STEEL DETAILERS' MANUAL ALAN HAYWARD CEng, FICE, FIStructE, MIHT
and FRANK WEARE CEng, MSc(Eng), DIC, DMS, FIStructE, MICE, MIHT, MBIM
Second Edition revised by ANTHONY OAKHILL BSc, CEng, MICE
b
Blackwell Science
STEEL DETAILERS' MANUAL
STEEL DETAILERS' MANUAL ALAN HAYWARD CEng, FICE, FIStructE, MIHT
and FRANK WEARE CEng, MSc(Eng), DIC, DMS, FIStructE, MICE, MIHT, MBIM
Second Edition revised by ANTHONY OAKHILL BSc, CEng, MICE
b
Blackwell Science
# Alan Hayward and Frank Weare 1989 (First Edition) # Alan Hayward, Frank Weare and Blackwell Science 2002 (Second Edition) Blackwell Science Ltd Editorial Offices: Osney Mead, Oxford OX2 0EL 25 John Street, London WC1N 2BS 23 Ainslie Place, Edinburgh EH3 6AJ 350 Main Street, Malden MA 02148 5018, USA 54 University Street, Carlton Victoria 3053, Australia 10, rue Casimir Delavigne 75006 Paris, France Other Editorial Offices: Blackwell Wissenschafts-Verlag GmbH Kurfu Èrstendamm 57 10707 Berlin, Germany Blackwell Science KK MG Kodenmacho Building 7Ð10 Kodenmacho Nihombashi Chuo-ku, Tokyo 104, Japan Iowa State University Press A Blackwell Science Company 2121 S. State Avenue Ames, Iowa 50014-8300, USA
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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, except as permitted by the UK Copyright, Designs and Patents Act 1988, without the prior permission of the publisher.
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Diagrams and details presented in this manual were prepared by structural draughtsmen employed in the offices of Cass Hayward and Partners, Consulting Engineers of Chepstow (Monmouthshire, UK), who are regularly employed in the detailing of structural steelwork for a variety of clients including public utilities, major design : build contractors and structural steel fabricators. Care has been taken to ensure that all data and information contained herein is accurate to the extent that it relates to either matters of fact or opinion at the time of publication. However neither the authors nor the publishers assume responsibility for any errors, misinterpretation of such data and information, or any loss or damage related to its use.
Contents
List of Figures
vII
List of Tables
viii
2
Foreword by the Director General of the British Constructional Steelwork Association Preface to the First Edition Preface to the Second Edition 1
ix x xi
Detailing Practice
35
2.1
General
35
2.2
Layout of drawings
35
2.3
Lettering
35
2.4
Dimensions
35
2.5
Projection
35
2.6
Scales
36
2.7
Revisions
36
2.8
Beam and column detailing conventions
36
Use of Structural Steel
1
2.9
Erection marks
37
1.1
Why steel?
1
2.10
Opposite handing
38
1.2
Structural steels
2
2.11
Welds
38
1.2.1
Requirements
2
2.12
Bolts
38
1.2.2
Recommended grades
3
2.13
Holding down bolts
38
1.2.3
Weather resistant steels
4
2.14
Abbreviations
38
1.3
Structural shapes
1.4
Tolerances
10
1.4.1
10
3.1
General
40
3.2
Load capacities of simple connections
40
12
3.3
Sizes and load capacity of simple column
1.4.2
General
6
Worked examples Ð welding distortion for plate girder
1.5
Connections
15
1.6
Interface to foundations
16
1.7
Welding
18
1.8
Design Guidance
bases
40
41
4
Detailing Data
51
5
Connection Details
83
1.7.1
Weld types
18
1.7.2
Processes
18
1.7.3
Weld size
19
Computer Aided Detailing
94
1.7.4
Choice of weld types
19
6.1
Introduction
94
1.7.5
Lamellar tearing
20
6.2
Steelwork detailing
94
20
6.3
Constructing a 3-D model of a steel structure
96
6.4
Object orientation
98
6.5
Future developments
98
Bolting 1.8.1
General
1.8.2
High strength friction grip (HSFG) bolts
1.9
3
6
20 22
Dos and don'ts
23
1.10 Protective treatment
23
1.11 Drawings
32
7
Examples of Structures
100
7.1
100
Multi-storey frame buildings 7.1.1
Fire resistance
100
1.11.1
Engineer's drawings
32
1.11.2
Workshop drawings
32
7.2
Single-storey frame buildings
104
1.11.3
Computer aided detailing
1.12 Codes of practice
32
7.3
Portal frame buildings
105
32
7.4
Vessel support structure
108
1.12.1
Buildings
33
7.5
Roof over reservoir
112
1.12.2
Bridges
33
7.6
Tower
115
vi
CONTENTS
7.7
Bridges
119
7.8
Single-span highway bridge
126
7.9
Highway sign gantry
133
7.10
Staircase
138
References
140
Further Reading
142
Appendix
145
Index
165
List of Figures
1.1
Principles of composite construction
2
4.1
Stairs, ladders and walkways
74Ð75
1.2
Stress : strain curves for structural steels
3
4.2
Highway and railway clearances
76Ð77
1.3
Corrosion rates of unpainted steel
5
4.3
Maximum transport sizes
1.4
Rolled section sizes
6
4.4
Weld symbols
1.5
Twisting of angles and channels
7
4.5
Typical weld preparations
1.6
Structural shapes
1.7
Welding distortion
11
5.1
Typical beam/column connections
1.8
Tolerances
13
5.2
Typical beam/beam connections
84
1.9
Welding distortion Ð worked example
14
5.3
Typical column top and splice detail
85
1.10
Flange cusping
14
5.4
Typical beam splices and column bases
86
1.11
Extra fabrication precamber
14
5.5
Typical bracing details
87
1.12
Bottom flange site weld
14
5.6
Typical hollow section connections
88
1.13
Web site weld
15
5.7
Typical truss details
89
1.14
Functions of connections
15
5.8
Workshop drawing of lattice girder Ð 1
90
1.15
Typical moment : rotation behaviour of beam/column connections
77 78 79Ð80
8Ð9 83
5.9
Workshop drawing of lattice girder Ð 2
91
16
5.10
Typical steel/timber connections
92
5.11
Typical steel/precast concrete
1.16
Continuous and simple connections
16
1.17
Locations of site connections
16
1.18
Connections in hot rolled and hollow sections
17
1.19
Connections to foundations
17
1.20
Butt welds showing double V preparations
18
1.21
Fillet welds
18
1.22
Sequence of fabrication
19
7.1 Ð7.6
Multi-storey frame buildings
101Ð103
1.23
Welding using lapped joints
20
7.7 Ð7.8
Single-storey frame buildings
104Ð105
1.24
Lamellar tearing
20
7.9 Ð7.10
Portal frame buildings
106Ð108
1.25
Black bolts and HSFG bolts
21
7.11Ð7.14
Vessel support structure
109Ð112
1.26
Use of `Coronet' load indicator
23
7.15Ð7.16
Roof over reservoir
113Ð114
1.27
Dos and don'ts
24
7.17Ð7.19
Tower
115Ð118
1.28
Dos and don'ts
26Ð27
7.20Ð7.24
Bridges
120Ð125
1.29
Dos and don'ts Ð corrosion
28Ð29
7.25Ð7.30
Single span highway bridge
127Ð132
7.31Ð7.33
Highway sign gantry
133Ð137
2.1
Drawing sheets and marking system
36
7.34Ð7.35
Staircase
138Ð139
2.2
Dimensioning and conventions
37
3.1
Simple connections
43
3.2
Simple column bases
47
connections
93
6.1
The central role of the 3-D modelling system
95
6.2
Typical standard steelwork connection library
97
List of Tables
1
3.2
Simple connections, bolts grade 8.8, members
leading properties
4
3.3
Simple connections, bolts grade 8.8, members
1.3
Main use of steel grades
4
grade S355
45
1.4
Guidance on steel grades in BS 5950 Ð 1 : 2000
3.4
Simple column bases
46
3.5
Black bolt capacities
48
3.6
HSFG bolt capacities
49
5
3.7
Weld capacities
50
7
4.1
Dimensions of black bolts
52
1.1
Advantages of structural steel
1.2
Steels to EN material standards Ð summary of
Ð design strengths 1.5
5
Guidance on steel grades in BS 5950 Ð 1 : 2000 Ð maximum thicknesses
1.6
grade S275
44
Sections curved about major axis Ð typical radii
1.7
Dimensional variations and detailing practice
12
4.2
Dimensions of HSFG bolts
1.8
Common weld processes
19
4.3
Universal beams Ð to BS 4-1: 1993
1.9
Bolts used in UK
22
4.4
Universal columns
57
1.10
Typical cost proportion of steel structures
23
4.5
Joists
58
1.11
National standards for grit blasting
25
4.6
Channels
4.7
Rolled steel angles
4.8
Square hollow sections
63
4.9
Rectangular hollow sections
64
1.12a Typical protective treatment systems for building structures
30
1.12b Summary table of Highways Agency painting
59 60±61
4.10 Circular hollow sections
65Ð66
8th edition (1998)
31
4.11 Metric bulb flats
67Ð68
BS 5950 Load factors gf and combinations
33
4.12 Crane rails
specifications for Highway Works Series 1900 Ð 1.13
53 54Ð55
68
4.13 Face clearances pitch and edge distance 2.1
Drawing sheet sizes
35
2.2
List of abbreviations
39
3.1
Simple connections, bolts grade 4.6, members
for bolts 4.14 Durbar floor plate 4.15 Plates supplied in the `normalised' condition
grade S275
71 72Ð73 81
4.16 Plates supplied in the `normalised rolled' 42
condition
82
Foreword BY THE DIRECTOR GENERAL OF THE BRITISH CONSTRUCTIONAL STEELWORK ASSOCIATION
The first volume of Steel Detailers' Manual by Alan Hay-
edition has attempted to cover the significant changes
ward and Frank Weare was published in 1989. It was written
brought about by these new requirements. Much of the
as an education tool and to advance the knowledge of all
discrete data is available elsewhere, but the Authors have
those who may become involved with steel in construction
drawn the detailing information together and provided it in
by giving guidance on, what was then, a much neglected
one volume.
aspect Ð that of detailing. The Authors rightly recognised that the viability and feasibility of steel structures relies on
The use of structural steel for building frames has continued
practical details which allow economical fabrication and
to show dramatic gains in market share compared with other
safe erection.
materials during the past 10Ð15 years. Clients, purchasers, designers and architects alike have recognised the distinct
This second edition is necessitated, as explained by the
advantages of using steel as the primary structure. The
Authors in the Preface, by the extensive developments in
ability of steel to achieve a rapidly executed secure frame-
steel construction which have taken place over the last
work with flexibility for future use continues to be a prin-
decade, and by developments in the UK and European
cipal benefit. Coupled with the important developments in
fabrication industry including the use of fully automated
computer aided design and detailing, steel now has the
techniques and processes.
added advantage that all parties in the construction process can provide assured input to the development of the
The aim of the first edition has been continued, which is to
structure, thereby producing substantial cost savings and
give the steelwork designer and detailer such information
the achievement of an efficient and safe building.
as is required to generate a complete and sufficient structure that can be manufactured and constructed effi-
The Authors have faced a difficult task in carrying out these
ciently and economically, and that will operate satisfac-
revisions but have successfully communicated in this book
torily for its entire design life. For example, the importance
the important features of effective and practical detailing
of appreciating and accommodating tolerances so as to
of steel structures.
avoid unnecessary site rectification is addressed. The examples of `do's and don'ts' are also a useful way of
Derek Tordoff
informing detailers of pitfalls that cause problems and
Director General
delays. Revised UK standards and new European codes on
British Constructional Steelwork Association
materials, design and construction have important implications for design, detailing, and fabrication. This second
May 2001
Preface to the First Edition
The purpose of this manual is to provide an introduction and
underlying the structure they are detailing. Equally the
guide to draughtsmen, draughtswomen, technicians,
authors are concerned that the designer should fully
structural engineers, architects and contractors in the
appreciate details and their practical needs which may
detailing of structural steel. It will also provide a textbook
dictate design assumptions.
for students of structural engineering, civil engineering and architecture. In addition, it will advise staff from any discipline who are involved in the fabrication and erection of steelwork, since the standards shown on the detailer's drawings have such a vital influence on the viability of the product and therefore the cost of the overall contract.
Examples of structures include single- and multi-storey buildings, towers and bridges. Some of these are taken from actual projects, and although mainly designed to UK Codes, will provide a suitable basis for similar structures built elsewhere. This is because the practices used for steelwork design, fabrication and erection are comparable in many
Detailing is introduced by describing common structural
countries of the world. Although variations will arise
shapes in use and how these are joined to form members and
depending upon available steel grades, sizes, fabrication
complete structures. The importance of tolerances is
and erection plant, nevertheless methods generally
emphasised and how these are incorporated into details so
established are adaptable, this being one of the attributes of
that the ruling dimensions are used and proper site fit-up is
the material. The examples show members' sizes as actually
achieved. The vital role of good detailing in influencing
used but it is emphasised that these might not always be
construction costs is described. Detailing practice and
suitable in a particular case, or under different Codes of
conventions are given with the intent of achieving clear and
Practice. Sizes shown however provide a good guide to the
unambiguous instructions to workshop staff. The authors'
likely proportions and can act as an aid to preliminary design.
experience is that, even where quite minor errors occur at
Generally the detailing shown will be suitable in principle for
workshop floor or at site, the cost and time spent in rec-
fabrication and erection in many countries. Particular
tification can have serious repercussions on a project. Some
steelwork fabricators have their own manufacturing tech-
errors will, of course, be attributable to reasons other than
niques or equipment, and it should be appreciated that
the details shown in drawings, but many are often due to lack
details might need to be varied in a particular case.
of clarity and to ambiguities in detailing, rather than actual mistakes. The authors' view is that the role of detailing is a vital part of the design : construction process which affects the success of steel structures more than any other factor. In writing this manual the authors have therefore striven to present the best standards of detailing allied to economic requirements and modern fabrication processes. The concept of engineer's drawings and workshop drawings is described and the purpose of each explained in obtaining quotations, providing the engineer's requirements, and in fabricating the individual members. Detailing data and practice are given for standard sections, bolts and welds. Protective treatment is briefly described with typical systems tabled. Examples are given of arrangement and detail drawings of typical structures, together with brief
The authors acknowledge the advice and help given to them in the preparation of this manual by their many friends and colleagues in construction. In particular, thanks are due to the British Steel Corporation [now Corus], the British Constructional Steelwork Association and the Steel Construction Institute who gave permission for use of data. Alan Hayward Cass Hayward & Partners Consulting Engineers York House, Welsh Street Chepstow, Monmouthshire NP16 5UW Frank Weare Polytechnic of Central London 35 Marylebone Road
descriptions of the particular design features. It is impor-
London NW1 5LS
tant that draughtsmen appreciate the design philosophies
May 1988
Preface to the Second Edition
It is more than a decade since this manual was first pub-
described. A complete description of all steelwork, bolts,
lished. Its purpose now, as then, remains unchanged,
welds, etc. which constitute all or part of a steel structure
namely to provide an introduction and guide to those in the
are contained in these 3-D models. The transfer of 3-D steel
constructional steelwork industry who are likely to be
information between different systems, often in different
involved with the principles concerning the detailing of
offices and between different companies, has transformed
structural steel.
the way of working in recent years.
In the UK and overseas, steelwork continues to maintain a
Codes of practice and engineering standards are constantly
high profile as the optimum choice for structural projects.
changing in the construction industry. Many British stan-
To mark the new millennium much additional construction
dards are now being superseded by European EN standards,
work has been undertaken worldwide. Clients, engineers
but many are still in the transition stage. The manual
and construction companies have turned to steel to provide
attempts to clarify the present situation. It is however
the exciting and stimulating structures which now adorn
recognised that this is a constantly changing target, and the
the landscape, whether located in a city centre or in a rural
reader is advised to consult British Standards or any other
setting.
recognised professional steelwork organisation to determine the latest information. It is to be hoped that future
In order to remain competitive, steelwork contractors have
editions of the manual will contain lists of more firmly
turned to new technologies in order to minimise their costs
established relevant European standards.
and meet the tighter deadlines which are being imposed by clients. To a very large extent the technological develop-
The authors acknowledge the advice and help given to them
ments associated with computer aided detailing have
in the preparation of this manual by their many friends and
played a major part in bringing profound improvements
colleagues in construction. In particular thanks are due to
across the industry. The art of steelwork detailing con-
the Corus Construction Centre, the British Constructional
tinues to play a pivotal role in the successful creation of any
Steelwork Association and the Steel Construction Institute
steel structure. New methods and procedures have given
who gave permission for use of data.
rise to a process which is now highly integrated and dependent upon both upstream and downstream activities. This manual now includes a new chapter on Computer Aided Detailing. This chapter describes the background developments which have enabled computer draughting systems to achieve the success currently enjoyed. The principles of steelwork detailing, using computers, are briefly explained and the concepts of both 2-D and 3-D graphical systems are
Anthony Oakhill
1
Use of Structural Steel
1.1 Why steel?
account intended sequences of construction and erection. Compared with other media, structural steel has attributes
Structural steel has distinct capabilities compared with
as given in Table 1.1.
other construction materials such as reinforced concrete, prestressed concrete, timber and brickwork. In most
In many projects the steel frame can be fabricated while
structures it is used in combination with other materials,
the site construction of foundations is being carried out.
the attributes of each combining to form the whole. For
Steel is also very suitable for phased construction which is
example, a factory building will usually be steel framed
a necessity on complex projects. This will often lead to a
with foundations, ground and suspended floors of
shorter construction period and an earlier completion
reinforced concrete. Wall cladding might be of brickwork
date.
with the roof clad with profiled steel or asbestos cement sheeting. Stability of the whole building usually relies upon
Steel is the most versatile of the traditional construction
the steel frame, sometimes aided by inherent stiffness of
materials and the most reliable in terms of consistent
floors and cladding. The structural design and detailing of
quality. By its very nature it is also the strongest and may be
the building must consider this carefully and take into
used to span long distances with a relatively low self
Table 1.1 Advantages of structural steel. Feature
Leading to
Advantage in buildings
in bridges
1. Speed of construction
Quick erection to full height of self supporting skeleton
Can be occupied sooner
Less disruption to public
2. Adaptability
Future extension
Flexible planning for future
Ability to upgrade for heavier loads
3. Low construction depth
Reduced height of structure
Cheaper heating Reduced environmental effect
Cheaper earthworks Slender appearance
4. Long spans
Fewer columns
Flexible occupancy
Cheaper foundations
5. Permanent slab formwork
Falsework eliminated
Finishes start sooner
Less disruption to public
6. Low weight of structure
Fewer piles and size of foundations Typical 50% weight reduction over concrete
Cheaper foundations and site costs
7. Prefabrication in workshop
Quality control in good conditions avoiding sites affected by weather
More reliable product Fewer specialist site operatives needed
8. Predictable maintenance costs
Commuted maintenance costs can be calculated. If repainting is made easy by good design, no other maintenance is necessary
Total life cost known Choice of colour
9. Lightweight units for erection
Erection by smaller cranes
10. Options for site joint locations
Easy to form assemblies from small components taken to remote sites
Reduced site costs Flexible construction planning
2
STEEL DETAILERS' MANUAL
weight. Using modern techniques for corrosion protection the use of steel provides structures having a long reliable
D
life, and allied with use of fewer internal columns achieves flexibility for future occupancies. Eventually when the
(a) stacked plates horizontal
useful life of the structure is over, the steelwork may be dismantled and realise a significant residual value not
deflection is only 1/25 that of (a)
achieved with alternative materials. There are also many cases where steel frames have been used again, re-erected elsewhere.
D
Structural steel can, in the form of composite construc-
(b) stacked plates vertical
tion, co-operate with concrete to form members which exploit the advantages of both materials. The most
slip
compression
frequent application is building floors or bridge decks where steel beams support and act compositely with a concrete slab via shear connectors attached to the top flange. The compressive capability of concrete is exploited to act as part of the beam upper flange, ten(c) non-composite beam and slab
sion being resisted by the lower steel flange and web. This results in smaller deflections than those to be
shear connectors prevent relative slip or uplift
expected for non-composite members of similar crosssectional dimensions. Economy results because of best use of the two materials Ð concrete which is effective in compression Ð and steel which is fully efficient when under tension. The principles of composite construction for beams are illustrated in figure 1.1 where the concept of stacked plates shown in (a) and (b) illustrates that much greater deflections occur when the plates are horizontal and slip between them can occur due to bending action. In composite construction relative slip is prevented by shear connectors which resist the horizontal shear created and which prevent any tendency of the slab to lift off the beam.
strain at mid-span
smaller beam used (d) composite beam and slab Figure 1.1 Principles of composite construction.
1.2 Structural steels 1.2.1 Requirements Steel for structural use is normally hot rolled from billets in
Structural steel is a material having very wide capabilities
the form of flat plate or section at a rolling mill by the steel
and is compatible with and can be joined to most other
producer, and then delivered to a steel fabricator's work-
materials including plain concrete, reinforced or pre-
shop where components are manufactured to precise form
stressed
and
with connections for joining them together at site.
earthenware. Its co-efficient of thermal expansion is vir-
Frequently used sizes and grades are also supplied by the
tually identical with that of concrete so that differential
mills to steel stockholders from whom fabricators may
movements from changes in temperature are not a serious
conveniently purchase material at short notice, but often
consideration when these materials are combined. Steel is
at higher cost. Fabrication involves operations of sawing,
often in competition with other materials, particularly
shearing, punching, grinding, bending, drilling and welding
structural concrete. For some projects different con-
to the steel so that it must be suitable for undergoing these
tractors often compete to build the structural frame in
processes without detriment to its required properties. It
steel or concrete to maximise use of their own particular
must possess reliable and predictable strength so that
skills and resources. This is healthy as a means of main-
structures may be safely designed to carry the specified
taining reasonable construction costs. Steel though is able
loads. The cost : strength ratio must be as low as possible
to contribute effectively in almost any structural project to
consistent with these requirements to achieve economy.
a significant extent.
Structural steel must possess sufficient ductility so as to
concrete,
brickwork,
timber,
plastics
3
USE OF STRUCTURAL STEEL
give warning (by visible deflection) before collapse condi-
The stress raiser can be caused by an abrupt change in cross
tions are reached in any structure which becomes unin-
section, a weld discontinuity, or a rolled-in defect within
tentionally loaded beyond its design capacity and to allow
the steel. Brittle fracture can be overcome by specifying a
use of fabrication processes such as cold bending. The
steel with known `notch ductility' properties usually iden-
ductility of structural steel is a particular attribute which is
tified by the `Charpy V-notch' impact test, measured in
exploited where the `plastic' design method is used for
terms of energy in joules at the minimum temperature
continuous (or statically indeterminate) structures in which
specified for the project location.
significant deformation of the structure is implicit at factored loading. Provided that restraint against buckling is
These requirements mean that structural steels need to
ensured this enables a structure to carry greater predicted
be weldable low carbon type. In many countries a choice
loadings compared with the `elastic' approach (which
of mild steel or high strength steel grades are available
limits the maximum capacity to when yield stress is first
with comparable properties. In the UK as in the rest of
reached at the most highly stressed fibre). The greater
Europe structural steel is now obtained to EN 100251
capacity is achieved by redistribution of forces and stress in
(which, with other steel Euronorm standards, has
a continuous structure, and by the contribution of the
replaced BS 4360). Mild steel grades, previously 43A, 43B,
entire cross section at yield stress to resist the applied
etc., are now generally designated S275. High tensile
bending. Ductility may be defined as the ability of the
steel grades, previously 50A, 50B, etc. are now generally
material to elongate (or strain) when stressed beyond its
referred to as S355. The grades are further designated by
yield limit shown as the strain plateau in figure 1.2. Two
a series of letters (e.g. S275JR, S355JO) which denotes
measures of ductility are the `elongation' (or total strain at
the requirements for Charpy V-notch impact testing.
fracture) and the ratio of ultimate strength to yield
There is no requirement for impact testing for those
strength. For structural steels these values should be at
grades which contain no letter. For other grades a dif-
least 18 per cent and 1.2 respectively.
ferent set of letters denotes an increased requirement (i.e. tested at a lower temperature). The main properties
stress N/mm2
for the most commonly used grades are summarised in Table 1.2.
specified minimum elongation strain plateau slope = stress = E (modulus of elasticity) strain ultimate strength de S355 eel gra t s X h ngt stre 275 S h g e i d h X l gra stee d l i m
500 yield
1.2.2 Recommended grades In general it is economic to use high strength steel grade S355 due to its favourable cost : strength ratio compared with mild steel grade S275 typically showing a 20% advan-
linear
tage. Where deflection limitations dictate a larger member size (such as in crane girders) then it is more economic to use mild steel grade S275 which is also convenient for very small projects or where the weight in a particular size is 0
5
10 15 strain or elongation %
20
less than, say 5 tonnes, giving choice in obtaining material from a stockholder at short notice.
Figure 1.2 Stress : strain curves for structural steels.
Accepted practice is to substitute a higher grade in case of For external structures in cold environments (i.e. typi-
non-availability of a particular steel, but in such cases it is
cally in countries where temperatures less than about 08C
important to show the actual grade used on workshop
are experienced) then the phenomenon of brittle frac-
drawings because different weld procedures may be
ture must be guarded against. Brittle fracture will only
necessary. Grades S420 and S460 offer a higher yield
occur if the following three situations are realised simul-
strength than grade S355, but they have not been widely
taneously:
used except for crane jibs and large bridge structures. Table 1.3 shows typical use of steel grades and guidance is
(1)
A high tensile stress.
given in Tables 1.4 and 1.5, the requirements for maximum
(2)
Low temperature.
thickness being based upon BS 5950 for buildings.2 BS 5400
(3)
A notch-like defect or other `stress raiser' exists.
for bridges3 has similar requirements.
4
STEEL DETAILERS' MANUAL
Table 1.2 Steels to EN material standards ± summary of leading properties. Impact energy (J8C) Grade
Tensile strength N/mm2
Nominal thickness
Yield strength N/mm2
Temp 8C
150 mm
>150 250 mm
S235 S235JR (1) S235JRG1 (1) S235JRG2 S235JO S235J2G3 S235J2G4
340/470 340/470 (1) 340/470 (1) 340/470 340/470 340/470 340/470
235 235 235 235 235 235 235
± +20 +20 +20 0 720 720
± 27 27 27 27 27 27
± ± ± 23 23 23 23
S275 S275 S275 S275 S275
410/560 410/560 410/560 410/560 410/560
275 275 275 275 275
± +20 0 720 720
± 27 27 27 27
± 23 23 23 23
S355 S355JR S355JO S355J2G3 S355J2G4 S355K2G3 S355K2G4
490/630 490/630 490/630 490/630 490/630 490/630 490/630
355 355 355 355 355 355 355
± +20 0 720 720 720 720
± 27 27 27 27 40 40
± 23 23 23 23 33 33
(1) Only available up to and including 25 mm thick Other properties of steel: Modulus of elasticity Coefficient of thermal expansion Density or mass Elongation (200 mm gauge length)
E = 205 6 103 N/mm2 (205 kg/mm2) 12 6 106 per 8C 7850 kg/m3 (7.85 tonnes/m3 or 78.5 kN/m3) Grade S275 S355 S460 S355JOW
20% 18% 17% 19%
Table 1.3 Main use of steel grades. BS EN 10025 BS EN 10113 (Pts 1 & 2)4
Yield N/mm2
As rolled cost : strength ratio
Type Mild High Strength Ditto Ditto Ditto
Buildings
S275 S355
275 355
1.00 0.84
Bridges
S420 S460 S690 (BS EN 10137)
420 460 690
± 0.81 ±
Cranes
1.2.3 Weather resistant steels
items such as bolts in critical locations. Protective treatment systems are generally applied to structural steel
When exposed to the atmosphere, low carbon equivalent
frameworks using a combination of painting, metal spraying
structural steels corrode by oxidation forming rust and this
or galvanising depending upon the environmental condi-
process will continue and eventually reduce the effective
tions and ease of future maintenance. Costs of main-
thickness leading to loss of capacity or failure. Stainless
tenance can be significant for structures having difficult
steels containing high percentages of alloying elements
access conditions such as high-rise buildings with exposed
such as chromium and nickel can be used to minimise the
frames and for bridges. Weather resistant steels which
corrosion process but their very high cost is virtually pro-
develop their own corrosion resistance and which do not
hibitive for most structural purposes, except for small
require protective treatment or maintenance were
5
USE OF STRUCTURAL STEEL
Thickness* less than or equal to mm
Design strength py N/mm2
16 40 63 80 100 150
275 265 255 245 235 225
S355
16 40 63 80 100 150
355 345 335 325 315 295
S460
16 40 63 80 100
460 440 430 410 400
Steel grade
S275
* For rolled sections, use the specified thickness of the thickest element of the cross-section.
Weather resistant steels contain up to 3 per cent of alloying elements such as copper, chromium, vanadium and phosphorous. The steel oxidises naturally and when a tight patina of rust has formed this inhibits further corrosion. Figure 1.3 shows relative rates of corrosion. Over a period of one to four years the steel weathers to a shade of dark brown or purple depending upon the atmospheric conditions in the locality. Appearance is enhanced if the steel has been blast cleaned after fabrication so that weathering occurs evenly.
300
corrosion – microns
Table 1.4 Guidance on steel grades in BS 5950 Ð 1:2000 Ð design strengths.
l
200 m
ee e st
e
es gan
man bon r a c al stri indu
100
marine WR steel
developed for this reason. They were first used for the John
industrial
Deare Building in Illinois in 1961, the exterior of which consists entirely of exposed steelwork and glass panels;
0
1
2
3
several prestigious buildings have since used weather resistant steel frames. The first bridge was built in 1964 in
n ari
4 5 time – years
6
7
8
Figure 1.3 Corrosion rates of unpainted steel.
Detroit followed by many more in North America and over 160 UK bridges have been completed since 1968. Costs of
BS EN 101555 gives the specific requirements for the
weather resistant steel frames tend to be marginally
chemical composition and mechanical properties of the
greater due to a higher material cost per tonne, but this
S355JOW grades rolled in the UK which are similar to Corten
may more than offset the alternative costs of providing
B as originated in the USA. Because the material is less
protective treatment and its long term maintenance. Thus
widely used weather resistant steels are not widely avail-
weather resistant steel deserves consideration where
able from stockholders. Therefore small tonnages for a
access for maintenance will be difficult.
particular rolled section should be avoided. There are a few
Table 1.5 Guidance on steel grades in BS 5950 Ð 1:2000 ± maximum thicknesses. Product standard
Steel grade or quality
Sections
Plates and flats
BS EN 100251 BS EN 10113-24
Hollow sections
S275 or S355
100
150
±
S275 or S355 S460
150 100
150 100
± ±
BS EN 10113-34
S275, S355 or S460
150
63
±
BS EN 10137-27
S460
±
150
±
BS EN 101555
J0WP or J2WP J0W, J2W or K2W
40 100
16 100
± ±
BS EN 10210-18
All
±
±
65
9
All
±
±
40
J0WPH J0WH or GWH
± ±
± ±
12 40
BS EN 10219-1 10
BS 7668
Max. thickness at which the full Charpy impact value given in the product standard applies.
6
STEEL DETAILERS' MANUAL
stockholders who will supply a limited range of rolled plate.
columns such that the depth is one half of the original
Welding procedures need to be more stringent than for
section. Hollow sections in the form of circular (CHS),
other high tensile steel due to the higher carbon equivalent
square (SHS) and rectangular (RHS) shape are available but
and it must be ensured that exposed weld metal has
their cost per tonne is approximately 20 per cent more than
equivalent weathering properties. Suitable alloy-bearing
universal beams and columns. Although efficient as struts
consumables are available for common welding processes,
or columns the end connections tend to be complex espe-
but for single run welds using manual or submerged arc it
cially when bolted. They are often used where clean
has been shown that sufficient dilution normally occurs
appearance is vital, such as steelwork which is exposed to
such that normal electrodes are satisfactory. It is only
view in public buildings. Wind resistance is less that of open
necessary for the capping runs of butt welds to use elec-
sections giving an advantage in open braced structures such
trodes with weathering properties.
as towers where the steelwork itself contributes to most of the exposed area. Other sections are available such as bulb
Until the corrosion inhibiting patina has formed it should be
flats and trapezoidal troughs as used in stiffened plate
realised that rusting takes place and run-off will occur
construction, for example box girder bridges and ships.
which may cause staining of concrete and other parts locally. This can be minimised by careful attention to
The range of UBs and UCs offers a number of section
detail. A suitable drip detail for a bridge is shown in figure
weights within each serial size (depth D and breadth B).
7.27. Drainage of pier tops should be provided to prevent
Heavier sections are produced with the finishing rolls fur-
streaking of concrete and, during construction, temporary
ther apart such that the overall depth and breadth
protection specified. Weather resistant steels are not
increase, but with the clear distance between flanges
suitable in conditions of total immersion or burial and
remaining constant as shown in figure 1.4. This is con-
therefore water traps should be avoided and columns ter-
venient in multi-storey buildings in allowing use of lighter
minated above ground level. Use of concrete or other light
sections of the same serial size for the upper levels. How-
coloured paving should be avoided around column bases,
ever, it must be remembered that the actual overall
and dark coloured brickwork or gravel finish should be
dimensions (D and B) will often be greater than the serial
6
considered. In the UK it is usual in bridges to design against
size except when the basic (usually lightest) section is used.
possible long term slow rusting of the steel by added
This will affect detailing and overall cladding dimensions.
thicknesses (1.5 mm for exposed face in very severe
Drawings must therefore state actual dimensions. For other
environments and 1 mm otherwise), severity being a func-
sections (e.g. angles and hollow sections) the overall
tion of the atmospheric sulphur level. Weather resistant
dimensions (D and B) are constant for all weights within
steel should not be used in marine environments and water
each serial size.
containing chlorides such as de-icing salts should be prevented from coming into contact by suitable detailing. At
Other rolled sections are available in the UK and elsewhere
expansion joints on bridges consideration should be given
including rails (for travelling cranes and railway tracks),
to casting in concrete locally in case of leakage as shown in
bearing piles (H pile or welded box) and sheet piles (Larssen
figure 7.27.
or Frodingham interlocking). Cellform (or castellated)
Extra care must be taken in materials ordering and control
B actual breadth serial breadth
during the fabrication of projects in weathering steel because its visual appearance is similar to other steels
heavier sections within range B
1.3 Structural shapes
constant RSA
D
vertently misplaced.
D actual depth serial depth
identification of material which may have been inad-
D
during manufacture. Testing methods are available for
Most structures utilise hot rolled sections in the form of universal beams (UBs), universal columns (UCs), channels and rolled steel angles (RSAs) to BS 4,11 see figure 1.6. Less frequently used are tees cut from universal beams or
UB & UC Figure 1.4 Rolled section sizes.
