Temporary Works - Their Role in Construction

291 Pages·1987·33.033 MB·English

by  J. R. Illingworth

TEMPORARY WORKS
their role in construction
J. R. ILLINGWORTH, BSc, FCIOB
Thomas Telford, London, 1987
Published by Thomas Telford Ltd, Thomas Telford House, 1 Heron
Quay, London E14 9XF
First published 1987
British Library Cataloguing in Publication Data
Illingworth, J. R.
Temporary works: their role in construction
1. Temporary structures (Building)
I. Title
624.1 TH528O
ISBN 978-0-7277-0393-4
© J. R. Illingworth, 1987
All rights, including translation, reserved. Except for fair copying, no part of this pub-
lication 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
written permission of the publisher. Requests should be directed to the Publications
Manager at the above address.
Set by Santype International Limited, Salisbury, Wiltshire.
Acknowledgements
The author wishes to express his grateful thanks to the following for
permission to use material from their publications and literature: the
Controller of Her Majesty's Stationery Office and the Health and Safety
Executive for the terms of reference of the Bragg Committee (in chapter
9); the British Standards Institution for extracts from BS 5975 :1982 (in
chapter 9) (complete copies can be obtained from BSI at Linford Wood,
Milton Keynes, MK14 6LE); British Rail; BSP International Founda-
tions Ltd; Building Employers Confederation; Liebherr-Great Britain
Ltd; Lilley Construction Ltd; London Regional Transport; National
Association of Scaffolding Contractors; D. Neal; Stent Foundations Ltd.
The author also wishes to express his gratitude to the following organ-
isations and individuals for permission to publish photographs, diagrams
and tables as individually acknowledged in the text: ACE Machinery
Ltd; Benford Ltd; British Insulated Callenders Cables; British Rail,
Eastern Region; BSP International Foundations Ltd; Building Advisory
Service and Building Employers Confederation; Cementation Piling and
Foundations Ltd; Coles Cranes Ltd; Department of the Environment
and Transport, Eastern Region; Howard Doris Ltd; Freeman Fox Ltd;
GKN Kwikform Ltd and Jayville Engineering Ltd; A. J. Goldsmith; Sir
William Halcrow & Partners; Highland Fabricators; John Howard and
Co. Ltd; ICI Agricultural Division; ICI Petrochemicals; Donald I.
Innes; Kwikform Ltd; John Laing Construction Ltd; Liebherr-Great
Britain Ltd; Lilley Construction Ltd; Sir Robert McAlpine & Sons Ltd;
Mechplant Ltd; J. Mustajew; Rapid Metal Developments Ltd; RDL-
Graham Joint Venture; Scaffolding (Great Britain) Ltd; Scaffolding
(Great Britain) Ltd, distributors of Krings Linings; Scanform, Denmark;
F. W. Schwing GmbH through their UK distributors Burlington Engi-
neers Ltd; G. W. Sparrow and Sons Ltd; Stelmo Ltd; Stent Foundations
Ltd; Successors to Acrow Engineers Ltd; Swift Plant Hire; Tarmac Con-
struction, National Contracts; Trollope and Colls Ltd; S. Wernick and
Sons Ltd; Wickham Engineering Ltd; George Wimpey pic; Wimpey
Laboratories Ltd.
Preface
Ask anyone in the construction industry what is meant by temporary
works and the chances are that the answer given will be something like,
'Oh! formwork and falsework; holding up excavations—that sort of
thing.' On further enquiry, mention may be made of crane tracks and
static bases. It is highly unlikely that any mention will be made of
scaffolding—yet scaffolding is the most commonly used item of tempor-
ary works in the construction field. So common, in fact, that it tends to
be taken for granted and is often not seen as temporary works at all.
Whether or not the above statements are true, many people in the
construction industry remain woefully ignorant about the scope of tem-
porary works, the important role they play in the construction process
and the significance of their cost as a component of the overall cost of a
project. Those who design have traditionally regarded temporary works
as no concern of theirs, and all the present forms of contract in use
reflect this view. It is only in recent years that temporary works have
been recognised, in some quarters at least, as an important part of con-
struction : making a significant contribution to the speed and efficiency of
construction, as well as the quality of the finished product.
It has been my view for many years that temporary works deserve a
better standing. As the structures being built have become more
complex, so the temporary works needed for their realisation have
needed greater skill from those responsible for their design and execu-
tion. At the same time, advances in permanent works design have often
only been possible if new ideas in temporary works could provide solu-
tions to their erection. Or, indeed, temporary and permanent works
could be combined into a single design-erect entity.
In today's world, therefore, temporary works can be seen as the inter-
