Page 1


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 Ăˆrstendamm 57 10707 Berlin, Germany Blackwell Science KK MG Kodenmacho Building 7Ă?10 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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The right of the Author to be identified as the Author of this Work has been asserted in accordance with the Copyright, Designs and Patents Act 1988.

A catalogue record for this title is available from the British Library

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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First Edition published in hardback 1989 Reprinted in paperback 1992 Second Edition published 2002

ISBN 0-632-05572-3

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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

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

Constructional Steelwork Association

ix

Preface to the First Edition

x

Preface to the Second Edition

xi

2.8

Beam and column detailing conventions

36

1

1

2.9

Erection marks

37

Use of Structural Steel 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

General

1.4.2

Worked examples Ă? welding distortion for plate girder

6

Design Guidance

40

10

3.1

General

40

3.2

Load capacities of simple connections

40

12

3.3

Sizes and load capacity of simple column

1.5

Connections

15

1.6

Interface to foundations

16

1.7

Welding

18

1.8

bases

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

Bolting 1.8.1

General

1.8.2

High strength friction grip (HSFG) bolts

1.9

3

Dos and don'ts

6

20 22

structure

96

6.4

Object orientation

98

6.5

Future developments

98

23

1.10 Protective treatment

23

1.11 Drawings

32

7

Examples of Structures

100

7.1

Multi-storey frame buildings

100

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

7.8

Single-span highway bridge

126

7.9

Highway sign gantry

133

7.10

Staircase

138

References

119

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

77

1.4

Rolled section sizes

6

4.4

Weld symbols

78

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

83

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

79Ð80

8Ð9

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

7.34Ð7.35

Staircase

138Ð139

2.1

Drawing sheets and marking system

36

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

1.1

Advantages of structural steel

1.2

Steels to EN material standards Ð summary of

1

leading properties

4

Main use of steel grades

4

1.4

Guidance on steel grades in BS 5950 Ð 1 : 2000

1.5 1.6

5

3.3

44

Simple connections, bolts grade 8.8, members grade S355

45

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

Guidance on steel grades in BS 5950 Ð 1 : 2000 Ð maximum thicknesses

Simple connections, bolts grade 8.8, members grade S275

1.3

Ð design strengths

3.2

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 Ă? 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 10Ă?15 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 Ă? concrete which is effective in compression Ă? 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 55 grade S3 steel X h t ng stre S275 e d high X l gra stee mild

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.

200

ri ma

ne nga

ma 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 0

consists entirely of exposed steelwork and glass panels;

1

2

3

several prestigious buildings have since used weather resistant steel frames. The first bridge was built in 1964 in

l

tee se s

ne

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

BS EN 100251 BS EN 10113-24 BS EN 10113-34 7

BS EN 10137-2 5

BS EN 10155

Sections

Plates and flats

S275 or S355

100

150

±

S275 or S355 S460

150 100

150 100

± ±

S275, S355 or S460

150

63

±

±

150

±

40 100

16 100

± ±

S460 J0WP or J2WP J0W, J2W or K2W

Hollow sections

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

considered. In the UK it is usual in bridges to design6 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

within any one serial size, the heavier sections can

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

section

deflection of long span beams) or to achieve permanent

n

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

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 coffern

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 (xĂ?x) 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 Âą 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: technical@anglering.co.uk

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 kg/1000 HD HT D6L 91 8 20 13 6 75 100 116 16 6 75 175 8 32 100 213 19 6 75 221 32 10 100 278 125 335 391 150 369 22 6 100 35 10 446 125 524 150

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

420 to 525 Larssen

weld Starred

Back to back Angles (RSA)

Box

t

t

425 to 483 t = 1.5 to 3.2 mm

143 to 311 Frodingham PILE SECTIONS

Figure 1.6 Structural shapes.

Channels back to back

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

B

Beams 127 6 76 6 13 to 914 6 419 6 388

Universal column (UC)

D

152 6 152 6 23 to 356 6 406 6 634

Bearing pile or H-pile

May need bearing stiffeners at supports and under point loads B 6 D = serial size Actual dimensions vary with weight (kg/m)

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

e.g. D6B6t

Equal angle (RSA)

25 6 25 6 3 to 250 6 250 6 35

shear centre angle B

40 6 25 6 4 to 200 6 150 6 18

Unequal angle (RSA)

D

B Structural tee

D

When used as beam torsion occurs relative to shear centre Restrain or use in pairs

D 6 B 6 kg/m 76 6 64 6 7 to 419 6 457 6 194 152 6 76 6 12 UC to 406 6 178 6 317

UB

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

3

Â

machined bearing plate

a tf

bearing

a

2 runs

5 V° 4

preset tf

3 runs

6

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

A (mm2)

Member area

Overall shrinkage (c)

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† ˆ 4:878 KCL  A K ˆ 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 ˆ 0:0024 CL KAwT …radians† dw AT

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)

ˆ

b

 AwB AB

C and K Ð see above L ˆ length of member (m) dw ˆ 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 ˆ 8 

p 2 ˆ 5:65 mm weld throat

tf ˆ 25 mm flange thickness a 5:65 ˆ ˆ 0:226 tf 25

N ˆ 1 for each weld

From figure 1.7(a) V ˆ 1:18 Bottom flange: a ˆ 8 

p 2 ˆ 5:65 mm

tf ˆ 50 mm flange thickness a 5:65 ˆ ˆ 0:113 tf 50 From figure 1.7(a)

Nˆ1

V ˆ 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 ˆ 4:878 kCL (Aw/A)

making allowances for welding distortion for the welded

where C ˆ 5:0 kN for N ˆ 4 weld runs

plate girder shown in figure 7.28.