HOLLOW SECTIONS
7
USE OF STRUCTURAL STEEL
beams are made from universal beam or column sections
Other general guidelines include:
cut to corrugated profile and reformed by welding to give a 50 per cent deeper section providing an efficient beam for
n
light loading conditions.
small sections can, logically, be curved to smaller radii than larger ones
n
Sections sometimes need to be curved about one or both
normally be curved to a smaller radius than the lighter
axes to provide precamber (to counteract dead load deflection of long span beams) or to achieve permanent
section n
universal columns can be curved to smaller radii about the major axis than universal beams of the same depth
curvature for example in arched roofs or circular coffer-
but, generally, the reverse applies about the minor axis
dams. Specialists in the UK can curve structural steel sections by either cold (roller bending) or hot (induction
within any one serial size, the heavier sections can
n
most open sections (angles, channels) can be curved to
bending) processes. In general, they can be curved to
a smaller radius about the minor axis than about the
single-radius curves, to multi-radius curves, to parabolic
major axis.
or elliptical curves or even to co-ordinates. They can also, within limits, be curved in two planes or to form
Fabricated members are used for spans or loads in excess of
spirals.
the capacity of rolled sections. Costs per tonne are higher because of the extra operations in profile cutting and
The curving process has merit in that most residual stresses
welding. Box girders have particular application where
(inherent in rolled sections when produced) are removed
their inherent torsional rigidity can be exploited, for
such that any subsequent heat-inducing operations such as
example in a sharply curved bridge. Compound members
welding or galvanizing cause less distortion than otherwise.
made from two or more interconnected rolled sections can
Although, usually more costly than cold rolling, hot induc-
be convenient, such as twin universal beams. For sections
tion bending enables steel sections to be curved to a very
which are asymmetric about their major (xÐx) axis such as
much smaller radius and with much less deformation, as
channels or rolled steel angles (RSAs) then interconnection
indicated in Table 1.6. The minimum radius to which any
or torsional restraint is a necessity if used as a beam. This is
section can be curved depends on its metallurgical prop-
to avoid torsional instability where the shear centre of the
erties (particularly ductility), its thickness, its cross-
section does not coincide with the line of action of the
sectional geometry and the bending method. Table 1.6
applied load as shown in figure 1.5.
gives typical radii to which a range of common sections can readily be curved about their major axes by cold or hot
Cold formed sections using thin gauge material (1.5 mm to
bending. Note that these are not minimum values so guid-
3.2 mm thick typically) are used for lightly loaded secon-
ance on the realistic minimum radii with regard to specific
dary members, such as purlins and sheeting rails. They are
sections should be sought from a specialist bending com-
not suitable for external use. They are available from a
pany. load
Table 1.6 Sections curved about major axis ± typical radii.
X
X
Typical radius (curved about major axis) Section size 838 6 292 6 226 UB 762 6 267 6 197 UB 610 6 305 6 238 UB 533 6 210 6 82 UB 457 6 191 6 74 UB 356 6 171 6 67 UB 305 6 305 6 137 UC 254 6 254 6 89 UC 203 6 203 6 60 UC 152 6 152 6 37 UC
Cold bending
Hot bending
75000 mm 50000 mm 25000 mm 25000 mm 20000 mm 10000 mm 10000 mm 6000 mm 4000 mm 2000 mm
12500 mm 10000 mm 8000 mm 5000 mm 4500 mm 3000 mm 2500 mm 2500 mm 1750 mm 1250 mm
Information in this table is supplied by The Angle Ring Co. Ltd, Bloomfield Road, Tipton, West Midlands DY4 9EH, UK. Email:
[email protected] Y shear centre
X
load
X
eccentricity Methods of restraint
Y Twisting relative to shear centre
Figure 1.5 Twisting of angles and channels.
8
STEEL DETAILERS' MANUAL
SHAPE Plate girders
t
Flanges < 650 6 60 (flat) > 650 6 60 (plate) Web t = 8 to 25 D = 4000 max.
t
D
USE Heavy beams Long span floors Bridges Crane girders
FABRICATED
Plated rolled sections
Box girders
b
D b B
COMMENTS
D = 4000 max. B = 3000 max. if D or B < 600 must seal up.
Fabrication automated web stiffeners usual
Shallow beams beyond capacity of UB
Plate girder often cheaper
Crane girders Bridge girders Heavy columns
Fabrication costly Diaphragms and stiffeners required
b = 50t max. (typical)
b B
Composite beams
HT
HD
ds
Floors Bridge decks
L
D
Headed shear stud
COMPOSITE
Composite columns
Cased UC
Multi-storey building columns
Concrete
Filled
Filler joists
Composite trough
Headed shear studs common sizes HD HT D6L kg/1000 20 13 6 75 91 8 100 116 16 6 75 32 175 8 100 213 19 6 75 221 32 10 100 278 125 335 150 391 22 6 100 369 35 10 125 446 150 524
Floors Bridge decks
Shear connectors may not be necessary
Floors Bridge decks
ds = 110 to 200 Floor may span between composite beams
ds
bridge rail
Crane girder
Twin UB
OTHER
Compound column
212 to 440
Channels back to back
420 to 525 Larssen
weld Starred
Back to back Angles (RSA)
Box
t
425 to 483 t = 1.5 to 3.2 mm
143 to 311 Frodingham PILE SECTIONS
Figure 1.6 Structural shapes.
t
Cold rolled purlins
254 max.
9
USE OF STRUCTURAL STEEL
SHAPE
UK SIZE RANGE
B
USE
COMMENTS
D 6 B 6 kg/m Universal beam (UB)
D
Beams 127 6 76 6 13 to 914 6 419 6 388
B 6 D = serial size Actual dimensions vary with weight (kg/m)
B Universal column (UC)
D
Bearing pile or H-pile
152 6 152 6 23 to 356 6 406 6 634
May need bearing stiffeners at supports and under point loads
Columns Shallow beams Heavy truss members Piles
B Joist
D
8° taper
76 6 76 6 12.65 to 254 6 203 6 81.85
Small beams
76 6 38 6 6.70 to 432 6 102 6 65.54
Bracings Ties Light beams
HOT ROLLED SECTIONS
B Channel
D
5° taper 15° taper
Equal angle (RSA)
shear centre angle B D
D
e.g. D6B6t 25 6 25 6 3 to 250 6 250 6 35
Unequal angle (RSA)
40 6 25 6 4 to 200 6 150 6 18
Structural tee
D 6 B 6 kg/m 76 6 64 6 7 UB to 419 6 457 6 194 152 6 76 6 12 UC to 406 6 178 6 317
B
When used as beam torsion occurs relative to shear centre Restrain or use in pairs
Bracings Truss members Tower members Purlins Sheeting rails
Truss chords Plate stiffeners
Cut from UB or UC D = 0.5 6 original depth
Light beams where services need to pass through beam
Made from UB D = 1.5 6 Ds (approx)
Castellated beam
B
Ds
D
191 6 76 6 13 to 1371 6 419 6 388
Ds t D
plate
t
HOLLOW SECTIONS
D
B
Rectangular hollow section (RHS)
t
Square hollow section (SHS)
D
Figure 1.6 Contd
Circular hollow sections (CHS) and tubes
t D
D
Bulb flat
120 6 6 6 7.31 to 430 6 20 6 90.8 D6t CHS 21.3 6 3.2 to 508 6 50 tubes up to 2020 6 25 D6B6t 50 6 25 6 2.5 to 500 6 300 6 20 20 6 20 6 2 to 400 6 400 6 20
Plate stiffeners in bridges or pontoons etc.
Good welding access
Space frames Columns Bracings Piles
End connections costly if bolted splice Supply cost per tonne approx 20% higher than open sections
Columns Vierendeel girders
Fully seal ends if external use
Columns Space frames
Clean appearance
10
STEEL DETAILERS' MANUAL
number of manufacturers to dimensions particular to the
Since the early 1980s many workshops have installed
supplier and are usually galvanised. Ranges of standard
numerically controlled (NC) equipment for marking, sawing
fitments such as sag rods, fixing cleats, cleader angles,
members to length, for hole drilling and profile cutting of
gable posts and rafter stays are provided, such that for a
plates to shape. This has largely replaced the need to make
typical single storey building only the primary members
wooden (or other) templates to ensure fit-up between
might be hot rolled sections. Detailing of cold rolled sec-
adjacent connections when preparation (i.e. marking,
tions is not covered in this manual, but it is important that
cutting and drilling) was performed by manual methods.
the designer ensures that stability is provided by these
Use of NC equipment has significantly improved accuracy
elements or if necessary provides additional restraint.
such that better tolerances are achieved without need for adjustments by dressing or reaming of holes. However, the
Open braced structures such as trusses, lattice or Vierendeel
main factor causing dimensional variation is welding dis-
girders and towers or space frames are formed from indi-
tortion, which arises due to shrinkage of the molten weld
vidual members of either hot rolled, hollow, fabricated or
metal when cooling. The amount of distortion which occurs
compound shapes. They are appropriate for lightly loaded
is a function of the weld size, heat input of the process,
long span structures such as roofs or where wind resistance
number of runs, the degree of restraint present and the
must be minimised as in towers. In the past they were used
material thicknesses.
for heavy applications such as bridges, but the advent of automated fabrication together with availability of wide
To an extent welding distortion can be predicted and the
plates means that plate girders are more economic.
effects allowed for in advance, but some fabricators prefer to exclude the use of welding for beam/column structures
1.4 Tolerances 1.4.1 General
and to use all bolted connections. However, welding is necessary for fabricated sections such that the effects of distortion must be understood and catered for.
In all areas of engineering the designer, detailer and con-
Figure 1.7 illustrates various forms of welding distortion
structor need to allow for tolerances. This is because in
and how they should be allowed for either by presetting,
practice absolute precision cannot be guaranteed for each
using temporary restraints or initially preparing elements
and every dimension even when working to very high
with extra length. This is often done at workshop floor
manufacturing standards. Very close tolerances are
level, and ideally should be calculated in consultation with
demanded in mechanical engineering applications where
the welding engineer and detailer. Where site welding is
moving parts are involved and the high costs involved in
involved then the workshop drawings should include for
machining operations after manufacture of such compo-
weld shrinkage at site by detailing the components with
nents have to be justified. Even here tolerance allowances
extra length. A worked example is given in 1.4.2.
are necessary and it is common practice for values to be specified on drawings. In structural steelwork such close
When site welding plate girder splices the flanges should
tolerances could only be obtained at very high cost, taking
be welded first so that shrinkage of the joint occurs
into account the large size of many components and the
before the (normally thinner) web joint is made to avoid
variations normally obtained with rolled steel products.
buckling. Therefore the web should be detailed with
Therefore accepted practice in the interests of economy is
approximately 2 mm extra root gap as shown in figure
to fabricate steelwork to reasonable standards obtainable
1.13.
in average workshop conditions and to detail joints which can absorb small variations at site. Where justified,
Table 1.7 shows some of the main causes of dimensional
operations such as machining of member ends after fabri-
variations which can occur and how they should be over-
cation to precise length and/or angularity are carried out,
come in detailing. These practices are well accepted by
but this is exceptional and can only be carried out by
designers, detailers and fabricators. It is not usual to
specialist fabricators. Normally, machining operations
incorporate tolerance limits on detailed drawings although
should be restricted to small components (such as tapered
this will be justified in special circumstances where accu-
bearing plates) which can be carried out by a specialist
racy is vital to connected mechanical equipment. Figure
machine shop remote from the main workshop and
1.8 shows tolerances for rolled sections and fabricated
attached before delivery to site.
members.
11
USE OF STRUCTURAL STEEL
WELDING DISTORTION
Type
This table shows common forms of distortion & how they are allowed for, reduced, or designed out. ! direction Sketch Solutions Calculation of distortion
Plate or flange cusping (a)
À
web
8 7 either or
flange
V° V8 = angular distortion
Á
2 runs
3
Â
machined bearing plate
a tf
bearing a
6 5 V° 4
preset tf
3 runs
à Use fillet welds of smallest size
1 run
2 1 0 .2
from strength requirements (generally 6 mm)
.4
.6 a/tf
.8
1.0
À
Plate distortion due to stiffeners (b)
Ð
Á Use jigged fabrication to retain flatness
Member area
Overall shrinkage (c)
A (mm2)
required
d
10
sub arc
C kN initial length = L (m) weld area Aw (mm2) N = No. of runs
5 MIG
Initial length made longer to offset shrinkage
MMA 0
1 2 3 4 5 10 N AW d
mm 4:878 KCL A K variability factor 0.8 to 1.2
Note: for simultaneous runs N = 1 for each pair
dw
Camber distortion ± unequal flanges (d)
AwT (mm2) 10 tw
AT (mm2)
10 tw
AB (mm2)
PRECAMBER
mm
END SLOPE
y 0:0024 CL KAwT dw AT
radians
L
Precamber to counteract weld shrinkage of unequal flanges
==
shrinkage
Figure 1.7 Welding distortion.
b
= =
AwB (mm2)
d
0:61 CL2 KAwT AT dw
AwB AB
e
tw
Butt weld shrinkage (unrestrained) (e)
b
AwB AB
C and K Ð see above L length of member (m) dw depth of web (m)
5 4 d 3 (mm) 2 1 0 10 20 b (mm)
30
12
STEEL DETAILERS' MANUAL
Table 1.7 Dimensional variations and detailing practice.
Worked example
Type of variation
Detailing practice
Question
Dimensions from top of beams down from centre of web Backmark of angles and channels
The plate girder has unequal flanges and is 32.55 m long
Tolerance gap at ends of beams. Use lapped connections not abutting end plates
web. For simplicity the plate sizes as at mid length are
1 Rolled sections ± tolerances
2 Length of members
For multi-storey frames with several bays consider variable tolerance packs 3 Bolted end connections
Black bolts or HSFG bolts in clearance holes For bolt groups use NC drilling or templates For large complex joints drill pilot holes and ream out to full size during a trial erection Provide large diameter holes and washer plates if excessive variation possible
4 Camber or straightness variation in members
Tolerance gap to beam splices nominal 6 mm
over end plates. Web/flange welds are 8 mm fillet welds which should use the submerged arc process, each completed in a single run, but not concurrently on either side of assumed to apply full length. The girder as simplified is shown in figure 1.9. It is required to calculate: (1) Amount of flange plate cusping which may occur due to web/flange welds. (2) Additional length of plates to counteract overall shrinkage in length due to web/flange welds. (3) Camber distortion due to unequal flanges so that extra fabrication precamber can be determined. (4) Butt weld shrinkage for site welded splice so that girders can be detailed with extra length.
Use lapped connections
Answer
5 Inaccuracy in setting foundations and holding down bolts to line and level
Provide grouted space below baseplates. Cast holding down bolts in pockets. Provide extra length bolts with excess thread
(1) Amount of flange cusping
6 Countersunk bolts/set screws
Avoid wherever possible
7 Weld size variation
Keep details clear in case welds are oversized
8 Columns prepared for end bearing
Machine ends of fabricated columns (end plates must be ordered extra thick) Incorporate division plate between column lengths
9 Cumulative effects on large structures
Where erection is costly or overseas delivery carry out trial erection of part or complete structure For closing piece on long structure such as bridge, fabricate or trim element to site measured dimensions
10 Fit of accurate mechanical parts to structural steelwork
Use separate bolted-on fabrication
Using figure 1.7(a) Top flange: a 8
p 2 5:65 mm weld throat
tf 25 mm flange thickness a 5:65 0:226 tf 25
N 1 for each weld
From figure 1.7(a) V 1:18 Bottom flange: a 8
p 2 5:65 mm
tf 50 mm flange thickness a 5:65 0:113 tf 50 From figure 1.7(a)
N1
V 0:58
The resulting flange cusping is shown in figure 1.10. Use of `strongbacks' or presetting as shown in figure 1.7(a) may need to be considered during fabrication, because although the cusps are not detrimental structurally they may affect details especially at splices and at bearings.
1.4.2 Worked example Ð welding distortion for plate girder Calculation of welding distortion
(2) Overall shrinkage Using figure 1.7(c)
The following example illustrates use of figure 1.7 in
Shortening d 4:878 kCL (Aw/A)
making allowances for welding distortion for the welded
where C 5:0 kN for N 4 weld runs
plate girder shown in figure 7.28.
L 32:55 m
13
USE OF STRUCTURAL STEEL
ROLLED SECTIONS
TOLERANCES & EFFECTS IN DETAILING
Tolerances
Type
RSA CHANNELS
CHANNELS, BEAMS & COLUMNS (BS 4)
DEPTH D at CL web
Value Joist/channel D to 305 +3.2 70.8 > 305 +4.0 to 406 71.6 > 406 74.8 71.6 +6.4 74.8 e A 3.2 D + 4.8
UB/UC
+3.2
Flange width B D > 102 to 305 > 305
Off-centre of web e
Out of squareness F + F1
4.8
B To 102 > 102 to 203 > 203 to 305 > 305
D + 6.4 F+F1 1.6
SKETCH
From top flange
B
CL web vertical B± e 2
reference level F1
X
n
X From CL of web
X C = [2t + 2 mm] * N = [B 7 C + 6 mm] * n=[D2 d] {
X
d
A D
F Allow for tolerances assuming web truly vertical
3.2 4.8
B ±e 2 C
N
6.4 + 212% (BS 4)
Rolling tolerance on specified weight
DIMENSIONS
X
Use backmark
X
X
FLATS & PLATES
Backmarks Thickness + 7 to 10 > 40 > 80 Width Range
Plates Flats Wide flats 0.5 0.4 0.5 0.8 1.0 1.05 1.0 1.3 1.25 Thick +7 2% 7 0, +30 to 35 0.5 to 150 1.5 (6> 5 mm) to 150 150 7 650 600 7 4000
Length
+0, 7 3 with end plates
Overall end plates from top flange CL of cross section
FABRICATED ITEMS
A
D e B or F B to 450 > 450 K ~
Camber
Straightness or bow
Deviation from camber
d 150
L
min 3 mm 100
From top of top flange From CL of web
X CL
D 2
D 2
X = (c/c– D – 4)
D CL col
c/c B
F
K X X
d
min. 3 mm
D
A
B ±e 2 F Mid-length values. Also at stiffeners for plate girders ___
X-DIMENSIONS TO BE SHOWN ON DRAWINGS Figure 1.8 Tolerances.
X
X X
D +2 2 CL col
L 1000 (min 12 mm)
X
X
X
Overall end plates
+4 +5 +6 +6 +9 B 150
X
Typical only
+4 with lapped end connections Cross section
X
X
L
Camber
Bow * Nearest 2 mm above { Nearest 1 mm
14
STEEL DETAILERS' MANUAL
site butt weld 8 8
dw = 1.3 m Top flange: 500 6 25 Btm flange: 600 6 50 Web plate: 14
L = 32.55 m over end plates Figure 1.9 Welding distortion ± worked example.
V = 1.1°
5.0 mm CUSP 500
AwB AB 0:0024 7:0 32:55 0:8 64 For k 0:8 y 1:30 14 460 End slope y
0:0024 CL kAwT dw AT
64 31 960
0:00065 radians For k 1:2 y 0:00139 radians Therefore extra fabrication precamber needs to be applied 2.9 mm CUSP
V = 0.5° 600
as shown in figure 1.11 additional to the total precamber specified for counteracting dead loads, etc. given in figure 7.25. This would not be shown on workshop drawings but would be taken account of in materials ordering and during
Figure 1.10 Flange cusping.
fabrication.
88 Aw 4 No 128 mm2 2
12 mm extra fabrication precamber
A
500 25
600 50
1300 14 60 700 mm2 k 0:8 to 1:2 For k 0:8 d 4:878 0:8 5:0 32:55 or for k 1:2
d 2:0 mm
128 1:3 mm 60 700
Therefore overall length of plates must be increased by 2 mm.
e = 0.00139 radians
130 specified precamber
Figure 1.11 Extra fabrication precamber.
(3) Camber distortion Using figure 1.7(d) 0:61 CL2 Precamber 4 dw
(4) Butt weld shrinkage kAwt AT
AwB AB
Using figure 1.7(e)
Bottom flange. See figure 1.12 for butt weld detail.
where C 7:0 kN for N 2 weld runs each flange L 32:55 m
2
dw 1.30 m k 0:8 to 1:2 88 AwT 2 No 64 mm2 2
2
AwB 64 mm2
= 2
2
AT
500 25
10 14 14 460 mm
AB
600 50
10 142 31 960 mm2 0:61 7:0 32:552 0:8 64 64 For k 0:8 4 1:30 14 460 31 960
= 60°
b = 13.0 mm
5:4 mm For k 1:2
4 11:5 mm (say 12 mm)
Figure 1.12 Bottom flange site weld.
40
15
USE OF STRUCTURAL STEEL
Shrinkage d 2:0 mm
cation work can be more expensive than a slightly heavier
Therefore length of flanges must be increased by 1 mm on
design with simple joints. Once the overall concept is
each side of splice and detailed as shown. Normal practice
decided the connections should always be given at least the
is to weld the flanges first. Thus the web will be welded
same attention as the design of the main members which
under restraint and should be detailed with the root gap
they form. Structural adequacy is not, in itself, the sole
increased by 2 mm as shown in figure 1.13.
criterion because the designer must endeavour to provide an efficient and effective structure at the lowest cost. With appropriate stiffening either an all welded or a high strength friction grip (HSFG) bolted connection is able to achieve a fully continuous joint, that is one which is cap-
Root root gap = 2 + 2 for flange shrinkage = 4 mm Figure 1.13 Web site weld.
able of developing applied bending without significant rotation. However such connections are costly to fabricate and erect. They may not always be justified. Many economical beam/column structures are built using angle cleat
In carrying out workshop drawings in this case, only item (4)
or welded end plate connections without stiffening and
should be shown thereon because items (1) to (3) occur due
then joined with black bolts. These are defined as simple
to fabrication effects which are allowed for at the work-
connections which transmit shear but where moment/
shop. Item (4) occurs at site and must therefore be taken
rotation stiffness is not sufficient to mobilise end fixity of
into consideration so that the item delivered takes into
beams or frame action under wind loading without sig-
account weld shrinkage at site.
nificant
deflection.
Figure
1.15
shows
typical
moment : rotation behaviour of connections. Simple con-
1.5 Connections
nections (i.e. types A or B) are significantly cheaper to
Connections are required for the functions illustrated in
necessary because the benefits of end fixity leading to a
figure 1.14. The number of site connections should be as
smaller maximum bending moment are not realised. Use of
few as possible consistent with maximum delivery/erection
simple connections enables the workshop to use automated
sizes so that the majority of assembly is performed under
methods more readily with greater facility for tolerance at
workshop conditions. Welded fabrication is usual in most
site and will often give a more economic solution overall.
workshops and is always used for members such as plate
However it is necessary to stabilise structures having simple
girders, box girders and stiffened platework.
connections against lateral loads such as wind by bracing or
fabricate although somewhat heavier beam sizes may be
to rely on shear walls/lift cores, etc. For this reason simple It is always wise to consider the connection type to be used
connections should be made erection-rigid (i.e. retain
at the conceptual design stage. A continuously designed
resistance against free rotation whilst remaining flexible)
structure of lighter weight but with more complex fabri-
so that the structure is stable during erection and before bracings or shear walls are connected. All connections shown in figure 1.15 are capable of being erection-rigid. Calculations may be necessary in substantiation, but use of seating cleats only for beam/column connections should be avoided. A top flange cleat should be added. Web cleat or flexible (i.e. 12 mm maximum thickness) end plate connections of at least 0.6 6 beam depth are suitable. Provision of seating cleats is not a theoretical necessity but they improve erection safety for high-rise structures exceeding 12 storeys. Behaviour of continuous and simple connections is shown in figure 1.16. Typical locations of site connections are shown in figure 1.17. At site either welding or bolting is used, but the latter is
Figure 1.14 Functions of connections.
faster and usually cheaper. Welding is more difficult on site
16
STEEL DETAILERS' MANUAL
cont
inuo
us site workshop
D yield of
moment
C beam section
B
simple
A
Figure 1.17 Locations of site connections.
rotation
Welding Ð Bolting
workshop
Ð site
For bridges continuous connections should be used to withstand vibration from vehicular loading and spans should usually be made continuous. This allows the numbers of deck expansion joints and bearings to be reduced thus minimising maintenance of these costly items which are vulnerable to traffic and external environment. black bolts
black bolts
HSFG bolts
HSFG bolts
For UK buildings, connection design is usually carried out
A
B
C
D
by the fabricator with the member sizes and end reac-
Figure 1.15 Typical moment : rotation behaviour of beam/column connections.
tions being specified on the engineer's drawings. It is important that all design assumptions are advised to the fabricator for him to design and detail the connections. If joints are continuous then bending moments and any axial loads must be specified in addition to end reactions.
‘continuous’
For simple connections the engineer must specify how stability is to be achieved, both during construction and finally when in service.
‘simple’ bracing required (or shear walls, etc.) vertical loading
lateral loading (e.g. wind)
Figure 1.16 Continuous and simple connections.
Connections to hollow sections are generally more costly and often demand butt welding rather than fillet welds. Bolted connections in hollow sections require extended end plates or gussets and sealing plates because internal access is not feasible for bolt tightening whereas channels or rolled steel angles (RSAs) can be connected by simple lap joints. Figure 1.18 compares typical welded or bolted
because assemblies cannot be turned to permit downhand
connections.
welding and erection costs arise for equipment in supporting/aligning connections, pre-heating/sheltering and non-destructive testing (NDT). The exception is a major
1.6 Interface to foundations
project where such costs can be absorbed within a larger
It is important to recognise whether the interface of
number of connections (say minimum 500). As a general
steelwork to foundations must rely on a moment (or rigid)
rule welding and bolting are used thus:
form of connection or not.
17
USE OF STRUCTURAL STEEL
HOT ROLLED SECTIONS
HOLLOW SECTIONS
Welded joint
tolerance available
no tolerance in length
gusset (expensive for what it does) 6 mm nominal gap Bolted joint
tolerance available
exact length A tolerance pack would be extra expense
Note: This detail eliminates all welding Figure 1.18 Connections in hot rolled and hollow sections.
Figure 1.19 shows a steel portal frame connected either by
For some structures it is vital to ensure that holding down
a pin base to its concrete foundation or alternatively where
bolts are capable of providing proper anchorage arrange-
the design relies on moment fixity. In the former case (a)
ment to prevent uplift under critical load conditions. An
the foundation must be designed for the vertical and
example is a water tower where uplift can occur at foun-
horizontal reactions whereas for the latter (b) its founda-
dation level when the tank is empty under wind loading
tion must additionally resist bending moment. In general
although the main design conditions for the tower members
for portal frames the steelwork will be slightly heavier with
are when the tank is full.
pin bases but the foundations will be cheaper and less susceptible to movements of the subsoil.
vertical loading
bending moment diagram
M
H
H
V
V PIN BASES
Figure 1.19 Connections to foundations.
FIXED BASES
18
STEEL DETAILERS' MANUAL
1.7 Welding
weld metal across the throat, the weld size (usually) being
1.7.1 Weld types
1.21.
specified as the leg length. Fillet welds are shown in figure
There are two main types of weld: butt weld and fillet weld. A butt weld (or groove weld) is defined as one in
1.7.2 Processes
which the metal lies substantially within the planes of the
Most workshops use electric arc manual (MMA), semi-
surfaces of the parts joined. It is able (if specified as a full
automatic and fully automatic equipment as suited to the
penetration butt weld) to develop the strength of the
weld type and length of run. Either manual or semi-
parent material each side of the joint. A partial penetra-
automatic processes are usual for short weld runs with fully
tion butt weld achieves a specified depth of penetration
automatic welding being used for longer runs where the
only, where full strength of the incoming element does not
higher rates of deposition are less, being offset by extra
need to be developed, and is regarded as a fillet weld in
set-up time. Detailing must allow for this. For example in
calculations of theoretical strength. Butt welds are shown
fabricating a plate girder, full length web/flange runs are
in figure 1.20.
made first by automatic welding before stiffeners are placed with snipes to avoid the previous welding as shown
A fillet weld is approximately triangular in section formed
in figure 1.22.
within a re-entrant corner of a joint and not being a butt weld. Its strength is achieved through shear capacity of the
Welding processes commonly used are shown in Table 1.8.
root gap depth of penetration
1 4 min.
fusion face incomplete penetration
root face FULL PENETRATION
PARTIAL PENETRATION
Figure 1.20 Butt welds showing double V preparations.
leg
leg
leg
angle between fusion faces
leg
toe
th
Figure 1.21 Fillet welds.
incomplete penetration
at ro
throat
19
USE OF STRUCTURAL STEEL
optimum depending upon design requirements. For light
first stage
fabrication using hollow sections with thickness 4 mm or less, then 4 mm size should be used where possible to reduce distortion and avoid burn-through. For thin plate-
automatic welds full length
work (8 mm or less) the maximum weld size should be 4 mm and use of intermittent welds (if permitted) helps to reduce
second stage
distortion. If it is to be hot-dip galvanised then distortion due to release of residual weld stresses can be serious if stiffeners, etc. added later – manual or semi-automatic welds
large welds are used with thin material. Intermittent welds should not be specified in exposed situations (because of corrosion risk) or for joints which are subject to fatigue
Figure 1.22 Sequence of fabrication.
loading such as crane girders, but are appropriate for internal areas of box girders and pontoons.
1.7.3 Weld size In order to reduce distortion the minimum weld size consistent with required strength should be specified. The
1.7.4 Choice of weld type
authors' experience is that engineers tend to over-design
Butt welds, especially full penetration butt welds, should
welds in the belief that they are improving the product and
only be used where essential such as in making up lengths of
they often specify butt welds when a fillet weld is suffi-
beam or girder flange into full strength members. Their
cient. The result is a more expensive product which will be
high cost is due to the number of operations necessary
prone to unwanted distortion during manufacture. This can
including edge preparation, back gouging, turning over,
actually be detrimental if undesirable rectification
grinding flush (where specified) and testing, whereas visual
measures are performed especially at site, or result in
inspection is often sufficient for fillet welds. Welding of
maintenance problems due to lack of fit at connections. An
end plates, gussets, stiffeners, bracings and web/flange
analogy exists in the art of the dressmaker who sensibly
joints should use fillet welds even if more material is
uses fine sewing thread to join seams to the thin fabric. She
implied. For example lapped joints should always be used in
would never use strong twine, far stronger, but which
preference to direct butting as shown in figure 1.23.
would tear out the edges of the fabric, apart from being In the UK welding of structural steel is carried out to
unsightly and totally unnecessary.
BS EN 1011 which requires weld procedures to be drawn up Multiple weld-runs are significantly more costly than single
by the fabricator. It includes recommendations for any
run fillet welds and therefore joint design should aim for a
preheating of joints so as to avoid hydrogen induced
5 mm or 6 mm leg except for long runs which will clearly be
cracking, this being sometimes necessary for high tensile
automatically welded when an 8 mm or 10 mm size may be
steels. Fillet welds should where possible be returned
Table 1.8 Common weld processes. Process
Automatic or manual
Shielding
Main use
Workshop or site
Comments
Maximum size fillet weld in single run
Manual metal arc (MMA)
Manual
Flux coating on electrode
Short runs
Workshop Site
Fillet welds larger than 6 mm are usually multirun, and are uneconomic
6 mm
Submerged arc (SUBARC)
Automatic
Powder flux deposited over arc and recycled
Long runs or heavy butt welds
Workshop or site
With twin heads simultaneous welds either side of joint are possible
10 mm
Metal inert gas (MIG)
Automatic or semi-automatic
Gas (generally carbon dioxide ± CO2)
Short or long runs
Workshop
Has replaced manual welding in many workshops. Slag is minimal so galvanised items can be treated directly
8 mm
}
20
STEEL DETAILERS' MANUAL
FPBW
fillet weld
greater volume of weld metal involved, but because further transverse strains will be caused by the heat input of backgouging processes used between weld runs to ensure fusion.
this material is extra but still cheaper than butt weld
The best solution is to avoid cruciform welds having full penetration butt welds. If cruciform joints are unavoidable then the thicker of the two plates should pass through, so
Lapped fillet welded DO
Butt welded DON'T
Figure 1.23 Welding using lapped joints.
that the strains which occur during welding are less severe. In other cases a special through thickness steel grade can be specified which has been checked for the presence of lamination type defects. However, the ultrasonic testing which is used may not always give a reliable guide to the
around corners for a length of at least twice the weld size to
susceptibility to lamellar tearing. Fortunately most known
reduce the possibility of failure emanating from weld ter-
examples have occurred during welding and have been
minations, which tend to be prone to start : stop defects.
repaired without loss of safety to the structure in service. However, repairs can be extremely costly and cause unforeseen delays. Therefore details which avoid the pos-
1.7.5 Lamellar tearing
sibility of lamellar tearing should be used whenever pos-
In design and detailing it should be appreciated that
sible. Figure 1.24 shows lamellar tearing together with
structural steels, being produced by rolling, possess dif-
suggested alternative details.
ferent and sometimes inferior mechanical properties transverse to the rolled direction. This occurs because nonmetallic manganese sulphides and manganese silica inclusions which occur in steel making become extended into thin planar type elements after rolling. In this respect the
1.8 Bolting 1.8.1 General
structure of rolled steel resembles timber to some extent in
Bolting is the usual method for forming site connections and
possessing grain direction. In general this is not of great
is sometimes used in the workshop. The term `bolt' used in
significance from a strength viewpoint. However, when
its generic sense means the assembly of bolt, nut and
large welds are made such that a fusion boundary runs
appropriate washer. Bolts in clearance holes should be used
parallel to the planar inclusion, the phenomenon of lamellar
except where absolute precision is necessary. Black bolts
tearing can result. Such tearing is initiated and propagated
(the term for an untensioned bolt in a clearance hole 2 or
by the considerable contractile stress across the thickness of
3 mm larger than the bolt dependent upon diameter) can
the plate generated by the weld on cooling. If the joint is
generally be used except in the following situations where
under restraint when welded, such as when a cruciform
slip is not permissible at working loads:
detail is welded which is already assembled as part of a larger fabrication then the possibility of lamellar tearing
(1) Rigid connections Ð for bolts in shear.
cannot be ignored. This is exacerbated where full pene-
(2) Impact, vibration and fatigue-prone structures Ð e.g.
tration butt welds are specified not only because of the
silos, towers, bridges.
T1
T1 P
rolling direction
P
T2
planar type inclusions
T2
specified penetration ‘P’
lamellar tear T1 > T2 SUSCEPTIBLE DETAIL (T1 > T2)
Figure 1.24 Lamellar tearing.
better
best
ALTERNATIVE DETAILS
fit if required
21
USE OF STRUCTURAL STEEL
(3)
Connections subject to stress reversal (except where
depth + washer + minimum thread projection past the nut)
due to wind loading only).
can be replaced by a variable projection beyond the tightened nut. This has a significant effect on the number of
High-strength friction grip (HSFG) bolts should be used in
different bolt lengths required.
these cases or, exceptionally, precision bolts in close tolerance holes (+0.15 mmÐ0 mm) may be appropriate.
