Reinforced Concrete Design to Eurocode 2 (EC2)

441 Pages·1996·73.55 MB·English

by  W. H. Mosley

Reinforced Concrete Design to EuroCode 2 (EC2)
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REINFORCED CONCRETE
DESIGN TO EUROCODE 2
(EC2)
W. H. Mosley
Nanyang Technological University, Singapore
R. Hulse
Coventry University
and
J. H. Bungey
University of Liverpool
© W. H. Mosley, R. Hulse and J. H. Bungey 1996
All rights reserved. No reproduction, copy or transmission
of this publication may be made without written permission.
No paragraph of this publication may be reproduced, copied
or transmitted save with written permission or in accordance
with the provisions of the Copyright, Designs and Patents Act
1988, or under the terms of any licence permitting limited
copying issued by the Copyright Licensing Agency,
90 Tottenham Court Road, London W1P 9HE.
Any person who does any unauthorised act in relation to
this publication may be liable to criminal prosecution and
civil claims for damages.
First published 1996 by
MACMILLAN PRESS LTD
Houndmills, Basingstoke, Hampshire RG21 6XS
and London
Companies and representatives
throughout the world
ISBN 978-0-333-60878-4 ISBN 978-1-349-13413-7 ( eBook)
DOl 10.1007/978-1-349-13413-7
A catalogue record for this book is available
from the British Library
Contents
Preface viii
Notation xi
1 Properties of Reinforced Concrete 1
1.1 Composite Action 1
1.2 Stress-Strain Relations 3
1.3 Shrinkage and Thermal Movement 8
1.4 Creep 13
1.5 Durability 14
1.6 Specification of Materials 15
2 Limit State Design 18
2.1 Limit States 19
2.2 Characteristic Material Strengths and Characteristic
Loads 20
2.3 Partial Factors of Safety 21
2.4 Global Factor of Safety 24
3 Analysis of the Structure 29
3.1 Loads 30
3.2 Load Combinations and Patterns 31
3.3 Analysis of Beams and Frames 33
3.4 Redistribution of Moments 56
4 Analysis of the Section 62
4.1 Stress-Strain Relations 63
4.2 Distribution of Strains and Stresses across a Section 65
4.3 Bending and the Equivalent Rectangular Stress Block 67
4.4 Singly Reinforced Rectangular Section in Bending 68
4.5 Rectangular Section with Compression
Reinforcement at the Ultimate Limit State 73
v
vi CONTENTS
4.6 Flanged Section in Bending at the Ultimate Limit
State 80
4.7 Moment Redistribution and the Design Equations 87
4.8 Bending Plus Axial Load at the Ultimate Limit State 92
4.9 Rectangular-Parabolic Stress Block 103
4.10 Triangular Stress Block 106
5 Shear, Bond and Torsion 113
5.1 Shear 113
5.2 Anchorage Bond 125
5.3 Laps in Reinforcement 129
5.4 Analysis of Section Subject to Torsional Moments 131
6 Serviceability, Durability and Stability Requirements 139
6.1 Detailing Requirements 140
6.2 Span-Effective Depth Ratios 148
6.3 Calculation of Deflection 150
6.4 Flexural Cracking 164
6.5 Thermal and Shrinkage Cracking 171
6.6 Other Serviceability Requirements 174
6.7 Limitation of Damage caused by Accidental Loads 178
7 Design of Reinforced Concrete Beams 185
7.1 Preliminary Analysis and Member Sizing 187
7.2 Design for Bending 190
7.3 Design for Shear 207
7.4 Bar Spacing 214
7.5 Continuous Beams 214
7.6 Cantilever Beams 221
7.7 Design for Torsion 222
8 Design of Reinforced Concrete Slabs 227
8.1 Shear in Slabs 228
8.2 Span-Effective Depth Ratios 233
8.3 Reinforcement Details 233
8.4 Solid Slabs Spanning in One Direction 234
8.5 Solid Slabs Spanning in Two Directions 242
8.6 Flat Slab Floors 248
8.7 Ribbed and Hollow Block Floors 257
8.8 Stair Slabs 261
8.9 Yield Line and Strip Methods 266
CONTENTS vii
9 Column Design 276
9.1 Loading and Moments 276
9.2 Column Classification and Failure Modes 279
9.3 Reinforcement Details 283
9.4 Short Columns Resisting Moments and Axial Forces 285
9.5 Non-Rectangular Sections 297
9.6 Biaxial Bending of Short Columns 301
9. 7 Design of Slender Columns 304
9.8 Walls 309
10 Foundations and Retaining Walls 311
10.1 Pad Footings 314
10.2 Combined Footings 322
10.3 Strap Footings 327
10.4 Strip Footings 329
10.5 Raft Foundations 332
10.6 Piled Foundations 333
10.7 Retaining Walls 338
11 Prestressed Concrete 350
11.1 Principles of Prestressing 352
11.2 Methods of Prestressing 354
11.3 Analysis of Concrete Section under Working Loads 357
11.4 Design for the Serviceability Limit State 363
11.5 Analysis and Design at the Ultimate Limit State 393
Appendix 407
Further Reading 421
Index 423
Preface
The purpose of this book is to provide a straightforward introduction to
the principles and methods of design for concrete structures. It is directed
primarily at students and young engineers who require an understanding