L ˆ 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 [2t + 2 mm]

C= * N = [B 7 C + 6 mm] * n=[D2 d] {

X

X

d

A D

F

B ±e 2

Allow for tolerances assuming web truly vertical

3.2 4.8

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

Wide flats Plates Flats 0.4 0.5 0.5 1.05 0.8 1.0 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

Typical only

FABRICATED ITEMS

A

D e B or F B to 450 > 450 K ~

Camber

Straightness or bow

Deviation from camber

d 150

X

X

X

X CL

X = (c/c– D – 4)

D CL col

c/c B

F

X

D 2

K X X

d

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

min. 3 mm

L 1000 (min 12 mm)

L …min 3 mm† 100

From top of top flange From CL of web

X

D 2 D +2 2 CL col

+4 +5 +6 +6 +9 B 150

X

Overall end plates

+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 ˆ 0:8 y ˆ 1:30 14 460 End slope y ˆ

 0:0024 CL kAwT dw AT

64 31 960



ˆ 0:00065 radians For k ˆ 1:2 y ˆ 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.

Aw ˆ

fabrication.

  88  4 No ˆ 128 mm2 2

12 mm extra fabrication precamber

A ˆ …500  25† ‡ …600  50† ‡ …1300  14† ˆ 60 700 mm2 k ˆ 0:8 to 1:2 For k ˆ 0:8 d ˆ 4:878  0:8  5:0  32:55  or for k ˆ 1:2

d ˆ 2:0 mm

128 ˆ 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 ˆ 4 ˆ 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 ˆ 7:0 kN for N ˆ 2 weld runs each flange L ˆ 32:55 m

2

dw ˆ 1.30 m k ˆ 0:8 to 1:2   88 AwT ˆ  2 No ˆ 64 mm2 2

2

AwB ˆ 64 mm2

=

AT ˆ …500  25† ‡ …10  142 † ˆ 14 460 mm2 AB ˆ …600  50† ‡ …10  142 † ˆ 31 960 mm2   0:61  7:0  32:552 0:8  64 64 For k ˆ 0:8 4 ˆ 1:30 14 460 31 960

= 60°

b = 13.0 mm

ˆ 5:4 mm For k ˆ 1:2

4 ˆ 11:5 mm (say 12 mm)

Figure 1.12 Bottom flange site weld.

40


15

USE OF STRUCTURAL STEEL

cation work can be more expensive than a slightly heavier

Shrinkage d Â&#x2C6; 2:0 mm 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’

vertical loading

bracing required (or shear walls, etc.) 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 at

Figure 1.21 Fillet welds.

incomplete penetration

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 â&#x20AC;&#x201C; 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 Âą 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

T2

planar type inclusions

P

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

bolt is tested to a stress above that which it will experience

of the proof load stress in kgf/mm2 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

25 min grout 50 mm excess thread nominal

Clearance of joints near welds

poor fit up

no grout 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

out any paint treatment to achieve friction. A

18

Swedish Standard 19

USA Steel Structures Painting Council

reduced slip factor must be assumed for galvanized steelwork. During painting in the workshop the

20

BS 7079

SIS 05 59 00

1st quality

Sa 3

White metal

2nd quality

Sa 212

Near white

3rd quality

Sa 2

Commercial

SSPC

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 in Table 1.12 based on UK conditions to BS EN ISO 1471321 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)

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 thicknesses less than 5 mm. Welded members, especially

overcoated. (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

aluminium spray give a durable coating more resis-

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 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

entire hole flame cut

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 DONâ&#x20AC;&#x2122;T 6 nominal gap int stiff

600 max. (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

If end plates are necessary

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

inner bolts only effective

Bolts in tension

Prying action

bolts cannot be entered/tightened

Bolt clearances

stagger holes if necessary to enter bolts 30 nom. min.

11/2 × bolt dia. or 30 (50 HSFG) greater 10 nom. Flush fixings (e.g. floor plates)

Site problem

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 Âą corrosion.

Bimetallic corrosion


29

USE OF STRUCTURAL STEEL

DETAIL

DO

DON'T

REMARKS

no access

d

Compound members

Maintenance easier

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


A

B

C

D

E

F

G

Interior

Interior

Interior

Exterior

Exterior

Exterior

Exterior

16±24 years

16±24 years

12±18 years

10±15 years

20 years

15 years

20±35 years

Time

Structure type

General

Piece-small fabrication

General

General

Buildings

Buildings

Buildings

Sa 3

± ±

ezs

±

zre

±

Sa 212 Hot dip galvanize

HB zpa

±

Sa 2

ezs

±

1 2

zre

HB zpa

± ±

1

Metal coating

Sa 3

Sa 212

Sa 212

Surface preparation

CR alkyd

±

HB zp

HB alkyd finish

CR alkyd

CR alkyd

HB alkyd finish

2 ±

3

HB MIO CR

±

Modified alkyd MIO

±

HB CR finish

HB CR finish

Paint coats

HB MIO CR

±

±

±

±

±

±

4

260

85 (min)

200

135

185

135

120

Total paint dry film thickness

Galvanize

Galvanize

Paint

Paint

Paint

Paint

Paint

Treatment of bolts

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

Abbreviations for paint coats:

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.

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.