Although the new European standards have been published, their adoption by the industry has not occurred. Bolt
If bolts of different grade or type are to be used on the same
manufacturers continue to produce bolts, nuts and washers
project then it is wise to use different diameters. This will
in compliance with the existing British standards. It is for
overcome any possible errors at the erection stage and
this reason that the technical information relating to
prevent incorrect grades of bolt being used in the holes. For
bolting in this manual refers generally to the relevant
example a typical arrangement would be:
British standard.
All grade 4.6 bolts Ð 20 mm diameter
Black bolts and HSFG bolts are illustrated in figure 1.25.
All grade 8.8 bolts Ð 24 mm diameter
The main bolt types available for use in the UK are shown in Table 1.9.
Previous familiar bolting standards BS 3692 and BS 4190 have been replaced by a range of European standards
The European continent system of strength grading intro-
(EN 24014, 24016Ð24018, 24032 and 24034). Whilst neither
duced with the ISO system is given by two figures, the first
the old nor the new standards include the term `fully
being one tenth of the minimum ultimate stress in kgf/mm2
threaded bolts', they do permit their use. Bolt manu-
and the second is one tenth of the percentage of the ratio
facturers have been supplying fully threaded bolts for some
of minimum yield stress to minimum ultimate stress. Thus
time to the increasing number of steelwork contractors
`4.6 grade' means that the minimum ultimate stress is
using them as the normal structural fastener in buildings.
40 kgf/mm2 and the yield stress 60 per cent of this. The
They are ordinary bolts in every respect except that the
yield stress is obtained by multiplying the two figures
shank is threaded for virtually its full length. This means
together to give 24 kgf/mm2. For higher tensile products
that a more rationalised and limited range of bolt lengths
where the yield point is not clearly defined, the stress at a
can be used. The usual variable of bolt length (grip + nut
permanent set limit is quoted instead of yield stress.
BLACK BOLTS
HSFG BOLTS
pretension shear stress friction
slip
bearing stress
clearance hole Figure 1.25 Black bolts and HSFG bolts.
clearance hole
22
STEEL DETAILERS' MANUAL
Table 1.9 Bolts used in UK. Type
BS No
Main use
Workshop or site
Black bolts, grade 4.6 (mild steel)
BS 419013 (nuts and bolts) BS 432014 (washers)
As black bolts in clearance holes
Workshop or site
High tensile bolts, grade 8.8
BS 369215 (nuts and bolts) BS 4320 (washers)
As black bolts in clearance holes As precision bolts in close tolerance holes
Workshop or site Workshop
HSFG bolts, general grade
BS 439516 Pt 1 (bolts, nuts and washers)
Bolts in clearance holes where slip not permitted. Used to BS 460417 Pt 1
Workshop or site
Higher grade
BS 439516 Pt 2 (bolts, nuts and washers)
Bolts in clearance holes where slip not permitted. Used to BS 460417 Pt 2
Workshop or site
Waisted shank
BS 439516 Pt 3 (bolts, nuts and washers)
Bolts in clearance holes where slip not permitted. Used to BS 460417 Pt 3
Little used
The single grade number given for nuts indicates one tenth 2
bolt is tested to a stress above that which it will experience
of the proof load stress in kgf/mm and corresponds with
in service. It may be said that if a friction grip bolt does not
the bolt ultimate strength to which it is matched, e.g. an 8
break in tightening the likelihood of subsequent failure is
grade nut is used with an 8.8 grade bolt. It is permissible to
remote. The bolt remains in a state of virtually constant
use a higher strength grade nut than the matching bolt
tension throughout its working life. This is most useful for
number and grade 10.9 bolts are supplied with grade 12
structures subject to vibration, e.g. bridges and towers. It
nuts since grade 10 does not appear in the British Standard
also ensures that nuts do not become loose with risk of bolt
series. To minimise risk of thread stripping at high loads,
loss during the life of the structure, thus reducing the need
BS 4395 high strength friction grip bolts are matched with
for continual inspection.
nuts one class higher than the bolt. Mechanical properties for general grade HSFG bolts (to
1.8.2 High strength friction grip (HSFG) bolts
BS 4395: Part 115) are similar to grade 8.8 bolts for sizes up to and including M24. Although not normally recom-
A pre-stress of approximately 70 per cent of ultimate load is
mended, grade 8.8 bolts can exceptionally be used as
induced in the shank of the bolts to bring the adjoining plies
HSFG bolts.
into intimate contact. This enables shear loads to be transferred by friction between the interfaces and makes
HSFG bolts may be tightened by three methods, viz:
for rigid connections resistant to movement and fatigue. HSFG bolts thus possess the attributes possessed by rivets,
(1) Torque control
which welding and bolts displaced during the early 1950s.
(2) Part turn method (3) Direct tension indication.
During tightening the bolt is subjected to two force components:
The latter is now usual practice in the UK and the wellestablished `Coronet'* load indicator is often used which is
(1) The induced axial tension.
a special washer with arched protrusions raised on one
(2) Part of the torsional force from the wrench applied to
face. It is normally fitted under the standard bolt head with
the bolt via the nut thread.
the protrusions facing the head thus forming a gap between the head and load indicator face. On tightening, the gap
The stress compounded from these two forces is at its
reduces as the protrusions depress and when the specified
maximum when tightening is being completed. Removal of
gap (usually 0.40 mm) is obtained, the bolt tension will not
the wrench will reduce the torque component stress, and
be less than the required minimum. Assembly is shown in
the elastic recovery of the parts causes an immediate
figure 1.26.
reduction in axial tension of some 5 per cent followed by further relaxation of about 5 per cent, most of which takes place within a few hours. For practical purposes, this loss is
* `Coronet' load indicators are manufactured by Cooper & Turner
of no consequence since it is taken into account in the
Limited, Vulcan Works, Vulcan Road, Sheffield S9 2FW, United
determination of the slip factor, but it illustrates that a
Kingdom.
23
USE OF STRUCTURAL STEEL
during fabrication and erection. Figures 1.27 and 1.28 show
bolt head ‘Coronet’ load indicator
a series of dos and don'ts which are intended to be used as a general guide in avoiding uneconomic details. Figure 1.29 gives dos and don't related to corrosion largely so as to permit maintenance and avoid moisture traps.
1.10 Protective treatment flat round washer
‘Coronet’ load indicator
special nut faced washer UNDER HEAD
When exposed to the atmosphere all construction materials deteriorate with time. Steel is affected by atmospheric corrosion and normally requires a degree of protection, which is no problem but requires careful assessment
UNDER NUT
depending upon:
Figure 1.26 Use of `Coronet' load indicator.
Aggressiveness of environment
1.9 Dos and don'ts
Required life of structure
The overall costs of structural steelwork are made up of a number of elements which may vary considerably in proportion depending upon the type of structure and site location. However a typical split is shown in Table 1.10.
Maintenance schedule Method of fabrication and erection Aesthetics. It should be remembered that for corrosion to occur air and moisture both need to be present. Thus, permanently
Table 1.10 Typical cost proportion of steel structures.
embedded steel piles do not corrode, even though in con-
Materials %
Workmanship %
Total %
tact with water, provided air is excluded by virtue of
Materials Fabrication Erection Protective treatment
30 0 0 5
0 45 15 5
30 45 15 10
impermeability of the soil. Similarly the internal surfaces of
Total
35
65
100
hollow sections do not corrode provided complete sealing is achieved to prevent continuing entry of moist air. There is a wide selection of protective systems available, and that used should adequately protect the steel at the
It may be seen that the materials element (comprising
most economic cost. Detailing has an important influence
rolled steel from the mills, bolts, welding consumables,
on the life of protective treatment. In particular details
paint and so on) is significant, but constitutes considerably
should avoid the entrapment of moisture and dirt between
less in proportion than the workmanship. This is why the
profiles or elements especially for external structures.
economy of steel structures depends to a great extent on
Figure 1.29 gives dos and don'ts related to corrosion. Pro-
details which allow easy (and therefore less costly) fabri-
vided that the ends are sealed by welding, then hollow
cation and erection. Minimum material content is impor-
sections do not require treatment internally. For large
tant in that designs should be efficient, but more relevant
internally stiffened hollow members which contain internal
is the correct selection of structural type and fabrication
stiffening such as box girder bridges and pontoons needing
details. The use of automated fabrication methods has
future inspection, it is usual to provide an internal pro-
enabled economies to be made in overall costs of steel-
tective treatment system. Access manholes should be
work, but this can only be realised fully if details are used
sealed by covers with gaskets to prevent ingress of moisture
which permit tolerance (see section 1.4) so that time
as far as possible, allowing use of a cheaper system. For
consuming (and therefore costly) rectification procedures
immersed structures such as pontoons which are inacces-
are avoided at site. Often if site completion is delayed then
sible for maintenance, corrosion prevention by cathodic
severe penalties are imposed on the steel contractor and
protection may be appropriate.
this affects the economy of steelwork in the long term. Adequate preparation of the steel surface is of the utmost For this reason one of the purposes of this manual is to
importance before application of any protective system.
promote the use of details which will avoid problems both
Modern fabricators are properly equipped in this respect
24
STEEL DETAILERS' MANUAL
DETAIL
DO
DON'T
REMARKS
distortion may occur
Welded attachment or joint
Uneconomic
FSBW
Impracticable
Bolted 908 joint
member will not enter unless exact dimension
stiff fitted both ends costly
gap (unless not permissible theoretically)
Site problem
6 Column splice or ends of bearing stiffener
Inferior result
FSBW sawn or machined and tight fit
distortion
25 min excess
HD bolts
no grout
25 min grout 50 mm excess thread nominal
Clearance of joints near welds
poor fit up
HD bolts cast in
Site problem
pocket 25 desirable 10 minimum
weld size specified
Site problem
welding may foul if oversized or if site adjustments required
Minimum edge distance for holes
Site problem
minimum specified edge distance +5 mm desirable
Holes requiring tolerance (e.g. for expansion or where site tolerance to be accommodated)
minimum edge distances may be contravened if hole enlargement becomes necessary at site to enter bolts
large diameter hole Uneconomic
slotted hole Disadvantages! (i)
Tolerance in only one direction (ii) Slot holes expensive (iii) Corrosion trap
Figure 1.27 Dos and don'ts.
25
USE OF STRUCTURAL STEEL
such that the life of systems has considerably extended. For
However, articles which are larger than the bath
external environments it is especially essential that all
dimensions can by arrangement sometimes be gal-
millscale is removed which forms when the hot surface of
vanized by double-dipping. Although generally it is
rolled steel reacts with air to form an oxide. If not removed
preferable to process work in a single dip, the cor-
it will eventually become detached through corrosion. Blast
rosion protection afforded through double-dipping is
cleaning is widely used to prepare surfaces, and other
no different from that provided in a single dip. Sizes
processes such as hand cleaning are less effective although
of articles which can be double-dipped should always
acceptable in mild environments. Various national stan-
be agreed with the galvanizers. By using double-
dards for the quality of surface finish achieved by blast
dipping UK galvanizing companies can now handle lengths up to 29.0 m or widths up to 4.8 m.
cleaning are correlated in Table 1.11. (4)
For HSFG bolted joints the interfaces must be grit
Table 1.11 National standards for grit blasting.
blasted to Sa212 quality or metal sprayed only, with-
British Standard
Swedish Standard
USA Steel Structures Painting Council
out any paint treatment to achieve friction. A
BS 707918
SIS 05 59 0019
SSPC20
1st quality
Sa 3
White metal
2nd quality
Sa 212
Near white
3rd quality
Sa 2
Commercial
reduced slip factor must be assumed for galvanized steelwork. During painting in the workshop the interfaces are usually masked with tape which is removed at site assembly. Paint coats are normally stepped back at 30 mm intervals, with the first coat taken 10 to 15 mm inside the joint perimeter. Sketches may need to be prepared to define painted/
A brief description is given for a number of accepted systems 21
in Table 1.12 based on UK conditions to BS EN ISO 14713 and
masked areas. (5)
Department of Transport guidance.22 Specialist advice may need to be sought in particular environments or areas.
For non friction bolted joints the first two workshop coats should be applied to the interfaces.
(6)
Micaceous iron oxide paints are obtainable in limited colour range only (e.g. light grey, dark grey, silver
The following points should be noted when specifying
grey) and provide a satin finish. Where a decorative
systems:
or gloss finish is required then another system of overcoating must be used.
(1)
(2)
Metal coatings such as hot dip galvanizing and
(7)
aluminium spray give a durable coating more resis-
loose scale and rust but may otherwise be untreated.
tant to site handling and abrasion but are generally
Treatment on adjacent areas should be returned for
more costly.
at least 25 mm and any metal spray coating must be
Hot dip galvanizing is not suitable for plate thick-
overcoated.
nesses less than 5 mm. Welded members, especially
(8)
Treatment of bolts at site implies blast cleaning
if slender, are liable to distortion due to release of
unless they have been hot dip galvanized. As an
residual stress and may need to be straightened. Hot
alternative, consideration can be given to use of
dip galvanizing is especially suitable for piece-small
electro-plated bolts, degreased after tightening fol-
fabrications which may be vulnerable to handling
lowed by etch priming and painting as for the adja-
damage, such as when despatched overseas. Examples are towers or lattice girders with bolted site (3)
Surfaces in contact with concrete should be free of
cent surfaces. (9)
Any delay between surface preparation and appli-
connections.
cation of the first treatment coat must be kept to the
Most sizes and shapes of steel fabrications can be hot
absolute minimum.
dip galvanized, but the dimensions of the galvanizing
(10)
bath determine the size and shape of articles that
tions exceeding say 10 tonnes in weight to avoid
can be coated in a particular works. Indicative UK maximum single dip sizes (length, depth, width) of assemblies are:
Lifting cleats should be provided for large fabricahandling damage.
(11)
The maximum amount of protective treatment should be applied at workshop in enclosed condi-
20.0 m 6 1.45 m 6 2.7 m
tions. In some situations it would be advisable to
7.5 m 6 2.0 m 6 3.25 m
apply at least the final paint coat at site after making
5.75 m 6 1.9 m 6 3.5 m
good any erection damage.
26
STEEL DETAILERS' MANUAL
DETAIL
DO
DON'T
Slotted holes
d
entire hole flame cut
min 2d + 2 mm
< 2d + 2 mm
20 rad. min to avoid notch angular and length tolerance
fillet weld
6 6 no weld attachments
butt welds cause distortion
stiff
welded attachment within 25 of flange edge
T1
T1 Cruciform details
Distortion & lack of tolerance
extra costs if connected to both flanges
30 to 50
25
Drill 2 holes & flame cut between
distortion excessive distortion
40 rad. cope hole
Plate girder details
REMARKS
T2 compression
lamellar tearing
T2 Lamellar tears
tight fit
See also fig 1.24
tension T1 > T2
T1 > T2
butt welded end plates
100 min.
15 min.
DO distortion Lack of tolerance
d
Splices
tolerance DON’T 6 nominal gap int stiff
600 max. distortion
If end plates are necessary
(if d > 100) t t = web thickness notch caused
15 min. for weld
butt weld
Local extensions
patch plate
Figure 1.28 Dos and don'ts.
distortion grinding flush is costly
Uneconomic
27
USE OF STRUCTURAL STEEL
DETAIL
DO
Corner or end details
DON'T
Uneconomic
10 nom. 10 nominal fillet weld
flush butt welds
Bolts in tension
inner bolts only effective
Prying action
bolts cannot be entered/tightened
Bolt clearances
Site problem
stagger holes if necessary to enter bolts
11/2 × bolt dia. or 30 (50 HSFG) greater 10 nom.
30 nom. min.
Flush fixings (e.g. floor plates)
nil gap
fillet weld
CSK set screws (or bolts)
6 mm plate washers Large dia holes CSK bolts
Re-entrant corner
REMARKS
10 radius unintended notch may result in brittle fracture minimum number of cuts
Gusset plates (or similar)
45° min.
Weld access
Unsafe practice
re-entrant corner 2 corners not necessary
Access for welding difficult
< 45°
same thickness where possible
Small plate quantities
Fixing difficult without excessive site rework
6 thick 10 thick
Uneconomic
Welds may be inferior
Uneconomic
8 thick taper washers Sloping or skew connection
Direction change of plates
Figure 1.28 Contd
tapered plate
Uneconomic
Uneconomic
bend radius min. 2 × t
t
butt weld
28
STEEL DETAILERS' MANUAL
DETAIL
DO
DON'T
REMARKS
corrosion
min. 200 Column bases
Corrosion at ground level
sacrificial weather flat
4
corrosion
min. 200
no access
Beams to walls
Corrosion at concrete interface
sacrificial weather plate
Bimetallic corrosion
aluminium
aluminium
insulation
corrosion
steel
steel
Bolts with sleeves and insulation washers
Figure 1.29 Dos and don'ts ± corrosion.
Bimetallic corrosion
29
USE OF STRUCTURAL STEEL
DETAIL
DO
DON'T
REMARKS
no access
Compound members
Maintenance easier
d
min.
d or 100 mm 6
Channels & angles
Corrosion trap
escape eacape hole hole ifif unavoidable unavoidable
Corrosion protection & repainting easier
( )
ds
30 min. ds min. 3
Girder stiffener
40 radius copehole
25 Inclined members
Figure 1.29 Contd
mi
n. Corrosion trap
drainage slot
30
Table 1.12a Typical protective treatment systems for building structures. Steelwork location
3
4
Total paint dry film thickness
HB alkyd finish
±
±
120
Paint
zre
CR alkyd
HB CR finish
±
135
Paint
±
ezs
CR alkyd
HB CR finish
±
185
Paint
Sa 2
±
HB zpa
HB alkyd finish
±
±
135
Paint
Sa 212
±
zre
HB zp
±
200
Paint
±
Hot dip galvanize
Sa 3
±
Environment category
Time
Structure type
Surface preparation
Metal coating
1
2
Interior
A
20±35 years
Buildings
Sa 212
±
HB zpa
Interior
B
15 years
Buildings
Sa 212
±
Interior
C
20 years
Buildings
Sa 3
Exterior
D
10±15 years
General
1 2
Exterior
E
12±18 years
General
Exterior
F
16±24 years
Piece-small fabrication
Exterior
G
16±24 years
General
± ezs
Paint coats
Modified alkyd MIO
Treatment of bolts
±
±
±
85 (min)
Galvanize
CR alkyd
HB MIO CR
HB MIO CR
260
Galvanize
Notes to Table 1.12a 1. Environments: A ± dry heated interiors B ± interiors subject to occasional condensation C ± interiors subject to frequent condensation D ± normal inland E ± polluted inland F ± normal coastal G ± polluted coastal 2. Time indicated is approximate period in years to first major maintenance. The time will be subject to variation depending upon the micro-climate around the structure. Maintenance may need to be more frequent for decorative appearance. 3. The number of coats given is indicative. A different number of coats may be necessary depending upon the method of application in order to comply with the dry film thickness specified. Abbreviations for paint coats: STEEL DETAILERS' MANUAL
CR ± chlorinated rubber ezs ± ethyl zinc silicate HB ± high build MIO ± micaceous iron oxide zp ± zinc phosphate zpa ± zinc phosphate modified alkyd zre ± zinc rich epoxy (2 pack) ± despatch to site and erect
Table 1.12b Summary table of Highways Agency painting specifications for Highway Works Series 1900 ± 8th edition (1998).
Access
System type
Metal spray
1st coat
2nd coat
3rd coat
4th coat
5th coat
MIO AR undercoat
AR finish
Inland
R
4
±
Zinc phosphate AR blast primer
Zinc phosphate AR undercoat
Zinc phosphate AR undercoat
Inland
R
4 Alt
±
Zinc phosphate HB/epoxy primer QD
MIO, HB QD epoxy undercoat
Polyurethane (2 pack) finish or MC polyurethane finish
Marine
R
8
±
Zinc phosphate AR blast primer
Zinc phosphate AR undercoat
Zinc phosphate AR undercoat
Marine
R
8 Alt
±
Zinc phosphate HB QD epoxy primer
MIO, HB QD epoxy undercoat
Polyurethane (2 pack) finish or MC polyurethane finish
Marine
D
10
Aluminium metal spray (100 mm)
Aluminium epoxy sealer
Zinc phosphate AR undercoat
MIO AR undercoat
MIO AR undercoat
Marine
D
10 Alt
Aluminium metal spray (100 mm)
Aluminium epoxy sealer
Zinc phosphate HB QD epoxy undercoat
MIO HB QD epoxy undercoat
Polyurethane (2 pack) finish or MC polyurethane finish
Zinc phosphate HB QD epoxy primer
MIO HB QD epoxy finish
±
T-wash
Zinc phosphate AR undercoat
MIO AR undercoat
Interiors of box girders
R or D
11
Bridge parapets
R or D
13
± Galvanize
±
6th coat
±
250
±
300
AR finish
300
±
300
±
250
±
±
300
±
±
±
200
MIO AR undercoat
±
±
150
MIO AR undercoat ±
±
Minimum total dry film thickness of paint system (mm)
AR undercoat ±
AR finish
USE OF STRUCTURAL STEEL
Environment location
Notes to Table 1.12b 1. Environments: Location of structures. Two locations are considered: `Inland' and `Marine'. Structures out of reach of sea salt spray are considered as being `Inland'. Structures which can be affected by sea salt spray are considered as being `Marine'. 2. Required durability: For the basic systems (except for lighting columns), the periods which will be sufficiently accurate for both access situations and the environments described above are: No maintenance up to 12 years Minor maintenance from 12 years Major maintenance after 20 years. 3. Standards of surface preparation quality and finish should relate to cleanliness (e.g. BS 7079 Part A1/ISO 8501-1) and profile (e.g. BS 7079 Part C to C4/ISO 8503-1 to 4). 4. Details given are based on UK Highways Agency `Specification for Highway Works', Volume 1 ± Series 1900 Protection of Steelwork Against Corrosion, and the accompanying `Notes for Guidance on the Specification for Highway Works', Volume 2 ± Series NG 1900. Abbreviations for paint coats:
31
D ± Difficult R ± Ready AR ± Acrylated Rubber MIO ± Micaceous Iron Oxide HB ± High Build QD ± Quick Drying MC ± Moisture-Cured ± Despatch to site and erect
32
STEEL DETAILERS' MANUAL
1.11 Drawings
Workshop drawings are necessary so that the steelwork
1.11.1 Engineer's drawings
numbers of similar members, but with each having
Engineer's drawings are defined as the drawings which describe the employer's requirements and main details. Usually they give all leading dimensions of the structure including alignments, levels, clearances, member size and show steelwork in an assembled form. Sometimes, especially for buildings, connections are not indicated and must be designed by the fabricator to forces shown on the engineer's drawings requiring submission of calculations to the engineer for approval. For major structures such as bridges the engineer's drawings usually give details of connections including sizes of all bolts and welds. Most example drawings of typical structures included in this manual can be defined as engineer's drawings. Engineer's drawings achieve the following purposes: (1) Basis of engineer's cost estimate before tenders are invited. (2) To invite tenders upon which competing contractors base their prices. (3) Instructions to the contractor during the contract (i.e. contract drawings) including any revisions and variations. Most contracts usually involve revisions at some stage due to the employer's amended requirements or due to unexpected circumstances such as variable ground conditions. (4) Basis of measurement of completed work for making progressive payments to the contractor.
contractor can organise efficient production of large slightly different details and dimensions. Usually each member is shown fabricated as it will be delivered on site. Confusion and errors can be caused under production conditions if only typical drawings showing many variations, lengths and `opposite handing' for different members are issued. Workshop drawings of members must include reference dimensions to main grid lines to facilitate cross referencing and checking. This is difficult to undertake without the possibility of errors if members are drawn only in isolation. All extra welds or joints necessary to make up member lengths must be included on workshop drawings. Marking plans must form part of a set of workshop drawings to ensure correct assembly and to assist planning for production, site delivery and erection. A General Arrangement drawing is often also required giving overall setting out including holding down bolt locations from which workshop drawing lengths, skews and connections have been derived. Often the engineer's drawings are inadequate for this purpose because only salient details and overall geometry will have been defined. Workshop drawings must detail camber geometry for girders so as to counteract (where required and justified) dead load deflection, including the correct inclinations of bearing stiffeners. For site welded connections the workshop drawings must include all temporary welding restraints for attachment and joint root gap dimensions allowing for predicted weld shrinkage. Each member must be allocated a mark number. A system of `material marks'
1.11.2 Workshop drawings Workshop drawings (or shop details) are defined as the
is also usual and added to the workshop drawings so that each stiffener or plate can be identified and cut by the workshop from a material list.
drawings prepared by the steelwork contractor (i.e. the fabricator, often in capacity of a subcontractor) showing each and every component or member in full detail for
1.11.3 Computer aided detailing
fabrication. A requirement of most contracts is that work-
Reference should be made to Chapter 6 Computer Aided
shop drawings are submitted to the engineer for approval,
Detailing for a review of the increasing use of CAD by
but that the contractor remains responsible for any errors or
engineers and steelwork contractors to improve their effi-
omissions. Most responsible engineers nevertheless carry out
ciency and minimise costly errors in their workshop fabri-
a detailed check of the workshop drawings and point out any
cation processes and site construction activities.
apparent shortcomings. In this way any undesirable details are hopefully discovered before fabrication and the chance of error is reduced. Usually a marked copy is returned to the
1.12 Codes of practice
contractor who then amends the drawings as appropriate for
In the UK appropriate UK and other European Standards
re-submission. Once approved the workshop drawings should
for the design and construction of steelwork are as sum-
be correctly regarded as contract drawings.
marised below. The introduction of the new European
33
USE OF STRUCTURAL STEEL
standards has led in recent years to a great deal of discussion and varied interpretation of the design methods which should be used for new structures to be built in the UK or which are designed by British firms for construction overseas.
The following must be satisfied: Specified loads g f
load factor
Material strength g m
material factor
where g m = 1.0 Values of the load factor are summarised in Table 1.13.
Currently some of these new standards Ð or Eurocodes Ð are used alongside the existing UK Codes of Practice for
Table 1.13 BS 5950 Load factors g f and combinations.
design and construction. In the structural Eurocodes, cer-
Loading
tain safety related numerical values such as partial safety factors are only indicative. The values to be used in practice have been left to be fixed by the national authorities in each country and published in the relevant National Application Document (NAD). These values, referred to as `boxed' values, which are used for buildings to be constructed in the UK are set down in the UK NAD, which is bound in with the European CEN text of the relevant Eurocode. The NAD also specifies the loading codes to be used for steel structures constructed in the UK, pending the availability of harmonised European loading information in the Eurocodes. It also includes additional recommendations to enable the relevant Eurocode to be used for the design of structures in the UK. The relevant NAD should always be consulted for buildings to be constructed in any other country. Different design criteria may need to be applied for example in the cases of varied loadings, earthquake effects, temperature range and so on.
Dead load Dead load restraining uplift or overturning Dead load acting with wind and imposed loads combined Imposed loads Imposed load acting with wind load Wind load Wind load acting with imposed load or crane load Forces due to temperature effects Crane loading effects Vertical load Vertical load acting with horizontal loads (crabbing or surge) Horizontal load Horizontal load acting with vertical load Crane load acting with wind load*
Load factor g f 1.4 1.0 1.2 1.6 1.2 1.4 1.2 1.2 1.6 1.4 1.6 1.4 1.2
* When considering wind or imposed load and crane loading acting together the value of g f for dead load may be taken as 1.2. For the ultimate limit state of fatigue and all serviceability limit states g f = 1.0.
In this manual any load capacities give are in the terms of BS 5950 ultimate strength (i.e. material strength g m = 1.0), generally a function of the guaranteed yield stress of the material from EN material standards. They
1.12.1 Buildings
must be compared with factored working loads as given
Steelwork in buildings is designed and constructed in the
is supplied then its appropriate proportions should be
UK to BS 5950. The revised Part 12 published in 2001 is a Code for the design of hot rolled sections in buildings. A guide is available26 giving member design capacities, together with those for bolts and welds. BS 5950 Part 22 is a specification for materials fabrication and erection, and BS EN ISO 1471321 gives guidance on protective treatment. BS 5950 Part 52 deals with cold formed sections. BS 5950 uses the limit state concept in which various limiting states are considered under factored loads. The main limit states are:
by Table 1.13 in satisfying compliance. If a working load multiplied by the load factors from Table 1.13. As an approximation a working load can be multiplied by an averaged load factor of say 1.5 if the contribution of dead and imposed loads are approximately equal. ENV 1993-1 `Eurocode 3: Design of Steel Structures: Part 1.1 General Rules for Buildings (EC3)'23 sets out the principles for the design of all types of steel structures as well as giving design rules for buildings. The transition from BS 5950 to EC3 is inevitably a slow process and for the present, at least, both these two design standards will be used by UK designers.
Ultimate limit state
Serviceability limit state
Strength (i.e. collapse)
Deflection
Stability (i.e. overturning)
Vibration
Fatigue fracture
Repairable fatigue damage
Bridges are designed and constructed to BS 54003 which
Brittle fracture
Corrosion
covers steel, concrete, composite construction, fatigue,
1.12.2 Bridges
34
STEEL DETAILERS' MANUAL
and bearings. It is adopted by the main UK highway and
assessment of material strengths are different so that any
railway bridge authorities. It has been widely accepted in
capacities given in this book, where applicable to bridges,
other countries and used as a model for other Codes. The
should not be used other than as a rough guide.
UK Highways Agency implements BS 5400 with its own standards which in some cases vary with individual Code
ENV 1993-2: 1997 Eurocode 3: Design of Steel Structures:
clauses. In particular the intensity of highway loading is
Part 2: Steel Bridges24 sets out the principles for the design
increased to reflect the higher proportion of heavy com-
of most types of steel road and railway bridges as well as
mercial vehicles using UK highways since publication of the
giving design rules for the steel parts of composite bridges.
code.
For the design of steel and concrete composite bridges ENV 1994-2: Eurocode 4: Part 225 will provide the future design
BS 5400 uses a limit state concept similar to BS 5950. Many
rules. Like building structures, the transition from BS 5400
of the strength formulae are similar but there are addi-
to EC3: Part 2 and EC4: Part 2 is inevitably a slow process
tional clauses dealing with, for example, longitudinally
and for the present, at least, all of these design standards
stiffened girders, continuous composite beams and fatigue.
will be used in the appropriate circumstances by UK
In BS 5400 the breakdown of partial safety factors and the
designers.
2
Detailing Practice
2.1 General
uniform letters and figures that will ensure they can be
Drawings of steelwork whether engineer's drawings or workshop drawings should be carried out to a uniformity of standard to minimise the possible source of errors. Present day draughting practice is a mix of traditional drawing board methods and computer aided detailing systems. Whichever methods are used individual companies will have particular requirements suited to their own operation, but the guidance given here is intended to reflect good practice. Certain conventions such as welding symbols are established by a standard or other code and should be used wherever possible.
read easily and produce legible copy prints. Faint guide lines should be used and trainee detailers and engineers should be taught to practise the art of printing which, if neatly executed, increases user confidence. Experienced detailers merely use a straight edge placed below the line when lettering. The minimum size is 2.5 mm bearing in mind that microfilming or other reductions may be made. Stencils should not be necessary but may be used for view of drawing titles which should be underlined. Underlining of other lettering should not be done except where special emphasis is required. Punctuation marks should not be used unless
2.2 Layout of drawings
essential to the sense of the note.
Drawing sheet sizes should be standardised. BS EN ISO 415728 gives the international `A' series, but many offices use the `B' series. Typical sizes used are shown in Table 2.1. Table 2.1 Drawing sheet sizes. Designation A0* A1* A2 A3* A4* B1
Size mm 1189 6 841 841 6 594 594 6 420 420 6 297 297 6 210 1000 6 707
Main purpose Arrangement drawings Detailed drawings Detailed drawings Sketch sheets Sketch sheets Detailed drawings
* Widely used.
All drawings must contain a title block including company
2.4 Dimensions Arrow heads should have sharp points, touching the lines to which they refer. Dimension lines should be thin but full lines stopped just short of the detail. Dimension figures should be placed immediately above the dimension line and near its centre. The figures should be parallel to the line, arranged so that they can be read from the bottom or right hand side of the drawing. Dimensions should normally be given in millimetres and accurate to the nearest whole millimetre.
name, columns for the contract name/number, client, drawing number, drawing title, drawn/checked signatures, revision block, and notes column. Notes should, as far as possible, all be in the notes column. Figure 2.1 shows
2.5 Projection
typical drawing sheet information.
Third angle projection should be used whenever possible
2.3 Lettering
placed that it represents the side of the object nearest to
No particular style of lettering is recommended but the
detail on a column, which by convention is shown as in
objective is to provide, with reasonable rapidity, distinct
figure 7.5.
(see figure 2.2). With this convention each view is so it in the adjacent view. The notable exception is the base
36
STEEL DETAILERS' MANUAL
841 notes columns A directions of view for detailing
B
C1A column grid number grid letter
A112 beam number floor number grid number grid letter
even numbers odd numbers
fold
594
fold
FIRST FLOOR PLAN
A1 sheet
revision columns REV
DESCRIPTION
INITIAL & DATE
A
Beam A112 was 533 x 210 x 82
A.B. May 2000
title block
LOADS FROM BEAMS MARKING SYSTEM
visible when drawing is folded PROJECT
CONSULTING ENGINEERS
CASS HAYWARD & PARTNERS YORK HOUSE WELSH STREET MONMOUTHSHIRE NP16 5UW
CHEPSTOW
YORK HOUSE CHEPSTOW MULTI-STOREY BUILDING
TITLE
STEELWORK MARKING PLAN
TEL:01291 626994 FAX:01291 626306 Email:
[email protected] Scales 1:50 Drawn Checked Approved Contract No.
1:100 A.B. C.D. E.F. 8002
Drawing No.
8002/3
May 2000 May 2000 May 2000 Rev.
A
Figure 2.1 Drawing sheets and marking system.
2.6 Scales
2.7 Revisions
Generally scales as follows should be used:
All revisions must be noted on the drawing in the revision column and every new issue is identified by a date and issue
1 : 5, 1 : 10, 1 : 20, 1 : 25, 1 : 50, 1 : 100, 1 : 200. Scales should be noted in the title block, and not normally repeated in views. Beams, girders, columns and bracings should preferably be drawn true scale, but may excep-
letter (see figure 2.1).
2.8 Beam and column detailing conventions
tionally be drawn to a smaller longitudinal scale. The sec-
When detailing columns from a floor plan two main views, A
tion depth and details and other connections must be
viewed from the bottom and B from the right of the plan,
drawn to scale and in their correct relative positions. A
must always be given. If necessary, auxiliary views must be
series of sections through a member should be to the same
added to give the details on the other sides, see figure 2.2.
scale, and preferably be arranged in line, in correct sequence.
