A cylindrical shell's surface is generated by moving a straight line parallel to itself along a cylindrical surface. The cylindrical surface can be a circular arc or any segment of a cylinder. At the ends, longitudinal edge beams simply supported or continuous are provided to stiffen the shell against the edge disturbance, bending and shear. These shells can be single ones spanning over many supports or can be multiple shells in transverse directions spanning over a single span. Sheet No. VIII.2.3 shows the reinforcement layout for a cylindrical shell with valley beams. The radius, thickness and span of the shell are 100 mm, 9.25 m and 22 m respectively. The edge beams are 0.25 m wide x 1.75 m deep. A similar layout will be required for non-circular cylindrical shells. Sheet No. VIII.2.3 shows a photograph of the completed structure.

The shell shown on Sheet No. VIII.2.3 has been designed for a load of 360kN/m2

excluding the weight of the edge beams. Longitudinal steel has been provided because of the tensile force occurring in that direction. Transverse and diagonal steels are provided for transverse stresses and principal tensile stresses. Starter bars are provided in the end zone to connect shell and beam reinforcement and to offset stresses occurring due to edge disturbance.


INVERTED UMBRELLA-TYPE HYPAR SHELL

SHEET NO. Vlll.2.4

24380

PLAN

1-830 1-830

T14-25

0-610 0-610

SECTION Y-Y


The hyperbolic paraboloid (hypar) shells can either be seen as a warped parallelogram or as a surface of translation. A number of these hypar shells are shown on Sheet No. VIII.2.2. The equation of the surface is first defined for the hypar types; forces and stresses are determined in the main shell and in the edge beams. Sheet No. VIII.2.4 shows an inverted umbrella-type hypar shell 24.38 m x 24.38 m. The roof is a combination of four units and of thickness 75 mm and is designed for a uniformly-distributed load of 345kN/m2. Sheet VIII.2.4 shows a detailed reinforcement plan and section of such a shell.


HYPAR SHELL IN BRAZIL SHEET NO. Vlll.2.5


Sheet No. VIII.2.5 shows a sectional elevation and a plan indicating reinforcement details of a kite-shaped hypar shell designed for a conference hall. Sheet Nos. VIII.2.6, VIII.2.7 and VIII.2.8 show complete details of the hypar shell layouts for Edens Theatre at Northbrook, designed and detailed by Perkins and Will of Chicago. The reader is left with original drawings in empirical units. Bar sizes and dimensions, etc., are converted into metric units using a standard conversion given in the text. Both kite-shaped hypar shells adopted are identical. The one shown in Sheet No. VIII.2.5 is half the size of that one given for Edens Theatre. These shells are also known as saddle shaped hypar shells. Generally their thicknesses are no more than 75 to 100 mm. The hypar shell types given on Sheet No. VIII.2.2 can similarly be designed and detailed once the geometry of the type given on Sheet No. VIII.2.6 has been decided. A typical drawing of the saddle shaped hypar between the dimensions (heights and plane projection, i.e. shell projected plan) is shown in VIII.2.2(H).


HYPAR SHELL (EDENS THEATRE) GEOMETRY

SHEET NO. Vlll.2.6


HYPAR SHELL (EDENS THEATRE) REINFORCEMENT DETAILS

*X\

SHEET NO. Vlll.2.7

•fa*

190 Special Structure»

HYPAR SHELL (EDENS THEATRE) ADDITIONAL STRUCTURAL DETAILS

SHEET NO. Vlll.2.8


Hyperbolic shells and the hyperboloid of revolution of one sheet which have a graceful appearance have been exploited. Cooling towers and water tanks are just two examples. A great advantage is that their surface is generated by two families of intersecting straight lines. A typical view of earthenware pots and the curvatures shaped by potters are the basis of such shells given on Sheet Nos. VIII.2.9 to VIII.2.12. Sheet Nos. VIII.2.9 and VIII.2.10 show general dimensions of a water tank of a hyperbolic shell and its reinforcement details with cut-off bars at specific levels. The bars are placed along the longitude and latitude of the shell. The cover is of domical type integrated with the hyperbolic shell part.


GENERAL DIMENSION OF WATER TANK

SHEET NO. Vlll.2.9


HYPERBOLIC SHELL SHEET NO. Vlll.2.10 REINFORCEMENT DETAILS OF WATER TANK

5000- -H-*-1500-*j

T 1400

12000

T12-200

Tl 2 -300 '

T12-300

T16-190

T12-300

T16-160

T16-200

T12-300

T16-200 6 _

(Courtesy of S.D. Castillo)


PRESTRESSED HYPERBOLIC SHELL OF WATER TANK

SHEET NO. Vlll.2.11

(a) General layout 152mm water i*v?'

• гг 660m . . ш и п и т i i i h i i i imn i

479mm

(b) Prestressing layout . 356mm

762mm


Sheet No. VIII.2.11 shows a hyperbolic shell surface of a water tank. Owing to its much larger size it became necessary to prestress the shell. The entire tank is supported on columns. Prestressing is done by continuously winding the prestressing strands around the tank. The strands are of low relaxation type given in Section V. (Some other types of shell structures adopted for water tanks or water-retaining structures are discussed in Section VI11.3.)


HYPERBOLIC SHELL (COOLING TOWER REINFORCEMENT)

SHEET NO. Vlll.2.12

Diet* 45251 «•

ТЮ-225И

Sectional elevation

WT36

Plan


The design of the cooling towers must take into consideration buffeting wind loads and sometimes earthquake effects. They are needed as exhausts for power stations. In plan they are placed in straight or zigzag rows. They stand in the higher region of the layer of air flow, which is usually unsteady and turbulent. A special dynamic analysis has been carried out to check the reinforcement layout of the cooling tower given on Sheet No. ViII.2.12.


SHELL OF CHRIST CHAPEL (INDIA)

SHEET NO. Vlll.2.13

GENERATOR PARABOLA

600 V NEOPRENE BEARING

CT R~ 11560

(a) Longitudinal section of groin showing the variation of thickness

,opSu«^L

(b) Plan showing layout of reinforcement in the shell


P.С. Varghese and A.C. Mathai designed Christ Chapel in Irinjalakuda, Kerala, India which was consecrated in May 1971. This wonderful shell design is unique, consisting of twelve identical shell units of groin type, each shell placed with a column at the end set at 30° intervals around the periphery of the hall. The shell roof has a varying diameter (24.38m to 26.52m) in plan. The columns are placed at 5.97 m centres. Sheet No. VIII.2.13 gives the longitudinal section and the plan which gives the variable shell thickness and the reinforcement details. The reinforcement layout and designation are based on current practices and are thus modified.