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

Notes to Table 1.12a

Environment category

Steelwork location

Table 1.12a Typical protective treatment systems for building structures.

30 STEEL DETAILERS' MANUAL


D

D

Marine

Marine

13

11

10 Alt

10

8 Alt

8

4 Alt

4

System type

Galvanize

±

Aluminium metal spray (100 mm)

Aluminium metal spray (100 mm)

±

±

±

±

Metal spray

T-wash

Zinc phosphate HB QD epoxy primer

Aluminium epoxy sealer

Aluminium epoxy sealer

Zinc phosphate HB QD epoxy primer

Zinc phosphate AR blast primer

Zinc phosphate HB/epoxy primer QD

Zinc phosphate AR blast primer

1st coat

Zinc phosphate AR undercoat

MIO HB QD epoxy finish

Zinc phosphate HB QD epoxy undercoat

Zinc phosphate AR undercoat

MIO, HB QD epoxy undercoat

MIO AR undercoat

±

Polyurethane (2 pack) finish or MC polyurethane finish

MIO AR undercoat

±

MIO AR undercoat

±

MIO AR undercoat

4th coat

±

±

±

AR finish

±

AR undercoat

±

AR finish

5th coat

±

±

±

±

±

AR finish

±

±

6th coat

150

200

300

250

300

300

300

250

Minimum total dry film thickness of paint system (mm)

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

Abbreviations for paint coats:

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.

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).

No maintenance up to 12 years Minor maintenance from 12 years Major maintenance after 20 years.

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:

MIO AR undercoat

±

MIO HB QD epoxy undercoat

MIO AR undercoat

Polyurethane (2 pack) finish or MC polyurethane finish

Zinc phosphate AR undercoat

Polyurethane (2 pack) finish or MC polyurethane finish

MIO, HB QD epoxy undercoat Zinc phosphate AR undercoat

Zinc phosphate AR undercoat

3rd coat

Zinc phosphate AR undercoat

2nd coat

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'.

Notes to Table 1.12b

R or D

R

Marine

Bridge parapets

R

Marine

R or D

R

Inland

Interiors of box girders

R

Access

Inland

Environment location

Table 1.12b Summary table of Highways Agency painting specifications for Highway Works Series 1900 ± 8th edition (1998). USE OF STRUCTURAL STEEL

31


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

TITLE

TEL:01291 626994 FAX:01291 626306 Email:casshayward@btinternet.com

YORK HOUSE CHEPSTOW MULTI-STOREY BUILDING STEELWORK MARKING PLAN

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

10 mm thick 101 kN 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 Â&#x2C6; 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

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.


Table 3.1 Simple connections, bolts grade 4.6, members grade S275. See figure 3.1.

42 STEEL DETAILERS' MANUAL


43

DESIGN GUIDANCE

2/100 × 100 × 10 RSA (S275)

Bc

10

S1 S2

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

r

Bc

S1 10

140 beam/column flanges 120 beam/beam

N

[(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

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

100

(N5 to N2)

140

beam column

N1 only Figure 3.1 Simple connections.

S1 S2

(N11 to N6)

30

8 8 6 6

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


Table 3.2 Simple connections, bolts grade 8.8, members grade S275. See figure 3.1.

44 STEEL DETAILERS' MANUAL


Table 3.3 Simple connections, bolts grade 8.8, members grade S355. See figure 3.1.

DESIGN GUIDANCE

45


Table 3.4 Simple column bases (see figure 3.2 opposite).

46 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

grip

The following data provide useful information for the

30°

detailing of steelwork. The dimensional information on standard sections is given by permission of Corus (pre-

s m

d1 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


Table 4.1 Dimensions of black bolts.

Bolts M24 6 80 to BS 3692 Âą 8.8 with standard nut and normal washer. All plated to BS 3382: Part 1.

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.

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.

52 STEEL DETAILERS' MANUAL


Table 4.2 Dimensions of HSFG bolts.

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.

Notes to Table 4.2 1. `Add to Grip For Length' allows for nut, one flat round washer and sufficient thread protrusion beyond nut.

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.

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.

2. Bolt length (l) normally available in 5 mm increments up to 80 mm length and in 10 mm increments thereafter.

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.

DETAILING DATA

53


The dimension N = [B 7 C + 6] to the nearest 2 mm above. n =

Table 4.3 Universal beams ± to BS 4-1: 1993. D 2

d to the nearest 2 mm above. C = t/2 + 2 mm to the nearest 1 mm.

54 STEEL DETAILERS' MANUAL


DETAILING DATA

55


Table 4.3 Contd

D

d

S3

t

r

C

S4

S2

B S1

S3

N

T

n

D

d

S3

t

r

C

S2 S4

B S1 N

S3

T

n

56 STEEL DETAILERS' MANUAL


D

2

d

to the nearest 2 mm above.

To BS 4-1: 1993.

C = t/2 + 2 mm to the nearest 1 mm.

n=

The Dimension N = [B 7 C + 6] to the nearest 2 mm above.

Table 4.4 Universal columns.

DETAILING DATA

57


D

2

d

to the nearest 2 mm above.

To BS 4-1: 1993.

C = [t/2 + 2] to the nearest 1 mm.

n=

The Dimension N = [B 7 C + 6] to the nearest 2 mm above.

Table 4.5 Joists.