Whenever possible columns should be detailed vertically on the drawing, but often it will be more efficient to draw
For bracing systems, lattice girders and trusses a con-
horizontally in which case the base end must be at the right
venient practice is to draw the layout of the centre lines of
hand side of the drawing with view A at the bottom and
members to one scale and superimpose details to a larger
view B at the top. If columns are detailed vertically the
scale at intersection points and connections.
base will naturally be at the bottom with view A on the left
37
DETAILING PRACTICE
site bolts CSK n/side CSK f/side shop bolts BOLT SYMBOLS
axis of handing
MARK Opposite hand. `B1X' (shows handed bracket) OPPOSITE HANDING
end plate 140 × 12 × 185 8
617 192
A
425
55
25
185 170
MARK
100 × 100 × 8 RSA (605 lg) 600 CL column
50
50 160 CL beam
A
80 80 CL plt 220 A–A
DIMENSIONING (showing dimension lines, hidden details, centre lines & adjoining member details
1-bracket req'd as drawn mark. `B1'. 1 bracket req'd opp. hand mark. `B1X'. THIRD ANGLE PROJECTION
Figure 2.2 Dimensioning and conventions.
of the drawing and view B at the right. Auxiliary views are
Holes in flanges must be dimensioned from centre-line of
drawn as necessary. An example of a typical column detail
web. Rolled steel angles (RSA), channels, etc. should when
is shown in figure 7.5.
possible be detailed with the outstanding leg on farside with `backmark' dimension given to holes.
When detailing a beam from a floor plan, the beam must always be viewed from the bottom or right of the plan. If a beam connects to a seating, end connections must be
2.9 Erection marks
dimensioned from the bottom flange upwards but if con-
An efficient and simple method of marking should be
nected by other means (e.g. web cleats, end plates) then
adopted and each loose member or component must have a
end connections must be dimensioned from top flange
separate mark. For beam/column structures the allocation
downwards (see figure 7.4).
of marks for members is shown in figure 2.2.
38 On beams the mark should be located on the top flange at the north or east (right-hand) end. On columns the mark should be located on the lower end of the shaft on the flange facing north or east. On vertical bracings the mark should be located at the lower end. To indicate on a detail drawing where an erection mark is to be painted, the word mark contained in a rectangle shall be shown on each detail with an arrow pointing to the position
STEEL DETAILERS' MANUAL
2.12 Bolts Bolts should be indicated using symbolic representation as in figure 2.2 and should only be drawn with actual bolt and nut where necessary to check particularly tight clearances.
2.13 Holding down bolts A typical holding down (HD) bolt detail should be drawn out
required.
defining length, protrusion above baseplate, thread length,
Care should be taken when marking weathering steel to
other HD bolts described by notes or schedules. Typical
anchorage detail pocket and grouting information and
ensure it does not damage finish or final appearance.
notes are as follows which could be printed onto a drawing
2.10 Opposite handing
Notes on holding down bolts
Difficulties frequently arise in both drawing offices and workshops over what is meant by the term opposite hand. Members which are called off on drawings as `1 As Drawn, 1 Opp. Hand' are simply pairs or one right hand and one left hand. A simple illustration of this is the human hand. The left hand is opposite hand to the right hand and vice-versa. Any steelwork item must always be opposite handed about a longitudinal centre or datum line and never from end to end. Figure 2.2 shows an example of calling off to opposite hand, with the item referred to also shown to illustrate the principle. Erection marks are usually placed at the east or north end of an item and opposite handing does not alter this. The erection mark must stay in the position shown on the drawing, i.e. the erection mark is not handed.
or issued separately as a specification.
(1) HD bolts shall be cast into foundations using template, accurately to line and level within pockets of size shown to permit tolerance. Immediately after concreting in all bolts shall be `waggled' to ensure free movement. (2) Temporary packings used to support and adjust steelwork shall be suitable steel shims placed concentrically with respect to the baseplate. If to be left in place, they shall be positioned such that they are totally enclosed by 30 mm minimum grout cover. (3) No grouting shall be carried out until a sufficient portion of the structure has been finally adjusted and secured. The spaces to be grouted shall be clear of all debris and free water. (4) Grout shall have a characteristic strength not less than that of the surrounding concrete nor less than 20 N/mm2. It shall be placed by approved means such that the spaces around HD bolts and beneath the baseplate are completely filled.
2.11 Welds Welds should be identified using weld symbols as shown in
(5) Baseplates greater than 400 mm wide shall be provided with at least 2 grout holes preferably not less than 30 mm diameter.
figure 4.4 and should not normally be drawn in elevation
(6) Washer plates or other anchorages for securing HD
using `whiskers' or in cross section. In particular cases it
bolts shall be of sufficient size and strength. They shall
may be necessary to draw weld cross sections to enlarged
be designed so that they prevent pull-out failure. The
scale showing butt weld edge preparations such as for
concrete into which HD bolts are anchored shall be
complex joints including cruciform type. Usual practice is
reinforced with sufficient overlap and anchorage
for workshop butt weld preparations to be shown on sepa-
length so that uplift forces are properly transmitted.
rate weld procedure sheets not forming part of the drawings. Site welds should be detailed on drawings with the dimensions taking into account allowances for weld
2.14 Abbreviations
shrinkage at site. Space should be allowed around the weld
It is economic to use abbreviations in using space eco-
whenever possible so as to allow downhand welding to be
nomically on drawings. A list of suitable abbreviations is
used.
given in Table 2.2.
39
DETAILING PRACTICE
Table 2.2 List of abbreviations. Description
Abbreviate on drawings
Description
Abbreviate on drawings
Overall length Unless otherwise stated Diameter Long Radius Vertical Mark Dimension Near side, far side Opposite hand Centre to centre Centre-line Horizontal Drawing Not to scale Typical Nominal Reinforced concrete Floor level Setting out point Required Section A±A Right angle 45 degrees Slope 1 : 20
O/A UOS DIA or F LG r or RAD VERT MK DIM N SIDE F SIDE OPP HAND C/C C L HORIZ DRG NTS TYP NOM RC FL SOP REQD A±A 908 458
GDR COL BEAM HSFG BOLTS M24 (8.8) BOLTS CSK FPBW BS EN 10025: 1993
20 number required
20 No
Girder Column Beam High strength friction grip bolts 24 mm diameter bolts grade 8.8 Countersunk Full penetration butt weld British Standard BS EN 10025: 1993 100 mm length 6 19 diameter shear studs Plate Bearing plate Packing plate Gusset plate 30 mm diameter holding down bolts grade 8.8, 600 mm long Flange plate Web plate Intermediate stiffener Bearing stiffener Fillet weld Machined surface Fitted to bear Cleat 35 pitches at 300 centres =10 500
203 6 203 6 52 kg/m universal column 406 6 152 6 60 kg/m universal beam 150 6 150 6 10 mm angle 305 6 102 channel
203 6 203 6 52 UC
70 mm wide 6 12 mm thick plate 120 mm wide 6 10 mm thick 6 300 mm long plate 25 mm thick 80 mm 6 80 mm plate 6 6 mm thick
70 6 12 PLT 120 6 10 PLT 6 300
127 6 114 6 29.76 kg/m joist 152 6 152 6 36 kg/m structural tee
1000
406 6 152 6 60 UB 150 6 150 6 10 RSA (or L) 305 6 102 or 305 6 102 CHAN 127 6 114 6 29.76 JOIST 152 6 152 6 36 TEE
50
100 6 19 SHEAR STUDS PLT BRG PLT PACK GUSSET M30 (8.8) HD BOLTS 600 LG FLG WEB STIFF BRG STIFF FW (but use welding symbols!) m/c FIT CLEAT 35 6 300 c/c = 10 500
25 THK 80 SQ 6 6 PLT
3
Design Guidance
3.1 General
Capacities in kN are presented under the following
Limited design guidance is included in this manual for selecting simple connections and simple baseplates which can be carried out by the detailer without demanding particular skills. Other connections including moment connections and the design of members such as beams,
symbols: Connection to beam
Bc Ð RSA cleats
Connection to column
S1 Ð one sided connection Ð
Be Ð End plates maximum
girders, columns, bracings and lattice structures will
S2 Ð two sided connection Ð
require specific design calculations. Load capacities for
total reaction from 2 incom-
members are contained in the Design Guide to BS 595026
ing beams sharing the same
and from other literature as given in the Further Reading. Capacities of bolts and welds to BS 5950 are included in Tables 3.5, 3.6 and 3.7 so that detailers can proportion elementary connections such as welds and bolts to gusset
bolt group Worked example The following example illustrates use of Tables 3.1, 3.2 and
plates etc.
3.3:
3.2 Load capacities of simple connections
Question
Ultimate load capacities for a range of simple web angle
factored end reaction of 750 kN. Design the connection
cleat/end plate type beam/column and beam/beam con-
using RSA web cleats:
A beam of size 686 6 254 6 140 UB in grade S275 steel has a
nections for universal beams are given in Tables 3.1, 3.2 and 3.3. The capacities must be compared with factored loads to BS 5950. The tables indicate whether bolt shear,
(a) To a perimeter column size 305 6 305 6 97 UC, of grade S275 steel via its flange.
bolt bearing, web shear or weld strength are critical so that
(b) To a similar internal column via its web forming a two
different options can be examined. The range of coverage
sided connection with another beam having the same
is listed at the foot of this page.
reaction.
Grade S275 RSA web cleats
Grade S275 end plates
Table
Steel grade
M20 bolts grade
To column
To beam
To columns
To beams
3.1 3.2 3.3
S275 S275 S355
4.6 8.8 8.8
100 6 100 6 10 100 6 100 6 10 100 6 100 6 10
90 6 90 6 10 90 6 90 6 10 90 6 90 6 10
200 6 10 200 6 10 200 6 10
160 6 8 160 6 10 160 6 10
Number of bolt rows to column/ beam Range N11 to N1
Welds to end plate N11 to N6
N5 to N1
8 mm fillet welds
6 mm fillet welds
41
DESIGN GUIDANCE
bearing to 2/10 mm S275 cleats 2 6 101 = 202 kN
Answer
bearing to UB web S275
(a) To perimeter columns
9 mm thick
Connection to beam: 686 6 254 6 140 UB 7 web thickness 12.4 mm From Table 3.1 (grade 4.6 bolts) maximum value of Bc = 556 kN for N8 type which is insufficient. Capacity cannot be increased by thicker webbed beam because bolt shear governs (because value is not in italics). So try grade 8.8 bolts: From Table 3.2 value of Bc = 770 kN for 12 mm web for N8 type = 898 kN for 14 mm web for N8 type Interpolation for 12.4 mm web gives Bc = 796 kN > 750 ACCEPT Connection to column: 305 6 305 6 97 UC 7 flange thickness 15.4 mm From Table 3.2 value of S1 = 1449 kN for 14 mm flange = 1449 kN for 16 mm flange Therefore S1 = 1449 kN for 15.4 mm flange > 750 ACCEPT Therefore connection is N8 with 100 6 100 6 10 RSA cleats, i.e. 8 rows of M20 (8.8) bolts. (b) To internal column connection to beam
Interpolation for 9.9 mm thick gives 100 kN therefore bearing to UC web governs So capacity is 16 bolts 6 100 = 1600 kN > 1500 ACCEPT Therefore M22 (8.8) bolts can be used instead of using grade S355 steel for the column.
3.3 Sizes and load capacity of simple column bases Ultimate capacities and baseplate thicknesses using grade S275 steel for a range of simple square column bases with universal column or square hollow section columns are given in Table 3.4. These capacities must be compared with factored loads to BS 5950. Baseplate thickness is derived to BS 5950-1 clause 4.13.2.2: 1 3w 2 tp c pyp where c
Connection to column: 305 6 305 6 97 UC 7 web thickness 9.9 mm. From Table 3.2, value of S2 = 1178 kN for 8 mm web = 1472 kN for 10 mm web Interpolation for 9.9 mm web gives S2 = 1457 kN < 2 6 750 = 1500 kN Therefore insufficient, but note that bolt bearing is critical (because value is in italics) so try grade S355 steel for
is the largest perpendicular distance from the edge of the effective portion of the baseplate to the face of
Connection to beam As for (a) i.e. N8 type using grade 8.8 bolts.
91 kN
10 mm thick 101 kN
the column cross-section. pyp is the design strength of the baseplate. w
is the pressure under the baseplate, based on an assumed uniform distribution of pressure throughout the effective portion.
Worked example Question The following example illustrates use of Table 3.4:
column.
A 305 6 305 6 97 UC column carries a factored vertical
From Table 3.3, value of S2 = 1408 kN for 8 mm web
ultimate strength of 30 N/mm2. Select a baseplate size.
load of 3000 kN at the base. The foundation concrete has an = 1760 kN for 10 mm web
Interpolation for 9.9 mm web gives S2 = 1742 kN > 1500 ACCEPT Alternatively try larger diameter bolts: For M22 (8.8) bolt: From Table 3.5: giving capacities of single bolts: double shear value = 227 kN
Answer From Table 3.4 width of base for concrete strength 30 N/mm2 is 500 mm for P = 300 kN. Thickness = 30 mm Therefore baseplate minimum size is 500 6 30 6 500 in grade S275 steel.
42
Table 3.1 Simple connections, bolts grade 4.6, members grade S275. See figure 3.1.
STEEL DETAILERS' MANUAL
43
DESIGN GUIDANCE
2/100 × 100 × 10 RSA (S275)
140 beam/column flanges 120 beam/beam
N
10
Bc
r
Bc
[(N –1) × 70] + 70
n = 30 (N5 to N1)
C
(N –1) × 70
35
*
100
D
n = 65 (N11 to N6)
D d +2 2
S1 S1 S2
10 cleat projection
2/90 × 90 × 10 RSA (S275) with 22 dia. holes for M20 (4.6) bolts
65
55
NOTE 100 for N11 to N6 * 65 for N5 to N2
50
100
beam/beam (or column web) 70
35
140
beam column
N1 only
ANGLE CLEATS n = 30 (N5 to N1)
C
140 beam/column flanges 120 beam/beam
N
10
(N –1) × 70
35
*
100
D
n = 65 (N11 to N6)
dD +2 22
Be
r
Be
10 thk. end plate (grade S275) with 22 dia. holes for M20 bolts
S1 (N11 to N6)
100
(N5 to N2)
140
beam column
S1 S2
30
8 8 6 6
N1 only Figure 3.1 Simple connections.
6 6
8 8 6 6 beam/beam (or column web)
END PLATES
(N11 to N6) (N5 to N2)
200 beam/column 170 beam/beam
44
Table 3.2 Simple connections, bolts grade 8.8, members grade S275. See figure 3.1.
STEEL DETAILERS' MANUAL
DESIGN GUIDANCE
Table 3.3 Simple connections, bolts grade 8.8, members grade S355. See figure 3.1.
45
46
Table 3.4 Simple column bases (see figure 3.2 opposite).
STEEL DETAILERS' MANUAL
47
DESIGN GUIDANCE
RHS
UC
6
B 2
B - 25 2
B - 25 2
B 2
B
6 100 6 100
2/M20 holes B 2
B
B 2
6 2/M20 holes
6
B - 25 2
B - 25 2
B
B B < 400
75 75 RHS
6
UC
B - 30 2
6 B - 30 2
B
B - 30 2
M24 holes B - 30 2
B - 30 2
M24 holes
B - 30 2
4/30 dia. grouting holes
B
B
2/30 dia. grouting holes
6
B - 30 2
B - 30 2
6 150 6 150
B B > 400
column end sawn or machine ended and fit tight
tp thick baseplate (grade S275)
2/M16 (4.6) holding down bolts × 400 long with nut and washer at top
4
50 nom. 30 nom.
50 nom. dia. pockets washer plate (see detail)
25
20 × 6 flat to prevent nut turning
min. thread
X
min. thread 12 (M20) 15 (M16)
40 nom.
tp thick baseplate (grade S275)
18 or 22 dia. holes
column end sawn or machine ended and fit tight
40 nom. X 50 nom.
40 nom.
100 × 100 × 6 (S275) washer plate 50 nom. dia. WASHER pockets PLATE DETAIL washer plate (see detail) 4/M20 (4.6) holding down bolts × 500 long with nut and washer at top
Figure 3.2 Simple column bases.
48 Table 3.5 Black bolt capacities. 4.6 Bolts in material grades S275 and S355
8.8 Bolts in material grade S275
8.8 Bolts in material grade S355
STEEL DETAILERS' MANUAL
DESIGN GUIDANCE
Table 3.6 HSFG bolt capacities. In material grade S275
In material grade S355
49
50
STEEL DETAILERS' MANUAL
Table 3.7 Weld capacities. (a) Strength of fillet welds. Leg length mm
Throat thickness mm
Capacity at 215 N/mm2 kN/m
Leg length mm
Throat thickness mm
Capacity at 215 N/mm2 kN/m
3.0 4.0 5.0 6.0 8.0 10.0
2.12 2.83 3.54 4.24 5.66 7.07
456 608 760 912 1216 1520
12.0 15.0 18.0 20.0 22.0 25.0
8.49 10.61 12.73 14.14 15.56 17.68
1824 2280 2737 3041 3345 3801
Capacities with grade E43 electrodes to BS EN 499(29) grades of steel S275 and S355. (b) Strength of full penetration butt welds. Thickness mm
Shear at 0.6 6 Py kN/m
Tension or compression at Py kN/m
Thickness mm
Shear at 0.6 6 Py kN/m
Tension or compression at Py kN/m
Grade of steel S275 6.0 8.0 10.0 12.0 15.0 18.0 20.0
990 1320 1650 1980 2475 2862 3180
1650 2200 2750 3300 4125 4770 5300
22.0 25.0 28.0 30.0 35.0 40.0 45.0
3498 3975 4452 4770 5565 6360 6885
5830 6625 7420 7950 9275 10600 11475
Grade of steel S355 6.0 8.0 10.0 12.0 15.0 18.0 20.0
1278 1704 2130 2556 3195 3726 4140
2130 2840 3550 4260 5325 6210 6900
22.0 25.0 28.0 30.0 35.0 40.0 45.0
4554 5175 5796 6210 7245 8280 9180
7590 8625 9660 10350 12075 13800 15300
4
Detailing Data
The following data provide useful information for the
grip 30°
detailing of steelwork. The dimensional information on
s m
d1
standard sections is given by permission of Corus (pre-
d
e
viously British Steel). These sections are widely used in
d2
many other countries. s1 BS 4190 (Grade 4.6)
grip
s
k
BLACK BOLTS & PRECISION BOLTS
BS 3692 (Grade 8.8)
m
clip where required
TAPERED WASHERS
w
flat round washer
l
b
6 g
1.2 d1
d2
e
d
s1
k
l
BS 4395 PART 1
4.76
c
HEXAGON HEAD
grip h
j
d3
38
7
for 5°
8
for 8°
c
90°
8
p
for 8° only c
COUNTERSUNK HEAD
58 OR 88
52
Table 4.1 Dimensions of black bolts.
Ordering example Bolts M24 size 80 mm long, grade 8.8 with standard length of thread. With standard nut grade 8.8 and normal washer. All cadmium plated. Bolts M24 6 80 to BS 3692 ± 8.8 with standard nut and normal washer. All plated to BS 3382: Part 1.
STEEL DETAILERS' MANUAL
Notes The single grade number for nuts indicates one tenth of the proof stress in kgf/mm2 and corresponds with the bolt ultimate strength to which it is matched. It is permissible to use a higher strength grade nut than the matching bolt number. Grade 10.9 bolts are supplied with grade 12 nuts because grade 10 does not appear in the British Standard series.
DETAILING DATA
Table 4.2 Dimensions of HSFG bolts.
Notes to Table 4.1 1. Commonly used sizes are underlined. Non-preferred sizes shown in brackets. Preferred larger diameters are M42, M56 and M64. 2. Bolt length (l) normally available in 5 mm increments up to 80 mm length and in 10 mm increments thereafter. 3. Sizes M16, M20, M24 and M27 up to 12.5 mm length may alternatively have a shorter thread length of 112d, if so ordered. This may be required where the design does not allow the threaded portions across a shear plane. 4. BS 4190 covers black bolts of grades 4.6, 4.8 and 10.9. BS 3692 covers precision bolts in grades 4.6, 4.8, 5.6, 5.8, 6.6, 6.8, 8.8, 10.9, 12.9 and 14.9. Tolerances are closer and the maximum dimensions here quoted are slightly reduced. Notes to Table 4.2 1. `Add to Grip For Length' allows for nut, one flat round washer and sufficient thread protrusion beyond nut. 2. Bolt length (l) normally available in 5 mm increments up to 100 mm length and 10 mm increments thereafter. 10 mm increments are normally stocked by suppliers.
53
Table 4.3 Universal beams ± to BS 4-1: 1993.
D
d 2
to the nearest 2 mm above. C = t/2 + 2 mm to the nearest 1 mm.
54
The dimension N = [B 7 C + 6] to the nearest 2 mm above. n =
STEEL DETAILERS' MANUAL
DETAILING DATA
55
56
Table 4.3 Contd
B S1 C
B S1 N
C
n
N
n
r r
D
d
D
d
t T
S3
S2 S4
T
S3 S3
S2 S4
S3
STEEL DETAILERS' MANUAL
t
Table 4.4 Universal columns. The Dimension N = [B 7 C + 6] to the nearest 2 mm above. D
d 2
to the nearest 2 mm above.
C = t/2 + 2 mm to the nearest 1 mm. To BS 4-1: 1993.
DETAILING DATA
n=
57
Table 4.5 Joists.
n=
D
d 2
58
The Dimension N = [B 7 C + 6] to the nearest 2 mm above. to the nearest 2 mm above.
C = [t/2 + 2] to the nearest 1 mm. To BS 4-1: 1993.
B S1 C
n
r2
d t T
=
=
STEEL DETAILERS' MANUAL
r1 D
N
Table 4.6 Channels. To BS 4-1: 1993. Designation
Depth
Width
Thickness
D
d 2
to the nearest 2 mm above. C = [t + 2] to the nearest 1 mm.
Distance
Root
Toe
radius r1
radius r2
Inside Slope
Depth d
Notch C
N
n
Max.
Area
Surface
S
hole dia.
of Section
Area per metre
Serial size
Mass per metre
D
B
Web t
Flange T
of y ey
mm
kg
mm
mm
mm
mm
cm
mm
mm
degrees
mm
mm
mm
mm
mm
mm
cm2
m2
4326102 3816102
65.54 55.10
431.8 381.0
101.6 101.6
12.2 10.4
16.8 16.3
2.32 2.52
15.2 15.2
4.8 4.8
5 5
362.5 312.6
14 12
94 96
36 36
55 55
20 20
83.49 70.19
1.21 1.11
3056102 305689 254689 254676
46.18 41.69 35.74 28.29
304.8 304.8 254.0 254.0
101.6 88.9 88.9 76.2
10.2 10.2 9.1 8.1
14.8 13.7 13.6 10.9
2.66 2.18 2.42 1.86
15.2 13.7 13.7 12.2
4.8 3.2 3.2 3.2
5 5 5 5
239.3 245.4 194.7 203.9
12 12 11 10
96 84 84 74
34 30 30 26
55 50 50 45
20 20 20 20
58.83 53.11 45.52 36.03
0.96 0.92 0.82 0.774
229689 229676 203689 203676
32.76 26.06 29.78 23.82
228.6 228.6 203.2 203.2
88.9 76.2 88.9 76.2
8.6 7.6 8.1 7.1
13.3 11.2 12.9 11.2
2.53 2.00 2.65 2.13
13.7 12.2 13.7 12.2
3.2 3.2 3.2 3.2
5 5 5 5
169.9 177.8 145.2 152.4
11 10 10 9
84 74 86 74
30 26 30 26
50 45 50 45
20 20 20 20
41.73 33.20 37.94 30.34
0.770 0.725 0.720 0.675
178689 178676 152689 152676
26.81 20.84 23.84 17.88
177.8 177.8 152.4 152.4
88.9 76.2 88.9 76.2
7.6 6.6 7.1 6.4
12.3 10.3 11.6 9.0
2.76 2.20 2.86 2.21
13.7 12.2 13.7 12.2
3.2 3.2 3.2 2.4
5 5 5 5
121.0 128.8 96.9 105.9
10 9 9 8
86 74 86 76
30 26 28 24
50 45 50 45
20 20 20 20
34.15 26.54 30.36 22.77
0.671 0.625 0.621 0.575
127664 102651
14.90 10.42
127.0 101.6
63.5 50.8
6.4 6.1
9.2 7.6
1.94 1.51
10.7 9.1
2.4 2.4
5 5
84.0 65.8
8 8
62 50
22 18
35 30
16 10
18.98 13.28
0.476 0.379
76638
6.72
76.2
38.1
5.1
6.8
1.19
7.6
2.4
5
45.8
7
38
16
22
10
8.56
0.282
DETAILING DATA
The Dimension N = [B 7 C + 6] to the nearest 2 mm above. n =
S C
N
n
y D
d
x
x t ey
r1
= B
T
59
y =
r2
60
Table 4.7 Rolled steel angles: (a) equal (see p. 62). Note: * Not included in BS EN 10056-1: 1999 To BS EN 10056-1: 1999 Designation
Recommended back marks
Thickness t
mm
mm
kg
cm2
cm
mm
mm
mm
mm
2506250
35 32 28 25
128.0 118.0 104.0 93.6
163.0 150.0 133.0 119.0
7.49 7.38 7.23 7.12
±
90
100
36
24 20 18 16
71.1 59.9 54.2 48.5
90.6 76.3 69.1 61.8
5.84 5.68 5.60 5.52
±
75
75
30
18 15 12 10
40.1 33.8 27.3 23.0
51.0 43.0 34.8 29.3
4.37 4.25 4.12 4.03
±
55
55
20
15 12 10 8
26.6 21.6 18.2 14.7
33.9 27.5 23.2 18.7
3.51 3.40 3.31 3.23
±
45
50
16
15 12 10* 8
21.9 17.8 15.0 12.2
27.9 22.7 19.2 15.5
3.02 2.90 2.82 2.74
55
±
±
24
12 10 8 7 6
15.9 13.4 10.9 9.6 8.3
20.3 17.1 13.9 12.3 10.6
2.66 2.58 2.50 2.41 2.46
50
±
±
24
10 8 6
11.9 9.6 7.3
15.1 12.3 9.4
2.34 2.26 2.17
45
±
±
20
2006200
1506150
1206120
1006100
90690
80680
Area of section
Distance of centre of gravity ex, ey
S1
S2
S3
Max. dia. bolt
STEEL DETAILERS' MANUAL
Size B
Mass per metre
61
DETAILING DATA
Table 4.7 Rolled steel angles: (b) unequal (see p. 62). To BS EN 10056-1: 1999 Designation Size
Thickness
D6B
t
Mass per metre
Area of section 2
Recommended back marks
Distance of centre of gravity
Max. dia. bolt For
For
ex
ey
S1
S2
S3
S1
S2 S3
mm
mm
kg
cm
cm
cm
mm
mm
mm
mm
mm
2006150
18 15 12
47.1 39.6 32.0
60.0 50.5 40.8
6.33 6.21 6.08
3.85 3.73 3.61
55
75
75
±
30
2006100
15 12 10
33.7 27.3 23.0
43.0 34.8 29.2
7.16 7.03 6.93
2.22 2.10 2.01
55
75
75
24
30
150690
15 12 10
26.6 21.6 18.2
33.9 27.5 23.2
5.21 5.08 5.00
2.23 2.12 2.04
50
55
55
24
20
150675
15 12 10
24.8 20.2 17.0
31.6 25.7 21.6
5.53 5.41 5.32
1.81 1.69 1.61
45
55
55
20
20
125675
12 10 8
17.8 15.0 12.2
22.7 19.1 15.5
4.31 4.23 4.14
1.84 1.76 1.68
45
45
50
20
20
100675
12 10 8
15.4 13.0 10.6
19.7 16.6 13.5
3.27 3.19 3.10
2.03 1.95 1.87
45
55
±
20
20
100665
10 8 7
12.3 9.94 8.77
15.6 12.7 11.2
3.36 3.27 3.23
1.63 1.55 1.51
35
55
±
±
20
80660
8 7 6
8.32 7.34 6.34
10.6 9.35 8.08
2.55 2.50 2.46
1.56 1.52 1.48
35
45
±
16
20
75650
8 6
7.41 5.67
9.44 7.22
2.53 2.44
1.29 1.21
28
45
±
12
20
65650
8 6 5
6.76 5.18 4.36
8.61 6.59 5.55
2.12 2.04 2.00
1.37 1.30 1.26
28
35
±
12
20
60630
6 5
4.00 3.38
5.09 4.30
2.20 2.16
0.73 0.68
20
35
±
±
16
40625
4
1.92
2.45
1.36
0.62
15
23
±
±
12
62
STEEL DETAILERS' MANUAL
y
ey
t
B
S3 r1 S2
x
r2 x
ex
t
y S1 B
Equal angles (a)
y
ey
t
B
S3 r1
r2 x
x S2
ex
t
y S1 B
Unequal angles (b)
63
DETAILING DATA
D
tolerance on radius 0.5 t to 2.0 t
D t
Table 4.8 Square hollow sections. * Thickness not included in BS EN 10210-2: 1997
Designation
Surface area per metre
Designation
Size DxD
Thickness t
m2
mm
mm
kg
cm2
m2
1.42 1.72
0.076 0.075
120 x 120
1.43 1.74 2.15
1.82 2.22 2.74
0.096 0.095 0.093
5.0 6.3 8.0 10.0
18.0 22.3 27.9 34.2
22.9 28.5 35.5 43.5
0.469 0.466 0.463 0.459
140 x 140
2.5* 3.0* 3.2
2.14 2.51 2.65
2.72 3.20 3.38
0.115 0.114 0.113
5.0 6.3 8.0 10.0
21.1 26.3 32.9 40.4
26.9 33.5 41.9 51.5
0.549 0.546 0.543 0.539
40 x 40
2.5* 3.0* 3.2 4.0
2.92 3.45 3.66 4.46
3.72 4.40 4.66 5.68
0.155 0.154 0.153 0.151
150 x 150
50 x 50
2.5* 3.0* 3.2 4.0 5.0
3.71 4.39 4.66 5.72 6.97
4.72 5.60 5.94 7.28 8.88
0.195 0.194 0.193 0.191 0.189
5.0 6.3 8.0 10.0 12.5 16.0
22.7 28.3 35.4 43.6 53.4 66.4
28.9 36.0 45.1 55.5 68.0 84.5
0.589 0.586 0.583 0.579 0.573 0.566
180 x 180
3.0* 3.2 4.0 5.0
5.34 5.67 6.97 8.54
6.80 7.22 8.88 10.9
0.234 0.233 0.231 0.229
6.3 8.0 10.0 12.5 16.0
34.2 43.0 53.0 65.2 81.4
43.6 54.7 67.5 83.0 104
0.706 0.703 0.699 0.693 0.686
200 x 200
70 x 70
3.0* 3.6 5.0
6.28 7.46 10.1
8.00 9.50 12.9
0.274 0.272 0.269
6.3 8.0 10.0 12.5 16.0
38.2 48.0 59.3 73.0 91.5
48.6 61.1 75.5 93.0 117
0.786 0.783 0.779 0.773 0.766
80 x 80
3.0* 3.6 5.0 6.3
7.22 8.59 11.7 14.4
9.20 10.9 14.9 18.4
0.314 0.312 0.309 0.306
250 x 250
90 x 90
3.6 5.0 6.3
9.72 13.3 16.4
12.4 16.9 20.9
0.352 0.349 0.346
6.3 8.0 10.0 12.5 16.0
48.1 60.5 75.0 92.6 117
61.2 77.1 95.5 118 149
0.986 0.983 0.979 0.973 0.966
300 x 300
100 x 100
4.0 5.0 6.3 8.0 10.0
12.0 14.8 18.4 22.9 27.9
15.3 18.9 23.4 29.1 35.5
0.391 0.389 0.386 0.383 0.379
10.0 12.5 16.0
90.7 112 142
116 143 181
1.18 1.17 1.17
350 x 350
10.0 12.5 16.0
106 132 167
136 168 213
1.38 1.37 1.37
400 x 400
10.0 12.5 16.0
122 152 192
156 193 245
1.58 1.57 1.57
Size DxD
Thickness t
mm
mm
kg
cm2
20 x 20
2.0 2.5*
1.12 1.35
25 x 25
2.0* 2.5* 3.2*
30 x 30
60 x 60
Area of section A
Area of section A
Surface area per metre
Mass per metre M
Mass per metre M
64
STEEL DETAILERS' MANUAL
B
tolerance on radius 0.5 t to 2.0 t
D t
Table 4.9 Rectangular hollow sections. * Thickness not included in BS EN 10210-2: 1997
DETAILING DATA
Table 4.10 Circular hollow sections. * Thickness not included in BS EN 10210-2: 1997
65
66
STEEL DETAILERS' MANUAL
Table 4.10 Contd
D
t
67
DETAILING DATA
d X 30° r
C
r
t
ey
Y
Y ex X
D
Table 4.11 Metric bulb flats. Depth
Thickness
Bulb Height
Bulb Radius
Area of section
b
t
c
r1
A
Size mm
mm
mm
mm
mm
cm2
kg/m
120 6 6 7 8 140 6 6.5 7 8 10 160 6 7 8 9 11.5 180 6 8 9 10 11.5 200 6 8.5 9 10 11 12 220 6 9 10 11 12 240 6 9.5 10 11 12 260 6 10 11 12 280 6 10.5 11 12 13 300 6 11 12 13 320 6 11.5 12 13 14
120
6 7 8 6.5 7 8 10 7 8 9 11.5 8 9 10 11.5 8.5 9 10 11 12 9 10 11 12 9.5 10 11 12 10 11 12 10.5 11 12 13 11 12 13 11.5 12 13 14
17 17 17 19 19 19 19 22 22 22 22 25 25 25 25 28 28 28 28 28 31 31 31 31 34 34 34 34 37 37 37 40 40 40 40 43 43 43 46 46 46 46
5 5 5 5.5 5.5 5.5 5.5 6 6 6 6 7 7 7 7 8 8 8 8 8 9 9 9 9 10 10 10 10 11 11 11 12 12 12 12 13 13 13 14 14 14 14
9.31 10.5 11.7 11.7 12.4 13.8 16.6 14.6 16.2 17.8 21.8 18.9 20.7 22.5 25.2 22.6 23.6 25.6 27.6 29.6 26.8 29.0 31.2 33.4 31.2 32.4 34.9 37.3 36.1 38.7 41.3 41.2 42.6 45.5 48.4 46.7 49.7 52.8 52.6 54.2 57.4 60.6
7.31 8.25 9.19 9.21 9.74 10.83 13.03 11.4 12.7 14.0 17.3 14.8 16.2 17.6 19.7 17.8 18.5 20.1 21.7 23.2 21.0 22.8 24.5 26.2 24.4 25.4 27.4 29.3 28.3 30.3 32.4 32.4 33.5 35.7 37.9 36.7 39.0 41.5 41.2 42.5 45.0 47.5
Designation
140
160
180
200
220
240
260 280
300 320
Mass per metre
Surface Area
Centroid
Moment of inertia
Modulus
ex
Ixx
Zxx
m2/m
cm
cm4
cm3
0.276 0.278 0.280 0.319 0.320 0.322 0.326 0.365 0.367 0.369 0.374 0.411 0.413 0.415 0.418 0.456 0.457 0.459 0.461 0.463 0.501 0.503 0.505 0.507 0.546 0.547 0.549 0.551 0.593 0.593 0.595 0.636 0.637 0.639 0.641 0.681 0.683 0.685 0.727 0.728 0.730 0.732
7.20 7.07 6.96 8.37 8.31 8.18 7.92 9.66 9.49 9.36 9.11 10.9 10.7 10.6 10.4 12.2 12.1 11.9 11.8 11.7 13.6 13.4 13.2 13.0 14.8 14.7 14.6 14.4 16.2 16.0 15.8 17.5 17.4 17.2 17.0 18.9 18.7 18.5 20.2 20.1 19.9 19.7
133 148 164 228 241 266 316 373 411 448 544 609 665 717 799 902 941 1020 1090 1160 1296 1400 1500 1590 1800 1860 2000 2130 2477 2610 2770 3223 3330 3550 3760 4190 4460 4720 5370 5530 5850 6170
18.4 21.0 23.6 27.3 29.0 32.5 39.9 38.6 43.3 47.9 59.8 55.9 62.1 67.8 76.8 74.0 77.7 85.0 92.3 99.6 95.3 105 113 122 123 126 137 148 153 162 175 184 191 206 221 222 239 256 266 274 294 313
68
STEEL DETAILERS' MANUAL
Table 4.11 Contd Depth
Thickness
Bulb Height
Bulb Radius
Area of section
b
t
c
r1
A
Size mm
mm
mm
mm
mm
cm2
kg/m
340 6 12 13 14 15 370 6 12.5 13 14 15 16 400 6 13 14 15 16 430 6 14 15 17 20
340
12 13 14 15 12.5 13 14 15 16 13 14 15 16 14 15 17 20
49 49 49 49 53.5 53.5 53.5 53.5 53.5 58 58 58 58 62.5 62.5 62.5 62.5
15 15 15 15 16.5 16.5 16.5 16.5 16.5 18 18 18 18 19.5 19.5 19.5 19.5
58.8 62.2 65.5 69.0 67.8 69.6 73.3 77.0 80.7 77.4 81.4 85.4 89.4 89.7 94.1 103 115
46.1 48.8 51.5 54.2 53.1 54.6 57.5 60.5 63.5 60.8 63.9 67.0 70.2 70.6 73.9 80.6 90.8
Designation
370
400
430
Mass per metre
Surface Area
Centroid
Moment of inertia
Modulus
ex
Ixx
Zxx
m2/m
cm
cm4
cm3
0.772 0.774 0.776 0.778 0.839 0.840 0.842 0.844 0.846 0.907 0.908 0.910 0.912 0.975 0.976 0.980 0.986
21.5 21.3 21.1 20.9 23.6 23.5 23.2 23.0 22.8 25.8 25.5 25.2 25.0 27.7 27.4 26.9 26.3
6760 7160 7540 7920 9213 9470 9980 10490 10980 12280 12930 13580 14220 16460 17260 18860 21180
Cranequip pad Mk.6 RB series Cranequip clip 9000 series
Cranequip clip 4000 series
610 × 305 × 149 UB
always check check for for minimum minimum beam bead width always width CROSS SECTION OF A55 RAIL ON RESILIENT PAD MOUNTING CRANEQUIP WELDED AND BOLTED RAIL FASTENING Table 4.12 Crane rails.