A FOLDED PLATE ROOF - REINFORCEMENT LAYOUT

SHEET NO. Vlll.2.14

о о I

о СИ

E1

CENTRE OF FOLDED PLATE J 1 о

E2 E3 3 7 0 0 2Z°L_21568 3 3 9 0

m

(a) Developed plan

(b) Reinforcement details of folded plate 450,620,700 c/c


NORTH-LIGHT SHELL - REINFORCEMENT LAYOUT

SHEET NO. Vlll.2.15

9000

4T30 in 2 l a y e r s

о о Csli

i n /

oo о

6 T 3 0 - 210 с

T10 - 120 crs t h r o u g h t h e

2 1 0 0

1 6 T 3 2 - U 0 i n 2 l a y e r s

PLAN 130

T12 130 crs 2100

6T30

240

T1 0-120 crs

T10 - 1 2 0 crs

Т12-1Э0 crs

16T30

9T30-210 crs

SECTION


NORTH-LIGHT SHELL-(HELSINKI)

SHEET NO. Vlll.2.16

N

ад

1Л

•E

о и


Folded plates, known as hipped plates, are developed by joining a series of rectangular slabs at suitable angles of inclination. They are monolithic along their common edges and they span between diaphragms. The various types formed are V-type, trough type, cylindrical type, Z-shaped type, north-light roofs, bunker shaped and troughs with lights at the top. Sheet Nos. VIII.2.14 and VIII.2.15 give the reinforcement details for a cylindrical hipped plate and the north-light shell. Sheet No. VIII.2.16 shows an interior photograph of the completed north-light shell.


SHALLOW DOME SHEET NO. Vlll.2.17

T10-1S0 TOP T10-150 BOTTOM

T10-300

T10-300

TOP PLAN (UNFOLDED) 28T20

T10-150 TOP

SECTION


Spherical domes are common in structural engineering. Reinforced concrete domes are comparatively popular. A constant thickness is considered. The reinforcement details are shown on Sheet No. VIII.2.17 for a segment of a spherical dome and its ring beam.

When the following modifications are carried out a similar layout can be prepared for either conoidal or elliptical domes in reinforced concrete:

Conoidal dome: The central line of revolution is moved outward from the centre line of revolution of the spherical dome to a distance (rcoscj) - r '), r is the radius of the spherical dome and r' is the distance moved beyond this. The angle ф is the latitude of the dome.

Elliptical dome: The dome surface is defined as

x2/a2 + y2/b2 = 1

where a and b are major and minor axes, x and у are co-ordinates.

Reinforced concrete chimney shells are generally lined with steel liners so that the flue gases which are too hot and corrosive are prevented from having direct contact with the reinforced concrete. The chimneys are about 180 to 215 m tall and their minimum diameter is about 4 m. They are subjected to wind and earthquake loads and thermal gradients. Sheet No. VIII. 2.18 gives a basic reinforcement layout for a chimney. The size of reinforcement depends on the height and the wind/seismic loads.


CHIMNEY SHEET NO. Vlll.2.18

4000

MESH OF REINFORCEMENT

T16 -250 t

T20-200t

T16 -250 b

T20-200

RADIAL BARS

10000

-CIRCUMFERENTIAL BARS

(a) Section through foundation of chimney

: - A

(b) Front view of reinforcement round an opening in a chimney shell

(c) Section A - A through opening

Section VIII. 3

Water Retaining Structures and Silos

VIII.3.1 Water-retaining structures

VII 1.3.1.1 General introduction

Water-retaining structures must be designed for serviceability, stability, flotation and settlement. For these structures watertightness and durability are especially required. Cracking due to external loads and early thermal and shrinkage effects must be assumed as a major design criterion.

Tanks as water-retaining structures are situated on the ground, underground and above ground supported on towers. Ground tanks and reservoirs can be circular or rectangular in shape. They must withstand pressure from the water they contain. If such structures are constructed on or below ground they must withstand external forces due to lateral earth pressure, uplift due to water in the surrounding ground and the weight of the earth cover if provided. The roof may be of the beam and slab or the flat slab type. In the case of large tanks, domical or truncated conical roofs are used. The walls can be cantilevered, pinned at the top or fixed at the top. Where floor slabs are involved, a polythene sheeting or similar may be used between the ground slab and the sub-base and a neoprene or rubber strip or similar between the roof and the top of the wall.

In-serviceability requirements for cracking have been seen to depend on the exposure conditions. Some basic data is given below.

Class A: exposure (exposed to moist or to corrosive atmosphere or subject to wetting and drying), the crack width w < 0.1 mm.

Class B: exposed to continuous contact with liquid, the crack width w S 0.2 mm. Class C: not exposed as severely as for either Class A or B, the crack width w <

0.3 mm.

The slab thickness in millimetres ranges between 200 and 500 plus.

Wall thickness (mm)

200 250 500 Over 500

Layers

single double double double

Bar type (mm)

MS 12-16 MS 12 MS 12, 16, 20 20

*Partial joint spacing (m)

0)

2.3-2.44 1.73 2.60-3.5 1.92

(2)

2.86-3.50 2.29 3-3.92 2.34

(3)

3.41-4.05 2.84 4.33 2.75

*(1) = no cracks (2) = 0.1mm cracks (3) = 0.2 mm cracks Where construction joints are used for:

all thickness less than 400mm: (1) = 4.8m; (2) = 5.3m; (3) = 5.9m all thickness equal to or greater than 500mm: (1) = 4.8m; (2) = 5.3m; (3) = 5.6m


CIRCULAR TANK SHEET NO. Vlll.3.1

о СЭ LTI CM

L 20

0CP

0009

•

n

WATER BAR

MIN KICKER 75mm \

T32-200 HOOP STEEL

й-

T25-250

T25-200

T25-200

T32-200

-T32-200 -T32-200

СЭ СЭ i n

СЭ СЭ СЭ CM

СЭ СЭ

о

WALL STEM SECTION SCALE- 1:50

41200 DIA

CD CD LTI О

T32-200ALT WITH T25-200

1000 S50

T20-200 T25-200

3350 450

^ш ' Special Structures 209

The recommended concrete grades are 25 and 30.

Jointing material may be joint fillers, water stops, joint sealants and joint stress inducers. All jointed material must be chosen by the structural engineer and must accommodate repeated movements in all weathers. It must never be soft in summer or brittle in winter. A reference is made in Section VI to types of watertight joints.