D d

r1

t

r2

C

B S1

=

=

N

T

n

58 STEEL DETAILERS' MANUAL


Mass per metre

kg

65.54 55.10

46.18 41.69 35.74 28.29

32.76 26.06 29.78 23.82

26.81 20.84 23.84 17.88

14.90 10.42

6.72

Serial size

mm

4326102 3816102

3056102 305689 254689 254676

229689 229676 203689 203676

178689 178676 152689 152676

127664 102651

76638

Designation

To BS 4-1: 1993.

76.2

127.0 101.6

177.8 177.8 152.4 152.4

228.6 228.6 203.2 203.2

304.8 304.8 254.0 254.0

431.8 381.0

mm

D

Depth

38.1

63.5 50.8 5.1

6.4 6.1

7.6 6.6 7.1 6.4

8.6 7.6 8.1 7.1

88.9 76.2 88.9 76.2

88.9 76.2 88.9 76.2

10.2 10.2 9.1 8.1

12.2 10.4

mm

Web t

6.8

9.2 7.6

12.3 10.3 11.6 9.0

D

1.19

1.94 1.51

2.76 2.20 2.86 2.21

2.53 2.00 2.65 2.13

13.3 11.2 12.9 11.2

2.32 2.52

cm

d x

7.6

10.7 9.1

t ey

C

S

2.4

2.4 2.4

3.2 3.2 3.2 2.4

3.2 3.2 3.2 3.2

13.7 12.2 13.7 12.2 13.7 12.2 13.7 12.2

4.8 3.2 3.2 3.2

4.8 4.8

mm

y

y =

radius r2

15.2 13.7 13.7 12.2

15.2 15.2

mm

radius r1

of y ey

Toe

B

=

r1

N

5

5 5

5 5 5 5

5 5 5 5

5 5 5 5

5 5

degrees

Inside Slope

x

r2

45.8

84.0 65.8

121.0 128.8 96.9 105.9

169.9 177.8 145.2 152.4

239.3 245.4 194.7 203.9

362.5 312.6

mm

Depth d

7

8 8

10 9 9 8

11 10 10 9

12 12 11 10

14 12

T

n

mm

C

to the nearest 2 mm above. C = [t + 2] to the nearest 1 mm.

Root

d

Distance

2

2.66 2.18 2.42 1.86

D

14.8 13.7 13.6 10.9

16.8 16.3

mm

Flange T

Thickness

101.6 88.9 88.9 76.2

101.6 101.6

mm

B

Width

The Dimension N = [B 7 C + 6] to the nearest 2 mm above. n =

Table 4.6 Channels.

38

62 50

86 74 86 76

84 74 86 74

96 84 84 74

94 96

mm

N

Notch

16

22 18

30 26 28 24

30 26 30 26

34 30 30 26

36 36

mm

n

22

35 30

50 45 50 45

50 45 50 45

55 50 50 45

55 55

mm

S

10

16 10

20 20 20 20

20 20 20 20

20 20 20 20

20 20

mm

hole dia.

Max.

8.56

18.98 13.28

34.15 26.54 30.36 22.77

41.73 33.20 37.94 30.34

58.83 53.11 45.52 36.03

0.282

0.476 0.379

0.671 0.625 0.621 0.575

0.770 0.725 0.720 0.675

0.96 0.92 0.82 0.774

1.21 1.11

m2

cm2 83.49 70.19

Area per metre

Surface

of Section

Area

DETAILING DATA

59


Thickness t mm 35 32 28 25 24 20 18 16 18 15 12 10 15 12 10 8 15 12 10* 8 12 10 8 7 6 10 8 6

Size B

mm

2506250

2006200

1506150

1206120

1006100

90690

80680

Designation

To BS EN 10056-1: 1999

11.9 9.6 7.3

15.9 13.4 10.9 9.6 8.3

21.9 17.8 15.0 12.2

26.6 21.6 18.2 14.7

40.1 33.8 27.3 23.0

15.1 12.3 9.4

20.3 17.1 13.9 12.3 10.6

27.9 22.7 19.2 15.5

33.9 27.5 23.2 18.7

51.0 43.0 34.8 29.3

90.6 76.3 69.1 61.8

71.1 59.9 54.2 48.5

2.34 2.26 2.17

2.66 2.58 2.50 2.41 2.46

3.02 2.90 2.82 2.74

3.51 3.40 3.31 3.23

45

50

55

±

±

±

5.84 5.68 5.60 5.52 4.37 4.25 4.12 4.03

±

mm

S1

7.49 7.38 7.23 7.12

cm

cm2 163.0 150.0 133.0 119.0

Distance of centre of gravity ex, ey

Area of section

128.0 118.0 104.0 93.6

kg

Mass per metre

Note: * Not included in BS EN 10056-1: 1999

Table 4.7 Rolled steel angles: (a) equal (see p. 62).

±

±

±

45

55

75

90

mm

S2

Recommended back marks

±

±

±

50

55

75

100

mm

S3

20

24

24

16

20

30

36

mm

Max. dia. bolt

60 STEEL DETAILERS' MANUAL


61

DETAILING DATA

Table 4.7 Rolled steel angles: (b) unequal (see p. 62). To BS EN 10056-1: 1999 Designation

Mass per metre

Area of section

mm

kg

2006150

18 15 12

2006100

Size

Thickness

D6B

t

mm

Recommended back marks

Distance of centre of gravity

Max. dia. bolt For

For

ex

ey

S1

S2

S3

S1

S2 S3

cm2

cm

cm

mm

mm

mm

mm

mm

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

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

6 min.

C1 or C2

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


* These values to be used with caution because reduction in bearing capacity occurs. Distance to value for HSFG bolts, t = minimum thickness of ply.

