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Steel Structures Steel Structures Practical design studies Second edition T.J.MacGinley Formerly Associate Professor Nanyang Technological University Singapore E & FN SPON London and New York Published by E & FN Spon, an imprint of Thomson Professional, 2–6 Boundary Row, London SE1 8HN, UK ...

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Steel Structures

Steel Structures Practical design studies Second edition

T.J.MacGinley Formerly Associate Professor Nanyang Technological University Singapore

E & FN SPON London and New York

Published by E & FN Spon, an imprint of Thomson Professional, 2–6 Boundary Row, London SE1 8HN, UK Thomson Science Professional, 2–6 Boundary Row, London SE1 8HN, UK Thomson Science Professional, Pappelallee 3, 69469 Weinheim, Germany Thomson Science Professional, 115 Fifth Avenue, New York, NY 10003, USA Thomson Science Professional, ITP-Japan, Kyowa Building, 3F, 2–2–1 Hirakawacho, Chiyoda-ku, Tokyo 102, Japan Thomson Science Professional, 102 Dodds Street, South Melbourne, Victoria 3205, Australia Thomson Science Professional, R.Seshadri, 32 Second Main Road, CIT East, Madras 600 035, India First edition 1981 This edition published in the Taylor & Francis e-Library, 2005. “To purchase your own copy of this or any of Taylor & Francis or Routledge’s collection of thousands of eBooks please go to www.eBookstore.tandf.co.uk.” Second edition 1998 © 1998 G.MacGinley ISBN 0-203-47428-7 Master e-book ISBN

ISBN 0-203-78252-6 (Adobe eReader Format) ISBN 0 419 17930 5 (Print Edition) Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the UK Copyright Designs and Patents Act, 1988, this publication may not be reproduced, stored, or transmitted, in any form or by any means, without the prior permission in writing of the publishers, or in the case of reprographic reproduction only in accordance with the terms of the licences issued by the Copyright Licensing Agency in the UK, or in accordance with the terms of licences issued by the appropriate Reproduction Rights Organization outside the UK. Enquiries concerning reproduction outside the terms stated here should be sent to the publishers at the London address printed on this page. The publisher makes no representation, express or implied, with regard to the accuracy of the information contained in this book and cannot accept any legal responsibility or liability for any errors or omissions that may be made. A catalogue record for this book is available from the British Library