VIII.3.1.2 Typical structural detailing of water-retaining structures

Section VIII.2.2 gives some examples of water-retaining structures. They have been included in that section owing to the importance given to the shell surfaces and reinforcement layouts. Sheet No. VIII.3.1 shows the structural detailing of the wall stem section of a reinforced concrete tank of internal diameter 41.2 m and internal height 10.5 m. The floor slab is sloping towards the centre. It is placed underground. Sheet No. VIII.3.2 shows the sectional elevation of a reinforced concrete rectangular-shaped tank. A double domed INTZE tank is given on Sheet No. VIII.3.3. Two types of reinforcement details are given for two different INTZE tanks. These tanks can be supported on elevated towers. A typical substructure for such towers is given on Sheet No. VIII.3.4. Sometimes a circular tank is supported on towers with columns. These columns can be arranged in a number of ways in plan. Some layouts of the supporting towers are given on Sheet No. VIII.3.5.

Many other tanks with novel shapes have been designed. A bibliography is given for the reader to study such tanks and to follow the rules established in this book.


ELEVATED RECTANGULAR WATER TANK

SHEET NO. Vlll.3.2

H = 2500

8000

225

T

— 275

W.L.

4000

о о un

Г-4Т25

V' T16 200 К 275

'JL--T16 200

HX S3

T^ 25

T10 150 LINKS

COLUMNS AT 4500 CRS.


INTZE TANK

T12-875

,R8-150

M -T12-290 HOOP 1450 mm LENGTH BARS

8800

SHEET NO. Vlll.3.3 100

4T10

T12-165 Г12-120

T12-135 BARS

865 mm LENGTH

3T16 IN FIRST 240mm 2T16 IN NEXT 240mm 2T16 IN NEXT 385mm

t

200

X *k. O x . •

^ V ^ 4 T г 30

R8-150

4T12

200

I - 1000 T16-330-a 20SIK—1

6T25

R8-150

R8-110


ELEVATED WATER TOWERS SHEET NO. Vlll.3.4

(a) Typical sectional elevation (b) Cross-section


SUPPORTS FOR OVERHEAD TANKS

SHEET NO. Vlll.3.5

(a) Plans CANTILEVERS

BEAMS

COLUMNS

(a) (b)

WIDE BEAM

RING BEAM^

(g) ~(Ю

(b) Typical elevations

9450x9450

I 600 _i_ T

A

VT19500

V: 17000

У:5000

2L0

(a) A ' зооо зооо зооо;

о о m

о о

2 • a i -

»•• - у

, ; = = = i -4 250

(b) le


REINFORCED CONCRETE HOPPER SHEET NO. Vlll.3.6

Section through hopper

E /

-ALTERNATE BARS

.T25-200

WALL SPANNING VERTICALLY

•T25-200

T25-200-

T20-200-

WALL SPANNING HORIZONTALLY "

В


VIII.3.2 Silos

VIII.3.2.1 General introduction

The irregularity of the crop yield and the uneven distribution of harvests can lead to a building-up of stocks which are best held in silos made in reinforced and prestressed concrete. They comprise tall cells of various cross-sections placed side by side. At the bottom they have discharge hoppers and at the top they are enclosed by a floor carrying the silo-filling equipment.

The silos have triangular, square, cylindrical or polygonal shapes. The walls of these silos are subject to maximum pressure due to the infilled or ensiled materials. The accurate values of these pressures depend on:

(a) internal friction: grain upon grain; (b) friction on smooth or rough walls; (c) natural angle of repose of the material and the angle of material wall friction; (d) bulk density of the material and the unconfined compressive strength of concrete.

A number of expressions have been developed to evaluate pressure on side walls and in the hopper area.

Hoppers are generally lined with stainless steel, mild steel and other types of abrasion-resistant materials. Various types of silo bottoms are used which include an elevated floor on columns, and a conical steel hopper attached to a concrete ring girder, integral with the silo wall or independently supported on columns or supported on pilasters.

VIII.3.2.2 Typical structural detailing of silos

A number of textbooks and proceedings have been published on the design of silos. In this section two examples are given for the structural detailing of silos. Sheet No. VIII.3.6 shows a sectional elevation of a reinforced concrete silo. This silo is supported on columns and is a part of a group of silos. The walls are 200 mm thick. The internal height (above the hopper line) and the internal height respectively are 35 m and 6 m. The hopper angle is 45°.

Horizontal reinforcement is provided to take the tension in each wall due to the pull of walls perpendicular to it. Owing to the continuity at corners, a horizontal bending moment is induced. For this bending moment it is sufficient to provide horizontal reinforcement equal to the vertical reinforcement of the vertical bending moment. Generally this reinforcement is limited to the vertical reinforcement at 3 of the wall height. Horizontal reinforcement is also provided at the bottom of the wall to resist direct tension. In the case of walls spanning horizontally, direct tension is considered and the section is designed for combined axial load and bending. The following additional data will be considered in the design of this silo:

Coefficient of friction 0.35 Angle of repose 28° Roof load 30 tonnes Density of material 890kg/m3.


PRESTRESSED CONCRETE 5 | I О parapet roof

SHEET NO. Vlll.3.7

(i)

anchorage with spiral reinforcement 800 400

epoxy grout pockef


Sheet No. VIII.3.7 shows a prestressed concrete silo with its major dimensions. Circumferential tendons are introduced between buttresses to resist the hoop tension. The cables are anchored at buttresses using the VSL multi-strand prestressing system having 19 prestressing anchorages. A guaranteed minimum breaking force of 184 kN was adopted for each cable. This silo has been designed on a wharf in Birkinhead, South Australia. Sheet No. VIII.3.8 shows a plan of a group of silos of the type shown on Sheet No. VIII.3.6. Two silos are interconnected using a 'cross' reinforcement. The connection is detailed on the lines suggested in the given section on Sheet No. VIII.3.8.


SILOS

GROUP OF SILOS

SECTION

FILLET

Section VIII. 4 Nuclear Shelter

VIII.4.1 General introduction

A nuclear shelter is just one of many devices designed to protect and shield humans from the effects of nuclear explosion and associated nuclear hazards. The nuclear blast can be in air, on the ground or underground. The characteristics of the blast waves and dynamic pressures caused by them have been well documented. Standard charts and numerous formulae are available to design such structures for any weapon yield. Blast loads and stresses (static and dynamic) have been fully documented in many texts, some of which are given in the bibliography.