5. BS 5950 edge distances demand as: Rolled edge Âą rolled, machined flame cut, sawn or planed edge. Sheared Âą sheared or hand plane cut edge and any edge.

4. Minimum desirable pitch for HSFG bolts based on 2 mm clearance between socket and bolt head.

3. c1 = clearance required for HSFG wrench across. c2 = minimum clearance with clipped washer assuming wrench other end.

2. Dimensions of HSFG power wrench from Structural fasteners and their application.30

Notes 1. See figure illustrating face clearances.

Table 4.13 Face clearances pitch and edge distance for bolts.

DETAILING DATA

71


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.

Safe uniformly distributed loads in kg/m2 on plates simply supported on four sides. Extreme fibre stress : 16.537 kg/m2.

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 load in kN/m2 on plates simply supported on two sides. Extreme fibre stress : 165 N/mm2.

Commercial quality Âą 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.

Table 4.14 Durbar floor plate.

72 STEEL DETAILERS' MANUAL


} 6.0 6.0

4.5 Âą

8.0

8.0

Thickness Range on Plain mm

10.0

10.0 12.5

12.5

t

27

9

depth of pattern 1.9 to 2.4

37.97 49.74 65.44 81.14 100.77

4.5 6.0 8.0 10.0 12.5

27

kg/m2

Thickness on Plain (mm)*

Weights per square metre or durbar plates

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.

1000 1250 1500 1750 1830

Width mm

Standard sizes and weights

Table 4.14 Contd

DETAILING DATA

73


74

STEEL DETAILERS' MANUAL

Use Private Public Factory Regular use Occasional

840 min. (1100 fire escapes) clear width

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

Clear min. width 800 1000

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 2500

3020

1364 1469 1624

running edge nominal standard gauge 1432

2000 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)

maximum height

830

of static load gauge

rolling stock 1510

675

915 (+0, -25)

570

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

open box beam

175 475

150

200

50

150

75 min.

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

300 min.

underbridge

50

150

URBAN MOTORWAY 1:40 typ.

1000 min.

1:40 typ.

600 min.

1000 1500 over railway

185

tensioned corrugated beam

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)

fillet weld

8 pen.

other side

8

reference line

6 leg

longitudinal dimensions (2)

75 (225)

6

arrow side

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

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

H

H

2–3 mm y = 908

Z Y e

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 H

H

2–3 mm

t | 3.2 > 5.0 6.3

> 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 Y e

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.

D/2 y < 608 Detail at X

2 mm max.

L

L Where d < D

90°

Z Y e

Figure 4.5 Contd

2 mm max.

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 25 15.5 15.5 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 <1500 mm wide are available by arrangement, if ordered in even numbers. 3. Plates 12.5 mm to 80 mm and <1500 mm wide may be available in longer lengths than those shown, by arrangement and if ordered in even numbers. 4. Plates >3750 mm wide are available by arrangement only. 5. Single plates 2000 mm wide, please refer to 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.


82

STEEL DETAILERS' MANUAL

Table 4.16 Plates supplied in the `normalised rolled' condition. Plate Plate width (mm) gauge 1220 >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 (12.5Âą30 mm) Lloyds AH36, DH36 (12.5Âą30 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 <1500 mm wide are available by arrangement, if ordered in even numbers. 4. Plates >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

double covers (single cover for sections up to 457 UB) COVER PLATES

COLUMN BASES

d

END PLATES

SHEAR PLATE

BOLTED

copehole

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 r a e int her p s a w 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

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

1 2

1850 CRS

600

2503

200

see detail 4

SOP

SOP

see detail 1

see detail 4

1850 CRS

22

32

SO

Pt

1850 CRS

oS

OP

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


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 â&#x20AC;&#x201C; 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 drawingsâ&#x20AC;&#x201C;-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 Ă?

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 Ă? 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

254 × 102 × 28 UB secondary beams

3

B

610 × 229 × 101 UB B211

150

canopy beam 152 × 152 × 23 UC

340 300

A

main beam

concrete slab/metal decking composite with steelwork 1st floor

200 canopy

2

C122

column

3000

406 × 140 × 39 UBs

1 entrance

150

roof

2 B221

254 × 102 × 28 UB secondary beams

1

2500 8000

wind bracing

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 B115

254 × 102 × 28 UB C112

35 35

610 × 229 × 101 UB

160

C115

100

35 B113

254 × 102 × 28 UB

35 35

C1C 180

B112

254 × 102 × 28 UB

N

20 [22]

C113

4000

C114

406 × 140 × 39 UB

C

533 × 210 × 82 UB

160

254 × 102 × 28 UB

4000

(-580) 152 × 152 × 23 UC

C1B

B111

20 [22]

406 × 140 × 39 UB

B114

100 100

B

C111

(-580) 152 × 152 × 23 UC

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

<5Ø > 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

167 150

65

for C112

10 rad

70

65 420

100 5 × 70 =350

MARK

1st floor

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.