of the basic theory and a concise guide to design procedures. Although
the detailed design methods are generally according to European
Standards (EuroCodes), much of the theory and practice is of a fund
amental nature and should, therefore, also be useful to engineers in
countries outside Europe.
The search for harmonisation of Technical Standards across the
European Community (EC) has led to the development of a series of
these Structural EuroCodes which are the technical documents intended
for adoption throughout all the member states. The use of these common
standards is intended to lower trade barriers and enable companies to
compete on a more equitable basis throughout the EC. EuroCode 2
(EC2) deals with the design of concrete structures, which has most recently
been covered in the UK by British Standard BS8110 which superseded
British Standard CPllO in 1985. Limit state principles established by
these British Standards are also adopted by EuroCode 2.
The code drafting committee has also produced a range of supporting
documents giving commentary and background explanation for some of
the requirements of the code. Further supporting documentation includes,
for each separate country, the National Application Document (NAD)
which includes information specific to the individual member states.
Additionally the British Cement Association has produced The Concise
EuroCode for the Design of Concrete Buildings which contains material
that has been distilled from EC2 but is presented in a way that makes it
more user-friendly than the main EuroCode and contains only that
information which is essential for the design of more everyday concrete
structures. It also contains information not included in EC2 such as
design charts and design methods drawn from previous British Standards
viii
PREFACE ix
such as BS8110 and CPllO. In this text, reference is made to both EC2
and the Concise Code.
The presentation of EC2 is quite different from that of BS8110.
However the essential feature of EC2 is that the principles of design
embodied in the document are almost identical to the principles inherent
in the use of BS8110. Hence, although there are some differences in
detail, engineers who are used to designing to the existing British Standard
should have no difficulty in grasping the essential features of this new
code.
Changes in terminology, arising partly from language differences, have
resulted in the introduction of a few terms which are unfamiliar to
engineers who have worked with BS8110. The most obvious of these is
the use of actions to describe the loading on structures and the use of the
terms permanent and variable actions to describe dead and imposed loads.
Notwithstanding this, UK influence in drafting the document has been
very strong and terminology is broadly the same as in existing British
Standards. Throughout this text, terminology has been kept as consistently
as possible in line with common accepted UK practice and hence, for
example, loads has been used instead of actions in subsequent chapters.
Other 'new' terminology will be identified at appropriate points in the
text.
The subject matter in this book has been arranged so that chapters 1 to
5 deal mostly with theory and analysis while the subsequent chapters
cover the design and detailing of various types of member and structure.
In order to include topics that are usually in an undergraduate course,
there is a section on earth-retaining structures and also a final chapter on
prestressed concrete.
Important equations that have been derived within the text are high
lighted by an asterisk adjacent to the equation number and in the Ap
pendix a summary of key equations is given. Where it has been necessary
to include material which is not directly provided by the EuroCodes, this
has been based on currently accepted UK good practice.
In preparing this book, the principal aim has been to retain the struc
ture and features of the well established book Reinforced Concrete Design
by Mosley and Bungey (Macmillan Press, 1990) which is based on British
Standards and is currently in its 4th edition. By comparing both books it
is possible to compare the essential differences between EuroCode 2 and
existing British Standards and to contrast the different outcomes when
structures are designed to either codes.
It should be emphasised that Codes of Practice are always liable to be
revised and readers should ensure that they are using the latest edition of
any relevant standard.
Extracts from European Standards are reproduced by permission of
the British Standards Institution, Linford Wood, Milton Keynes, Bucks.,