K H F A 45 A 55 A 65 A 75 A 100 A 120 A 150 28 BR 35 BR 56 CR 89 CR CR 73 CR 100 MRS 87A MRS 87B MRS 125
F (mm)
K (mm)
H (mm)
Linear weight (kg/m)
125 150 175 200 200 220 220 152 160 171 178 140 155 152.4 152.4 180
45 55 65 75 100 120 150 50 58 76 102 100 120 101.6 102.4 120
55 65 75 85 95 105 150 67 76 101.5 114 135 150 152.4 152.4 180
22.1 31.8 43.1 56.2 74.3 100 150.3 28.62 35.38 56.81 89.81 73.3 100.2 86.8 86.8 125
313 335 357 379 390 402 428 455 481 476 507 537 568 594 628 700 804
69
DETAILING DATA
mounting with pad
mounting without pad 5
M16
5
Rh C
M16
C
D B
B D
25
F P L
25
N
70
STEEL DETAILERS' MANUAL
mounting with pad
mounting without pad 4
4
Rh M16
C
M16
C
D B
B D
N
8 F S L
8
flat round washer to BS 4395 (for C1) or clipped washer (for C2) socket
washer to BS 4320
clipped washer to BS 4395
8 weld assumed
a
2 min.
r
2 min. for C2
C1 or C2 6 min.
e 2 min.
20 desirable 2 min.
r
h
8 weld assumed
Fabricated Rolled section Black bolts
socket
C1 min.
g b
C1 desirable
8
Fabricated
Rolled section (wrench other end)
HSFG bolts
Typical HSFG power wrench
DETAILING DATA
Table 4.13 Face clearances pitch and edge distance for bolts.
Notes 1. See figure illustrating face clearances. 2. Dimensions of HSFG power wrench from Structural fasteners and their application.30 3. c1 = clearance required for HSFG wrench across. c2 = minimum clearance with clipped washer assuming wrench other end. 4. Minimum desirable pitch for HSFG bolts based on 2 mm clearance between socket and bolt head. 5. BS 5950 edge distances demand as: Rolled edge ± rolled, machined flame cut, sawn or planed edge. Sheared ± sheared or hand plane cut edge and any edge. * These values to be used with caution because reduction in bearing capacity occurs. Distance to value for HSFG bolts, t = minimum thickness of ply.
71
Table 4.14 Durbar floor plate.
72
Commercial quality ± tensile range between 355 and 525 N/mm2 with minimum range of 77 N/mm2 BS EN 10025: S275 Lloyds and other Shipbuilding Societies Specifications. Other specifications by arrangement. Safe uniformly distributed load in kN/m2 on plates simply supported on two sides. Extreme fibre stress : 165 N/mm2.
The above safe loads include the weight of the plate. To avoid excessive deflection, stiffeners should be used for spans over 1.1 metres. Safe uniformly distributed loads in kg/m2 on plates simply supported on four sides. Extreme fibre stress : 16.537 kg/m2.
STEEL DETAILERS' MANUAL
The above safe loads include the weight of the plate. The deflections on the larger spans should be checked and stiffeners used if found to be necessary.
DETAILING DATA
Table 4.14 Contd Standard sizes and weights Width mm 1000 1250 1500 1750 1830
Thickness Range on Plain mm
}
4.5
6.0
8.0
10.0
12.5
±
6.0
8.0
10.0
12.5
Consideration will be given to requirements other than standard sizes where they represent a reasonable tonnage per size, i.e. in one length and one width. Lengths up to 10,000 mm can be supplied for plate 6 mm thick and over.
Weights per square metre or durbar plates kg/m2
4.5 6.0 8.0 10.0 12.5
37.97 49.74 65.44 81.14 100.77
27
Thickness on Plain (mm)*
9 27
t
depth of pattern 1.9 to 2.4
73
74
STEEL DETAILERS' MANUAL
Use Private Public Factory Regular use Occasional
840 min. (1100 fire escapes) clear width
Clear min. width 800 1000
weld or bolt (min. M12) 40 mm min.
1000 750
690 mm 760 mm
610
100 mm max. if used by children
40 mm min.
2000 min. 900 1100
15 (1 00 m 80 sh 0 m in. or in tf . 3– ligh 4 ts ste ps )
pitch line
kicking plate to three sides of landing 100 mm sphere not to pass through (if used by children)
continuous handrail both sides if clear g = going width 1000 min. (prefer 45–50 Ø)
min. of 3 vertical members positioned inside hoops
HANDRAIL CONNECTION TO TOP SAFETY HOOP grind off excess and sharp edges
150 max. 3 min. to 16 max. risers between r= rise landings 16 min.
STAIRCASE (BS 5395: 2000)
4 4
65 × 10 mm min.
4 (this weld for external structure only)
RUNG DETAIL Figure 4.1 Stairs, ladders and walkways.
20 Ø min.
75
DETAILING DATA
CIRCULAR PATTERN
RECTANGULAR PATTERN HOOP DIMENSIONS (EEUA HANDBOOK No. 7) (Bottom hoop to be 2500 above floor)
VERTICAL LADDER
SLOPING LADDER OVER 758 STAIRS, LADDERS AND STEP LADDERS (EEUA HANDBOOK No. 7) Note: Ladders to be provided with hoops where rise exceeds 2Ð3 m
Figure 4.1 Contd
ACCESS WALKWAYS
STEP LADDER 65Ð758
76
STEEL DETAILERS' MANUAL
normal structure gauge for overbridge
railway operational structures
kinematic envelope
250 normal 100 min.
variant see note *
station platform
3020 2500
570
1469 1624
running edge nominal standard gauge 1432
50 730 300
3400
2340
8080
RAILWAY STRUCTURE GAUGE Standard gauge
railway structure gauge standard gauge
4500
2800
1500
4000 3500
4250
5500
ACCOMMODATION BRIDGE
CATTLE UNDERPASS
FARM TRAFFIC
1500 (over railway)
50 min.
1150 (1800 bridleway)
2450 (2750 if > 23 m long) 1800
FOOTBRIDGE
Figure 4.2 Highway and railway clearances.
rail level
Footway Cycleway SUBWAY
recess for signal wires and cables if required clear as far as possible of permanent obstructions
masts carrying overhead line equipment NOTE * Normal 380 Min. new lines 200 Min. existing 100
normal limit of underbridge etc.
50
2080 2185 2340
structures less than 2 m in length (excluding masts carrying overhead line equipment)
2000 915 (+0, -25)
1364
maximum height
830
of static load gauge
rolling stock 1510
675
3415
4640 minimum
structures on platforms
> | 23 m long > 23 m long 2300 2600 2400 2700
77
DETAILING DATA
ROADWAY HEADROOM H Type Overbridge Footbridge Sign gantry
New construction 5300 5300* 5700
Maintained 5029 5029 5410
* 5700 for >80 km/h
3350 (min. 2000 – 60 km/h) (min. 2600 – 80 km/h)
central reserve 3000 (2000 min.) 1500 min. 1100 min.
H 2000 min.
central reserve 4000 1450 min.
hardshoulder D3 carriageway 3300 11000 H
600 min.
tensioned RHS
250
blocked out beam
50 to 100
high containment
vehicle pedestrian parapet 50 to 100
motorway
1:40
NOTE * Hard strips required if heavy traffic
all purpose over railway
all purpose
8000 1000
CRASH BARRIER TYPES
1500
625
710
175 475
300 min.
150
open box beam
50 150
75 min. 200
vehicle pedestrian
RURAL MOTORWAY
600 min.
1000
150 200
100 × 100 660
75 min.
*
1000 2000
7300 (min. 5500) H 100
*
1:40 typ. RURAL ALL PURPOSE ROAD
MAXIMUM TRANSPORT SIZES (Typical for UK) NORMAL No or little restriction
SPECIAL Restrictions and permission apply
18.3 m
2.9
27.4 m
4.3
4.5
5.0
ROAD
21.0 m
2.4
33.0 m
2.4
12.0 m
SHIP
2.4
CONTAINER
Figure 4.3 Maximum transport sizes.
3.0
2.75
RAIL
2.4
760
300 min.
185
tensioned corrugated beam
50 150
URBAN MOTORWAY 1:40 typ.
underbridge
1:40 typ.
600 min.
1000 1500 over railway
185
1000 min.
600 min.
1:40 typ.
800
underbridge
UNLIMITED BUT NESTING ESSENTIAL FOR ECONOMY DECK CARGO
78
STEEL DETAILERS' MANUAL
WELDING SYMBOLS These welding symbols are based upon BS 499 and are a selection of those most commonly used. They should be used on engineer's & workshop drawings.
weld dimensions (1)
other side
8
reference line fillet weld
6 leg
longitudinal dimensions (2)
75 (225)
6
arrow side
8 pen. butt weld NOTES Ð À Fillet Ð leg length Butt Ð penetration (no dimension indicates full penetration) Á Length of weld (no dimension indicates full length)  For other butt weld symbols see typical butt weld preparations à /G?indicates ground flat and direction
All around
Fillet
Concave fillet
Plug
Spot
G
Site
G Ground flat (4)
Convex as welded
Sealing run
Backing strip
Butt single-V WELDING SYMBOLS EXAMPLES Type
Detail
Symbol
Type
Detail
Symbol
G One side Ð this side
One side Ð fillet Other side partial pen. butt + fillet
Figure 4.4 Weld symbols.
Double V ground flat
8 Double V partial pen.
6 8
6
6 (150)75(225) 6 75 (150)
Weld all around
75
225
225 75 150
75
either or
G
Slot
8 leg
8 6 8
8
6
6 8
8
Welded from this side
6
12
50(100)
50 100 50 15 Ø
Plug
Fillet & butt
Both sides
6 6
6 leg
Fillet
One side Ð hidden side Intermittent Ð both sides staggered
either or
6 6
Butt (3)
6
150
15
(150)
79
DETAILING DATA
TYPICAL BUTT WELD PREPARATIONS Ð full penetration These details are a typical selection only conforming with the recommended preparations in BS EN 1011-1: 1998 and BS EN 1011-2: 2001. Weld preparations should not be detailed on engineers drawings but are required on workshop drawings. Weld & symbol
Thickness T mm
Gap G mm
Angle a
Root face R mm
T
0Ð3 3Ð6
0Ð3 3
Ð Ð
Ð Ð
T
3Ð5 5Ð8 8Ð16
6 8 10
Ð Ð Ð
Ð Ð Ð
5Ð12 > 12
2 2
608 608
1 2
6
458
0
10
208
0
3
608
2
3
608
2
> 20
Ð
208
5
> 20
Ð
208
5
T
5Ð12 > 12
3 3
458 458
1 2
T
> 12
3
458
2
Detail
Open square butt
G
Open square butt backed
G
3–6 Single V butt
a
T
R G Single V butt backed
a > 10
G T
R 3 mm min.
{
2 mm max.
Double V butt
a G R
> 12
T a a G
Asymmetric double V butt
2 3
> 12
R
T
T
a Single J butt
a T
5
R
5 a
Single U butt
5
R Single bevel butt
T
a R G
Double bevel butt
a R G
Figure 4.5 Typical weld preparations.
80
STEEL DETAILERS' MANUAL
TYPICAL PREPARATIONS FOR HOLLOW SECTIONS | 30 mm) Circular Ð butt welds (t >
t
t
t
H
X
H
H
2–3 mm y = 908
Z e
2–3 mm
1–2.5 mm 2–3 mm
d
t
1–2.5 mm
1–2.5 mm
1–2 mm 2–3 mm H
Y
D/2
y = 308Ð908 Detail at X
y = 908
G
t
t
y = 308Ð908 Detail at Z
= =
1–2.5 mm H min = t
t > 6.3
t | 3.2 > 5.0 6.3
H
H 2–3 mm
> 20
2–3 mm D>d
d=D
60° 5–8 mm
6 t > 6.3 End to end
Detail at Y Rectangular Ð butt welds
Circular & rectangular
t
t
t 1–2.5 mm 1–2.5 mm
1–2.5 mm H d X e
Y
D/2
H min = t
Detail at X
y < 608
Detail at Z
t
t 1–2.5 mm
2–3 mm
2–3 mm y = 608Ð908
2–3 mm Where d < D
Z
H
H
H
1–2.5 mm 20–25°
2–3 mm
2–3 mm Where d < D Detail at Y
Where d = D
Rectangular Ð fillet welds (typical for circular)
L
L y > 608
d X
L = Leg length | 308 y>
2 mm max.
2 mm max.
2 mm max.
D/2 y < 608 Detail at X
2 mm max.
L
L Where d < D
90°
Z Y e
Figure 4.5 Contd
L 2 mm max.
Where d = D Detail at Y
L Detail at Z
G 3Ð5 5Ð6 6Ð8
81
DETAILING DATA
Table 4.15 Plates supplied in the `normalised' condition. Plate gauge 1220 >1250 >1300 (mm) 1250 1300 1500 5 12.0 12.0 12.0 6 12.0 13.5 13.5 7 12.0 13.5 13.5 8 13.5 13.5 13.5 9 15.5 15.5 15.5 10 15.5 15.5 15.5 12 15.5 15.5 15.5 12.5 15.5 15.5 15 15.5 15.5 20 15.5 15.5 15.5 15.5 25 30 15.5 15.5 35 15.5 15.5 40 15.5 15.5 45 14.7 14.1 50 13.2 12.7 55 12.0 11.5 60 11.0 10.6 9.2 65 10.1 9.7 8.4 70 9.4 9.0 7.8 75 8.8 8.4 7.3 80 8.2 7.9 6.9 90 12.9 12.4 10.7 100 11.6 11.1 9.7 120 9.7 9.3 8.1 140 8.3 8.0 6.9 150 7.7 7.4 6.5
17.0
>1500 1600 12.0 13.5 13.5 13.5 15.5 15.5 15.5
>1600 1750 12.0 13.5 13.5 13.5 15.5 15.5 15.5
>1750 1800 12.0 13.5 13.5 13.5 15.5 15.5 15.5
>1800 2000 12.0 13.5 13.5 13.5 15.5 15.5 15.5
Plate width (mm) >2000 >2100 >2250 >2500 2100 2250 2500 2750 12.0 12.0 12.0 13.5 13.5 12.5 12.5 13.5 13.5 13.5 13.5 13.5 13.5 13.5 13.5 15.5 15.5 15.5 15.5 15.5 15.5 15.5 15.5 15.5 15.5 15.5 15.5
>2750 >3000 >3050 >3250 >3460 >3500 >3750 3000 3050 3250 3460 3500 3750 4000 12.5 13.5 13.5 15.5 15.5 15.5
12.5 13.5 13.5 15.5 15.5 15.5
12.5 13.5 13.5 15.5 15.5 15.5 15.5 15.5 15.5
15.5 15.5 15.5
15.0 15.0 15.0
17.0
16.0 16.0 16.0 16.0 15.1 12.9 12.0
16.0 16.0 16.0 16.0 13.8 11.8 11.0
16.0 16.0 16.0 16.0 13.4 11.5 10.7
16.0 16.0 16.0 14.5 12.0 10.3 9.6
16.0 16.0 15.3 13.8 11.5 9.8 9.2
16.0 16.0 14.3 12.9 10.7 9.2 8.6
16.5 15.4 14.5 12.9 11.6 9.6 8.3 7.7
16.2 15.0 14.0 13.1 11.7 10.5 8.8 7.5 7.0
16.1 14.8 13.8 12.9 12.0 10.7 9.6 8.0 6.9 6.4
15.8 14.6 13.5 12.6 11.9 10.5 9.5 7.9 6.8 6.3
16.2 14.8 13.7 12.7 11.9 11.1 9.9 8.9 7.4 6.4 5.9
16.7 15.2 13.9 12.9 11.9 11.1 10.4 9.3 8.4 7.0 6.0 5.6
16.5 15.0 13.8 12.7 11.8 11.0 10.3 9.2 8.3 6.9 5.9 5.5
15.0 15.0 15.0 15.0 15.0 15.0 14.0 12.9 11.9 11.0 10.3 9.6 8.6 7.7 6.4 5.5 5.1
12.0 12.0 12.0 12.0 12.0 12.0 12.0 10.0 10.0 10.0 8.0 8.0 7.0 6.0 5.0 5.0 4.5
Maximum Length in Metres. Longer lengths (>17.0 metres) available by arrangement, plates 22.0 metres may be supplied, by agreement at the time of initial enquiry. Not Available
Intermediate Gauges & Widths
Typical Qualities Structural Steels:
Boiler Steels:
Ship Plate:
BS EN 10025 S355JR, JO, J2G3 BS 4360 50D, 50EE ASTM A572-50
BS EN 10028 P295GH, P355 NL1 BS 1501 151/161 (>40 mm) BS 1501 224, 225 ASTM A516 Gr70
Lloyds A (>50 mm) NVA (>50 mm) Lloyds DH36, EH36
For an intermediate gauge (eg 18 mm) please use the nearest gauge shown on the table (ie for 18 use 20 mm) as a guide and refer for precise plate length available for the width band required. For an exact width in a band (eg 2600 mm in 2500 to 2750 mm) please refer for precise length available if required.
Notes 1. Plates >100 mm thick and/or >14.5 tonnes, please refer for confirmation of availability. 2. Plates >80 mm thick and 1250 >1300 >1500 >1600 >1750 >1800 >2000 >2100 >2250 >2500 >2750 >3000 >3050 >3250 >3460 >3500 >3750 (mm) 1250 1300 1500 1600 1750 1800 2000 2100 2250 2500 2750 3000 3050 3250 3460 3500 3750 4000
8 9 10 12 12.5 15 20 25 30 35 40 45 50
13.5
13.5
13.5
13.5
13.5
13.5
13.5
13.5
13.5
13.5
13.5
13.5
13.5
13.5 10.0 10.0 13.5
18.3
15.0 15.0 15.0 18.3(a) 18.3(b) 16.5
15.9 16.7
16.5
15.0 15.0 15.0 15.0 15.0 15.0
12.0 12.0 12.0 12.0 12.0 12.0
This matrix refers to `Normalised Rolled' (NR) only. The matrix can be used as a guide for plates supplied in the `Thermo-Mechanical Controlled Rolled' (TMCR) condition. Note that all TMCR plates >3000 mm wide are supplied by arrangement only; in addition plates 3000 mm wide may have restricted range, please refer for confirmation of requirements.
18.3 Maximum Length in Metres. Not available
Typical Qualities
18.3(a) Longer lengths (>18.3 metres) available by arrangement. Plates 27.4 metres may be supplied, depending on quality, gauge and width. Plates >27.4 to 31.5 metres may be available, for a limited quality and size range, by agreement at the time of initial enquiry.
Structural Steels:
Ship Plate:
BS EN 10025 S355JR, JO, J2G3 BS 4360 50B, C, D (Some qualities have a restricted gauge range)
Lloyds AH32 (12.5±30 mm) Lloyds AH36, DH36 (12.5±30 mm)
18.3(b) Longer lengths (>18.3 metres) available by arrangement, plates 22.0 metres may be supplied, by agreement at the time of initial enquiry. Intermediate Gauges & Widths For an intermediate gauge (eg 18 mm) please use the nearest gauge shown on the table (ie for 18 use 20 mm) as a guide and refer for precise plate length available for the width band required. For an exact width in a band (eg 2600 mm in 2500 to 2750 mm) please refer for precise length available if required.
Notes 1. Plates >14.5 tonnes, please refer for confirmation of availability. 2. Plates can also be supplied in the `Thermo-Mechanically Controlled Rolled' condition by arrangement. 3. Plates >40 mm to 50 mm thick and 3750 mm wide are available by arrangement only. 5. Single plates 2000 mm wide, please refer for confirmation of availability. 6. Plates for Structural, Boiler & Pressure Vessel applications are also available to the requirements of European, ISO, ASTM, ASME, other national and customer standards. 7. Plates for Ship Construction are also available to the requirements of major Classification Societies such as Lloyds Register, American Bureau of Shipping, Det Norske Veritas, Bureau Veritas and Korean Register of Shipping.
5
Connection Details
Following are sketch examples of typical connection
Reference should also be made to a series of publications
details. These show the principles of some of the types of
(see Further Reading, Design, (10), (11) and (12)) produced
connection commonly used. Both simple and continuous
by BCSA and SCI which advocate the adoption of a range of
connections are shown as applicable to beam/column
connections to provide cost-effective design solutions.
structures. A typical workshop drawing of a roof lattice
These books provide details of standardised simple and
girder is included in figures 5.8 and 5.9. Sketches of typical
continuous connections, including capacity tables, dimen-
steel/timber and steel/precast concrete connections are
sions for detailing and information on fasteners.
shown in figures 5.10 and 5.11 respectively.
SIMPLE
D 2 +2 D
Connections are flexible & not suitable for continuous design methods. Frame must be erected braced.
10 cleat projection
Connections must be designed for full continuity but need not be braced.
column ends sawn or machine ended and tight fit
D 2 +2
HSFG bolts
or
BOLTED* CLEATS
WELDED END* PLATE
EXTENDED END PLATE
TONGUE PLATE
8 or 10 thick end plate
twin RSA cleats
UC
CONTINUOUS
* See load capacities in tables 15, 16 & 17
D 2 +2
or
10 cleat projection
HSFG bolts
6 gap HSFG bolts
alternative top cleat SEATING CLEAT
D 2 +3
stiffener if required
8 or 10 thick cleat WELDED WEB CLEAT (suitable light loads)
UC or RHS column WELDED SEATING CLEAT Figure 5.1 Typical beam/column connections.
tee cut from UB
UB stub double web plates BEAM STUB
TEE CONNECTIONS
84
STEEL DETAILERS' MANUAL
SIMPLE
( )
( )
C= t2 +2
N
N 20
n
n
C= t2 +2
CONTINUOUS
10 r
8 or 10 end plates
BOLTED CLEATS
WELDED END PLATE
LAP PLATE
END PLATE
Note! Notch dimensions are illustrated as detailed in table 24 t 2 +10
fitted bearing stiffener if required
WELDED WEB CLEAT (suitable light loads)
Figure 5.2 Typical beam/beam connections.
BEAM OVER
85
CONNECTION DETAILS
SIMPLE
CONTINUOUS
cap plate
HSFG bolts
COLUMN TOP
extended end plates
UC
RHS
RHS
UC UC
RHS
UC
RHS
packs division plate
UC
UC
Figure 5.3 Typical column top and splice detail.
RHS
RHS
column ends sawn or machine ended for full bearing
500 above floor typical
COLUMN SPLICE
column ends sawn or machine ended for full bearing
RHS
UC UC
RHS
86
STEEL DETAILERS' MANUAL
SIMPLE
PINNED
CONTINUOUS 6 gap
sawn or machine bearing edges
BEAM SPLICES
6 gap
copehole double covers (single cover for sections up to 457 UB) COVER PLATES
COLUMN BASES
d
END PLATES
SHEAR PLATE
BOLTED
SITE WELDED
holes in baseplate (d + 4) for tolerance RHS bolt box
grout HD bolt pockets grout filled after erection drainage copehole
(d + 40) nominal EXTENDED FOUR BOLT FLUSH TWO BOLT (Achieves nominal fixity) (Minimal fixity)
Figure 5.4 Typical beam splices and column bases.
LINEAR ROCKER
GUSSETED
BOLT BOXES
87
CONNECTION DETAILS
cap plate UB rafter
UC stanchion
UB rafter
RSA cleat 8 no. bolts
gusset plate 2 no. bolts
tee cleat
gusset plate 6 no. bolts
tee cleat CHS bracing CHS bracing
RSA bracing ex
RSA bracing gusset plate 2 no. bolts
RSA bracing n. mi ax. 0 1 m 40
CHS bracing
gusset plate 2 no. bolts
ex
Figure 5.5 Typical bracing details.
end plate 6 no. bolts tee or RSA cleat
gusset plate 6 no. bolts
BRACING IN ONE PLANE
ex
88
STEEL DETAILERS' MANUAL
RHS & CHS JOINTS
d
12 min. gusset
d sealed plate 20 d min.
4 min. 4
chord RHS (OR CHS) LATTICE JOINT
eccentricity
e
l
ALL ENDS
l ≥ 0.3 × d sin e
RHS (OR CHS) LATTICE OVERLAP JOINT Note! Design must take account of eccentricity
CHS (OR RHS) LATTICE OVERLAP JOINT
d gusset
d min. cap plate stiff plates 4 no. bolts CHS LATTICE MULTIPLE JOINT
tee RSA cleat 1 no. bolt
bracing omitted for clarity
LATTICE GIRDER TO RHS COLUMN CAP
end plates 8 no. bolts FLANGED SPLICE JOINT NOTE: All hollow sections to be fully sealed by welding Figure 5.6 Typical hollow section connections.
89
CONNECTION DETAILS
WELDED check bolt clearance
fitted stiffeners
tee chord tee chords
WELDED TRUSS Ð SITE RIDGE JOINT
n. mi ng 30 to ldi gap w we o all WELDED JOINT
WELDED TRUSS SUPPORT
TRUSS JOINTS BOLTED
backmark back to back RSA chords
ate edi cks m a er int her p s wa BOLTED TRUSS SUPPORT Figure 5.7 Typical truss details.
BOLTED JOINT
ex
BOLTED TRUSS Ð RIDGE JOINT
90
STEEL DETAILERS' MANUAL
30 006 SOP to SOP 10 no. panels at 2500 = 25 000
2503
1
1
2 1
2 1
2 1
2 2
X
see detail 3
2 2
2 2
site splice
2 2
1 2
1 2
1 2
1
1850 CRS
600
2503
1
X
30 000 SOP to SOP
14 971 over 150 × 150 × 6.3 RHS grade S355JO
40
14 971 over 150 × 150 × 6.3 RHS grade S355JO standard purlin cleat
mark this end of girder ‘ridge’
200
200
see detail 4
SOP
SOP
see detail 1
see detail 4
1850 CRS
22 32 S
OP
to
1850 CRS
SO
P
88°51’
91°9’
see bracing member details
91°9’ SOP
see detail 5 55°57’
88°51’ SOP
55°57’
SOP
SOP
see detail 2 240
14 738 over 150 × 100 × 6.3 RHS grade S355JO
14 738 over 150 × 100 × 6.3 RHS grade S355JO 50
GENERAL NOTES: 1. All materials to EN 10025 grade S275JO UOS. 2. All welds 6 fillet both sides of all joints UOS. All hollow sections to be sealed by welding. 3. All bolts M20 (4.6). 4. All holes 22 dia. 5. Treatment Ð see spec. Figure 5.8 Workshop drawing of lattice girder ± 1.
20 GIRDERS REQD AS DRAWN MK T1
240
91
CONNECTION DETAILS
Shoe% 1 No. 350 6 12 PL 6 310 long 1 No. 100 6 12 PL 6 350 long 2 No. 150 6 10 PL (shaped)
3 mm to bracing/chord node point
140 140
65 6 100
240
10 thick fabricated 75 tee section 170 long SOP
35
35
90 ==
8 thick gusset plates at points marked ‘X’ only
DETAIL 2
35
splice plates 250 × 25 × 300 long 300 full strength butt weld 10 holes for M20 HSFG bolts 75 80 75 ==
250 115 115 300
DETAIL 4
55°57’
55°57’ 2082
35
40 splice plates 150 × 20 × 300 long 4 holes for M20 HSFG bolts
90 90
40
35
35
70
200
50 120
standard purlin cleat 130 × 10 PL × 200 long
DETAIL 3
50
170
35
35 60 110 110 60 35
SOP
60 60
1850 chord CRS
350
235
1850 chord CRS
310 12
DETAIL 1
70 150
SOP
DETAIL 5
Bracing mark 100 6 50 6 5 RHS S355JO Ð 1. Bracing mark 90 6 50 6 5 RHS S355JO Ð 2. NOTE! For fabrication works with templating facility this detail not necessary.
Figure 5.9 Workshop drawing of lattice girder ± 2.
92
STEEL DETAILERS' MANUAL
timber battens flooring
plaster ceiling timber noggins wedged between joists and spiked
floor joists notched around steel beam and spiked to bearers
bearing timbers bolted through web
flooring
timber plate shot fixed to flange
timber battens shot fixed to flange
floor joists notched over timber plate and spiked to it
floor joists notched around steel beam
flooring
timber noggins to support ceiling
plaster ceiling fire protective casing and ceiling
timber noggins wedged between joists and spiked
UC section used as beam to provide flush soffit
rafter birdsmouthed over timber plate timber purlin timber purlin and spiked to it M16 (4.6) (4.6) bolt bolt M16 70sq ××33 washer washer plates plates –- 70sq angle anglecleat cleat M16 (4.6) bolts at 1200 c/c – 70sq × 3 washer plates
plaster ceiling
Figure 5.10 Typical steel/timber connections.
galvanised mild steel strap
ceiling joists
93
CONNECTION DETAILS
in situ infill reinforcement
in situ infill
in situ infill shear studs
6
prestressed concrete planks 75 min.
shelf angles 100 × 100 × 12 RSA (typical)
75 (225)
top flange to be notched back near supports to let in flooring planks
prestressed concrete planks 75 min.
prestressed concrete planks
UC
75 min. UB UB
sealant sealant
screed
screed
75 min.
60
‘Omnia’prefabricated prefabricated ‘Omnia’ weldedlattice latticetruss truss welded
60
50 50
‘Omnia’ ‘Omnia’plank plank planks planks maingirder girder bedded main beddedon on plate girder girder plate shearstud stud waterproof shear waterproof (or UB) UB) (or sealant sealant
PART PRECAST DECK USING `OMNIA' SYSTEM
prestressed concrete planks holes for rebars UB cased in concrete
Figure 5.11 Typical steel/precast concrete connections.
prestressed concrete planks
UB
6
Computer Aided Detailing
6.1 Introduction
systems perform what, to the end user, is the same drawing task.
Civil and structural engineers were one of the first groups to make use of computers. The ability to harness the
In the early days much computer draughting development
computer's vast power of arithmetic made matrix methods
was undertaken by large companies who produced and
of structural analysis a practical proposition. From this
maintained their own `in-house' systems. Virtually no
early beginning a whole range of computer programs and
interaction could take place between these individual
associated software have been developed to deal with most
systems, principally due to the inconsistent computer lan-
aspects of analysis and design. In the early days the use of
guage adopted by each company. Also most of these sys-
the computer to produce drawings, while possible, did not
tems were driven by the company's mainframe computer
receive much widespread attention. But now the use of
which lacked sufficient memory, and because other soft-
computers for design and draughting can be said to have
ware was used alongside (accounts, purchasing, etc.), the
been the second industrial revolution.
real time delays in carrying out work produced much frustration among staff.
Computer draughting systems have been available as commercial products since the 1970s. Most of the early
With the evolution of the PC from a non-graphical low spec
systems were developed by the electronics industry to
computer to the modern high-speed graphics workstation
meet its own needs in the production of printed and inte-
the power and the capabilities have developed to put very
grated circuits. To the civil and structural engineer these
sophisticated tools in the hands of the detailer.
early systems seemed little more than electronic tracing machines and of no great practical use. However, they formed the basis for the subsequent developments of systems more suited to construction.
6.2 Steelwork detailing It is a well known fact that structural steelwork is a highly complex three dimensional problem. Within a steel struc-
The use of the computer to produce drawings differs in
ture, connections will often comprise several intersecting
many ways from its use in analysis, design and other
members, originating from any number of different direc-
numeric activities, and computer draughting is sub-
tions. The tasks of resolving such geometry into sound
stantially different from the traditional manual method.
connection details and the production of fabrication drawings have always been extremely problematical.