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

8 8

136 (=N) 100

55

for C212

200 × 8 end plate × 420 with 12-22 dia holes at 140 c/c (std N6)

8 (=C)

2742

65

55

MARK

CL254 × 102 × 22 UB

420

70

2500 1 row shear studs 75 × 19 dia at 150 c/c = 7650 55 55

5 × 70 =350

CL254 × 102 × 22 UB

2645

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

65 70 70

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

column end sawn and fitted tight

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 Aâ&#x20AC;&#x201C;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 Bâ&#x20AC;&#x201C;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

7500 max. typ.

gable stanchions

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

UB gable trimmer beam

cold rolled purlin

The structure supports a carbon dioxide vessel weighing

139.7×5 CHS roof bracing (S275 JO) 165 × 152 × 27 tee (S275) (ex.305 × 165 × 54 UB) UB gable stanchion

12 tonnes and 1.9 m diameter 6 5.2 m long, approximately

stanchion

ridge height from FFL

eaves height from FFL

1

300 min. typical

inside a building. It comprises a main frame with four rigid connections supporting the vessel cradle supplied by

rafter stays

rafter10(typ)

brick cladding

steelwork within industrial complexes and was installed

others. Access platforms are provided at two levels below

purlin s e centr

height to top of crane rail

3.1 m above ground level. It is typical of small supporting

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

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

3800

CL platform and vessel

1603

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

Ps

1145

SO

1000

37

1000

Ps

3000

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

F

2686 2706 o/all column

3

section F–F

230 sq. base plates × 10 thick with 4 – 22 dia. holes 115 2440

G

115

60 D

140 section G–G

115

60

D-D

3000 C-C

1 ± SUPPORT PLATFORM REQ'D AS DRAWN Figure 7.13 Vessel support structure.

35 70 35

115

10

4/203 × 203 × 52 UCs 2486 long

54

G

35 50 4

CL UC

60

F

cleat as section F–F

400

60

10

D 8 70 325

E

70 325

200 203 260

10

10 360 10

70

360

10

70 E

200 250100 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

2400 (approx.)

205 nominal

frame

55 169 inside of walls

gable frame (no tie bar) ridge level 1500

frame

frame

frame

gable post

80 × 80 × 8 RSA tie rod hanger 356 × 1 7 1 × 45 UB (S3 55 JR) rafte

1500

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

within an electricity power generating station in India. It

590

40 40

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

5R SA

5L

×6

×6

4000

60

5

60

RS

dim. ‘A’

4000

5

RS

A

3

225

5R SA

PC 0×

×6

×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

0× SECTION 28-28

2863

55 000

1000

SECTION 19-19

9

6500 × 6500

A

3302

13

MA

28K

A

1768

37 970

16

5L

o/o 8 plate

A A

PC

A

18 17

C

×6

×6

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

* note diagonal bracing prefixed with section level e.g. 24D, 25D, etc.

A

31

11 120 × 120 × 15 RSA

*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

A

1000

10

70

×7

C

10 28E

SECTION 31-31 (steelwork at level 31 to be constructed as one welded unit)

70

×

28X

× 70

6L

29A

29

6L 28X 28G

28C

28

70 × 70 × 6 L 70 ×7 0× 6L 27X 27C

27B 27A

SA

15B

5R

SA

15B

CL splice

0× 25X

500

SECTION 15-15

6L

A

×7

2710

26

70 × 70 × 6 L 70

80 × 80 × 6 RSA

A

26B 26A

60

×6

PC

26C

900

5R

1210

27

70 × 70 × 6 L 6L 0× 7 × 26X 70

25A

25B

25

70 × 70 × 6 L 6L 0× 7 × 70 24X

25C

24A

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 L ×6 0 × 7 22X 70

*C

dim ‘B’

23A

23

50 × 50 × 5 RSA

A

6L

23D

23X

typical for each corner

24C

×7

24B

70

8 plate welded to gusset so that plan bracing is horizontal

*A

24

60 × 60 × 5 L

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

150 883

30C

30B

890

127 × 64

A

o/o 8 plate

225

6L

30

900

70 × 70 × 6 L

890

MA

×6

31

30A

1020

60

31A

C 235

127 × 64

127

EXAMPLES OF STRUCTURES


118

STEEL DETAILERS' MANUAL

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

H2

6430 c/c 35

450

50

35

30 nom. grout

15

65

6430 c/c 35

50

4 nom. gap

65

100 100 154 100 100

11G

450 sq. × 40 thick base plate with 34 dia. holes for HD bolts

100 125 125 100

11F

3 thick pack 2/

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

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

18AN

18AL

outer splice plt. only

18Z

18AM

18AN

18AC

safety bolts required up one main leg from platform up to level 31

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

13

35 nom. 50 plinth min.

50

40 × 40 × 3.2 RHS

1000 above paved surface

268

50

268

A

25

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

C

loose washers

3 no. slot welds in 100 face for each half 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 Ă? 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 50 rad 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°

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 girder mks 12

fixed end

run off strip required this side for girder 12

ELEVATION

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

3

Bearing fixity Free to slide Guided Fixed

bracing

bracing

4

2

run off strip

1 expansion joint

10 950

10 350

buried rotation point

10 950

PLAN RC high containment parapet 35 020 3300 hard shoulder 1 in 28.8 X 1

570

17 510 17 000 11 000 carriageway 120 finishes 255 slab

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

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

1920 580

2140

2140

1725

1725

1725

1725

10 950 25 530 bottom flange

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.