VIII.4.2 Generalized data for a domestic nuclear shelter

A shelter for a family of six has been designed by the author. The following data is considered:

1 megatonne burst at a distance of 3 km from ground zero Velocity of the shock front = 500 m/s Ductility ratio u = 5 Drag coefficient: roof = —0.4; wall = +0.9 Yield strength of reinforcement = 425 N/mm2

fcu (dynamic) = 1.25 ftu (static) fy (dynamic) = 1.10 fy (static) Main reinforcement <0.25% bd (b = width, d = effective depth) Secondary reinforcement <0.15bd The ultimate shear stress >0.04fcu

The dynamic shear stress for mild steel > 172N/mm2.

VIII.4.3 Design of the scheme and structural detailing

Sheet No. VIII.4.1 shows a layout for an underground nuclear shelter for a family of six. All important provisions are indicated on this sheet including the locations and types of doors. Sheet No. VIII.4.2 shows a complete layout of the reinforcement details at various sections and a detail of the hatch opening.


UNDERGROUND NUCLEAR SHELTER

SHEET NO. Vlll.4.1

a -~\

s. Ч\ \ \ \Ч \ \ Чч V "

s I-.

- J

=*£

V

= ? < ^ =

V

SECTION C-C

>5<300 TIMBER PLATE HASP AND STAPLE BOLTED OOWN 1?mm METAL

' COVER -

ШЩ DAMPROOFIND - ^ LAYER ^ - » |

| , / . .' COVER

BARREL BOLT ЩЩ

12mm DIAMETER BY 200mm ANCHOR BOLT! CAST IN EONCRETE

DETAIL OF HATCH OPENING

SHEET No.

у Т20-200

'

1 C-l

~ " \ УТ20-200

уT20 -200

• •

, уТ2О-200

SECTION B-B

rue pEstav OF

5HEI T&cs

/:£5 £ i: t°

ожышь permit

[<Ш\/

1 7 3 > EH H Z П - п

3? m

о

CO

>

О

on I m

О <

Section VIII. 5 Nuclear, Oil and Gas Containments

VIII.5.1 Nuclear power and containment vessels

Nuclear reactors are generally housed in large prestressed concrete pressure and containment vessels. Some of the pressure vessels containing gas-cooled reactors with their respective parameters are listed below.

Plant

Oldbury Dungeness В Hinkley Point В Hunterston В St Laurent 1, 2 Bugey 1 Fort St Vrain Ventrop THTR

}

H,(m)

18.3 17.70

19.40

36.30 38.25 22.85 15.75

D, (m)

23.45 19.95

18.90

19.00 17.08 9.45

15.90

dT (m)

6.40 3.66

6.33

5.70 7.46 4.73 5.10

d B (m)

6.71 5.95

7.51

6.00 7.46 4.73 5.10

dw (m)

4.58 3.81

5.03

4.75 5.49 2.74 4.45

where H, = internal height; D[ = internal diameter; dT, dB = top and bottom cap thickness; dw = wall thickness.

In all the above-constructed vessels the gas boilers or circulators are either inside the vessel or placed elsewhere along the periphery of the vessel in an annular space. In addition multi-cavity vessels are proposed in which boiler and circulators are placed vertically inside the thickness of the vessel. The internal surface of these vessels is covered by a steel liner about 20 to 40 mm thick, the latter is for certain critical areas. These vessels are designed for an internal design pressure of 2.66 MN/m2 to 7MN/m2. The prestressing tendons are arranged in vertical and circumferential directions to withstand external loads and internal gas pressure. Vertical tendons are slightly curved to offset extreme stresses at the corners. The circumferential tendons are anchored at buttresses. Sheet No. VIII.5.1 shows the prestressed tendon layout for the Dungeness В vessel. In the case of the Oldbury vessel, a single helical prestressing system is used


to replace vertical and hoop tendons and their effects are similar to the Dungeness В vessel. In the case of multi-cavity vessels, owing to the placement of boilers and circulators in vertical directions, the circumferential tendons are replaced by a wire strand winding system as shown on Sheet No. VIII.5.2.

The main purposes of the containment structures are (i) to prevent the escape of radioactive materials, (ii) to protect the reactor system from damage due to external hazards, e.g. aircraft crashes, missile impact, tornadoes and hurricanes and explosion, and (iii) to provide biological shielding against nuclear radiation. A number of these vessels have been designed for Boiling Water Reactors and Pressurised Water Reactors. Some of them are listed below.

Plant Ht (m) D[ (m) dw (m) Description

Palisades Wall Monts d'Arree Fessenheim Super-Phenix* TVA Sizewell В

* = total height H; (H, = H - D, - thickness)

The internal pressure is about 344.75 kN/m2 for Sizewell B, as shown on Sheet No. VIII.5.3. The number of vertical tendons are about 76 at 0.97m centres in the wall. The number of circumferential tendons in the wall are about 120 at 0.317 m centres. In the dome latitude the circumferential tendons are 38 No. and along the longitude 24 No. with 16 No. in the rings.

57.90 35.40 1.07

56.00 46.00 0.60 51.30 37.00 1.00 90.00 64 1.00 (see Sheet No. VIII.5.4) 0.915 63 41.88 1.00

(see Sheet No. VIII.5.3)

Spherical dome on circular wall

ft tt П It tt

tt tf ft If It

ft ft It ft tf

Elliptical dome on circular wall it tt и и tt


PRESSURE VESSEL -DUNGENESS В TYPE

SHEET NO. Vlll.5.1

0 1 2 3 4 scale in feet L_J 1 4 _ l

1 scale in metres j—vessel symmetrical about SL

plan 2 - 2

vessel symmetrical about <£ — ci

с reheat_ ^ outlet

^ plan 3 - 3 лТ*^=

-active vessel cooling header area


HTGCR VESSEL SHEET NO. Vlll.5.2

L L

К


SIZEWELL В CONTAINMENT WITH SPHERICAL DOME - MAIN DIMENSIONS AND PRESTRESSING LAYOUT

SHEET No. Vlll.5.3(a)


Buttress shown out of phase

IOOO

1500

1300

SHEET NO. Vlll.5.3.(b)

6100 t

4-6.400 m OD

4 0 0 0 ЗООО"

6 Linear 4 »J

\

/

22860

L+23.873 , - 2 1 . 0 2 8

FFL+6.55m OD

Containment

Q]—10.913

U та

Main plant access operating floor level

6 Linear plate

j + 2 . 0 8 7 m OD

< . - 2 . 7 4 6 m OD

3 0 0 0

Vertical section through main plant access

41° Buttress

C?360°

Buttress 281 270'

Plan of dome


TVA CONTAINMENT BUILDING WITH ELLIPTICAL DOME - PRESTRESSING LAYOUT

SHEET NO. Vlll.5.4

<£ layer ' C <£ layer *B'

£ layer 'A'

1.678 m -4

EL 266.4 tendon layers 'A' & ' C are rotated in this section in order to clarify their position in their vertical plane

true elliptical curve (major axis = 41.175 m) (minor axis = 24.248 m)

EL 258.9

vertical angles (typ)

horizontal channels (typ;

secondary containment

533 mm -vertical tendons

3.06 m

.EL 189.7

1.22 m

Q _ 0 . 6 I

EL 187.1 EL 186.8

EL 185 EL 184.5

coupling device


A sectional elevation for Tennessee Valley Authority (TVA) with prestressing tendons in the elliptical dome and the wall is shown on Sheet No. VIII.5.4. The Sizewell containment has 11 MN tendons. Almost all containments are protected by a steel liner lugged to concrete and the thickness of the line varies from 6 mm to 12 mm.