The equipment now used typically consists of a visual dis-
Traditionally, skilled draughtsmen with many years of
play unit (or monitor) and the computer processor drive
detailing experience have been required.
unit, all of which is known as the `workstation'. A keyboard and mouse complete the equipment. Add-on peri-
The constructional steelwork industry has experienced
pherals might include plotters and scanners. While the
enormous economic and technological upheavals in recent
input to and output from a draughting system are in
years. In order to remain competitive, steelwork con-
graphical form, the computer's own representation of a
tractors have turned to new technologies in order to
drawing is as a mathematical model. This is a very impor-
minimise their costs and meet the tighter deadlines which
tant point as it is the nature of this `model' that dictates
are being imposed by clients. The advent of 2-D and 3-D
the ease or difficulty with which different draughting
CAD modelling of structural steelwork has proved to be one
95
COMPUTER AIDED DETAILING
of the most viable solutions to the problems faced by
draughting. The steelwork structure is modelled in 3-D,
steelwork fabricators.
rather than each item being drawn separately. The draughtsman does not in fact draw, instead he models.
In building design, the principal means of communicating
However, he is still a draughtsman, as the 3-D modelling
design intent is the drawing, whether it is a sketch, a
system is his new tool and it will require his input and
concept design or a construction document. The tradi-
detailing knowledge.
tional method of pen and drawing board requires skilled draughtsmen who over the years have been in ever-
The 3-D model, then, is a complete description of all
decreasing supply. Each item is detailed independently
steelwork, bolts, welds, etc. which constitutes all or part of
and substantial checking is required to ensure that
a steel structure. It may contain any information whatso-
elements fit together. It is difficult to standardise details
ever about any element within the structure. The steel
on a contract divided between several draughtsmen. All
structure actually exists, perfectly to scale, inside the
material lists, bolt lists and computer numerical control
computer. At any stage of the construction of the 3-D
(CNC) programs must be produced manually by interpret-
model, detailed drawings, listings or any other information
ing the detailed drawings. There are many potential
may be produced completely automatically by the system.
sources for error.
Once created, the database of information can be utilised by other parts of the software, to generate data in different
The first CAD systems were effectively electronic drawing
ways such as detail drawings, general arrangements,
boards, allowing the user to create lines, circles, text and
materials lists, numerical control (NC) data, etc. The
dimensions which duplicated the manual process, with the
steelwork contractor knows that if the data (i.e. the model)
objective of creating the same drawing as before. In 2-D
is correct, then all the subsequent data will also be correct,
CAD, basic facilities such as move, copy, rotate, delete,
so there is no need to check the drawings for dimensional
etc. will, however, speed up the process. Some 2-D CAD
accuracy. The 3-D model is the central source of all infor-
systems may have several parametric routines and libraries
mation, as shown in figure 6.1.
specifically for detailing steelwork. These will assist the manual detailing process and enable better standardisation. However, each item is still detailed independently and will generally require the same substantial checking as manual draughting.
tender docs. preliminary drawings
In the links between the designer and detailer, finite element analysis programs required the engineer to directly create a data file, which the analysis program could read. Most packages now have some sort of graphi-
material requirements estimating
crude 3-D model
commercial 3-D drawings, drawings,G.A.s, GAs, typical details
cal input but are aimed specifically at creating analysis model data. 2-D CAD programs are then used to create the drawings that communicate this design intent to the steelwork fabricator. The engineer of course needs software to enable him to model the steel structure for his
contract is awarded architects engineers drawings
own benefit, for analysis/design and integration with other disciplines. The fabricator can then use the resultant steel model with the detailed model returned to the
standard steel connection library – macros
structural analysis member design packages
detailed 3-D model
interactive modelling for non-standard connection details
engineer for checking and monitoring purposes. The relative ease of use and cost-effectiveness of 2-D systems means that they are still a valid solution, particularly for
alldrawings drawings–-G.A.s, GAs, all fabrication details, fitings, 3-D fittings, 3-D views views
interactive library of non-standard connection details
the creation of GAs, especially in the design and build arena.
all material lists members, fittings, bolts, shop and site
management information purchasing, stock control, estimating, prod. planning
all NC data sawing, drilling, punching, notching
The 3-D modelling solution, on the other hand, is an entirely different concept from manual or 2-D CAD
Figure 6.1 The central role of the 3-D modelling system.
96
STEEL DETAILERS' MANUAL
6.3 Constructing a 3-D model of a steel structure
an existing standard library connection. In addition to the
All steelwork structures are created within a 3-D frame-
required to be carried out on the member, for example
work of vertical grids and horizontal datum levels. The
cutting a member to a plane (such as a rafter to the face of
draughtsman will input these into the 3-D model, in
a stanchion) or cutting out parts of members to create
accordance with the architect's or consulting engineer's
openings or notches. The draughtsman must be able to
general arrangement drawings.
easily create and modify any type of detail which it is
creation of actual elements such as plates, bolts and welds, there is also the definition of the operations which are
possible to manufacture in the fabrication workshop. In The sizes of the principal members in a structure will
addition, it must be possible to save interactively modelled
generally have been determined by an engineer. In addi-
details to a library, so that they may be reused on any
tion, end reactions are often supplied to the fabricator for
particular contract.
the design of connections. It is often the case that members will have been offset horizontally and/or vertically from
The 3-D modelling system must allow automatic production
grids and levels to meet architectural requirements.
of output at any stage of the model construction. There are generally two levels in this hierarchy. The first is Phase Ð
The draughtsman will input members into the 3-D model,
this is the subdivision of a building or a contract; it could be
complete with correct sizes, offsets and end reactions (if
a floor or the columns or an independent structure. The
supplied). Modern systems can model the member defini-
second is Lot Ð this is a further subdivision to facilitate
tion as well. This can have significant benefits with com-
planning of fabrication and delivery to site; it could be a
plicated setting-out problems. The definition of principal
lorry load or an erection group. Many steelwork contractors
members will be extremely simple, in fact similar to
manufacture steelwork in phases which are linked to the
drawing lines in 3-D. Initial member definition is done
erection programme. Very often the phase of steelwork is
between set-out points and before connections are added.
allied to the allowable limit carried on a transport lorry. It must therefore be possible to produce a `phased' output of
Having established the geometric layout of the structural
fabrication details, material lists and CNC data from the
frame, the draughtsman must select the types of connec-
3-D model. It should be noted that CNC is not specifically
tions to use. The 3-D modelling system must have a com-
the direct link to the workshop machinery. In fact it is more
prehensive library of different connection types for the
a case of links to the NC machine software systems. DSTV
standard connections used in the construction of commer-
has grown from being a German standard to become the de
cial and industrial buildings. In addition, the library may
facto worldwide standard for the definition of geometry in
also include connections for the cold rolled products of
NC systems for structural steelwork. DSTV is what most
major manufacturers. Figure 6.2 shows part of a typical
systems will now produce by default.
connection library for a 3-D modelling system. In summary then the 3-D modelling system should be capThe connection library should allow the draughtsman to set
able of producing and easily revising all of the following
up all the parameters for any connection type to suit both
different forms of output:
his company's and his client's standards and preferences. A single parametric set up for any connection type can then be applied to all kinds of different configurations and member sizes. The library should also be capable of designing a wide range of common connections (with associated calculation output) for the end reactions input
(1) Shop fabrication details For all members, assemblies and fittings. (2) Full size templates For gusset plates and wrap-around templates for tubes.
by the draughtsman onto the `wireframe' model.
(3) General Arrangement drawings
It is considered essential by many that the 3-D modelling
(4) Erection drawings
Plans, elevations, sections, foundations, etc. system should incorporate a powerful interactive modelling
Realistic 3-D hidden views for any part of the struc-
facility. The term `interactive modelling' is used to
ture.
describe the process of constructing a detail from first principles. This could also be used to modify and enhance
(5) Materials lists Cutting, assembly, parts, bolts, etc.
97
COMPUTER AIDED DETAILING
CAD STANDARD CONNECTION LIBRARY
AMEP - apex moment end plate
ASC - angle seating cleat
BCS - bearing column splice
BFI - bolted flange ‘I’ section
BGP - bolted gusset plate
BIT - bolted ‘I’ truss
BSP - bolted splice plate
CB - cranked beam
CCP - column cap plate
DAC - double angle cleats
EMEP - extended moment end plate
ETP - end toe plate
FEP - flexible end plate
FMEP - flush moment end plate
FP - fin plate
FPH - fin plate for hips
FWE - fully welded end
FWT - fully welded truss
GEP - general end plate
GPB - gusset plate bracing
CGPB - corner gusset plate bracing
GPT - gable post top
HMEP - haunch moment end plate
MSEBC - eaves beam to column
non-bearing NBCS - non bearing column splice
RBP - rectangular base plate
SGP - slotted gusset plate
SPB - stiffener plate bracing
WRC - wall restraint cleat
XGPB - cross gusset plate bracing
Figure 6.2 Typical Standard Steelwork Connection Library.
98
STEEL DETAILERS' MANUAL
(6) CNC manufacturing data
They are becoming platforms to enable software applica-
Direct links to all types of workshop machinery.
tions to model and manipulate `objects' in an intelligent
(7) Interfaces to Management Information Systems (MIS)
way. The concept of `object modelling' is that the defini-
Purchasing, stock control, estimating, production
tion of an object is contained within the object itself upon
management, accounting, databases, etc.
creation. Obviously, the software that created the object
(8) Connection design calculations
in the first place understands what it is and what the data
For standard connections, in accordance with BS 5950
mean. The idea is that different software packages can
and UK industry accepted publications.
access the object and deal with the different aspects of the data as required.
CNC sawing, cutting and drilling machines as well as robot welding machines will derive their instructions from infor-
For instance the various elements of a steel modelling
mation contained within a 3-D model. The entire manage-
system will understand the concepts of what a piece of
ment of steelwork design, manufacture and construction is
steel is, the meaning of a section size, the relevance of a
now in the computerised hands of the Management Infor-
bending moment and connection design forces. If one piece
mation System.
of steel clashes with another, say a beam and a column, or if something changes, then the system has rules or
3-D modelling systems are now well established in the
`methods' to determine what action to take. By creating
structural steelwork industry. Fabricators can already
the model from real components such as beams, columns,
place orders with their suppliers through MIS links from
slabs, etc. on to which the engineer can apply loading and
their 3-D systems. The design and detailing of steel struc-
constraints, and by further defining the type of con-
tures has become more integrated, with consulting engi-
nectivity, the system will determine the appropriate
neers and design offices imparting information to
degree of restraint. This will eventually be taken into
fabricators electronically, instead of providing general
account when the element and connection design is carried
arrangement drawings. However, where a 3-D model has
out.
been created in an engineer's office it generally will exist in some other software model. This will require the transfer of 3-D steel information between different systems. The
6.5 Future developments
Steelwork Detailing Neutral File (SDNF) has become a vir-
The widespread adoption of CAD by all sectors of the con-
tual (if limited) standard to transfer main steel member
structional steelwork industry has enabled drawings to be
positions and sizes.
sent electronically from one office to any other office. The CAD drawing is read into another system, probably using
In recent years CIMsteel Integration Standards CIS/1 and
DXF (data exchange file), to be used as a basis for sub-
now CIS/2 have been developed to provide a means of
sequent drawings. DXF is either a 2-D drawing or a 3-D
transferring complete building model information between
graphical image. It contains no real intelligence. This can
the various types of system employed in the industry. The
give rise to the question of responsibility for data integrity,
CIS are a set of information specifications. They provide
since it is still possible to create a CAD drawing incorrectly.
standards against which the vendors of engineering appli-
Currently, it is the norm that paper representation of the
cation software can develop and implement translators.
CAD drawing and its interpretation are probably viewed as
These translators enable the users of such software to
more valid than an electronic version. Generally, at
export engineering data from one application and import
present, if the engineer wishes to give approval to the
into another. Thus, the CIS (developed from the Eureka
fabricator's work then the only way is still from the detail
CIMsteel Project) can be used to transfer `product data'
drawings, since he has no way of using the data in the
(information about a specific steel frame) between appli-
fabricator's model. Similarly, if the steelwork contractor
cations software packages, whether they are located
wants to issue information to a sub-contractor then he will
within the same company or in different companies.
issue it as paper drawings, or at best as CAD files.
6.4 Object orientation
A 3-D DXF model imported into a 3-D steel modelling system
Traditional CAD systems, such as AutoCAD, are now not
be done. The only benefit is that it can be used as a back-
simply methods of creating lines and text on a drawing.
ground image to which objects can be snapped. Ideally
generally has no use. In certain circumstances it still cannot
99
COMPUTER AIDED DETAILING
what is needed is the intelligent transfer of data between
There are still many problems with this flow of information
systems, whether that information be based on analysis,
which ultimately waste time and money for all those con-
design or detailing. The preferred solution here rests with
cerned. Better use of software technology and applications
the successful adoption by the industry of CIS product
should in the long term be able to improve this situation.
developments.
Those working in structural steelwork have for some time had a wide range of software tools to assist them. There is,
When the model is passed to others in the design chain,
however, a new way of working emerging which involves an
then the data include not only the sizes and positions of
integrated approach with the steelwork supply chain and
members but also the forces, connection design assump-
other disciplines working together to generate full building
tions and any other necessary information. This is the basis
models in 3-D. Steelwork detailers are well advanced in
for co-operative working in a quality assured environment.
their use of models but there is a whole range of tools
The proliferation of the Internet has provided an over-
needed in other parts of the supply chain. These involve
powering means for communicating and sharing the data. It
both the data standards to permit the sharing and transfer
is likely that in the future the data will not be passed from
of information together with the development of the
one company to another but will actually be stored cen-
objects to take full advantage of the opportunities which
trally and accessed by each member of the design team as
can be derived from the emerging technology.
required.
7
Examples of Structures
Following are examples of various types of structures
universal beams, supported by columns formed from UCs.
utilising structural steelwork. Some of these are taken from
The spacing of secondary beams is dictated by the floor
actually constructed projects designed by the authors. The
type, typically 2.5 m to 3.5 m. An important design decision
practices and details shown will be suitable for many
is whether stability against horizontal forces (e.g. due to
countries of the world. The member sizes are as actually
wind or earthquake) is to be resisted using rigid connections
used where shown, but it is emphasised that they might not
or whether bracing is to be supplied and simple connections
always be appropriate in a particular case, because of
used. Alternatively other elements may be available such
variations in loading or requirements of different design
as lift shafts or shear walls, allied with the lateral rigidity of
codes.
floors, to which the steelwork can be secured. In this case temporary stability may need to be supplied using diagonal
A brief description of each structure type is included giving
bracings during erection until a means of permanent
particular reasons for use and any particular influences
stability is provided.
which affect the method of construction or details employed.
The example shown in figures 7.1 to 7.5 is a two-storey office building with floors and roof of composite profiled
7.1 Multi-storey frame buildings
steel decking. Beam to column connections are of simple
Multi-storey steel frames provide the structural skeleton
within certain external walls. Because there are only two
from which many commercial and office buildings are
storeys the columns are fabricated full height without
supported. Steel has the advantage of being speedy to
splices. The top of the columns can be detailed to suit
erect and it is very suitable in urban situations where
future upward extension if required. Connections for the
conditions are restrictive. This is further exploited by the
cantilevered canopy beams are of rigid end plate type.
type and stability is provided by wind bracings installed
use of rapidly constructed floors and claddings. This means that a `dry envelope' is available at the earliest possible
Figure 7.2 is a first floor part plan, being part of the engi-
date so that interior finishes can be advanced and the
neer's drawings, which gives member sizes and ultimate
building occupied sooner. Floor systems used include pre-
limit state beam reactions for the fabricator to design the
cast concrete and composite profiled galvanised metal
connections. Typical connections are shown in figure 7.3.
decking which can also be made composite with the steel
Workshop drawings of a beam and a column are shown in
frame. Such decking is supplied in lengths which span over
figures 7.4 and 7.5 respectively which are prepared by the
several secondary beams and shear studs are then welded
fabricator after designing the connections.
through it. Mesh reinforcement is provided to prevent cracking of the concrete slab.
7.1.1 Fire resistance
The structural layout of beams and columns will largely
Generally, multi-storey steel framed buildings are required
depend upon the required use. Modern buildings require
by Building Regulations to exhibit a degree of fire resis-
extensive services to be accommodated within floors and
tance that is dependent on the building form and size. Fire
this may dictate that beams contain openings. Here cas-
resistance is specified as a period of time, e.g.
tellated or tapered beams can be useful. In general, floors
1 hour, 2 hours, etc., and is normally achieved by insulation
are supported by secondary and main beams usually of
in the form of cladding. The thickness of cladding required
1 2
hour,
101
EXAMPLES OF STRUCTURES
533 × 210 × 82 UB
610 × 229 × 101 UB
C114
C
main beam
D
C1C
762 × 267 × 147 UB
E ground floor foundation 2750
40
wind bracing
C112
see detail 203 × 203 × 52 UC
3500 2920
3
B
610 × 229 × 101 UB 254 × 102 × 28 UB secondary beams
B211
150
1st floor
340 300
2
main beam
concrete slab/metal decking composite with steelwork
canopy beam 152 × 152 × 23 UC
200 canopy
1 A
C122
column
3000
406 × 140 × 39 UBs
2
entrance
150
roof
B221
254 × 102 × 28 UB secondary beams
1
wind bracing 2500 8000
2750
8000
F
KEY PLAN
C PART CROSS SECTION AT LINE * MULTI-STOREY FRAME
wind bracing wind bracing
Figure 7.1 Multi-storey frame building.
3
2 2750
2750
8000 2500
2750
2750
1250
1250
C2A 305 × 127 × 37 UB 80
80
C2/3A
C3A 305 × 127 × 37 UB
A212
80
35
A
80
A214
80
80
8000 2500
35
1
STEELWORK FIRST FLOOR PLAN
A311
305 × 127 × 37 UB
80 80
C3B
B311 C311
180
80
80
305 × 127 × 37 UB
180
305 × 127 × 37 UB
A215 35 35
254 × 102 × 28 UB 254 × 102 × 28 UB
B215 35 35
C212
C215
610 × 229 × 101 UB
254 × 102 × 28 UB
254 × 102 × 28 UB
A213 B212
B213
254 × 102 × 28 UB
35 35 254 × 102 × 28 UB
610 × 229 × 101 UB
C213
260
180 180
GENERAL NOTES 1. Reactions are factored loads to BS 5950 in kN. Bending moments if any in kNm in brackets e.g. [180]. 2. All steel to EN 10025 grade S275. 3. All beam marks to be at north or east end. All column marks to be on flange facing north or east. 4. All beams at 150 below 1st floor except where shown in brackets e.g. (7580). 5. $ indicates the direction of metal decking or cladding. Figure 7.2 Multi-storey frame building.
35 35
C2B 180
B211
762 × 267 × 147 UB
35 254 × 102 × 28 UB
B115 35 35
C112
160
C115
610 × 229 × 101 UB
254 × 102 × 28 UB
35 254 × 102 × 28 UB
100
B112
B113 C113
35 35
C1C 180 254 × 102 × 28 UB
N
406 × 140 × 39 UB
4000
C114
20 [22]
533 × 210 × 82 UB
160
B111
406 × 140 × 39 UB
4000
(-580) 152 × 152 × 23 UC
C
C1B
100 100
B114
20 [22]
C111
(-580) 152 × 152 × 23 UC
B
80
2000 canopy
A211
4000
305 × 127 × 37 UB
wind bracing
C3C
102
STEEL DETAILERS' MANUAL
1
95 × 19 shear studs site welded through metal decking
slab depth adequate to ensure fire insulation requirements metal decking (Holorib shown)
A
1st floor
20mm min. 65
55
30
254×102×28UB
B113
C113
55
TYPICAL AVAILABLE `WELD THROUGH' DECK STUDS
85
40
C114
254 × 102 × 28 UB
reaction 180 kN
trim flange to clear connection
* NOTE: 19 mm studs on some small sections may not meet this requirement.
Ø
reaction 20 kN
H
CL secondary beam
610 × 229 × 101 UB main beam
55
T
T
450 mm or 600 mm if decking secured to beam with fixings at 450 min. C/C
70
70
stud spacing
70
560 cantilever canopy beam 152 × 152 × 23 UC
< 0.4 Ø stud Ø > 19 mm Ø > 2.5 T
min. 35 mm after welding
130
50
< 1.5 Ø
15 mm min.
65
50
stud length < 3 × dia
A L = length after weld
C112 bending moment 22 kNm
L 70 95 120
A CL column 203 × 203 × 52 UC
é 19 19 19
A 10 10 10
H 31.7 31.7 31.7
A±A
NOTE: Section A ± A gives requirements for metal deck flooring to BS 5950 Part 4 and for through-deck stud welding.
C1C
TYPICAL CONNECTIONS AT FIRST FLOOR 1 ±* C GRID REF * Figure 7.3 Multi-storey frame building.
CL
CL 203 × 203 × 52 UC
762×267×147 UB 8000
167 55
65 70
200 × 8 end plate × 420 with 12-22 dia holes at 140 c/c (std N6)
8 8
GENERAL NOTES Unless otherwise stated 1. All material to EN 10025 grade S275 2. All bolts M20 grade 4.6 3. All holes 22 dia 4. Treatment Ð see spec.
Figure 7.4 Multi-storey frame building.
MARK
150
65 420
5 × 70 =350
100
for C212
serial size – 610 × 229 × 101 UB actual size – 602 × 228 × 7871 lg 7887 O/all
1-BEAM REQ'D AS DRAWN & NOTED MK'D C112 1-BEAM REQ'D AS DRAWN & NOTED MK'D C212
WORKSHOP DRAWING Ð BEAM DETAIL
for C112
136 (=N)
1st floor
10 rad
8 8
100
55
MARK
8 (=C)
2742
65
70
CL254 × 102 × 22 UB
2500 1 row shear studs 75 × 19 dia at 150 c/c = 7650 55 55
420
2645
5 × 70 =350
CL254 × 102 × 22 UB 105
200 × 8 end plate × 420 with 12-22 dia holes at 140 c/c (std N6)
103
EXAMPLES OF STRUCTURES
406 × 140 × 39 UB
406 × 140 × 39 UB 3000
3585 65 70 70
column end sawn and fitted tight
150
150
150
35 406 × 140 × 39 UB
3000
610 × 229 × 101 UB
150
610 × 229 × 101 UB
3000 100
5 × 70 = 350
300
3500 ground floor
406 × 140 × 39 UB
3550
340
5 × 70 = 350
100
foundation
140
140
65 70 70
2 grout holes 75 30 dia
75
MARK
100
425 365 = =
A
150
150 150
85 55 40 152
1st floor
roof
serial size – 203 × 203 × 52 UC actual size – 206 × 204 × 6615 long
= = 365 425
3220 152 × 152 × 23 UB
580
A
3390
425 sq × 35 thick base plate with 4 – holes 24 dia for M20 HD bolts
3260
6650 O/all column
GENERAL NOTES 4 – 60 × 8 thick × 100 Unless otherwise stated stiff’s (10 × 10) snipes 1. All steel to EN 10025 grade S275. 2. All welds 6 fillet both sides of all joints. 3. All bolts M20 grade 4.6. 4. All holes 22 dia. 5. Paint treatment Ð see specification.
55
55
A±A
1-COLUMN REQ'D AS DRAWN MK'D Ð C1C WORKSHOP DRAWING Ð COLUMN DETAIL
Figure 7.5 Multi-storey frame building.
is therefore dependent on material type and period of resistance. Traditional materials such as concrete, brickwork and plasterboard are still used but have to a great
BOARD FIXING TO COLUMN
noggings fitted to stanchion
concrete floor slab
extent been replaced by modern lightweight materials such as vermiculite and mineral fibre. Asbestos is no longer used for health reasons. steel straps
Lightweight claddings are available in spray form or board; sprays, being unsightly, are generally used where they will not be seen, e.g. floor beams behind suspended ceilings. Boards can be prefinished or decorated and are fixed typically by screwing mainly to noggins or wrap-around steel straps. Typical arrangements are shown in figure 7.6. The thickness of cladding and fixing clearly affects building details and therefore warrants early consideration.31
corner angle bead
fixing screws, joints also bonded double thickness of board for two hours fire resistance
BOARD FIXING TO FLOOR BEAM Figure 7.6 Multi-storey frame building.
fire cladding board
104
STEEL DETAILERS' MANUAL
7.2 Single-storey frame buildings
the steel frame terminates at least 300 mm below floor
Single-storey frame buildings are extensively used for industrial, commercial and leisure buildings. In many countries of the world they are economically constructed in steel because the principal loads, namely the roof and wind are relatively light, yet the spans may be large, commonly up to about 45 m. Steel with its high strength : weight characteristics is ideally suited. The frame efficiently carries the roof cladding independently of the walls thus offering flexibility in location of openings or partitions. Side cladding is directly attached to the frame which gives stability to the whole building. This system is also ideally suited to structures in seismic areas. Sometimes solid side cladding such as brickwork is used part or full height, and it is often convenient to stabilise this by attachment to the frame although vertical support is independent. Generally
level upon its own foundations. This permits flexibility in future use of the floor which may need to contain openings or basements and be replaced periodically if subjected to heavy use. Any internal walls or partitions are generally not structurally connected to the frame so that there is flexibility in relocation for any different future occupancy. Figure 7.7 shows a number of frame types. A single bay is indicated but multiple bays are often used for large buildings for economy when internal columns are permitted. Portal frames, the most common type, are described in section 7.3. Requirements for natural lighting by provision of translucent sheeting or glazing often govern roof shape and therefore the type of frame. In particular the monitor roof secondary beams
roof truss UB or castellated UB stanchion
pinned connection
fixed base
(e) STANCHION AND BEAM FRAME
secondary beams (a) STANCHION AND TRUSS FRAME
lattice girder main beam lattice beam
pinned base
(f) STANCHION AND LATTICE FRAME
A (b) STANCHION AND LATTICE FRAME
A
section A–A trimmer lattice girders
roof truss (g) STANCHION AND TRIMMER LATTICE FRAME
overhead travelling crane
gantry girder on bracket
fixed base two layer space grid
(c) STANCHION AND TRUSS FRAME WITH LIGHT CRANE
roof truss
gantry girder
EOT crane
B latticed (or battened) stanchion
vertical lights
B fixed base
(d) LATTICE STANCHION AND TRUSS FRAME WITH HEAVY CRANE Figure 7.7 Single-storey frame building.
(h) STANCHION AND SPACE GRID
section B–B
lattice girders
(j) STANCHION AND LATTICE FRAME WITH MONITOR ROOF
105
EXAMPLES OF STRUCTURES
sway link
The wide use of lightweight claddings, especially profiled steel sheeting (usually galvanised and plastic coated in a range of colours), which have largely displaced other
centres adjustable
adjustable packs
materials, permits economic roofs of shallow pitch (typically 1 : 10 or 68). Such cladding is available with an insulation layer, which can, if necessary, be incorporated
slotted holes
level adjustable
type (figure 7.7(j)) provides a high degree of natural light.
below purlin level to produce a flush interior if needed for hygienic reasons. Flat roofs, but with provision for drainage
TYPICAL GANTRY GIRDER DETAIL
falls, covered by proprietary roof decking are also used, but at generally greater expense. Sufficient camber or crossfall must be used to ensure rainwater run-off. Depending upon the required use, provision of a suspended ceiling may also decide the frame type. For industrial buildings internal cranes are usually required in the form of electric overhead travelling (EOT) type supported by gantry girders mounted on the frame. Clearances and wheel loads for the crane (or
Figure 7.8 Single-storey frame building.
cranes) must be considered, which will vary according to the particular manufacturer.
such as space for personnel between end of crane and structures and positioning of power cables must be met.
The structural form most generally used is the portal frame described in section 7.3. Figure 7.7 shows a number of other types. The stanchions and truss type frames (a) and
7.3 Portal frame buildings
(c) are more suited to roofs having pitch greater than 3 : 10.
Steel portal frames are the most common and are a parti-
Presence of the bottom tie is convenient for support of any
cular form of single-storey construction. They became
suspended ceilings, but a disadvantage is that the stanchion
popular from the 1950s and are particularly efficient in
bases must be fixed to ensure lateral stability. The lattice
steel, being able to make use of the plastic method of rigid
stanchion and truss frame (d) is suitable for EOT cranes
design which enables sections of minimum weight to be
exceeding 10 tonnes capacity. Where appearance of the
used. Frame spacings of 4.5 m, 6.0 m and 7.5 m with roof
frame is important or where industrial processes demand
pitch typically 1 : 10, 2 : 10 and 3 : 10 are common. Portal
clean conditions, hollow section members are suitable
frames provide large clear floor areas offering maximum
using triangular lattice girders as (g) or space grids (h). The
adaptability of the space inside the building. They are
latter are uneconomic for spans up to about 40 m, but are
easily capable of being extended in the future and, if
suitable for long spans if internal stanchions are not per-
known at the design stage, built-in provision can be made.
mitted.
Multiple bays are possible. Variable eaves heights and spans can be achieved in the same building and selected internal
Bolted site connections are generally necessary between
columns can be deleted where required by the use of valley
stanchions and roof structure with the latter fabricated full
beams. Portal frames can be designed to accommodate
span length where delivery allows. Truss or lattice roofs
overhead travelling cranes typically up to 10 tonnes capa-
usually have welded workshop connections. Secondary
city without use of compound stanchions.
members in the form of sheeting rails or purlins are usually of cold formed sections (see section 7.3). A vital con-
Normally, wind loads on the gable ends are transferred via
sideration is longitudinal stability, especially during erec-
roof and side bracing systems within the end bays of the
tion, which requires the provision of bracing to walls taking
building to the foundations. The gable stanchions also
account of the location of side openings. Roof bracing is
provide fixings for the gable sheeting rails, which in turn
also necessary except where plan rigidity is inherent such
support the cladding. Cold rolled section sheeting rails and
as with a space grid. Gantry girders for EOT cranes should
purlins are usual, but alternatively hot rolled steel angle
incorporate details which permit adjustment to final posi-
sections are suitable. Various proprietary systems are
tion as shown in figure 7.8, and possible replacement of
available using channel or zed sections. The sleeved system
rails during the life of the structure. Safety requirements
is popular whereby purlins extend over one bay between
106
STEEL DETAILERS' MANUAL
services 12 000 max. typ. 3 10 suspended ceiling CANTILEVER CANOPY
TIED PORTAL
eaves extension 3000 max. typ. 2 10
EOT crane production area EAVES EXTENSION
storage area
PROPPED PORTAL Ð 2 BAY
parapet columns
10
1
EOT crane production area
SIDE CLAD Ð TO RIDGE LEVEL
office
PROPPED PORTAL Ð 2 BAY
crane
cladding
MANSARD PORTAL angle cold-rolled struts sheeting rails
gable stanchions
7500 max. typ.
EXTRA HEIGHT PORTAL
sagrods
TYPICAL GABLE END
C/C portal frames
roof bracing
ROOF BRACING
Figure 7.9 Portal frame buildings.
FLAT BRACED BEAM
eaves beam
eaves height up to 4500
eaves height 4500–7500
SIDE BRACING roof purlins not shown
107
EXAMPLES OF STRUCTURES
UB or RSJ eaves beam eaves flashing
8.8 bolts
gutter bracket
UB rafter
eaves gutter UB cutting
cold rolled eaves purlin
6 6
diagonal stays
UB or UC stanchion
sag rod push fit
EAVES (showing cold rolled zed purlins) SAGRODS
ZED PURLINS
RSA brickwork restraint member (if required) • M16 (4.6) bolt each end • slot hole 40 × 18 for vertical alignment
M16 (4.6) bolts typical
cold rolled purlin ‘sleeved’ system shown
45 × 4 × 2 cold rolled angle (or RSA)
UB rafter
DIAGONAL STAYS (adjacent to rafter haunch)
260 cavity brickwork (inner skin is often concrete blockwork)
30
2 no. 30 Ø grout holes
40
30
SIDEWALL (cladding overlapping)
2 no. HD bolts × 400 lg (anchored) typical M20 (4.6) minimum PINNED BASE Figure 7.10 Portal frame buildings.
20 thick baseplate 6
150 × 12 gussets typical
6
25 thick baseplate typical 150 typ.
300 typical minimum
floor slab
FIXED BASE
HD bolts × 500 lg (anchored) typical M20 (4.6) minimum
108
STEEL DETAILERS' MANUAL
used. Either pinned or fixed bases may be used. Main
Span of purlins No. rows > | 4500 Ð > 4500 to 7600 1 > 7600 to 10000 2 Sag rods
ridge capping
frames of tapering fabricated section are used by some fabricators, some of whom offer their own ranges of standard portal designs. cladding profile filler
cladding profile filler
valley gutter
Bracing is essential for the overall stability of the structure especially during erection. Different arrangements from those illustrated may be necessary to accommodate door or
interior ridge trim
window openings. It is important to provide restraint
UB or RSJ valley beam
tee or RSA purlin cleats
against buckling of rafters in the eaves region, this usually being supplied by an eaves beam together with diagonal
grade 8.8 gusset plate (or UB cutting haunch bolts for large spans) RIDGE
stays connected to the purlins. Wind uplift forces often exceed the dead weight of portal frame buildings due to VALLEY
low roof pitch and light weight, such that holding down bolts must be supplied with bottom anchorage. Reversal of bending moments may also occur at eaves connections.
verge trim
purlin cleat
cold rolled purlin 139.7×5 CHS roof bracing (S275 JO) 165 × 152 × 27 tee (S275) (ex.305 × 165 × 54 UB) UB gable stanchion
UB gable trimmer beam
ridge height from FFL
eaves height from FFL
1
300 min. typical
3.1 m above ground level. It is typical of small supporting steelwork within industrial complexes and was installed inside a building. It comprises a main frame with four rigid connections supporting the vessel cradle supplied by
rafter stays
rafter10(typ)
brick cladding
12 tonnes and 1.9 m diameter 6 5.2 m long, approximately
others. Access platforms are provided at two levels below
purlin s e centr
height to top of crane rail
The structure supports a carbon dioxide vessel weighing
columns and beams made as one welded fabrication with
GABLE END
cold rolled purlins
7.4 Vessel support structure
centres of crane girders haunch FFL
span 15 000 to 40 000 typical
stanchion TYPICAL PORTAL FRAME Figure 7.10 Contd
and above the vessel with hooped access ladders.
Drawing notes (1) All steel to be EN 10025 grade S275 UOS. (2) All bolts to be black bolts grade 4.6. To be M16 diameter UOS. (3) All welds to be fillet welds size 5 mm UOS continuous on both sides of all joints. (4) Protective treatment all at workshop: Grit blast 2nd quality and zinc rich epoxy prefabrication primer. 2 coats zinc rich epoxy paint after fabrication.
portal frames, but are made continuous over intermediate portals by a short sleeve of similar section. The systems often offer a range of fitments including rafter cleats, sag rods, rafter restraints, eaves beams, etc. Main frame members are normally of universal beams with universal columns sometimes being used for the stanchions only. Tapered haunches (formed from cuttings of rafter section) are often introduced to strengthen the rafters at eaves, especially where a plastic design analysis has been
Total nominal dry film thickness 150 microns.
109
EXAMPLES OF STRUCTURES
platform supports 203 × 133 × 25 UBs
10
0 30 1146
660
vessel cradle
10 plt
520 580 1100
90
300
254
35 grout
110 35
2700
1603
3800
CL platform and vessel
3000 CRS END VIEW `B±B'
Figure 7.11 Vessel support structure.