1725 10 350

1725

1725

1725

1725

1725

2140

32 610 o/all

5 no. 120×14 thk 2 at 300 crs 12000

see details below

0

17

47

72 2140 10 950

1920

7080 bottom flange

typical elevation on girders 2 to 11 (longitudinal dimensions neglect precamber) 500×25 (S355 JOW) 600×50 1300×14 see details below

93

106

117

124

129

130

310

precamber symm’l

top flg btm flg web int stiffs

lifting lugs

8 8

720 180

150 25

7025 top flange 7025 web plate CL optional splice

720 580

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

truly vertical on completion 400

70 150 150

line of finished road level 125 × 19 studs to 100 C/C – 800 trimmer top flg 100 5050 100

200 C/C max

190 IP

Transflex or similar expansion joint bolt to concrete

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

150

complete web/flange welds at site locally to allow fairing of joint

200

35

80

35

50

150

temporary supports 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 WELDED SPLICE

80

10 000 crs of lugs

150 × 30 thick × 280 long (S275) cleat LIFTING LUG DETAIL (suitable for 10 tonne per lug)

Figure 7.29 Contd


132

STEEL DETAILERS' MANUAL

Alternative Lift Points

see detail ‘A’ 8 6 73 67 73

391

457 × 191 × 80 150150 80 98 UB cutting 10 plate each side fitted into UB fillet

30

54

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

ug

86 87 115 86 86 100 611

2 o /al ll

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

20 dia.

150 dia.

10

175 316 50 83

30

75

1000

8

625

r

40

20

25

350 86 86 86 46

all other details as per 282 section B–B 11 5r 30 plate

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 Ă? marine environment. Grit blast 1st quality after fabrication. Metal coating Ă? 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 B

6

15 thick side plates

15 thick internal stiffeners 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

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 A

1000

200

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

50 30

69

A

100

28 610

150 721

2/200 × 10 flats × 3310 long

533

70

249 70 tread width 1000 17 overlap

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 l l ra 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

32

63 457

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 Âą 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 Âą 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

concrete structures, Part 2: Bridges (together with

coating. Swedish Standards Commission, Stockholm,

United Kingdom National Application Document). 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 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.

coatings. Introduction.

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.

21

EN 1994-2: Eurocode 4: Design of composite steel and

surfaces and preparation grades prior to protective 1971. 20

25

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 Ă? Volume 2: Practical

(11)

Joints in Steel Construction: Moment Connections,

Applications, BCSA and SCI, 1992. 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 Ă? exterior environments, Leaflet Ref. No. GS S 005 5.10.89, British Steel Corporation.


143

FURTHER READING

Erection (1)

BS 5531: 1988 Code of practice for safety in erecting

(2)

BS 5975: 1996 Code of practice for falsework.

Part 1: 1991 Glossary for welding, brazing and thermal cutting. Part 2: 1999 European arc welding symbols in chart

structural frames. (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)

BS 709: 1983 Methods of destructive testing of fusion

(5)

BS EN 1435: 1997 Non-destructive examination of

welded joints and weld metals in steel. welds. Radiographical examination of welded

International symposium on steel bridges, ECCS/ BCSA, Publication No. E97/96, Rotterdam, 1996.

(3)

(4)

Composite Steel Highway Bridges, A.C.G. Hayward,

joints. (6)

welded joints. Ultrasonic examination of welded

British Steel (now Corus), Revised 1997. (4)

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. (7)

BS 6072: 1981 Method for magnetic particle flaw

(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

detection. Part 1: 1997 Penetrant testing. General principles. fusion welds. Visual examination. acceptability of flaws in metallic structures.

Corporation, 1986.

Welding (1)

Design of welded structures, O.W. Blodgett and

Abbreviations BS

Sales Department, Linford Wood, Milton Keynes,

1966.

MK14 6LE.

Introduction to the welding of structural steelwork, J.L. Pratt, 3rd Edn, SCI, 1989.

British Standard Ð British Standards may be obtained from: British Standards Institution,

James F. Lincoln, Arc Welding Foundation, USA, (2)

BS EN 1714: 1998 Non-destructive examination of

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


Metric conversion of units

152

STEEL DETAILERS' MANUAL


Metric conversion of units Contd APPENDIX

153


SI (metric) units ± multiples and submultiples

Metric conversion of units Contd 154 STEEL DETAILERS' MANUAL


Mass

Building materials APPENDIX

155


Mass

Building materials

156

STEEL DETAILERS' MANUAL


Mass

Packaged materials

APPENDIX

157


Angle of internal friction and mass of materials

bunkers and hoppers.

Note: The above data should not be used in the design calculations for silos, bins,

The above values of Ka assume vertical walls with horizontal ground surface.

The effect of wall friction d on active pressures is small and is usually ignored.

pa = mass 6 depth of material 6 Ka

pa, in kN/m2.

This table may be used to determine the horizontal pressure exerted by material,

Values of Ka (coefficient of active pressure) for cohesionless materials

design.

All materials should be tested under appropriate conditions prior to use in final

158 STEEL DETAILERS' MANUAL


3

data should always be used for final design.

The above average figures are for guidance in preliminary design. Manufacturers'

and strengths.

Open steel floors are available from various manufacturers to particular patterns

Steel floors

Lightweight concrete is assumed to have a mass of 1800 kg/m .

a mass of 2400 kg/m3.

Dense concrete is assumed to have natural aggregates and 2% reinforcement with

Reinforced concrete floors

Approximate mass of floors

Walls

Walls and partitions Âą mass

The solid timber joists are based on a density of 5.5 kN/m3.

Timber floors Solid timber, joist sizes, mm. Mass in kN/m2 APPENDIX

159


Positions of centre of gravity

Volumes

Areas

Areas and volumes

Partitions

Walls and partitions Âą mass

The Greek alphabet

Metric equivalents of standard wire gauges 160 STEEL DETAILERS' MANUAL


e 2

R

L

B

C

V

W

X

e

Y

R

The following formulae may be used for exact geometrical calculations.