OIL CONTAINMENT SHEET NO. Vlll.5.5

63.0 m *

30.0m

STEEL DECK TRUSS

0.0 m *

THREE CONCRETE TOWERS


VIII.5.2 Oil containment structures

Most concrete platforms for offshore facilities have been provided with hollow caissons for oil storage (approximately one million barrels) to allow continuous production over an emergency period such as the stoppage of tanker loading in bad weather or pipeline shutdown during the operation of the platform. In the design, apart from the environmental loads, tanker collision, drop weights on the deck and explosion, significant thermal stresses must be included which can be caused by the difference between the ambient sea water temperature (about 5°C) and the stored oil in the cell (about 40°C).

Sheet No. VIII.5.5 shows a sectional elevation and plan of a group of cells designed in reinforced concrete. Alternatively, these cells can be designed and constructed using prestressed tendons on the lines suggested for the TVA and Sizewell В containments as shown on Sheet Nos. VIII.5.3 and VIII.5.4 respectively. The Dungeness В Vessel layout can be adopted with approximate concrete thickness of barrel walls and caps for storing oil. These cells have domes resting on cylindrical walls with drill shafts and decks at the centre. They are constructed in a dry dock and are towed to the installation site. A number of these platforms have been designed, detailed and constructed, the most well known are Condeep, Ninean, Statfjord, Murchison and Tor. Some basic data are given below.

Condeep Water depth (in the area) 145 m to 188 m Cells (hollow 16No.) 20.1m diameter x 50m high Cell walls, etc. 0.61 m thick, 109 m high with three main shafts above cells with outside diameter tapered from 20.1m to 11.9m Deck weight with equipment 22.68 million kilogram Weight of the support structure 2.72 million kilogram Reinforcement bar size 12 and 25.

Platform

Frigg Brent Cormorant A

Water depth (m)

104 140 152

Caisson plan (area/height)

72m2/42m 91m2/57m

100m2/56m

No. of towers

2 4 4

Ext/int dia. (m)

14/13.4 15/14.4 16/15.4

Steel (tonne)

5800 11400 13930

Concrete grade 50 is always recommended.


PRESTRESSED CONCRETE LNG TANK

SHEET NO. Vlll.5.6

700

WALL DETAIL SHOWING PRESTRESSINQ SYSTEMS

SCALE 1:50

T15 SEISMIC CABLE 7 GALVANISED WIRE STRANDS AT 11S0CRS. IN 50mm DIA. RUBBER SLEEVE

MAX. LIQUID LEVEL

-50mm QUNITE OVERCOAT TO PROTECT CIRCULAR PRESTRESSING

•VERTICAL PRESTRESSING

-CIRCULAR PRESTRESSING

-R=24300

VJJc^

T12-100 BOTH DIRECTIONS 1 5 0 150x10 PVC WATERSTOP

- j ^p^bd. . . . '

T

150x10 P'

= <

14T32 OUTSIDE WATERSTOP

T20 INSIDE WATERSTOP

T10-100 RADIAL

T16 BARS

WOOD FLOAT FINISH

FILLET THICKNESS t - 190

16-180 HAIRPINS

T16-180CRS

SHELL THICKNESS d = 110

VENTILATOR HOLE

? 5 0 PRESTRESSING CABLES P=4137 KN/M"

FILLET LENGTH F= 5060


VIII.5.3 Liquefied natural gas containments

Liquefied natural gas (LNG) can be contained in a fixed concrete storage structure in the form of a vessel on shore or can have a series of mobile marine structures for its storage offshore. The most common way to store large quantities of gas in preparation for marine transportation is to liquefy it. It is well known that liquefied gases are stored and shipped at low temperatures, e.g., propane at -46°C and LNG at — 160°C. The need for special materials, insulation etc., imposes constraints on the mobile structure design: sea conditions, wind, current directions, seismic conditions and soil conditions. For on-shore conditions, wind, temperatures, seismic and soil conditions must be included in the design of these containments or storage structures. Dykman's BBR of San Diego, California, USA are the designers and constructors of a large number of such structures worldwide. These containments can be of a single walled or doubled walled type, reinforced or prestressed.

Sheet No. VIII.5.6 shows typical details of the LNG concrete containments of 50m diameter with 10 m wall height and an elliptical dome of maximum height at the centre of 5.5 m. The maximum liquid height is 9m.

Section VIII.6 Hydro-Electric and Irrigation/Hydraulic Structures

VIII.6.1 Hydro-electric structures

VIII. 6.1.1 General introduction

Hydro-electric structures are designed for use in water supply, electricity generation and navigation. Ecological and environmental considerations have a great influence on the planning, design and operation of such structures. Next in turn is hydrological studies and the economical selection of dams and other structures for multi-purpose hydro-electric schemes. Dams may be classified into a number of different categories -classification by use, by hydraulic design and by materials. Here only concrete dams and other relevant concrete structures are considered.

(a) Concrete gravity dams They are suitable for sites where there is a sound rock foundation, although low structures may be founded on alluvial foundations if suitable cut-offs are provided. They are well suited for use as overflow spillway crests. They may be either straight or curved in plan.

(b) Concrete arch dams They are suitable for sites where the ratio of the width between abutments to the height is not great and where foundations at the abutments are solid rock capable of resisting arch thrusts. There are two types of arch dams - the single and the multiple arch dam. A single arch dam spans a canyon (crest height/length = 1/10) as one structure and its design includes small thrust blocks on both abutments. A multiple arch dam may be either a uniformly thick cylindrical barrel shape spanning 15 m or so between buttresses or it may have single arch dams supported on massive buttresses spaced several hundred metres on centres. The loads considered are water pressure, ice pressure, silt pressures, dead loads, earthquakes and ice combinations and other imposed loads.