110
STEEL DETAILERS' MANUAL
510 622
900 1100
580
B
1373 2500 SOPs 2703 6865 o/all platform
60 × 60 × 8 RSA bracing
C
10 250
kick flat A
203
Ps
A
C support beam 2245
2440 ELEVATION
Figure 7.12 Vessel support structure.
254
B
35 grout
2446 2706 o/all column
10 225
1000
93
SO
1330
34
12 tonne vessel
1025
4155 o/all ladder 900 2355 12 CRS at 235 = 2820
10 102
1520
111
EXAMPLES OF STRUCTURES
360
1135 1017
400
36 ra 0 8 d
245 360
10 thk durbar floor plate
450
400
103
300
203 × 133 × 25 UB platform beams
8 212 212 8 440
1000
1000
37
SO Ps
1145
3000
Ps
SO
36 65
09
2794 SOPs 2100 CRS
1500 1100
203 × 203 × 52 UC 1290
1500 1100
203 × 203 × 52 UC
100 × 100 × 8 RSA bracing
245 605
927
450
928 2245 SOPs
103
400
100 × 100 × 8 RSA bracing
203 × 133 × 25 UB platform beams
750
2440 SOPs 5290
8 70 325
D 8 70 325
F
2686 2706 o/all column
cleat as section F–F
400
4/203 × 203 × 52 UCs 2486 long
3
section F–F
230 sq. base plates × 10 thick with 4 – 22 dia. holes 60
115 2440
G
115
60 D
35 70 35 140 section G–G
115
60
D-D
3000 C-C
1 ± SUPPORT PLATFORM REQ'D AS DRAWN Figure 7.13 Vessel support structure.
54
G
35 50 4
CL UC
60
F
115
10
10 360 10
200 203 260
10
E
200 250100 10
70
360
10
70 E
10
PLAN VIEW A-A At deck level
112
STEEL DETAILERS' MANUAL
75
230 × 10 thick cap plates × 730 long with 2 – 18 × 48 long slot holes 115115
10 2442 2462
203 × 133 × 25 UB × 2442 long
SOP
4/270 × 10 shaped plates × 300
100
200 200 600
100
300 300 600
10
65
300
48 long
203 × 203 × 52 UC × 2794 long
203 × 203 × 52 UC × 2794 long
PLAN E-E 100 × 100 × 8 RSAs with 100 18 dia. hole required 65 one column only
203 203
35
240 70 100 70
55
203 × 133 × 25 UB × 2432 long
8
730 545 185 15 15
100 × 100 × 8 long bracing
134 32 70 32
60
90
g Ps cin SO bra 09 ll 37 o /a 74
230
203 × 133 × 25 UB × 2432 long
35
2100
SOP
600 sq. base plate × 10 thick with 2 – 22 dia. holes
PLAN ON BASE PLT
2 - COLUMNS REQ'D AS DRAWN Figure 7.14 Vessel support structure.
7.5 Roof over reservoir
Drawing notes
The roof provides a protective covering over a fresh water
(1) All steel to be EN 10025 grade S275 UOS.
reservoir with a span of about 19.5 m which is clad with
(2) All bolts to be black bolts grade 4.6 UOS.
profiled steel sheeting. It comprises pitched universal beam rafters which are tied at eaves level with RSA ties because the reservoir edge walls are not capable of resisting outward horizontal thrust. The ties are supported
To be M16 diameter UOS. (3) All welds to be fillet welds size 6 mm UOS continuous on both sides of all joints. (4) Protective treatment:
from the ridge at mid-length to prevent sagging. Roof plan
Grit blast 2nd quality and zinc rich epoxy prefabrica-
bracing is supplied within one internal bay to ensure
tion primer.
longitudinal stability of the roof
One coat zinc rich epoxy paint at workshop. One coat zinc rich epoxy paint at site after erection. Total nominal dry film thickness 150 microns.
113
EXAMPLES OF STRUCTURES
zed purlin
356 × 171 × 45 rafter
80 × 80 × 8 RSA (S275) gable post 80 × 80 × 8 RSA (S275) sheeting rail
80 × 80 × 8 RSA (S275)
100 × 100 × 8 baseplate 25 nom 55 575 1/M16 HD bolt
CL frame 34
203 237
GABLE END DETAILS
100 × 100 × 8 RSA (S275) plan bracings
CL wall and bearing
frame
frame
frame
frame
9 bays × 6.175 = 55 575 19 591 c/c HD bolts 1500 10°
1727 205 nominal
2400 (approx.)
frame
55 169 inside of walls
gable frame (no tie bar) ridge level 1500
frame
frame
frame
gable post
1500
80 × 80 × 8 RSA tie rod hanger 356 × 1 71 × 45 UB (S3 55 JR) rafte
rs
100 × 65 × 8 RSA tie
top of wall
brick on edge coping
brick lining 225 concrete 300 concrete base Figure 7.15 Roof over reservoir.
100 × 65 × 8 RSA 2 – M24 – 8.8 bolts each end TYPICAL CROSS SECTION
114
STEEL DETAILERS' MANUAL
sheeting – galvanized steel CORUS Longrib 900 – 0.70 mm or similar
200 × 100 × 10 RSA (S275) zed purlin ‘Metsec 23224 overlap’ or similar – galvanized CL 100 100
1–sag bar per bay
alternative purlins
10 10
40 45
60 × 60 × 8 RSA
80 × 80 × 8 RSA (S275) 2/60 × 60 × 8 (S275) cleats 1/M16 (4.6) bolt 150 × 10 × 200 base plate
A
60 50 nom. 119
118
6 6
200 2/M24 (8.8) 1500 to CL 2/180 × 15 end plates 100 × 100 × 8 RSA (S275) plan bracing 6/M24 (8.8) bolts (centre bay only) 1/M16 bolt (4.6) 80 × 80 × 8 RSA (S275) each end A tie hanger 1/M20 bolt each end 2/M16 HD bolts × 350 long, threaded 50 mm cast in pockets 50 dia. A–A RAFTER DETAILS
Figure 7.16 Roof over reservoir.
115
EXAMPLES OF STRUCTURES
7.6 Tower
70 × 70 × 6 RSA × 820 long 35 40 40
590
40 40
within an electricity power generating station in India. It
40
The tower is 55 m high and supports electrical equipment was fabricated in the UK and transported piecemeal by ship
18 dia. holes TYPICAL WORKSHOP DETAIL
in containers. The major consideration in the design of tower structures is wind loading due to the height above ground and comparatively light weight of the equipment carried. Open braced structures are usual for towers so as to offer minimal wind resistance. Either hollow sections or former have an advantage in providing for smooth air flow
34
400
rolled angles would have been suitable and although the
5
ra
d.
and thus less wind resistance, the latter were chosen to simplify the connections. Use of bolted connections using ally fabricated using NC saw/drilling equipment. (1)
All steel to be to EN 10025 grade S275 UOS.
(2)
All bolts to be grade 4.6. To be M24 diameter UOS.
safety cage material hoops 50 × 10 flat (S275) straps 50 × 10 flat (S275) all fixing bolts M12 × 40 lg cup head
840
ladder splice (4 no. places)
2 no. 65 × 10 covers (weld to ladder one side of splice)
300 approx.
gusset plates meant that all members could be economic-
ladder stringers o/o 65 × 10 flat rungs o/o 20 dia. bar (S275) Figure 7.17 Tower.
330
CL ladder parallel to slope of tower face
TYPICAL LADDER DETAILS
116
STEEL DETAILERS' MANUAL
10 plate welded inside angle (typical) C 60
1000
10 000
L
A
C
1000
225
5
19C
RS
2483 2154
55 000
×6
0×
5
60
×6
0×
5R
SA
37 970
4000
60
RS
dim. ‘A’
4000
5
RS
A
3
225
SA 5R
0×
0×
×6
PC
×6
60
60
4000
60 × 60 × 5 RSA 60 × 60 × 5 RSA
4000
A
GC
GC
5
4000
GC
A 30
1
Figure 7.18 Tower.
gusset bent so plan bracing is horizontal
GC
7
ELEVATION
5L
SECTION 28-28
SECTION 19-19
9
6500 × 6500
0×
A
1768
A
28K
1000
2863
13
MA
3302
16
5L
o/o 8 plate
A A
0×
A
18 17
C
×6
0×
×6
PC
28H
1000
×6
60
60
7168
1768
60
o/o 8 plate 28J
SECTIONS 23-23 TO 30-30 EXCEPT 28-28
7000
100 × 100 × 12 RSA 90 × 90 × 6 RSA 100 × 100 × 12 RSA 100 × 100 × 12 RSA
5
A
31
11 120 × 120 × 15 RSA
0×
* note diagonal bracing prefixed with section level e.g. 24D, 25D, etc.
*D
23
120 × 120 × 15 RSA
×6
dim. ‘A’ SECTION 3-3 ~ DIM.`A' = 5913 SECTION 7-7 ~ DIM.`A' = 4754 SECTION 11-11 ~ DIM.`A' = 3596
A
C
117
o/o 8 plate 31B
0×
70 × 70 × 6 L
30
225
150
30C
30B
70
6L
×7
883
×6
31
30A
o/o 8 plate 1020
MA
60
31A
C 235
127 × 64
127
EXAMPLES OF STRUCTURES
28X
0×
6L
29A
29
C 1000
10
10 28E
SECTION 31-31 (steelwork at level 31 to be constructed as one welded unit)
70
0 ×7
×6
L
890
A
28X 28G
28C
28
70 × 70 × 6 L 70 ×7 0× 6L 27X
890
A
27C
27B 27A
SA
15B
0×
5R
SA
15B
0× 25X
500
SECTION 15-15
6L
A
×7
CL splice
70
2710
26
70 × 70 × 6 L
80 × 80 × 6 RSA A
26B 26A
60
×6
PC
26C
900
5R
1210
0×
27
70 × 70 × 6 L 6L 0× 7 × 26X 70
25A
25B
25
70 × 70 × 6 L 6L 0× 7 × 70 24X
25C
24A
60 × 60 × 5 L
dim ‘B’
*A
SECTION 2-2 DIM.`B' = 1480. SECTION 4-4 DIM.`B' = 1335. SECTION 6-6 DIM.`B' = 1191. Figure 7.18 Contd
1048 23E
70 × 70 × 6 L 6L 0× 7 × 22X 70
*C
dim ‘B’
23A
23
50 × 50 × 5 RSA
A
6L
23D
0×
23X
typical for each corner
24C
×7
24B
70
8 plate welded to gusset so that plan bracing is horizontal
*A
24
A SECTION 8-8 DIM.`B' = 1191. SECTION 10-10 DIM.`B' = 901.
SECTION C-C (from level 23 up) (showing typical member marks)
52
×6
80 × 80 × 6 RSA
80 × 80 × 6 RSA
80 × 80 × 6 RSA
2710
60
900
127 × 64
118
STEEL DETAILERS' MANUAL
35
35
35
H
SOP 6500
H1
150 sq. × 15 washer plate with keep flat welded to underside to prevent nut turning
45
TYPICAL SPLICE
76.1 × 3.2 CHS
125 125
6430 c/c 35
30 nom. grout
15
65
6430 c/c 35
50
4 nom. gap
65
100 100 154 100 100
11G
450
50
3 thick pack 2/
450 sq. × 40 thick base plate with 34 dia. holes for HD bolts
100 125 125 100
11F
M30 × 700 long grade 8.8 HD bolts with 2 no. M30 nuts and 1 no. washer, bar threaded each end to suit 15 thk (welded) 40 80
4/
490
70 × 12 plate
100 125 125 100 450 TYP. ENLARGED PLAN
nut welded to bolt
H2
ELEVATION
19X
19D
19 ladder stringer 19F
19ES
VIEW ON B-B (between levels 18 & 19 safety cage to ladder omitted)
section 1–1 1
1 18C 18CC
18CB
18CS
18C 18Y
outer splice plt. only
18Z
18AN
18AL
safety bolts required up one main leg from platform up to level 31
18AC 18AM
18AN
18AM
18A 18AK
18AG 18AR
18AJ
18AE
18AK
18AP
18AP
10 dia. earthing holes typical 8 no. places
18E
17X 18B
Figure 7.19 Tower.
18G
17X
18B
18
119
EXAMPLES OF STRUCTURES
7.7 Bridges Several developments since the late 1970s have improved the status for steel in bridges increasing its market share over concrete structures in a number of countries of the world. Developments include: (1)
Fabricators have improved their efficiency by use of automation.
(2)
Stability of steel prices with wider availability in many countries by opening of steel plants.
(3)
Use of mobile cranes to erect large pre-assembled components quickly, thus reducing number of mid-air joints.
(4)
Composite construction economises in materials.
(5)
Permanent formwork or precasting for slabs.
(6)
Improved protection systems using fewer paint coats having longer life.
(7)
Use of unpainted weathering steel for inaccessible bridges.
(8)
Use of site welded or HSFG bolted joints to achieve continuous spans.
(9)
Better education in steel design.
For multiple short (up to 30 m) and medium spans (30 m to 150 m) continuity is common with welded or HSFG bolted site joints to the main members. Articulation between deck and substructures is generally provided using sliding or pinned bearings mounted on vertical piers often of concrete but occasionally steel. Constant depth main girders are usual, with fabricated precamber to counteract deflection. Curved soffits are sometimes used (as shown in figure 7.20). Curved bridges are often formed using straight fabricated chords with change of direction at site splices. Composite deck type cross sections are usual for highway bridges as shown in figure 7.21 and suit the width of modern roads except where construction depth is very restricted when half-through girders are used, especially for railway bridges as shown in figure 7.22. Multiple rolled sections are used for
short spans with plate girders being used when the span exceeds about 25 to 30 m. Intermediate lateral bracings are provided for stability. Sometimes they are proportioned to assist in transverse distribution of live load, but practices vary between different countries. Box girders as shown in figure 7.22 are also used and open top boxes `bathtubs' are extensively used in North America. Problems can arise during construction due to distortion and twisting of open top boxes prior to the rigidifying effect of the concrete slab being realised and temporary bracings are thus essential. Most early composite bridges used in situ slabs cast on removable formwork supported from the steelwork. Recently the high costs of timber and site labour have encouraged permanent formwork. Various types are in use including profiled steel sheeting (especially in the USA), glass reinforced plastic (grp), glass reinforced concrete (grc) and part depth concrete planks. The `OMNIA' type of precast unit is being used (see figure 5.11) which incorporates a welded lattice truss to provide temporary capacity to span up to about 3.5 m between steel flanges, whose lower chord is cast in. Extra reinforcement is incorporated supplemented by further continuous rebars at the `vee' joints to resist live loads. Detailing of the slab needs to be carefully done to avoid congestion of reinforcement and allow proper compaction of concrete. For footbridges steel provides a good solution because the entire cross section including parapets can be erected in one piece. Cross sections are shown in figure 7.23. Economic solutions use half-through lattice or Vierendeel girders with members of rolled hollow section and deck plate with factory applied epoxy-type non-slip surfacing 6 mm or less in thickness. Columns, staircases and ramps are also commonly of steel using hollow sections. For urban areas the
half-through
section
achieves
minimum
length
approach stairs or ramps. Further space can be saved by using stepped ramps which achieve an average slope of 1 in 6 compared with 1 in 10 for sloping ramps.
120
STEEL DETAILERS' MANUAL
230 slab
15 220 overall deck width 510 1100 footway
12 000 carriageway
100 mm surface over protected waterproof membrane (UK practice)
1610
vehicle pedestrian parapet (steel or aluminium)
services bolted connections
girder 1230 to 2330
fascia composite cross girders at 3500 centres external stiffeners at supports only sliding bearing braces at piers only knee braces at 7000 either side of piers
2110 1350 diameter RC pier
maintenance runway beam
11 000 SECTION AT PIERS
RIVER BRIDGE free
free
roadway expansion joint
36 000
free S
S
26 000
36 000
high water level
28 000
S-site splice (bolted or welded)
42 000 98 000 navigation clearance ELEVATION
Figure 7.20 Bridges.
fixed bearings
pier foundation 28 000
abutment foundation
variable depth composite plate girder
121
EXAMPLES OF STRUCTURES
200 to 230 mm
overall deck width 320 mm
1000 to 3300
2500 to 3500
TWIN PLATE GIRDER & STRINGER (spans 40 to 100 m
200 to 230 mm
200 to 240 mm
MULTIPLE UNIVERSAL BEAM (spans > | 30 m)
2500 to 3500
> 7000
3000 to 3500 C/C
1000 to 1750 typical MULTIPLE PLATE GIRDER (spans 25 to 50 m)
TWIN PLATE GIRDER & CROSS GIRDERS (spans 40 to 100 m)
200 to 230 mm
300 to 320 mm
1000 to 3300
4000 to 6000
TWIN PLATE GIRDER & HAUNCHED SLAB (spans 30 to 100 m) Figure 7.21 Bridges.
6000 to 7000
1000 to 3300
6000 to 7000
TWIN PLATE GIRDER & STEEL CANTILEVERS (spans 40 to 100 m)
3000 to 3500 C/C
122
STEEL DETAILERS' MANUAL
BOX GIRDER HIGHWAY BRIDGES
RAIL BRIDGES
9000 typ.
200 to 240 mm
900 to 1200
3000 to 3500 C/C TWIN BOX & CROSS GIRDERS (spans 40 to 150 m)
steel cantilevers if slab extends >3300
1200 typ. composite cross girder
200 to 250 mm
structure gauge
HALF THROUGH PLATE GIRDERS
1970 (2070 span for > 22 m) for span >22) 1432
1620 1432 750
1755 typ.
915 885 typ.
2500 to 3500 steel floor plate integral with cross girder
7890 typ. HALF THROUGH BOX GIRDERS
200 to 250 mm
OPEN TOP BOX (`BATH TUB') (spans 40 to 100 m)
900 to 1200
610
250 to 350 mm 600
610
2500 to 3500 at mid-span
at pier
MULTIPLE BOX (spans 30 to 60 m)
5400
5400
COMPOSITE DECK TYPE (>30 m span) Figure 7.22 Bridges.
310
900 to 1200
123
EXAMPLES OF STRUCTURES
1150 min.
1800 min.
1000 typical 100
150
800 typical
in situ or PC units
in situ or PC units
STEEL BOX (span 20 to 60 m)
COMPOSITE BOX (span 20 to 60 m)
1000 TWIN UB/COMPOSITE UB (span > | 35 m)
RHS members
VIERENDEEL
150
CL
WARREN
OPEN BRACED (span > | 40 m)
Figure 7.23 Bridges.
non-slip finish
VIERENDEEL
WARREN
TWIN UB/STEEL PLATE (span > | 35 m)
124
STEEL DETAILERS' MANUAL
5 sealing plates
CL end post
longitudinals 100 × 50 × 3.2 RHS (S355JO)
site welded full strength butt joints
100 max.
all posts 100 × 100 × 6.3 RHS (S355JO)
top of plinth
paved surface 460
3800 max. lower mesh support 40 × 40 × 3.2 RHS (S275JO)
wire mesh panels with 8 dia. wire frame and welded fabric infill using 3.25 dia. wires at 25.4 centres vertically and 5.38 dia. wires at 76.2 centres horizontally
TYPICAL ARRANGEMENT
18Ø × 30 long slotted holes in top angle to rail
A 12 50
18Ø holes in bottom angle to post M16 × 40 long (4.6) bolts
B
12 B 250 max.
grout
34 34
60 × 30 × 6 angles (S275) × 110 long to post × 120 long to rail
168
52
LONGITUDINAL TO POST CONNECTION
10 slot in 6 plate (S275) for M8 button head socket screws with 40 × 25 × 5 washer plates
paved surface
steel washers for adjustment 70 long socket top bolt M20 to BS 3692 grade 8.8
25
35 nom. 50 plinth min.
50
40 × 40 × 3.2 RHS
1000 above paved surface
268
50
268
A
13
5 sealing plate
11
36 58
hole drilled 38Ø approx. bottom bolt M20 to BS 3692 grade 8.8 ‘Selfix’ resin bonded
11
VIEW ON A-A
500 typ.
2 no. 10Ø slotted holes in 6 plate (S275)
TYPICAL SECTION
3
102
180
45
PLAN ON BASEPLATE Figure 7.24 Bridges.
45
45
180
270
13
4 no. slotted holes 22Ø × 46 long 15 270 × 30 thick × 270 long baseplate (S275)
28
22 22 VIEW ON B-B
15
65
45
270
12
125
EXAMPLES OF STRUCTURES
note: parapets using this joint should be galvanized
4 no. 22 Ø holes each end of RHS 25
100 × 50 × 3.2 RHS
460 long plates (S275) 4 nom. 140 63 63 140
25
90
20
20
5 chamfers
holes tapped M20 – 4 no. per plate
4 no. set screws per side M20 × 25 long (8.8) with MS washer under head of each BOLTED JOINT FOR PARAPET RAILS
3 fillet weld this face only for each half
loose washers
3 no. slot welds in 100 face for each half C C
50
shear pin 41 min. 42 max. long 2 × 2 chamfer ends 28.5 Ø min. 28.7 Ø max.
222 6 min.
222 38 max.
100
SECTION THROUGH EXPANSION JOINT
3 no. 10 wide slots in one face only
20
32 89 30Ø hole elongated
29Ø hole
76
60 PLAN ON C-C
DETAIL OF JOINT PLATE
8 min. gap 40 × 3 (S275) backing strip
40 full strength butt weld
SITE JOINT IN LONGITUDINALS Figure 7.24 Contd
127 76
89 100 = =
89 2×2 = = chamfer
457 254 important dimension
EXPANSION JOINT FOR PARAPET RAILS GENERAL NOTES 1. posts to be vertical Ð rails to follow longitudinal fall 2. all welds to be 5 mm fillet weld all around unless stated otherwise
126
7.8 Single-span highway bridge The bridge carries a motorway across railway tracks with a clear span of 31.5 m between r.c. abutments and an overall width of 35.02 m. It is suitable for dual three-lane carriageways, hard shoulders and central reserve. It can be adapted to suit different highway widths. Plan curvature of the motorway is accommodated by an increased deck width. Use of steel plate girders with permanent slab formwork allows rapid construction over the railway and would also be suitable across a river. Weathering steel is used to avoid future maintenance painting. Composite plate girders at 3.08 m centres support the 255 mm thick deck slab and finishes. The edge girders are 1.6 m deep and carry the extra weight of the parapets
STEEL DETAILERS' MANUAL
steel channel trimmers occur at each abutment to restrain the girders during construction and to stiffen the slab ends. Within the span two lines of transverse channel bracings are provided for erection stability. All site connections are made up using HSFG bolts. For erection the girders were placed in groups of up to three using a lifting beam as shown in figure 7.29. This is convenient where the erection period is limited by short railway occupations and was used to erect the prototype of the bridge described.
Drawing notes (1) All steel to be weather resistant unpainted to EN 10155 grade S355 J2G1W UOS. (2) All bolts to be HSFG to BS 4395 Part 1. Chemical composition to ASTM A325 Type 3, Grade A, or
which are solid reinforced concrete `high containment'
equivalent weather resistant. To be M24 diameter
type. In other locations a lighter open steel parapet is more usual as shown in figure 7.24. Inner girders are 1.3 m deep. They are shown fabricated in a single length, but in the UK special permission is required for movement of loads exceeding 27.4 m and this is normally only feasible if good road access is available from the fabrication works, or if rail transport is used. Alternative
UOS. (3) Intermediate stiffeners may be radial to camber. (4) All welds to be fillet welds size 6 mm UOS continuous on both sides of all joints. (5) Butt welds Ð all transverse welds to flanges and webs to be full penetration welds. (6) All welding electrodes shall be to BS EN 499. Welds shall possess similar weather resisting properties to
bolted or welded site splices are shown in figure 7.28. The
the steel such that these are retained, including
minimum number of flange thickness changes are made,
possible loss of thickness due to slow rusting. The
consistent with available plate lengths. This avoids the high
design allows for loss of thickness of 2 mm on all
costs of making full penetration butt welds. The girders are precambered in elevation so as to counteract dead load deflection and to follow the road geometry. For calculation of the deflection, girder self weight and concrete slab are assumed carried by the girder alone, whilst finishes and parapets are taken by the composite section. It may be noted that a typical precamber for composite girders is
exposed surfaces. (7) Temporary lifting cleats may remain in position within slab. (8) Temporary welds shall not occur within 25 mm of any flange edge. (9) Complete trial erection of three adjacent plate girders shall be performed. During the trial erection the
about 0.25% to 0.5% of span. Girders are fixed against longitudinal movement at one abutment and free to move at the other. Bearings are proprietary `pot' or `disc' type bearings comprising a rubber disc contained within a steel cylinder and piston arrangement. The rubber, being contained, is able to withstand high vertical loads whilst permitting rotation. The free abutment bearings incorporate ptfe (polytetrafluoroethylene) stainless steel sliding surfaces to cater for thermal movements and concrete shrinkage. Composite
true relative levels of the steelwork shall be modelled. (10)
The exposed outer surfaces of web top flange and bottom flange including soffit to girders 1 and 12, together with all HSFG interfaces, shall be blast cleaned to 3rd quality BS 7079. All other surfaces shall be maintained free from contamination by concrete, mortar, asphalt, paint, oil, grease and any other undesirable contaminants.
127
130 precamber
EXAMPLES OF STRUCTURES
32 250 + 24 = 32 274 25 200 + 19 = 25 219
12
1300
12
over endplates 7050 + 5 = 7055
310
neutral axis 6
6 7050 - 3 = 25 200 - 9 = 25 191 32250-12=32238 over endplates 7047 25 530 - 9 = 25 521 32 598 bottom flange
32 599 PRECAMBER SKETCH (NTS)
7080 - 3 = 7077
Notes! 1. Cambers shown do not take account of fabrication effects & weld shrinkage. 2. Camber shape shall approximate to a parabolic curve.
Figure 7.25 Single span highway bridge.
Top surfaces of all bottom flange butt welds to be ground flush
direction of grinding
13
60° web side
40
2
100 50 50 100
30 rads
Y
2 60°
240 × 25 stiffener (S355 JOW)
INTERMEDIATE STIFFENERS
2 50 max. 40 min.
30 max. 20 min.
2 6
60°
6 6
19 web plate
Figure 7.26 Single span highway bridge.
TOP FLANGE BUTT WELD
6
section Y–Y
2 12 6
110 × 14 thick stiffs fitted into vertical stiffeners
19
120 × 14 stiff
20
60°
30 rads 14 or 19 web plate
BOTTOM FLANGE BUTT WELD
20
14
Y
2 60°
50 rad
25
350
6 6
25
50
40
60°
WEB BUTT WELD
Precamber at mid-span Girders 2 to 11 Girder weight Slab etc. Finishes Shrinkage Final precamber Total Specified precamber
21 62 15 15 15 128 130
128
STEEL DETAILERS' MANUAL
31 500 clear
375
RC abutments
375
32 250 c/c bearings
12
fixed end
run off strip required this side for girder 12
ELEVATION
girder mks
fixed end
run off strip
11
X
no welds 50 2500 to section CL bearings X–X 40 × 19 strip (S355 JOW) welded as shown
bracing
bracing
9
150
35 020
8 7
motorway
exterior face 20
X
10
CL girders 1 and 12
PLAN ON BTM FLANGE GIRDER 1 SHOWING RUN OFF STRIPS (For bridge using unpainted weathering steel)
6 5 4 bracing
bracing
3
Bearing fixity Free to slide Guided Fixed
2
run off strip
1 buried rotation point
expansion joint
10 950
10 350
10 950
PLAN RC high containment parapet 35 020 3300 hard shoulder 1 in 28.8 X 1
570
X X Y Y 1600 1300 web web 3 depth 2 depth
Y
Y
Y
4
17 510 17 000 11 000 carriageway
4000 600
510 3300 hard shoulder
600
2500
510 600 min. verge
17 510 17 000 11 000 carriageway 120 finishes 255 slab
1 in 28.8
Y
CL joint
X
5
6
Y
X
Y
Y
Y
8
7
Y
9
Y
X
10
X
X
11 crs at 3080 = 33 880
570
12
11
CROSS SECTION
no intermediate stiffeners to outside face
Figure 7.27 Single span highway bridge. 150 over end plate 25 end plate
32 250 25 475 top flange 16 595 web plate 110×14 longitudinal stiffeners
1300 web
400
8880 web plate finished road level
lifting lugs
580
2140
2140
1725
1725
1725
1725
10 950
1725 10 350
1725
1725
1725
1725
1725
2140 10 950
2140
0
17
47
72
93
106
117
124
129
precamber symm’l 1920
130
310
8 8
720 180
150 25
7025 top flange 7025 web plate CL optional splice
1920
720 580
25 530 bottom flange
7080 bottom flange 32 610 o/all
top flg btm flg web int stiffs shear 19Ø studs 125 no. spacings
1300×19 2 no. 240×25 thk 4 at 200 crs
4 no. 120×14 thk 4 at 300 crs 8100
Figure 7.28 Single span highway bridge.
typical elevation on girders 2 to 11 (longitudinal dimensions neglect precamber) 500×25 (S355 JOW) 600×50 1300×14 see details below
5 no. 120×14 thk 2 at 300 crs 12000
see details below
500×20 (S355 JOW) 600×40 1300×19 4 no. 120×14 thk 4 at 300 crs 8100
2 no. 240×25 thk 4 at 200 crs
180
129
EXAMPLES OF STRUCTURES
Transflex or similar expansion joint bolt to concrete
line of finished road level 125 × 19 studs to 100 C/C – 800 trimmer top flg 100 5050 100
truly vertical on completion
190 IP
400
70 150 150
200 C/C max
80
65 71
15
65
2035
120
80
2 no. 180 × 19 fitted stiff’s
40 min.
432 × 102 RSC trimmer
400 C/C max 125×19 studs
6565 40
180
500 × 25 (S355 JOW)
500 wide plt
tapered plate (S355 JOW) to suit bearing
25 fitted
HD bolt pocket CL bearing
proprietary pot type bearing bolted to taper plate
355
30 nom.
horizontal
ABUTMENT DETAIL
line of finished road level
150
400
150
150
550
150
400
line of finished road level
30 rad cope holes
30 rad cope holes
550
30 rad ‘typ’
X
40 min.
165
55
110 40 230
100 100 40
30 max 20 min
120 section X–X
3080
CL girders 2–5, 8–11
BRACING TYPE `Y'
3080
30 max 20 min
19 thk plate
14 thk plate
Figure 7.28 Contd
65 65 65
20 min 30 max
100 100 305 × 89 RSC (S355JOW)
28.8
165
X
52
30 rad ‘typ’
330
180
CL girder 6 BRACING TYPE `X'
130
STEEL DETAILERS' MANUAL
40
4 × 65
700 100
4 × 65
extra studs required in place of studs not on cover plate
40
19 web
2 mm
3 mm
6 nom. CL splice (max 4 × stud height) 300
150
150
450
450 65 100 65
A–A
460 × 12 thick plate × 700 lg (40 bolts) 150
150
300 40
40
120
460 140 120
40
2/200 × 12 thick plates × 700 long
3 × 75
1300
1300 web depth
6 × 110 = 660
460 × 5 thick pack × 700 long
2/310 × 10 thick covers × 1190 long (52 – bolts)
A
40
50
100
A
3 × 75 90
25
20
40
14 web
2/full size packs
560 × 25 thick cover × 1480 long (84 – bolts)
6 nom. gap
40
200
70
150
180 560
560 × 10 thick pack
2/230 × 25 thick shaped plates × 1480 long
40
10 × 65
100 1480 BOLTED SPLICE
Figure 7.29 Single span highway bridge.
10 × 65
40
2.5 × bolt dia. min. plus 5 to allow tightening
150
40
131
EXAMPLES OF STRUCTURES
20° 20°
root face
4
40 d ra
4
5
1
web 19
root 5 face
5 rad
5 rad
14 web
2 root face
60°
as fabricated approx. 2 mm after welding flanges
4
1
root gap zero (to + 4 max. tolerance)
WELD DETAILS
NOTES 1. Weld preparations shown follow typical forms shown in BS EN 1011. Other preparations may be suitable 2. For shop butt welds double vee butt welds are usual
100 × 100 × 12 angle (S275) cleats, remove after welding and grind flush
150
6
75
alternative landing cleat if welded in erected position
26 dia. holes for temporary bolts
150
complete web/flange welds at site locally to allow fairing of joint
200
35
80
35
50
temporary supports 150
150 150
1
taper if flanges of different widths
ALTERNATIVE STEPPED SPLICE (suitable if splice welded in erected position)
40 × 40 snipe 70 dia hole
70 80
4
150
10
200
80 10 000 crs of lugs
WELDED SPLICE
150 × 30 thick × 280 long (S275) cleat LIFTING LUG DETAIL (suitable for 10 tonne per lug)
Figure 7.29 Contd
132
STEEL DETAILERS' MANUAL
see detail ‘A’ 8 6 73 67 73
54
457 × 191 × 80 150150 80 98 UB cutting 10 plate each side fitted into UB fillet
100 10 2 no. 100 × 30 × 2000 long doubler plates to 100 10 top and bottom flanges
50 46 DETAIL `A'
6
SECTION `B-B' 5-positions
VIEW ON `C-C' 230630 thick lifting lug
Figure 7.30 Single span highway bridge.
SECTION `E-E' All other details as View on C-C
lug
86 87 115 86 86 100 611
2 o /al l
G
77
20
150 dia.
75 dia. hole to suit 55 t anchor shackle
20
11 SECTION G-G
5
23
G 0 11
1000
SECTION `D-D' All other details as View on C-C
73 73 41
175
350 × 200 × 30 plt pack
strops to girder lifting lugs
73
73
350 × 200 × 30 plt pack
75 dia.
30
625
46
6
60 dia. 130 × 10 hole to suit 25 t flat anchor shackle 227 41 350
10 100
dia.
20
391
10
30
30
50 83
20
75
1000
175 316
r
40
8
625
25
350 86 86 86 46
all other details as per 282 section B–B 11 5r 30 plate
150 dia.
Alternative Lift Points
5 DETAIL `F' 5-positions
133
EXAMPLES OF STRUCTURES
7.9 Highway sign gantry The gantry displays destination signs (or traffic surveillance equipment) signals above a three-lane carriageway road. As shown it is suitable for mounting of internally illuminated signs. For larger directional signs as used on motorways external illumination is more usual with lighting units mounted on a walkway located in front of and below the signs. Such a walkway could also be used for maintenance access and a heavier type of gantry results. Location is adjacent to the coast. Rectangular hollow sections are used throughout to give a clean appearance. The legs support a U-girder of Vierendeel form with the signs mounted within the rectangular openings bounded by suitably positioned vertical chords. A proprietary cable tray is carried which also serves as an access walkway. Sign cables are conveyed within the legs inside steel conduits so as to prevent damage or being unsightly. Welded joints are used throughout except for the leg to girder connections which are site bolted using ten-
The holding down bolt arrangement is designed to allow rapid erection during a night road closure. This is achieved using a `bolt box' arrangement with loose top washer plates for tolerance. `Finger' packs are supplied so that accurate levelling and securing of the gantry can be achieved, with final grouting of the bases later.