face between design and construction. It is also not invalid to assert that,
at times, the design of temporary works can be more challenging than
that of the permanent works.
In writing this book my objectives have been threefold:
(a) to present temporary works as they deserve—as challenging and
worthwhile areas of the construction field—whether in relation to
their design or in solving the problems presented by the require-
ments of the permanent works; at all times emphasising the need
to be cost-conscious
viii PREFACE
(b) to fill significant gaps in relation to methods and provide ideas
and solutions in the less well known areas of temporary works
(c) to draw together all the parties involved in the construction
process, emphasising the major benefits that can arise from the
design-construct team working to achieve the most cost-
beneficial result, in overall terms.
To achieve my objectives has involved the assistance of many organis-
ations, companies and individuals. The willingness of such parties to
assist has been exceptional and I would like them to know how much I
appreciate the trouble they have gone to on my behalf. They are individ-
ually acknowledged elsewhere.
If I have been successful in giving temporary works a better status
then they have previously enjoyed, and communicated something of the
challenge and satisfaction that they have given me over many years, I
will feel that the effort has been very worthwhile.
J. R. Illingworth
London 1986
Contents
1 Introduction 1
2 Contractual, legal and code requirements 10
3 Cost and the construction team 19
4 The effect of the site and its boundaries 27
5 Plant-associated temporary works 44
6 Scaffolding 77
7 Support of excavations 103
8 Use of permanent works as temporary support
of excavations 137
9 Falsework 165
10 Formwork 195
11 Erection of structural frames 220
12 Miscellaneous temporary works 241
13 The site set-up 260
References and further reading 276
Index 281
1
Introduction
All construction, to a greater or lesser degree, will involve the need for
temporary works. While certain items of temporary works receive a
good deal of publicity (notably falsework when a spectacular collapse
occurs), the wide scope of temporary works is often not realised.
Temporary works can be defined as 'any temporary construction that
may be necessary to allow the permanent works to be carried out'. Such
temporary works will normally be removed from the site upon-com-
pletion of their usefulness. There are, however, circumstances where they
may be left behind as part of the permanent structure; permanent form-
work being a case in point.
From this definition, a moment's thought will recognise that the range
of activities included within the definition is very wide. Indeed, they
range from quite minor matters to structures of great complexity and
large scale, requiring great skill in their design and execution.
One of the simplest activities is the laying of sleepers to provide a
temporary crossing of a railway line or pavement, to establish access into
a construction site (Fig. 1.1). At the other end of the scale, perhaps the
most spectacular example is the design and construction of the flotation
collar for a North Sea oil jacket. With this method, the jacket is built on
its side, resting on the flotation collar and securely anchored to it. When
complete, the jacket is towed out to its resting place supported by the
flotation collar. On arrival at the desired location, the whole assembly is
made to turn to an upright position by systematic flooding of parts of
the structure. At the critical moment, when this operation is under way,
the jacket and the flotation collar are made to part company from each
other, by explosives. The collar is then towed back to the fabrication
yard and used again for the next jacket. Although this method of con-
struction is outmoded today, it is an excellent example of a highly
sophisticated type of temporary works. The need for the integration of
the design of such a structure with the structure that it will have to carry
is all too apparent. The sheer scale of the collar is well illustrated in Fig.
1.2. The length is some 200 m; the width at the widest end (carrying the
base of the jacket) is in the order of 75 m. The anchorage points for the
jacket members that will sit on the flotation collar are visible as circular
elements sitting on top of the collar. They are shown in detail in Fig. 1.3.
The arrangement whereby the split collar is locked on to the jacket unit
2 TEMPORARY WORKS
Fig. 1.1. Temporary sleeper crossing to railway line to provide access for
muck-shifting vehicles
Fig. 1.2. Flotation collar for Forties Field jacket (Highland Fabricators Ltd)
INTRODUCTION 3
Fig. 1.3. Flotation collar release mechanism (Highland Fabricators Ltd)
Fig. 1.4. Repetitive beam forms for ground beams
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