Structures or Why things don't fall down

Structures or Why things don't fall down

J.E.Gordon University of Reading Reading, England

PLENUM PRESS NEW YORK AND LONDON

Library of Congress Cataloging in Publication Data

Gordon, James Edward, 1913-Structures.

Bibliography: p. Includes index. 1. Structures, Theory of. 2. Structural engineering. I. Title.

TA645.G65 624'.17 78-19068 ISBN-13: 978-1-4615-9076-7 e-ISBN-13: 978-1-4615-9074-3 DOl: 10.1007/978-1-4615-9074-3

Copyright J. E. Gordon, 1978 Softcover reprint of the hardcover 1st edition 1978 First published by Penguin Books Ltd, Harmondsworth, Middlesex, England

Plenum Press, New York is a division of Plenum Publishing Corporation 227 West 17th Street, New York, N.Y. 10011

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No part of this book may be reproduced, stored in a retrieval system, or transmitted, in any form or by any meaIt's, electronic, mechanical, photocopying, microfilming, recording, or otherwise, without written permission from the Publisher

To my grandchildren, Timothy and Alexander

Among the innumerable mortifications which waylay human arrogance on every side may well be reckoned our ignorance of the most common objects and effects, a defect of which we become more sensible by every attempt to supply it. Vulgar and inactive minds confoundfamiliarity with knowledge and conceive themselves informed of the whole nature of things when they are shown their form or told their use; but the speculatist, who is not content with superficial views, harasses himself with fruitless curiosity, and still, as he inquires more,perceives only that he knows less. Samuel Johnson, The Idler (Saturday, 25 November 1758)

Contents

List of Plates 11 Foreword 13 Acknowledgements 15

1 The structures in our lives - or how to communicate with engineers 17

Part One The difficult birth of the science of elasticity 2 Why structures carry loads - or the springiness

o/solids 33 3 The invention of stress and strain - or Baron

Cauchy and the decipherment 0/ Young's ~~~ ~

4 Designing for safety - or can you really tr~t strength calculations? 60

5 Strain energy and modem fracture mechanics - with a digression on bows, catapults and kangaroos 70

Part Two Tension structures 6 Tension structures and pressure vessels

- with some remarks on boilers, bats and Chinese junks 113

7 Joints, fastenings and people - also about creep and chariot wheels 132

8 Soft materials and living structures - or how to design a worm 149

Part Three Compression and bending structures 9 Walls, arches and dams - or cloud-capp'd

towers and the stability 0/ masonry 171 10 Something about bridges - or Saint Bhzezet

and Saint Isambard 198 11 The advantage of being a beam - with

observations on roofs, tr~ses and masts 210

10 Contents

12 The mysteries of shear and torsion - or Polaris and the bias-cut nightie 24S

13 The various ways of failing in compression - or sandwiches, skulls and Dr Euler 'Il2

Part Four And the consequence was 14 The philosophy of design - or the shape,

the weight and the cost 303 15 A chapter of accidents - a study in -sin, error

and metal fatigue 324 16 Efficiency and aesthetics - or the world we

have to live in 354 Appendix 1 Handbooks and formulae 374 Appendix 2 Beam theory 377 Appendix 3 Torsion 384 Appendix 4 The efficiency of columns and panels under

compression loads 385 Suggestions for further study 388 Index 391

List of Plates

1 Bent masonry column in Salisbury CathedraL 2 Stress concentration at crack tip (courtesy

Dr Richard Chaplin). 3 'Aneurism' in cylindrical balloon. 4 Section of artery wall tissue (courtesy

Dr Julian Vincent). 5 Corbelled vault at Tiryns. 6 Semi-corbelled postern gate at Tiryns. 7 Clare bridge, Cambridge (courtesy Professor

Adrian Horridge, F.R.S.). a Temple of the Olympian Zeus, Athens. 9 Skeletons of gibbon and gorilla.

10 Maidenhead railway bridge. 11 Menai suspension bridge (courtesy

Institution of Civil Engineers). 12 Severn suspension bridge (courtesy British

Steel Corporation). 13 King's College Chapel, Cambridge. 14 H.M.S. Victory (courtesy H.M.S. Victory

Museum. Crown copyright). 15 American trestle bridge. 16 Britannia bridge (courtesy Institution of

Civil Engineers). nand 1a Vionnet dresses (courtesy Mrs Nethercot

and Vogue magazine).

12 List of Plates

19 Wagner tension field (courtesy The Fairey Company Ltd).

20 Tacoma Narrows bridge (courtesy Institution of Civil Engineers).

21 Portsmouth block-making machinery (Crown copyright. Science Museum, London).

22 Watson steam yacht (courtesy G. L. Watson & Co. Ltd).

23 The Parthenon. 24 The Lion Gate, Mycenae.

Foreword

I am very much aware that it is an act of extreme rashness to attempt to write an elementary book about structures. Indeed it is only when the subject is stripped of its mathematics that one begins to realize how difficult it is to pin down and describe those structural concepts which are often called' elementary'; by which I suppose we mean 'basic' or 'fundamental'. Some of the omis-sions and oversimplifications are intentional but no doubt some of them are due to my own brute ignorance and lack of under-standing of the subject.

Although this volume is more or less a sequel to The New Science of Strong Materials it can be read as an entirely separate book in its own right. For this reason a certain amount of repeti-tion has been unavoidable in the earlier chapters.

I have to thank a great many people for factual information, suggestions and for stimulating and sometimes heated discussions. Among the living, my colleagues at Reading University have been generous with help, notably Professor W. D. Biggs (Professor of Building Technology), Dr Richard Chaplin, Dr Giorgio Jeronimidis, Dr Julian Vincent and Dr Henry Blyth; Professor Anthony Flew, Professor of Philosophy, made useful suggestions about the last chapter. I am also grateful to Mr John Bartlett, Consultant Neurosurgeon at the Brook Hospital. Professor T. P. Hughes of the University of the West Indies has been helpful about rockets and many other things besides. My secretary, Mrs Jean Collins, was a great help in times of trouble. Mrs Nethercot of Vogue was kind to me about dressmaking. Mr Gerald Leach and also many of the editorial staff of Penguins have exercised 'their accustomed patience and helpfulness.

Among the dead, lowe a great deal to Dr Mark Pryor - lately of Trinity College, Cambridge - especially for discussions about biomechanics which extended over a period of nearly thirty years. Lastly, for reasons which must surely be obvious, lowe a humble oblation to Herodotus, once a citizen of Halicamassus.

Acknowledgements

We acknowledge with gratitude permission to quote from various authors. For Douglas English's poem, Punch Publications Ltd; for quotations from Weston Martyr's The Southseaman, Messrs. William Blackwood Ltd; for the quotation from Rudyard Kipling's The Ship that Found Herself; Messrs. A. P. Watt & Son and the executors of the late Mrs Bambridge and the Macmillan Co. of London and Basingstoke. Also to Mr H. L. Cox for the quotation from his book The Design of Structures of Least Weight. The quotations from the New English Bible (Second Edition 1970) are by kind permission of the Oxford and Cambridge University Presses.

We are also most grateful to all those named in the List of Plates who have so kindly provided illustrations and given permission to reproduce them.

We have received a great deal of help from many people and organi-zations with regard to both quotations and illustrations. If we have, in any instance, failed to make proper acknowledgement, we offer oUr apologies.