Circular arcs

Q A

QC T C2 T p R ‡ R2 X A

Y

B

L q 2 N2 ‡ 14

Y

R 2N 0q1 N2 ‡ 14 1 A R@ N

C2 2Q p 1 2 C2 2 4R

p C2 T2 q C N2 ‡ 12

W+V

W

L

V versine R

C2 2R

R 2…N2 ‡ 14†

Q

R radius

2QN

RN N2 ‡ 12

2 …W ‡ V†

T Q2 ‡ 2 2T

T2 ‡ Q2 2Q R CN

2Q …N2 ‡ 12†

p 2RQ

T

i y ˆ

R q N2 ‡ 14

2LN

p R2 T2

B R@1

N C qA N2 ‡ 14

T …N2 ‡ 14† N 0 1

R

p 2RQ Q2

p T2 ‡ Q2

y5 etc: …y Radians† 30240 s T R 1 2Q 2Q 4 r C2 R2 T2 cos y ˆ 1 cos y ˆ 2R2 R

y3 72C

C chord length

y 12

T R R  y radians

R 2L

1 y

Expressions

y length

N ratio

For

C2 V ‡ 8V 2

NW q 2 N ‡ 14 N

T 2N

p E2 Q2

r R2 1 C2 4 p R  R2 T2 2T T tan y ˆ p 2 R T2

APPENDIX

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) vˆR

1 2

ˆ 60

p 4R2 C2 p 1 2 202 2 4  60

C2 ˆW 8R

A ˆ 4V ˆ

ˆ 0:839 m YˆV

(b) At 14 point Xˆ

 1

C2 2R

y C 4V ˆ ˆ 2 2R C

4X2 C2



C 20 ˆ ˆ 5:000 m 4 4

yˆv

ˆ 0:839

R

p R2 X2 p 60 ‡ 602 52

e

Slope of beam at ends ws y ˆ 1

Y

X

ˆ 0:630 m (c)

C2 8V

2

2

C 20 ˆ1 ˆ 0:94444 2R2 2  602

; y ˆ 19:1888 or 0:3349 radians y Slope at ends ˆ ˆ 9:5948 or 0:1675 radians 2 (d) Arc length ˆ R  y radius

X2 2R

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

ˆ 60  0:3449 radians

to be determined so as to counteract deflection. The shape

ˆ 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 C 2

Y

X C

C 2

uniform stiffness EI


163

APPENDIX

Deflected form Central deflection: Vˆ

For shaded area under curve: Rotation at ends:

5 WC4 384 EI

Area ˆ

y WC3 ˆ 2 24EI

  2 C  V 3 2

   ˆ 0:375  C X 2

V

Y

 ˆ 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 ˆ V 1 4:8 C C Slope at any point:  3 ! y 3X X 4 yxˆ 2 C C

Parabolic arcs

Given

To find

Formula

bpw

f

bw

m

q …b ‡ p†2 ‡ 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

 YˆV 1

X

X C

ta ng en t

e 2

y 4V ˆ 2 C  2 4X C2 8VX yxˆ 2 C

Approximate arc length ˆ 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

Parallel bracing

Given

To find

Formula

bpw

f

bnw

m

q …b ‡ p†2 ‡ w2 q …b n†2 ‡ w2

bnp

d

b…b

n†  …2b ‡ p

bnp

e

b…b ‡ p†  …2b ‡ p

bfnp

a

bf  …2b ‡ p

bmnp

c

bm  …2b ‡ p

bnpw

h

bw  …2b ‡ p

afw

h

aw  f

cmw

h

cw  m

k ˆ …log B

log T†  no. of panels. Constant k plus the

logarithm of any line equals the log of the corresponding line in the next panel below. a ˆ TH  …T ‡ e ‡ p†

b ˆ TH  …T ‡ e ‡ p† q c ˆ …12 T ‡ 12 e†2 ‡ a2 d ˆ ce  …T ‡ e† log e ˆ k ‡ log T log f ˆ k ‡ log a

b

log g ˆ k ‡ log b

p

d

e

log m ˆ k ‡ log c log n ˆ k ‡ log d

a

w

log p ˆ k ‡ log e

c

h

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 ‡ p†2 ‡ w2 q …b ‡ k†2 ‡ v2

bkpvw

d

bw…b ‡ k†  ‰v…b ‡ p† ‡ w…b ‡ k†Š

bkpvw

e

bv…b ‡ p†  ‰v…b ‡ p† ‡ w…b ‡ k†Š

bfkpvw

a

fbv  ‰v…b ‡ p† ‡ …w…b ‡ k†Š

bkmpvw

c

bmw  ‰v…b ‡ p† ‡ w…b ‡ k†Š

bkpvw

h

bvw  ‰v…b ‡ p† ‡ w…b ‡ k†Š

afw

h

aw  f

cmv

h

cw  m

b

a

d c

e A H

f

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

properties, 161

beam splice details, figure 5.4, 86

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 crane rail cross section, 68

clearances, figure 4.2, 76 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 engineer's drawings, 32 environmental conditions, effect on steel, 31 erection lifting beam, 132

materials self properties, 158 self weights, 152 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 Ă? 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 Âą third angle, 37 protective treatment, 23

vessel support structure, 108 symbols, the Greek alphabet, 160

systems, table 1.12, 30 purlins Âą 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

type choice, 19

structural shapes, figure 1.6, 6, 8

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

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