(c) Spillways Spillways are provided for storage and detention dams to release surplus or flood water that cannot be contained in the allotted storage space. They are also used as diversion dams to by-pass flows exceeding those turned into the diversion systems. The safety of the spillway is of paramount importance since many failures of dams have been caused by improperly designed spillways. The layout is influenced by many factors including spillway size, type, overflow characteristics, the selection of location, and terrain. It may be an integral part of the dam (overflow section of the concrete dam) or it may be


a separate structure. A major component is the control device which prevents outflows below a fixed reservoir level and regulates releases when the reservoir rises above that level. The control drives may be straight, curved, semi-circular, U-shaped, or round. The flow is conveyed to the stream bed below the dam in a discharge channel or waterway. Spillways may be (i) free overfall (straight drops), (ii) Ogee (overflow), (iii) side-channel type, (iv) labyrinth, (v) chute (open channel or trough), (vi) conduit and tunnel, (vii) drop inlet (shaft or Morning Glory), (viii) baffled В chute or (ix) culvert.

(d) Intakes and penstocks This type of structure is an inlet or the entrance to the outlet work and accommodates a control device already discussed above. The intake structures are of different shapes and are each selected according to several factors: (i) the range in reservoir head under which it must operate, (ii) the discharge it must handle, (iii) reservoir ice and wave conditions and (iv) frequency of reservoir draw down (the frequency of cleaning trash racks).

An intake may be either submerged or extended in the form of a tower above the maximum reservoir surface. The former is considered only where it is an entrance to outlet conduits or where trash cleaning is unnecessary. A tower must have a control and is needed where an operating platform is needed for trash removal or installing stop logs. The conduit may be placed vertically, inclined or horizontally. The sill level must be higher than the conduit level. Trash bars of thin flat steel are placed on edge from 75 mm to 150mm apart and assembled in a grid pattern. The shape of trash rack structures may vary according to their mounting techniques and the shape of the intake.

Penstocks are large concrete pipes or conduits, mounted at suitable intervals on the slopes to deliver water to turbines in the power plant. They can be made in steel.

(e) Power plant The penstocks are connected to turbine casings in the hydro-electric plant producing electricity.

(f) Spillway bridge A bridge is generally provided for traffic on the dam spillway.

VIII.6.1.2 Hydro-electric structures - typical data on dams

(a) Djen Djen Dam, Algeria Crest length Maximum height Span of barrels Barrel thickness No. of buttresses Minimum thickness at buttress

(b) Sefid Rud Dam, Iran Crest length Maximum height No. of buttresses Buttress thickness and width

530 m 85 m 35 m 2.3 m 11 3.084 m

384 m 107 m 14 5m, 14m

Many others have been constructed; see the bibliography in this book, where additional information is available.


DAM-SPILLWAY BRIDGE -CONCRETE OUTLINE AND REINFORCEMENT

SHEET NO. Vlll.6.1

Special Structures 2У1

VIII. 6.1.3 Hydro-electric structures - structural detailing

Note: The author has kept the details in their original forms. They can easily be converted into SI units.

Sheet No. VIII.6.1 gives a typical layout and structural details of a dam-spillway steel-concrete (composite) bridge for traffic in and out of the site. Sheet No. VIII.6.2 shows a dam-spillway and its piers.

Here reinforcement details are provided for a typical dam-spillway and its piers which hold revolving steel gates. The bars shown can easily be converted from the American system to SI units using conversion or similar bar sizes given in Section 1.

Sheet No. VIII.6.3 shows a typical plan for spillway intakes, penstocks and power house units. Sheet Nos. VIII.6.4 and VIII.6.5 indicate sectional elevations of the layout given on Sheet No. VIII.6.3. For a very different job a different type of intake is shown with upstream and downstream elevations and a section on Sheet No. VIII.6.6. For this intake various reinforcement details are shown on Sheet No. VIII.6.7 which include sectional plans, elevations and particular reinforcement details for piers and gate slots. Sheet No. VIII.6.8 gives the complete reinforcement details for the training wall of the dam intake. A complex reinforced concrete detailing of a typical unit bay of a power house is shown on Sheet No. VIII.6.9. The conduit is transitioned to suit the turbine casings. It also shows the legend for two stages of concrete.

Sheet No. VIII.6.10 shows structural plans and sections for electric manholes for the same switchyard. These details are practically universal for any switchyard.

Sheet No. VIII.6.11 gives a comparative study of different shaped tunnels used in various multi-purpose hydro-electric schemes.


DAM-SPILLWAY AND PIERS -ABOVE EL.253.00 REINFORCEMENT

SHEET NO. Vlll.6.2


DETAILED PLAN OF HYDRO POWER STRUCTURES

SHEET NO. Vlll.6.3

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DAM-INTAKE SECTION AND SHEET NO. Vlll.6.6 ELEVATIONS CONCRETE OUTLINE

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DAM-INTAKE SECTIONS AND DETAILS CONCRETE OUTLINE AND REINFORCEMENTS

SHEET NO. Vlll.6.7


DAM-INTAKE TRAINING WALL SHEET NO. Vlll.6.8 CONCRETE OUTLINE AND REINFORCEMENTS


POWERHOUSE UNIT BAYS TYPICAL REINFORCEMENT

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SHEET NO. Vlll.6.9

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161 KV SWITCHYARD CONCRETE FOOT NGS

SHEET NO. Vlll.6.10


161 KV SWITCHYARD ELECTRICAL MANHOLES

SHEET NO. Vlll.6.11

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TYPICAL SECTION IN SWITCHYARD

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Section VIII.6.2 Hydraulic and Irrigation Structures

VIII.6.2 Irrigation structures

VIII.6.2.1 General introduction

Irrigation structures are extremely important and they must be properly designed and detailed. Some selected structures will be outlined later to inform the reader about their specific aspects of structural detailing. The general requirements include the following: (a) water demand, (b) acreage to be irrigated, (c) duty of water, (d) seepage losses, (e) evaporation, (f) flow capacity, (g) site layout and structural curvatures and lining, (h) free board, (i) bank top width and beam, (j) flow formulae, (k) membrane lining and slopes, (1) loadings and (m) design considerations.

VIII.6.2.2 Main structures

(a) Spillway sections (b) Dam with control gates (c) Buttress overflow sections (d) Cut-off walls (e) Wing walls (f) Stop logs (g) Overchute and chutes (h) Feeder сада! (i) Sluice (j) Trash rack (k) Outlets (1) Siphons and tunnels (m) Flumes and drops.

