Supervision of Concrete Construction 1

218 Pages·1986·27.337 MB·\218

by  Dr J Richardson (Author)

Supervision
of
concrete
construction
..J. G. Richardson, MIWM MICT
1
C\.
Taylor & Francis
~ Taylor&FrancisGroup
LONDON AND NEW YORK
First published 1986
Volume I
12.088
ISBN: 0 86310 012 0
published by:
Taylor & Francis
2 Park Square, Milton Park,
Abingdon, Oxon, OX14 4RN
England
Transferred to Digital Printing 2006
© Palladian Publications Limited
Any recommendations made and opinions expressed in this book are the
authors', based on their own personal experience. No liability or re-
sponsibility of any kind (including liability for negligence) is accepted by
the Publisher, its servants or agents.
Printed and bound by Antony Rowe Ltd, Eastbourne
Contents
Volume 1
lll Foreword 42 Admixtures
42 Pfa (fly-ash)
lll Author's note 45 Steel reinforcement
45 Bond strength
1. Introduction 45 Cover to reinforcement
47 Corrosion
3 2. Drawings and documentation 47 Carbonation
3 Specification 47 Structural mechanics
4 Bills of Quantities 50 Compression and tension
7 Drawings and schedules 51 Prestressed concrete
8 Steel reinforcement details and schedules 51 Concrete for prestressing
8 Drawings and details prepared by the contractor 52 Fire resistance ofp restressed and reinforced
10 Checklist concrete
53 Lightweight concrete
11 3. Planning the construction process 54 Air-entrained concrete
12 Graphs
12 Histograms 55 6. Supervisory skills
12 Bar charts 55 The role of the supervisor within the construction
12 Precedence diagrams industry
14 Networks 60 Training for the supervisor
16 Line of balance 60 The supervisor and his colleagues in supervision
17 Planning procedures for a small concreting 61 Development of sup_ervisory skills
operation 62 Checklist
20 Planning for pumping operations
20 Site layout 63 7. The prime mix method of mix design by
21 Precast site or works layout P.L. Owens
23 Location ofs tores and services 63 Introduction
24 Planning for the use of cranes 63 The process ofm ix design
25 Checklist 63 Materials
65 Mix composition
27 4. Safety and health in the construction industry 65 Objectives of mix proportioning
27 Common Law rights 65 Aggregates
27 Statute Law 70 Workability
28 Defining an accident 72 Compressive strength
28 Action in the event of an accident 72 The prime mix method
28 The problems facing supervision 73 Examples
30 Hazards in construction 80 Quality control and mix design
33 Avoiding hazards in construction 82 Routine testing of materials
33 The Health and Safety Inspector 83 Routine testing of concrete
34 Checklist 84 Control of the mix proportions by tests
85 Adjustment of the mix
35 5. Reinforced concrete 85 Conclusion
35 Concrete 85 Appendix: Workability and cohesion
36 Thermal movements
36 Strain 87 8. Accuracy in construction
36 Creep and drying shrinkage 87 Achieving the required accuracy
39 Swelling and plastic shrinkage 96 Checklist
39 Heat ofh ydration
40 Durability 97 9. Joints
41 Cracking 97 Construction joints
42 Maturity of concrete 100 Joints between precast concrete elements
106 Points ofs upervision 158 Loading
106 Checklist 158 Supports
159 Checking
107 10. The concrete construction process 161 Propping andre-propping
107 Working conditions 162 Quickstrip systems
107 Preliminaries 164 Checklist
109 Setting out
109 Excavation 165 13. Formwork
112 Blinding 166 Preparing a formwork scheme
114 Ground beams and pile caps 168 Alternative methods ofc onstruction
115 Setting up forms on blinding 17 0 Pressures on formwork
115 Slab casting operations 171 Striking formwork
119 Walling-sequence of operations 171 Reference material
125 Single sided wall construction 171 Traditional form work
125 Column casting 172 Proprietary formwork
126 Beam construction 173 Purchase or hire
129 Floor casting-suspended floors 173 Main proprietary items off orm work
130 Table forms in slab construction 177 System formwork for slabs
130 Domes, barrels and geometrical work 177 Ties
131 Spandril walls 181 Special formwork
133 Access ramps 181 Other form materials
133 Stair construction 185 Circular work
135 Bin and hopper construction 186 Checklist
136 Culvert, tunnel and shaft construction 187 Points ofs upervision
136 Supervising the construction process
138 Checklist 189 14. Surface finish
189 Specification covering surface finish
191 Supervising the surface finish of concrete
139 11. Groundwork by R. Wilson
202 The consideration ofd etail in production of visual
139 Footings and foundations
concrete
147 Piling
205 Precast surfaces
151 Diaphragm wall construction
206 Visual concrete using tooling to texture the surface
156 Points ofs upervision
or expose the aggregate
207 Abrasive blasting
157 12. Falsework and temporary works 208 Efflorescence and lime bloom
157 Definition 209 Points ofs upervision
157 Statutory requirements
157 The falsework co-ordinator 210 Bibliography-Volume 1
11
Author's note Foreword
Of necessity, a publication such as Supervision ofC oncrete To the onlooker, concrete construction must appear to be
Construction, takes some years to prepare. Where the a haphazard and somewhat hazardous process, indeed for
reader requires to refer to a specific British Standard or many years this was the case. In today's construction
Code of Practice, it is advisable to check the status of such industry, however, with all the pressures of time and
information with the BSI Catalogue-an annual publica- responsibilities, it is essential that the process should be
tion, or by telephoning the British Standards Institution. carried out in a logical, economic and workmanlike
The author is indebted to the British Standards Institu- manner. Much of the pressure devolves upon the super-
tion for permision to reproduce those parts of Codes used visor, be he section engineer, general foreman, clerk of
in this publication. works or trades foreman, and it is with these people in
mind that the present work has been prepared. The
coverage is such that all the activities of supervision are
considered and a vocabulary established to enable the
supervisor intelligently to deal with matters outside his
normal discipline.
The.extent of the detail has determined the length of the
work and necessitated publication of the book in two
volumes. The author wishes to thank the staff of Palladian
Publications Limited and in particular Mandi J Forrest-
Holden for all the assistance received in the preparation
of the book.
J G Richardson
Apri11986
111