Drawing notes (1)
All steel to be to EN 10025 grade S275 UOS. Hollow sections to be grade S275JO.
(2)
Protective treatment Ð marine environment. Grit blast 1st quality after fabrication. Metal coating Ð aluminium spray Paint coats: 1st aluminium epoxy sealer 2nd zinc phosphate CR/alkyd undercoat 3rd zinc phosphate CR/alkyd undercoat 4th MIO CR undercoat 5th CR finish. Minimum total dry film thickness 250 microns.
sioned screwed rods to ensure rigid portal action of the gantry.
TYPICAL CHORD DETAILS
Figure 7.31 Highway sign gantry.
PART SECTION THROUGH
134
STEEL DETAILERS' MANUAL
M38 rod × 850 long grade 8.8 with 3 no. HSFG nuts and hardened washers
120 sq. × 15 top plate supplied loose 6
B
15 thick side plates
100
200× 15 plate with 90 Ø hole for nut and washer, also holes for electrical conduits
20
15
10
10
31 nominal
325
6 15 thick internal stiffeners
430 thread
18.9 1000
10
6
415 projection out of slab
10 thick top cover with 2 no. 70 Ø holes
200
600
75 Ø steel tube tacked to 2 no. 80 × 80 × 8 angles × 800 long and 150 sq. × 30 plate
120 thread
grout under full length after errection
300
180 sq. × 10 bed plate with 3 no. 2 mm finger packs bed plate levelled and HD rod placed and grouted before erection
B DETAILS AT GANTRY BASE Figure 7.31 Contd
SECTION B-B
135
EXAMPLES OF STRUCTURES
11 900 span at top chord 2150
900
200
these openings to suit internally lit signs
2450
900
2450
full strength butt weld shop welds
880
2/100 × 100 × 10 RHS
2/100 × 100 × 10 RHS
2/150 × 150 × 10 RHS legs
5500
4 no. open panels (both faces)
1000 47 30Ø steel conduits to these 2 legs only
10 000 width of 3 lane highway 12 500 centres of HD bolts ELEVATION
SIDE ELEVATION
SECTION A-A
PLAN ON BOTTOM CHORD
Figure 7.32 Highway sign gantry.
900
2150
facia plate on east face only for mounting electrical equipment
136
STEEL DETAILERS' MANUAL
11900 A 25
6
4 no. holes in this face to suit flanged couplings
25
130 × 15 thick end plate × 260 long with 2 no. 28 Ø holes
10
75
50 50
200
60
200 nom. length
90 × 75 × 15 end plates 4 no. 130 × 85 × 18 ave. thick plates tapered to suit slope of leg
150 × 150 × 10 RHS
620
100 × 100 × 10 RHS
6
880 over chords
160
150 × 100 × 10 angle
bolt boxes 60 × 60 × 5 RHS internal bolt boxes 50 × 50 × 5 RHS 130 × 15 thick × 100 long landing plate 4 no.30 Ø heavy duty electrical conduits
6
detail as for welding of posts
6
6
heavy duty cable tray 160
100 × 100 × 10 RHS
50 × 10 thick flat 200
A
1000
150 × 150 × 10 RHS
bend line
18.9
100 × 10 ledge plate × 550 long
1000
47
END VIEW Figure 7.33 Highway sign gantry.
SECTION ON CONNECTION BETWEEN GANTRY CHORDS AND LEG
137
EXAMPLES OF STRUCTURES
800
4 no.6 Ø csk. set screws (ss)
200 sq. × 10 cover plate 200 sq. × 10 top plate 200 sq. × 4 neoprene gasket 6
top end of conduits supplied with screw on bushes and holes in inner plate sealed with continuous weld
130 sq. × 10 inner plate drilled to suit conduits
85
chamfer edges of hole in leg for 6 mm continuous fillet weld ends of internal bolt box and welds ground flush with face of leg
8 mm chamfer to top edge of landing plate for 5 mm sealing weld 600 cable tray SECTION THRO' BOLT BOX
6 cable tray fixed throughout with 3 no. M10 ss cup head bolts with locking type nuts at each end of panel
70 nut and washer this end
200 5 mm radius 20
150
500 overall length DETAIL OF TENSIONED ROD Figure 7.33 Contd
550
150
125
SECTION A-A
70 nut and hardened and load indicating washers
M24 rod grade 8.8 with HSFG nuts
138
STEEL DETAILERS' MANUAL
7.10 Staircase The staircase occurs within an industrial complex and is an
handrail spigot joints
essential structure. It is typical of many staircases built within factories and would be suitable as fire escape stairs in public buildings. Figure 7.34 shows one landing/flight unit which is connected to similar elements to form a zigzag staircase. Certain design standards relate to staircases regarding proportions of rise: going, length of landings, number of risers between landings, etc. and these are
28
2/60 × 60 × 6 L’s × 838 long 25
shown in figure 4.1. The staircase comprises twin steel flat stringers to which are bolted stair treads and tubular handrails. The stringers rely upon the treads to maintain stability against buckling.
100
Channel stringers are also often used. Stair treads and
120 10
floor/landing panels are of proprietary open bar grating type formed from a series of parallel flat load bearing bars
100
625
10
A-A
stood on end and equi-spaced with either indented round or
200 ×10 flat × 120 long
square bars. These are resistance welded into the top surface of the load bearing bars primarily to keep them
425
60 × 60 × 6 L × 740 long
125
upright. Panels typically 1 m wide and 6 m long or more are supported for elevated walkways and platforms. Normal treatment is galvanizing which ensures that all interstices receive treatment, but between dip treatment can be used for less corrosive conditions. Stair treads are of similar
C
C 200 ×10 flat × 765 long
80 × 80 × 10 L × 625 long
construction. A number of manufacturers supply this type of flooring. PLAN B-B
Handrail standards are proprietary solid forged type with
25
10
35
light or heavy duty applications.
740 notch stringer 30 × 740
GENERAL NOTES 1. All stair stringer joints to be full strength butt welds. 2. All other welds to be 6 fillet continuous UOS. 3. All holes for handrail standards and stair treads to be 14 dia. for M12 grade 4.6 bolts. 4. All other holes are to be 22 dia. for M20 grade 4.6 bolts. 5. All dimensions & details shown for handrailing, standards & treads are to Redman Fisher standard pattern. 6. Standards: 32 dia. solid steel bars. 7. Handrailing: 25 dia. nom. bore tubes. (Spigot joints to be arranged as req'd.) 8. Stairtreads: Ref. FD509 serrated load-bearing bars Ð 30 6 3 41 pitch 6 525 long. Dim.`A' = 249 & Dim.`B' = 100. 9. Finish Ð all materials to be galvanized except for stair & landing stringers, which are painted as per specification. 10. Materials Ð to be to EN 10025 (S275) UOS. Figure 7.34 Staircase.
450 C-C
150
70
These are available from several manufacturers for either
760 10
30
tubular rails made from steel tube to BS EN 1775 grade 13.
139
EXAMPLES OF STRUCTURES
533
A
B 60
B STAIR FLIGHT
70
69 A
50
533
100
28 610
150 721
2/200 × 10 flats × 3310 long 30
70
1000 17 overlap
32
63 457
249 70 tread width
45 69 781.28 108
41 32
60 51 51 150 holes in f/s stringer
450 760
69 163 76 39 45
50
20
140 70 60
2/200 × 10 flats × 829 long
69
898
11 goings at 232 = 2552
80 × 80 × 10 L × 625 long
Figure 7.34 Contd
102
615 overall panel length
slip resistant front edge to match stair tread ref. FD509 990 overall panel width 41 pitch SECTION THROUGH LOAD BEARING BARS
th 625 leng ll a r ove
TYPICAL FLOOR PANEL FLOOR PANEL SPECIFICATIONS Redman Fisher: flowforge open steel flooring type 41/102 serrated load bearing bars 25 6 5 4 fixing clips reqd per panel clip ref. FD500 (all materials galvanized). Figure 7.35 Staircase.
dim ‘A’ .
slip resistant front edge STAIR TREAD DETAIL Ref. FD509 ‘B’
11 risers at 181.36 = 1995
419
51 51 60
610
28
2/200 × 10 flats × 888 long
138
References
1 BS EN 10025: 1993 Hot rolled products of non-alloy structural steels. Technical delivery conditions. 2 BS 5950 Structural use of steelwork in building. Part 1: 2000 Code of practice for design ± Rolled and
highway structures. Department of Transport, 1981. 7 BS EN 10137: Plates and wide flats made of high yield strength structural steels in the quenched and tempered or precipitation hardened conditions.
welded sections. Part 2: 1992 Specification for materials, fabrication and erection ± Rolled and welded sections. Part 4: 1994 Code of practice for design of composite
Part 2: 1996 Delivery conditions for quenched and tempered steels. 8 BS EN 10210: Hot finished structural hollow sections of non-alloy and fine grain structural steels.
slabs with profiled steel sheeting. 3 BS 5400 Steel, concrete and composite bridges.
Part 1: 1994 Technical delivery requirements. 9 BS EN 10219: Cold formed welded structural hollow
Part 1: 1988 General statement.
sections of non-alloy and fine grain steels.
Part 2: 1978 Specification for loads. Part 3: 2000 Code of practice for design of steel
Part 1: 1994 Technical delivery requirements. 10 BS 7668: 1994 Specification for weldable structural
bridges. Part 4: 1990 Code of practice for design of concrete
steels. Hot finished structural hollow sections in weather resistant steels.
bridges. Part 5: 1979 Code of practice for design of composite
11 BS 4: Part 1: 1993 Specification for hot rolled sections. 12 BS EN 1011 Welding. Recommendations for welding of
bridges. Part 6: 1999 Specification for materials and work-
metallic materials. Part 1: 1998 General guidance for arc welding.
manship, steel. Part 7: 1978 Specification for materials and workmanship, concrete, reinforcement and prestressing
Part 2: 2001 Arc welding of ferritic steels. 13 BS 4190: 2001 ISO metric black hexagon bolts, screws and nuts. Specification.
tendons. Part 8: 1978 Recommendations for materials and workmanship, concrete, reinforcement and pre-
14 BS 4320: 1968 Metal washers for general engineering purposes. Metric series. 15 BS 3692: 2001 ISO metric precision hexagon bolts,
stressing tendons. Part 9.1: 1983 Bridge bearings. Code of practice for
screws and nuts. Specification. 16 BS 4395 High strength friction grip bolts and asso-
design of bridge bearings. Part 9.2: 1983 Bridge bearings. Specification for materials, manufacture and installation of bridge bearings.
ciated nuts and washers for structural engineering. Part 1: 1969 General grade. Part 2: 1969 Higher grade.
Part 10: 1980 Code of practice for fatigue. 4 BS EN 10113 Hot rolled products in weldable fine grain
17 BS 4604 The use of high strength friction grip bolts in structural steelwork.
structural steels. Part 2: 1993 Delivery conditions for normalised/nor-
Part 1: 1970 General grade. Part 2: 1970 Higher grade.
malised rolled steels. Part 3: 1993 Delivery conditions for thermomechanical
18 BS 7079-0: 1990 Preparation of steel substrates before application of paints and related products. Intro-
rolled steels. 5 BS EN 10155: 1993 Structural steels with improved atmospheric
6 Departmental Standard BD7/81. Weathering steel for
corrosion
delivery conditions.
resistance.
Technical
duction. (Reference should also be made to other parts of BS 7079 and to BS EN ISO 8502, BS EN ISO 8502 and BS EN ISO 11124).
141
REFERENCES
19
Swedish Standard SIS 05 59 00 Rust grades for steel
25
United Kingdom National Application Document).
coating. Swedish Standards Commission, Stockholm, 1971. 20
26
SCI, 2001.
Painting Council, Pittsburgh, USA. 27
3.1: Code of practice for design of simple and con-
BS EN ISO 14713: 1999 Protection against corrosion of
tinuous composite beams.
iron and steel in structures. Zinc and aluminium coatings. Introduction. 22
28
BS EN ISO 8560 and BS EN ISO 9431).
works. Series NG 1900 Protection of steelwork 29
and fine grain steels. Classification.
EN 1993-1-1: Eurocode 3: Design of steel structures, Part 1.1: General rules for buildings (together with
30
Structural fasteners and their application, BCSA,
31
Fire protection for structural steel in buildings, SCI,
1978.
United Kingdom National Application Document). 24
EN 1993-2: Eurocode 3: Design of steel structures, Part 2: Bridges (together with United Kingdom National Application Document).
BS EN 499: 1995 Welding consumables. Covered electrodes for manual metal arc welding of non alloy
(with later amendments). 23
BS EN ISO 4157: 1999 Construction drawings. Designation systems. (Reference should also be made to
Notes for guidance on the specification for highway against corrosion. Highways Agency, HMSO, 1998
BS 5950 Structural use of steelwork in building. Part 3: 1990 Design in composite construction. Section
Volume 2: 1973 systems and specification. 21
Steelwork design guide to BS 5950-1: 2000. Volume 1: Section properties and member capacities,
Steel structures painting manual. Steel Structures Volume 1: 1966 Good painting practice.
EN 1994-2: Eurocode 4: Design of composite steel and concrete structures, Part 2: Bridges (together with
surfaces and preparation grades prior to protective
1992.
Further Reading
Design (1)
Steel Designers' Manual 5th Edn (revised). SCI and Blackwell Science, 1994.
(2)
BS 6399 Loading for buildings. Part 1: 1996. Code of practice for dead and imposed loads.
(3)
BS 5502 Buildings and structures for agriculture. Part 21: 1990 Code of practice for selection and use of construction materials. Part 22: 1993 Code of practice for design, construction and loading.
(4)
BS 2573 Rules for the design of cranes. Part 1: 1983 Specification for classification, stress calculations and design criteria for structures.
(5)
BS 2853: 1957 Specification for the design and testing of steel overhead runway beams.
(6)
BS 466: 1984 Specification for power driven overhead travelling cranes, semi-goliath and goliath cranes for general use.
(7)
Code of Practice for factory steel stairways, ladders and handrails, Handbook 7 (revised 1973), Engineering Equipment Users Association.
(8)
BS 5395: Stairs, ladders and walkways. Part 1: 2000 Code of practice for the design, construction and maintenance of straight stairs and winders.
(9)
Plastic design, L.J. Morris & A.L. Randall, SCI, 1975.
(10)
Joints in Simple Construction Ð Volume 2: Practical Applications, BCSA and SCI, 1992.
(11)
Joints in Steel Construction: Moment Connections, SCI and BCSA, 1995.
(12)
Joints in Steel Construction: Composite Connections, SCI and BCSA, 1998.
(3) BS 8888: 2000 Technical product documentation (TPD). Specifications for defining, specifying and graphically representing products. (4) BS EN ISO 1660: 1996 Technical drawings. Dimensioning and tolerancing of profiles. (5) BS EN ISO 7083: 1995 Technical drawings. Symbols for geometrical tolerancing. Proportions and dimensions. (6) Structural steel detailing, AISC, 2nd Edn, 1971.
Steel sections (1) Handbook of structural steelwork. Properties and safe load tables. BCSA and SCI, 1990. (2) BS 1387: 1985 Specification for screwed and socketed steel tubes and tubulars and for plain end steel tubes suitable for welding or for screwing to BS 21 pipe threads. (3) Steel bearing piles guide, SCI, 1997.
Protective treatment (1) BS EN ISO 1461: 1999 Hot dip galvanized coatings on fabricated iron and steel articles. Specifications and test methods. (2) BS EN 12329: 2000 Corrosion protection of metals. Electrodeposited coatings of zinc with supplementary treatment on iron or steel. (3) BS EN 12330: 2000 Corrosion protection of metals. Electrodeposited coatings of cadmium on iron or steel. (4) BS EN 22063: 1994 Metallic and other inorganic coatings. Thermal spraying. Zinc, aluminium and their alloys. (5) BS 3382: 1961 Electroplated coatings on threaded
Detailing (1)
Metric practice for structural steelwork, Publication No. 5/79, 3rd Edn, BCSA, 1979.
(2)
Prefabricated floors for steel framed buildings, BCSA, 1977.
components. Part 1 Cadmium on steel components. Part 2 Zinc on steel components. (6) Steelwork corrosion protection guide Ð exterior environments, Leaflet Ref. No. GS S 005 5.10.89, British Steel Corporation.
143
FURTHER READING
Erection (1)
Part 1: 1991 Glossary for welding, brazing and thermal cutting.
BS 5531: 1988 Code of practice for safety in erecting
Part 2: 1999 European arc welding symbols in chart
structural frames. (2)
BS 5975: 1996 Code of practice for falsework.
(3)
Erectors' Manual, BCSA, 1993.
(4)
Health and Safety Executive Guidance Notes GS28.
Composite construction (1)
form.
Weld testing (1)
procedures for metallic materials. Part 3: 1992 Welding procedure tests for the arc
Composite structures of steel and concrete, R.P. Johnson and R.J. Buckby. Volume 1 Beams, slabs, columns, and frames for
welding of steels. (2)
Blackwell Science).
BS EN 287 Approval testing of welders for fusion welding.
buildings, 2nd Edn, 1994. Volume 2 Bridges, 2nd Edn, 1986, Collins (now
BS EN 288 Specification and approval of welding
Part 1: 1992 Steels. (3)
BS 4872 Approval testing of welders when welding procedure approval is not required. Part 1: 1982 Fusion welding of steel.
Bridges (1)
Steel bridges, Derek Tordoff, BCSA publication No. 15/85.
(2)
Composite Steel Highway Bridges, A.C.G. Hayward,
(5)
The Design of Steel Footbridges, D.C. Iles, British Steel (now Corus).
International (1)
International structural steelwork handbook, Publication No. 6/83, BCSA.
(2)
Iron and steel specifications, 6th Edn, British Steel
joints. (6)
(1)
Design of welded structures, O.W. Blodgett and
joints. (7) (8)
BS EN 571. Non-destructive testing.
(9)
BS EN 970: 1997 Non-destructive examination of
(10)
BS 7910: 1999 Guide on methods for assessing the
Part 1: 1997 Penetrant testing. General principles. fusion welds. Visual examination. acceptability of flaws in metallic structures.
Abbreviations BS
British Standard Ð British Standards may be obtained from: British Standards Institution, Sales Department, Linford Wood, Milton Keynes,
1966.
MK14 6LE.
Introduction to the welding of structural steelwork, J.L. Pratt, 3rd Edn, SCI, 1989.
BS 6072: 1981 Method for magnetic particle flaw detection.
James F. Lincoln, Arc Welding Foundation, USA, (2)
BS EN 1714: 1998 Non-destructive examination of welded joints. Ultrasonic examination of welded
Corporation, 1986.
Welding
BS EN 1435: 1997 Non-destructive examination of welds. Radiographical examination of welded
British Steel (now Corus), Revised 1997. (4)
BS 709: 1983 Methods of destructive testing of fusion welded joints and weld metals in steel.
International symposium on steel bridges, ECCS/ BCSA, Publication No. E97/96, Rotterdam, 1996.
(3)
(4)
BCSA
British
Constructional
(3)
ANSI/AWS D1, 1Ð81 Structural welding code, USA.
Limited,
(4)
BS EN 756: 1996 Welding consumables. Wire elec-
London SW1A 2ES.
trodes and wire-flux combinations for submerged arc welding of non alloy and fine grain steels.
SCI
BS EN 760: 1996 Welding consumables. Fluxes for
(6)
BS 499 Welding terms and symbols.
submerged arc welding. Classification.
Whitehall
Court,
Association Westminster,
Steel Construction Institute, Silwood Park, Ascot, Berkshire SL5 7QN.
Classification. (5)
4
Steelwork
AISC
American Institute of Steel Construction, One East Wacker Drive, Suite 3100, Chicago, IL, 60601Ð 2001.
144 HMSO
STEEL DETAILERS' MANUAL
Her
Majesty's
Stationery
Office,
now
The
Stationery Office Ltd, Publications Centre, 51 Nine Elms Lane, London SW8 5DR.
Corus
Corus Construction Centre, PO Box 1, Brigg Road, Scunthorpe, North Lincolnshire DN16 1BP.
Appendix
The Appendix contains useful information including weights of bars and flats, conversion factors and trigonometrical expressions.
APPENDIX
Mass of round and square bars Kilogrammes per linear metre
Suppliers should be consulted regarding availability of sizes.
147
148
STEEL DETAILERS' MANUAL
Mass of flats Kilogrammes per linear metre
For actual widths and thicknesses available, application should be made to manufacturers. Masses for greater widths and/or thicknesses than those tabulated may be obtained by appropriate addition from the range of masses given.
APPENDIX
Mass of flats Contd Kilogrammes per linear metre
149
150
STEEL DETAILERS' MANUAL
Mass of flats Contd Kilogrammes per linear metre
For actual widths and thicknesses available, application should be made to manufacturers. Masses for greater widths and/or thicknesses than those tabulated may be obtained by appropriate addition from the range of masses given.
APPENDIX
Mass of flats Contd Kilogrammes per linear metre
151
152
Metric conversion of units
STEEL DETAILERS' MANUAL
APPENDIX
Metric conversion of units Contd
153
Metric conversion of units Contd 154
SI (metric) units ± multiples and submultiples
STEEL DETAILERS' MANUAL
Building materials APPENDIX
Mass
155
Mass
156
Building materials
STEEL DETAILERS' MANUAL
APPENDIX
Packaged materials Mass
157
158
Angle of internal friction and mass of materials
All materials should be tested under appropriate conditions prior to use in final design.
Values of Ka (coefficient of active pressure) for cohesionless materials This table may be used to determine the horizontal pressure exerted by material, pa, in kN/m2. pa = mass 6 depth of material 6 Ka
The effect of wall friction d on active pressures is small and is usually ignored.
Note: The above data should not be used in the design calculations for silos, bins, bunkers and hoppers.
STEEL DETAILERS' MANUAL
The above values of Ka assume vertical walls with horizontal ground surface.
Approximate mass of floors Reinforced concrete floors
APPENDIX
Timber floors Solid timber, joist sizes, mm. Mass in kN/m2
The solid timber joists are based on a density of 5.5 kN/m3. Dense concrete is assumed to have natural aggregates and 2% reinforcement with a mass of 2400 kg/m3. 3
Lightweight concrete is assumed to have a mass of 1800 kg/m .
Walls and partitions ± mass Walls
Steel floors
Open steel floors are available from various manufacturers to particular patterns and strengths. The above average figures are for guidance in preliminary design. Manufacturers' data should always be used for final design.
159
Metric equivalents of standard wire gauges
160
Walls and partitions ± mass Partitions
Areas and volumes Areas
The Greek alphabet
Volumes
STEEL DETAILERS' MANUAL
Positions of centre of gravity
For
Expressions 1 y
N ratio
The following formulae may be used for exact geometrical calculations.
y 12
R 2L
B
L
Q
y length
T R R y radians
C chord length
R q N2 14
i y
y5 etc:
y Radians 30240 s T R 1 2Q 2Q 4 r C2 R2 T2 cos y 1 cos y 2R2 R p 2RQ
p T2 Q2 p 2RQ Q2
T
RN N2 12
2QN
Q
R 2
N2 14
C2 2R
A
p C2 T2 q C N2 12
W R radius
V
y3 72C
R
p R2 T2
2LN
2Q
N2 12
Y
e 2
V versine
R
C2 2Q p 1 2 C2 2 4R
T2 Q2 2Q R CN
X L
C
W
R
R
R 2N 0q1 N2 14 1 A R@ N
W+V
L q 2 N2 14
A
QC T C2 T p R R2 X
B
e
Y
Y
T
N2 14 N 0 1 B R@1
r R2 1 C2 4 p R R2 T2 2T T tan y p 2 R T2
APPENDIX
Circular arcs
p E2 Q2 T 2N NW q 2 N 14 N C2 V 8V 2
N C qA N2 14
T Q2 2 2T
2
W V
161
162
STEEL DETAILERS' MANUAL
Circular arcs Ð large radius to chord ratios
Worked example
The following simplified formulae are approximate but are
Question
usually sufficiently accurate, typically when
A beam is 20 m long and is to be cambered to a circular
R C X > 5 or > 40 or > 20 C V Y
vertical curve of radius 60 m. Find (a) vertical offset at mid-length (b) vertical offset at 14 points (c)
W
e 2
slope of beam at ends
A R
(d) true length of beam
V
e
Y X
C
Answer (a) offset at mid length (or versine) vR
1 2
60
V
p 4R2 C2 p 1 2 202 2 4 60
C2 W 8R
A 4V
0:839 m YV
(b) At 14 point X
1
R
C2 2R
y C 4V 2 2R C
4X2 C2
C 20 5:000 m 4 4
yv
R
0:839
R
p R2 X2 p 60 602 52
e
Slope of beam at ends ws y 1
Y
X
0:630 m (c)
C2 8V
2
Y
2
C 20 1 0:94444 2R2 2 602
; y 19:1888 or 0:3349 radians y Slope at ends 9:5948 or 0:1675 radians 2 (d) Arc length R y radius
X2 2R
y
X R
Precamber for a simply supported beam The following formulae can be used to provide deflection and slope values for a beam of uniform stiffness which is uniformly loaded. This enables a precise precamber shape
60 0:3449 radians
to be determined so as to counteract deflection. The shape
20:094 m
will generally be suitable for beams which are not loaded uniformly. Often a circular or parabolic profile is adopted in practice, and is sufficiently accurate. arc length 20 094 W unit loading V = 839
end slope 9.594°
C = 20 000
Y = 630
V
e 2
Y
X
C 2 C
C 2
uniform stiffness EI
163
APPENDIX
Deflected form Central deflection: V
For shaded area under curve: Rotation at ends:
5 WC4 384 EI
Area
y WC3 2 24EI
2 C V 3 2
0:375 C X 2
V
Y
0:4 V Y ex
e 2
X C
Braced frame geometry
Precambered form to counteract deflection Precamber at any point: 2 4 ! X X 3:2 Y V 1 4:8 C C Slope at any point: 3 ! y 3X X 4 yx 2 C C
Parabolic arcs
Given
To find
Formula
bpw
f
bw
m
q
b p2 w2 p b2 w2
bp
d
b2
2b p
bp
e
b
b p
2b p
bfp
a
bf
2b p
bmp
c
bm
2b p
bpw
h
bw
2b p
afw
h
aw f
cmw
h
cw m
The following formulae may be used for calculations of parabolic arcs which are often used for precambering of beams. b e
equal V
d h
a
p
c
equal w V Y
ta
YV 1
X
X C
ta ng en t
e 2
y 4V 2 C 2 4X C2 8VX yx 2 C
Approximate arc length s 2 C 4 V2 2 2 3
where
w
ex
Y
V < 0:05 C
ng
en
t
f
m
164
STEEL DETAILERS' MANUAL
Given
To find
bpw
f
bnw
m
Parallel bracing
Formula
k
log B
q
b p2 w2 q
b n2 w2
logarithm of any line equals the log of the corresponding line in the next panel below.
bnp
d
b
b
n
2b p
n
bnp
e
b
b p
2b p
n
bfnp
a
bf
2b p
bmnp
c
bm
2b p
n n
bnpw
h
bw
2b p
afw
h
aw f
cmw
h
cw m
log T no. of panels. Constant k plus the
a TH
T e p
n
b TH
T e p q c
12 T 12 e2 a2 d ce
T e log e k log T log f k log a
b
log g k log b
p
d
e
log m k log c log n k log d
w
log p k log e
c
h
a
w
m
f
The above method can be used for any number of panels. In the formulas for `a' and `b' the sum in parenthesis, which in the case shown is (T e p), is always composed of all the horizontal distances except the base.
n T
Given
To find
Formula
A
bpw
f
bkv
m
q
b p2 w2 q
b k2 v2
bkpvw
d
bw
b k v
b p w
b k
b
a
d c
e
bkpvw
e
bv
b p v
b p w
b k
bfkpvw
a
fbv v
b p
w
b k
bkmpvw
c
bmw v
b p w
b k
bkpvw
h
bvw v
b p w
b k
afw
h
aw f
cmv
h
cw m
A f H
g
n
p A
b k
d
e
a
p
c
h
B w
v
m
f
h
m
Index
abbreviations, table 2.2, 39
cad connection library, figure 6.2, 97
angle section
cad modelling, 95
backmarks, 62
camber distortion, 14
sizes, table 4.7, 60
centre of gravity, 160
areas, 160
channel section sizes, table 4.6, 59 circular arcs
bars, mass of round & square sections, 147 beam splice details, figure 5.4, 86
properties, 161 worked example, 162
beams, universal sizes, table 4.3, 54
clearances around highways and railways, figure 4.2, 76
bolt edge distances, 71
cold formed sections, 7
bolt load capacities, 48
column base
bolted connections, load capacity, table 3.1, 42
details, 47
bolted trusses, figure 5.7, 89
details of holding down bolts, 47
bolting, 20
size and load capacity, 41
bolts black
column splice detail, figure 5.3, 85 columns, universal sizes, table 4.4, 57
dimensions of, 52
composite railway bridge, figure 7.22, 122
mechanical properties, table 4.1, 52
composite construction, figure 1.1, 2
details, 51 HSFG
in building floors, 102 computer aided detailing, 94
coronet load indicator, figure 1.26, 23
computer draughting systems, 94
dimensions of, table 4.2, 53
connection, load capacities, 40
mechanical properties, table 4.1, 53 types used in UK, table 1.9, 22
typical details, 83 connections, 15
braced frame geometry formula, 163
beam to beam continuous, figure 5.2, 84
bracing details, figure 5.5, 87
beam to column continuous, figure 5.1, 83
bridges, 119
beam to column simple, figure 5.1, 83
abutment detail, figure 7.28, 129
beam to column with angle cleats, 43
cross sections
beam to column with end plates, 43
beams, figure 7.21, 121
bracing details, figure 5.5, 87
box girders, figure 7.22, 122
dos and don'ts, figure 1.27, 23, 24
railway, figure 7.22, 122
hollow sections, figure 5.6, 88
parapet rail details, figure 7.24, 124
hot rolled and hollow tubes, figure 1.18, 17
precamber sketch, figure 7.25, 127
moment/rotation, figure 1.15, 16
splice detail, figure 7.29, 130
precast concrete floors, figure 5.11, 93
building materials, self weights, 155
simple, table 3.1, 42
buildings, 33
site locations, figure 1.17, 16
bulb flat cross sections, 67
simple and continuous, figure 1.16, 16
bulb flats sizes, table 4.11, 67
steel to timber, figure 5.10, 92
butt weld shrinkage, 14
worked examples, 40
166
INDEX
conversion of units, 152
headroom requirements, 76
corrosion, dos and don'ts, figure 1.29, 28
highway
crane gantry girder details, figure 7.8, 105
clearances, figure 4.2, 76
crane rail cross section, 68
sign gantry, 133
crane rails, table 4.12, 68
holding down bolts, 38
curved sections (about major axis), table 1.6, 7
hollow sections circular sizes, table 4.10, 65
design guidance, 40
rectangular sizes, table 4.9, 64
detailing
square sizes, table 4.8, 63
abbreviations, 38 bolts, 38
weld preparations, figure 4.5, 79 HSFG bolts, 22
conventions, 36
dimensions, 53
data, 51
load capacity, 53
opposite handing, 38
HSFG power wrench details, 70
welds, 38 dimensional variations, table 1.7, 12
joist section sizes, table 4.5, 58
dimensions, 35 drawing layout, figure 2.1, 35, 36 marking system, figure 2.2, 37
ladders, layout, figure 4.1, 74 lamellar tearing, 20 details, figure 1.24, 20
projection, 35
lattice girders, figure 5.8, 90
revisions, 36
lettering on drawings, 35
scales, 36
lifting beam, figure 7.30, 132
drawings, 32
load factors and combinations, 33
durbar floor plate, table 4.14, 72 marking system, figure 2.1, 36 electric overhead travelling cranes, 105
materials
engineer's drawings, 32
self properties, 158
environmental conditions, effect on steel, 31
self weights, 152
erection lifting beam, 132
metal coatings, 25 multi-storey frame buildings, 100
marks, 37 natural light requirements, 104 fabrication sequence, 19 fire protection, board connection, figure 7.6, 103
omnia plank, connection to beams, figure 5.11, 93
fire resistance, 100 flats, mass of, 148
packaged materials self weight, 157
floor plates, 72
paint treatments, 30
floors, self weights, 159
plate girder
footbridges cross sections, figure 7.23, 123 handrail details, 123 foundations, interface with structure, 16
cross section details, figure 7.26, 127 splice detail, figure 7.29, 130 plates, available lengths normalised condition, table 4.15, 81 normalised rolled condition, table 4.16, 82
gable ends Ð portal frame building, figure 7.9, 106
portal frame building
galvanizing, 25
details, 108
girders
gable ends, figure 7.10, 108
gantry girders, 105 lattice girders, 90 grit blasting, 25
roof bracing, figure 7.10, 108 portal frame buildings, 105 precamber for simply supported beam, 162
167
INDEX
projection ± third angle, 37 protective treatment, 23
vessel support structure, 108 symbols, the Greek alphabet, 160
systems, table 1.12, 30 purlins ± cold rolled sections, 107
timber, connection to steelwork, 92 tolerances, 10
railway clearance, figure 4.2, 76
rolled sections, figure 1.8, 13
references, 140
tower structure, 115
rolled sections, tolerances and effects, figure 1.8, 13
transport sizes, maximum, figure 4.3, 77
roof over reservoir, 112
truss details, bolted and welded, figure 5.7, 89 tube sizes, see hollow sections, 63
single storey building, cross sections, figure 7.7, 104
twisting of angles and channels, figure 1.5, 7
single storey buildings, 104 site bolting, 15
units, conversion table, 152
site welding, 15
universal beam, hole spacing, 54
splice detail, bridge plate girder, 130
universal column
splices in beams, figure 5.4, 86
hole spacing, 57 sizes, 57
in columns, figure 5.3, 85 in hollow sections, figure 5.6, 88 staircase, 138
vessel support structure, 108 volumes, 160
stairs, layout, figure 4.1, 74 steel
walkways, see stairs and ladders, 74
advantages of its use, 1
walls and partitions, self weights, 159
guidance on grades, table 1.4, 5
weld
main use of steel grades, table 1.3, 4
load capacities, table 3.7, 50
properties, table 1.2, 4
preparation details, figure 4.5, 79
recommended grades, 3
process, table 1.8, 19
requirements, 2
shrinkage, worked example, 12
stress strain curve, 3
size considerations, 19
weather resistant types, 4
symbols, figure 4.4, 78
step ladders, 75 structural shapes, figure 1.6, 6, 8
type choice, 19 types, fillet and butt welds, 18
structural tolerances, 10
welded trusses, figure 5.7, 89
structures
welding, 18
bridges, 119 highway sign gantry, 133
welding distortion, 10 worked example for plate girder, 12
multi-storey frame buildings, 100
welding distortions, figure 1.7, 11
portal frame buildings, 105
wire gauges, standard, 160
roof over reservoir, 112
workshop drawing
single span highway bridge, 126 single-storey frame buildings, 104 staircase, 138 tower, 115
beam detail, figure 7.4, 102 column detail, figure 7.5, 103 workshop drawings, 32