Some of these have already been disscussed in Section VIII.6.1. To accomplish an irrigation project (for producing crops or increasing crop production), water delivery to specific sites must be provided by a reliable and efficient irrigation system. A canal is frequently used to convey water to meet requirements for municipal, industrial and outdoor recreational uses. Canal head-work structures are needed to regulate canal discharge at the source of the water supply. These structures must also be able to raise the canal water level higher than it would normally be when the canal is flowing at less than design capacity. Most of these structures, apart from water pressures, must withstand dead and imposed loads, lateral soil pressures, loads such as ice and wind loads, wheel loads and railroad loads.


Spillways, dams with control gates, buttress overflow sections cut-off and wing walls, trash racks, etc. have been dealth with in Section VIII.6.1. The functions of others are given below.

(f) Stop logs are control structures They are control structures and their layout is different but their performance is identical to chute which is described below.

(g) Overchute and chute These are structures that carry flood or drainage water across and above the canal prism. They are used where the cross-drainage gradient is sufficiently high to provide a free board over the canal water surface without excessive ponding at the inlet. A rectangular concrete flume is generally used for large flows. Chutes are used to convey water from a higher elevation to a lower elevation. A chute structure may consist of an inlet, a chute section, an energy dissipater and an outlet transition. The inlet is provided with a control to prevent racing and scouring in the channel. Control is achieved by combining a check, a weir or a control notch with the inlet.

(h) A feeder canal This is a canal that feeds water, it is often related to an overchute type structure. Sheet No. VIII.6.12.a shows the sectional elevation and R.C. details for a feeder canal.

Sheet No. VIII.6.12.b shows structural details of a typical feeder canal and an overchute. Reinforcement details are given at important sections.


SECTIONAL ELEVATION AND R.C. DETAILS OF A FEEDER CANAL

SHEET NO. Vlll.6.12(a)

PIPE RAILINQ NOT SHOWN - .

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C_ 150 RUBBER WATERSTOP-,

ELEVATION N-N Ш TTT? V !*606"i Т16-300У ' '•''"'DRAINS NOT SHOWN- - ' • • ' " 6 °

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SECTION U-U

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SECTION D-D

SECTION E-E

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900 IN EARTH.AS DIRECTED IN ROCK

900 IN EARTH AS DIRECTED IN ROCK

-T12- I .50 Я >н- — 31T12 150 END ALT BARS AT H

HALF WALL HEIGHT

PROVIDE CUSHION (150 MIN THICKNESSI OF COMPACTED BACKFILL OF APPROPRIATE MATERIAL WHEREVER ROCK MATERIAL IS ENCOUNTERED

46T12-225 -П200 900 MIN IN EARTH, AS DIRECTED IN ROCK

LONGITUDINAL SECTION OF OUTLET


(к) Outlets Sheet No. VIII.6.13 gives structural details (plan and sections) for a typical outlet. Reinforcement details of the base slab and of the construction joint near to the transition zone are shown at the longitudinal section.

(1) Siphons and tunnels Tunnels are described in Section VIII.6.1, inverted siphons or sagpipes are used to convey canal water by gravity under roads, railroads and other structures. Typical cross-sections are given for various tunnel shapes with support systems on Sheet No. VIII.6.14. All reinforcement details are given for various sections.

(m) Flumes and drops Flumes are specially designed in-line open channel structures in which canal water flows along a broad, flat converging section through a narrow downward sloping throat section and then diverges on an upward sloping roof. A drop is to convey water from a higher to a lower elevation. Check drops are those without blocks. For drops where the drop elevation is greater than 4.5 m and where the water is conveyed for a long distance, drops are replaced by chutes.

Where gates are used on spillways, Sheet No. VIII.6.15 gives the structural details of a gate and reinforced concrete supporting structure.

Hydraulic structures cannot overlook culverts. Typical reinforcement details are given for a culvert on Sheet No. VIII.6.16.


OUTLET WORKS SHEET NO. Vlll.6.14

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Typical tunnel support sections


SPILLWAY GATE AND R.C. SUPPORTING STRUCTURE

SHEET NO. Vlll.6.15

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CULVERT REINFORCEMENT SHEET NO. Vlll.6.16

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Bibliography Books Abeles, P.W. & Bardhan-Roy, B.K. (1981) Prestressed Concrete Designers' Handbook,

View Point Publications, London. Bangash, M.Y.H. (1989) Concrete and Concrete Structures: Numerical Modelling and

Applications, Elsevier, London. Bangash, M.Y.H. (1992) Impact and Explosions - Structural Analysis and Design,

Blackwell Scientific Publications. Billington, D.P. (1965) Thin Shell Concrete Structures, McGraw Hill Book Co, New

York. Creasy, L.R. (1961) Prestressed Concrete Cylindrical Tanks, John Wiley & Sons, New

York. Faulkener, D., Cowling, M.J. & Frieze, P.A. (1981) Integrity of Offshore Structures,

Elsevier Applied Science. Fintel, M. (Ed.) (1974) Handbook of Concrete Design, Van Nostrand Reinhold, New

York. Gaylord, E.H. & Gaylord, L.R. (1979) Structural Engineering Handbook, McGraw

Hill, New York. Gray, W.S. (1969) Water Towers, Bunkers, Silos and other Elevated Structures,

Concrete Publications, London. Hartland, R.A. (1975) Design of Precast Concrete, Surrey University Press, London. Institution of Structural Engineers (IStruct E) (1978) Structural Joints in Precast

Concrete, London. Konz, T. (1967) Manual of Prestressed Concrete Construction, 3 vols, Bauverlag,

Wiesbaden and Berlin. Leonhardt, F. (1964) Prestressed Concrete Design and Construction, 2nd edn, Wilhelm

Ernst & Sohn, Berlin. PCI Design Handbook (1971) Prestressed Concrete Institute, Chicago. Peck, R., Hanson, W. & Thornburn, T. (1974) Foundation Engineering, 2nd edn.

John Wiley & Sons, New York. Pinfold, G.M. (1975) Reinforced Concrete Chimneys and Towers, View Point

Publications, London. Ramaswamy, G.S. (1968) Design and Construction of Concrete Shell Roofs, McGraw

Hill, New York. Safarian, S.S. & Harris, E.C. (1985) Design and Construction of Silos and Bunkers,

Van Nostrand Reinhold, New York.