1. Introduction
The author, John Richardson, has written this book with in the course of training events at Fulmer Grange, and in
the intention of providing useful and informative material companies within the United Kingdom and overseas. The
for the supervisor in the construction industry who needs practices described are, in many instances, based on
to "know about concrete". Like John's other books in the traditional construction techniques. There is some men-
VIEWPOINT PUBLICATIONS series, Precast concrete tion of continually developing technology of concrete.
production and Formwork construction and practice, this Space is also devoted to statistics and, for those whose
book is intended as a practical guide for the man who schooling has been left far behind, there is some basic
must take charge of and be responsible for a particular mathematics (calculator batteries do sometimes fail!).
part of the construction task, in this instance, construc- The author has concentrated on those aspects of
tion using concrete. concrete construction where he has the most to offer,
This book is not intended as a textbook or reference where in his own experience he met with certain difficul-
work, and equally is not intended as a do-it-yourself ties and where points arise which may be of assistance to
instruction manual. It is intended as an introduction to a others in the same situation. Most chapters are accompa-
number of facets of concrete construction with which the nied by a summary of key points and/or a checklist for the
supervisor will become involved when he undertakes supervisor.
decision-making in the planning and execution of con- The whole, it is hoped, will provide a basic, easy to
crete work. Where possible, the use of figures and follow discussion of concrete construction, and the
calculations has been avoided, except where essential to control of concrete operations with sufficient technical
the supervisor. The book sets down general principles of and technological background to set these activities into
construction methods and outlines proven techniques. perspective. Armed with the book, the supervisor who
The material contained herein is based upon information comes into concrete from a trades background, from the
gathered during the course of more than 30 years drawing office, the services or any other of the diverse
involvement within the concrete construction industry. routes by which supervisors do develop, will have what is
The author has worked as an army engineer, a draughts- virtually a ready-reckoner, an "aide-memoire" to which
man, formwork designer/supervisor, concrete supervisor he can turn for assistance when in need. It is the author's
and construction manager and latterly as a lecturer on hope too, that the book will prove helpful to those
construction topics with the Cement and Concrete students who, having completed the City and Guilds of
Association. At the Training and Conference Centre of London Institute Course Concrete Practice are studying
the Cement and Concrete Association, John organises for their Certificates in Concrete Technology and Con-
courses on various aspects of formwork and precast struction, General Principles and Practical Applications.
concrete. Here it has been borne in mind that the student often
Practical material discussed in this publication results comes from some specialist employment yet must gain a
from the author's involvement with tradesmen and general knowledge of construction principles.
operatives as well as professional engineers and architects On reading the book, the reader may become aware of
in the construction of structures including chimneys, different styles of writing from various other writers,
shafts, dams, silos, multi-storey construction and civil specialists in their own particular fields, who have been
engineering works. The technical information on con- invited to contribute towards this publication. The author
crete has been largely derived during the author's employ wishes to thank his colleagues at the Cement and
with the Cement and Concrete Association and contact Concrete Association for help and advice so freely given,
with lecturers and research personnel. John gratefully in particular Mr Chris Harris and Mr Bob Wilson.
acknowledges the continuous input of ideas and informa- Mention must also be made of those chapters in the book
tion which he receives from the 3000 or more people, written by Mr R Lavery, Mr Philip Owens, Mr Geo S
craftsmen, students, technicians and professionals such as Richardson, Mr D Wilshere and Mr Bob Wilson, who
architects and engineers, with whom he works each year have contributed on specialist topics.