Codes of practice and standards American Concrete Institute (ACI), Detroit, USA ACI (1977) Reinforced Concrete Structures in Seismic Zones, sp3. ACI (Committee 313) (1977) Recommended Practice for the Design and Construction of

Concrete Bins, Silos and Bunkers for Storing Granular Materials. ACI (Committee 307) (1977) Specification for the Design and Construction of

Reinforced Concrete Chimneys.

258 Bibliography

ACI (1978) Guide for the Design and Construction of Offshore Concrete Structures, J. ACI, 75(12), pp. 684-709.

ACI (1983) Building Code Requirements for Reinforced Concrete, ACI, Standard 318-277.

API, Recommended Practice for Fixed Offshore Platforms, AP-RP2A, American Petroleum Institute, (1972-1975-1989).

British Standards Institute (BSI) British Standard or BSI 8110 (1978) The Structural Use of Concrete, Part I, British

Standards, London. BS 5337 (1976; as amended 1982) The Structural Use of Concrete for Retaining Aqueous

Liquids, pp. 16.

HMSO (1981) Domestic Nuclear Shelters - Technical Guidance, Her Majesty's Stationary Office.

DIN (1988) Composite Steel and Concrete Structures, Part 1: Composite Columns. DIN 18806, Deutsches Institut fur Normang. Ev, Berlin.

DIN (1988) Structural Use of Concrete, Design and Construction, DIN 1045, Deutsches Institut fur Normang, Ev.

DIN (1988) Reinforcing Steel, Reinforcing Steel Fabric and Wire: Design and Dimensions and Masses, DIN 488 Part 4, Deutsches Institut fur Normang, EV.

EUL (1984) Common Unified Rules for Concrete Structures, Commission of European Community (Draft).

Index

abbreviations, 7 aggregates, 10, 12 anchorage, 20-23

bars arrangement, 10, 13 curtailment, 26-7, 34 diameter, 22 fabric, 10 length, 22 shapes, 14-19 spacing, 10, 12 types, 10 U-bars, 20

beam(s) cantilever, 24-5 continuous, 34, 42, 47, 104 grid, 24-5 holes in, 24-5 monolithic with wall, 24-5 reinforced, 42-7 simple, 42 T-beam, 43, 46-7

bed blocks, 156, 172 bending moments, 27 bends, 20 bent bars, 28-9, 46 bent-up bars, 24-5 bridges

arch, 153, 167-71 beam, girder, 152, 157, 159-60, 164-6 box,153,161 cable-stayed, 153 frame, 153, 163 loads, 153 slab, 152, 156, 157, 162 structural details, 154 suspension, 153 T-beam, 152, 158

buttresses, 248, 252

chimney, 205-6 chutes, 249

column links, 28-9 columns, 72-9, 112, 114-21 composite construction, 37, 108-11, 113 concrete,

cast-ins itu, 109 precast, 64, 67-70 prestressed, 86-106

construction joints, 119-25, 207 containments

gas, 232-3 nuclear, 222-9 oil, 230-31

couplers, 22-3 coupling anchors, 88-90 culverts, 253, 256 curbs see kerbs curtailments, 26-7

dams, 234-44 deck structures, 154 design, 40 dimensioning, 4 dimensional tolerance, 11 drawing instruments, 4 drawings, 3 drop panels, 32-3 , 54 drops, 253

elevation marker, 7

fabric detailing, 10 schedules, 11

feeder canal, 249-51 flumes, 253 footings see foundations foundations

balanced, 130-31 basement, 143-7 cantilever, 130-31 circular, 132-3 hexagonal, 132-3 pile, 133-8

260 Index /

raft, 141 rectangular, 128 strip, 130-31 well, 140-41

frames, 80, 83-4

gas containment, 232-3 grids, 5-6

hand rails, 176 holes, 8-9, 25 hooks in reinforcement, 20-23 hydro electric structures, 243-7

intakes, 235, 237

irrigation structures, 248-56

joints, 22, 119, 123-5

kerbs, 8-9

lap lengths, 20-23 levels, 5-6 line thickness, 4 linework dimensions, 4 links, 46 loading, 153 local bond, 23

nibs, 8-9 nuclear

containment, 222-9 shelters, 218-21

oil containment, 230-31 outlets, 252-4

penstocks, 235, 237, 239 piers, 172-4, 237, 238 piling, 134-9 pockets, 8-9 portals, 80, 83 precast construction, 108, 114-15 prestressed concrete, 85-106

recesses, 8-9 reinforcement

cover, 11 designation, 39 fabric, 10-11 joints, 23 sizes, 10

reservoirs, 207 rockers, 177-8

shape codes, 14-21 shear connectors, 108 shells

conoidol, 205 cylindrical, 180, 183-4 elliptical, 203 hipped plate, 200-203 hyperbolic, 180, 191-6 hyperbolic paraboloids, 179, 181, 184 north-light, 191, 193-4

shelters, 219-21 silos, 214-18 siphons, 253 slabs,

basement floor, 143, 146 cantilever, 30 continuous, 30, 33, 47, 57, 104 flat, 32-3 , 54-5 floor, 56 reinforced, 49-58 simple, 30, 48-50 supported, 48 suspended, 48 target, 58

slab reinforcement, 30-31 spacers, 11, 13 spillways, 234, 236-8, 253, 255 stairs and staircases

beam slab arrangement, 64 Birchwood, 67-70 dimensions, 58 reinforcement, 60-61 slab construction, 62 types, 61

steel, 37 stop logs, 249 structural details, 40 symbols, 7

tabular method, 38 tanks, 191-5 ties, 121-2 towers, 209, 212 tunnels, 253-4

walls, 80-82 retaining, 148-50

water retaining structures, 207-13

TD314fl5 DD14DAD Ьз¥

This book provides a comprehensive manual of details in reinforced, prestressed, precast

and composite concrete, including:

• reinforced concrete beams and slabs

• stairs and staircases

• columns, frames and walls

• prestressed concrete details

• composite construction, precast concrete elements, joints and connections

• concrete foundations and earth retaining structures.

A further specialised section of case studies provides a range of integrated structures,

including:

• bridges

• concrete shells

• water retaining structures

• silos

• nuclear shelter

• nuclear, oil and gas containments

• hydroelectric and irrigation/hydraulic structures.

This book will be invaluable for design offices who are increasingly concerned with

producing structural details and for contractors responsible for preparing construction

drawings. It will also be a useful reference for students of civil and mechanical engineering.

Dr M.Y.H. Bangash is a chartered civil and structural engineer and is in practice as a

consulting engineer. He is the director of Ban and Del Educational Consultants Ltd.

He has recently completed another reference book for Blackwell Scientific Publications,

Impact and Explosion.