2. Drawings and documentation
The supervisor commencing control of concrete construc- Where the specification is set down in performance terms,
tion, whether as a senior person in charge of the main then only the outcome in terms of appearance, accuracy
construction or as a section supervisor responsible only and other physical properties will be noted.
for the activities relating to the concrete element (steel The following commentary on requirements of typical
reinforcement, formwork and concrete handling, place- clauses from a standard specification is intended for the
ment, compaction and curing), must be conversant with guidance of the concrete supervisor in preparing and
the detail, specification and commercial considerations organising his approach to the concreting operation:
governing that part of the contract. All information
received, including drawing and detail, schedules for steel
Points covered in
reinforcement and inclusions such as fixings, specification
Specification
and construction programme, must be recorded and,
clause Points ofs upervision
whilst this will probably be carried out as part of the
Schedule of Ensure that requirements are clearly
overall contract procedure, the supervisor would be well
finishes; means understood-know where samples
advised to keep his own local records, entries in a diary for
of achieving are and how samples were
instance, in much the same way as would a Clerk of
finishes; prepared.
Works. Such records are of immense value throughout
provision of Check drawings to ensure that the
the course of operations right up to the stage of preparing
samples finishes for each part of the job are
final accounts.
clearly indicated.
Inspect samples and consider any
Specification particular problems arising such as
maintenance of consistency, access
for tooling, and timing of
The supervisor must make himself conversant with local
operations.
specifications and take time to study the various refer-
ences made in the local specification to British Standards View priced samples if not on
current contract. Study publications
Institution Codes of Practice and Specifications. Much
has been written on the topic of specifications and, in giving recommendations on
achieving finishes.
recent years, specifications have improved considerably.
In the past, specifications were other than specific to a Make any samples called for by
particular task and were written using a jargon which, on contract, ensuring that these are
examination, proved to be irrelevant, uninformative and, representative of attainable
in some instances, misleading. Phrases such as "all true to standards.
line and level" and "of the best quality" are quite Accuracy The supervisor should familiarise
meaningless and can lead to argument and upset. Today, clauses himself with the specific
specifications generally establish acceptable quality in requirements for the contract and
terms of British Standard requirements or in terms of ensure necessary arrangements are
locally established standards exhibited in site examples, made in form construction to avoid
trial panels and the like. Attempts to improve a specifica- abrupt irregularities, ensure
tion have resulted in various degrees of success. In terms continuity of line, the location of
of the attribute of external appearance, it is current building elements within the limits
practice to nominate existing samples or to set aside of the permissible deviations
money within the Bill of Quantities for the provision of regarding level and plumb, and the
sample panels of sufficient size to allow the establishment control of sheathing joints and
of what is an acceptable standard. construction joints to avoid lips,
With regard to the specification governing concrete, the fins and dislocation due to
supervisor will be concerned with the problems of deflections.
achieving not only quantity of concrete output, but also Construction Check that formwork system and
with the maintenance of quality and accuracy. The joint location specified joint locations are
specification may, in the case of method-type presen- relative to compatible and the locations allow
tation, set down in detail the steps to be carried out in length and areas gainful work for all trades. Discuss
form preparation, casting of concrete, curing and so on. of concrete in detail with engineers.
3