Contents

1

Preface

xi

Preface to First Edition

xii

Acknowledgements

xiii

Steel structures—structural engineering

1

1.1

Need for and use of structures

1

1.2

Structural materials—types and uses

1

1.3

Types of structures

2

1.3.1

General types of structures

2

1.3.2

Steel structures

3

1.4

Foundations

4

1.5

Structural engineering

4

1.5.1

Scope of structural engineering

4

1.5.2

Structural designer’s work

5

1.6

Conceptual design, innovation and planning

7

1.7

Comparative design and optimization

8

1.7.1

General considerations

8

1.7.2

Aims and factors considered in design comparison

8

1.7.3

Specific basis of comparisons for common structures

9

1.8

Load paths, structural idealization and modelling

11

1.8.1

Load paths

11

1.8.2

Structural idealization

12

1.8.3

Modelling

12

1.9

Drawings, specifications and quantities

12

1.9.1

Steelwork drawings

12

1.9.2

Specification

13

1.9.3

Quantities

15

1.10

Fabrication

15

1.11

Transport and erection

16

2

Structural steel design

17

Design theories

17

2.1 2.1.1

Development of design

17

v

2.1.2

Design from experience

17

2.1.3

Elastic theory

17

2.1.4

Plastic theory

18

2.1.5

Limit state theory and design codes

19

2.2

Limit states and design basis

20

2.3

Loads, actions and partial safety factors

20

2.3.1

Loads

20

2.3.2

Load factors/partial safety factors and design loads

21

2.4

Structural steels—partial safety factors for materials

21

2.5

Design methods from codes—ultimate limit state

21

2.5.1

Design methods from BS 5950

21

2.5.2

Analysis of structures—Eurocode 3

23

2.5.3

Member and joint design

23

2.6

Stability limit state

24

2.7

Design for accidental damage

24

2.7.1

Progressive collapse and robustness

24

2.7.2

Building Regulations 1991

25

2.7.3

BS 5950 requirements for structural integrity

25

2.8

Serviceability limit states

26

2.8.1

Deflection limits

26

2.8.2

Vibration

26

2.9

Design considerations

26

2.9.1

Fatigue

26

2.9.2

Brittle fracture

27

2.9.3

Corrosion protection

28

2.9.4

Fire protection

28

Preliminary design

31

3.1

General considerations

31

3.2

Need for and scope of preliminary design methods

31

3.3

Design concept, modelling and load estimation

31

3

3.3.1

Design concept

31

3.3.2

Modelling

32

3.3.3

Load estimation

32

3.4

Analysis

32

3.4.1

Statically determinate structures

32

3.4.2

Statically indeterminate structures

35

3.5

Element design

38

vi

3.5.1

General comments

38

3.5.2

Ties and struts

39

3.5.3

Beams and girders

40

3.5.4

Beam-columns

41

3.5.5

Members in portal frames

42

3.6

Examples

43

3.6.1

Ribbed dome structure

43

3.6.2

Two pinned portal—plastic design

45

4

Single-storey, one-way-spanning buildings

48

4.1

Types of structures

48

4.2

Pinned-base portal—plastic design

48

4.2.1

Specification and framing plans

48

4.2.2

Dead and imposed loads

49

4.2.3

Wind loads

50

4.2.4

Design load cases

52

4.2.5

Plastic analysis and design

52

4.2.6

Dead and wind loads

54

4.2.7

Plastic design checks

55

4.2.8

Rafter under wind uplift

59

4.2.9

Portal joints

60

Serviceability check

62

4.2.10 4.3

Built-up tapered member portal

63

4.3.1

General comments

63

4.3.2

Design process

63

4.4

Two-pinned arch

63

4.4.1

General considerations

63

4.4.2

Specification

64

4.4.3

Loading

65

4.4.4

Analysis

65

4.4.5

Design

65

4.4.6

Construction

67

4.4.7

Lattice arch

67

5 5.1

Multistorey buildings

72

Outline of designs covered

72

5.1.1

Aims of study

72

5.1.2

Design to BS 5950

72

5.2

Building and loads

72

vii

5.2.1

Specification

72

5.2.2

Loads

73

5.2.3

Materials

74

5.3

Simple design centre frame

75

5.3.1

Slabs

75

5.3.2

Roof beam

75

5.3.3

Floor beam

75

5.3.4

Outer column—upper length 7–10–13

75

5.3.5

Outer column—lower length 1–4–7

75

5.3.6

Centre column—upper length 8–11–14

76

5.3.7

Centre column—lower length 2–5–8

76

5.3.8

Joint design

77

5.3.9

Baseplate—centre column

77

5.4

Braced rigid elastic design

78

5.4.1

Computer analysis

78

5.4.2

Beam design

78

5.4.3

Column design

81

5.4.4

Joint design

82

5.5

Braced rigid plastic design

83

5.5.1

Design procedure

83

5.5.2

Design loads and moments

84

5.5.3

Frame design

85

Semirigid design

90

5.6 5.6.1

Code requirements

90

5.6.2

Joint types and performance

91

5.6.3

Frame analysis

91

5.6.4

Frame design

94

5.7

Summary of designs

100

Floor systems

101

6.1

Functions of floor systems

101

6.2

Layouts and framing systems

101

6.3

Types of floor construction

102

6.4

Composite floor slabs

103

6.4.1

General comments

103

6.4.2

Design procedure

103

6

6.5 6.5.1

Composite beam design Design basis

104 104

viii

6.5.2

Effective section

105

6.5.3

Plastic moment capacity

105

6.5.4

Construction

106

6.5.5

Continuous beam analysis

106

6.5.6

Design of members

106

6.5.7

Shear connectors

107

6.5.8

Longitudinal shear

108

6.5.9

Deflection

109

6.6

Simply supported composite beam

109

6.6.1

Specification

109

6.6.2

Moment capacity

110

6.6.3

Shear

110

6.6.4

Shear connectors

110

6.6.5

Longitudinal shear

110

6.6.6

Deflection

110

6.7

Continuous composite beam

111

6.7.1

Specification

111

6.7.2

Floor loads

112

6.7.3

Elastic analysis and redistribution

113

6.7.4

Section design checks

116

6.7.5

Shear connectors

118

6.7.6

Longitudinal shear

119

6.7.7

Deflection

120

Tall buildings

122

7.1

General considerations

122

7.2

Structural design considerations

123

7.3

Structural systems

123

7

7.3.1

All-steel braced structure

123

7.3.2

Rigid frame and mixed systems

124

7.3.3

All-steel outrigger and belt truss system

125

7.3.4

Composite structures

126

7.3.5

Suspended structures

127

7.3.6

Tube structures

128

7.3.7

SWMB structures

129

7.4

Construction details

129

7.4.1

Roofs and floors

129

7.4.2

Walls

131

ix

7.4.3 7.5

Steel members Multistorey building—preliminary design

131 131

7.5.1

Specification

131

7.5.2

Dead and imposed loads

132

7.5.3

Beam loads and design

133

7.5.4

Design of perimeter column PC1

136

7.5.5

Braced core wall—vertical loads

139

7.5.6

Wind loads

140

7.5.7

Stability, foundations and bracing

144

8

Wide-span buildings

146

8.1

Types and characteristics

146

8.2

Tie-stayed roof—preliminary design

147

8.2.1

Specification

147

8.2.2

Preliminary design

149

8.2.3

Stability and wind load

153

8.3

Space decks

155

8.3.1

Two-way spanning roofs

155

8.3.2

Space decks

157

8.3.3

Space deck analysis and design

157

Preliminary design for a space deck

158

8.4 8.4.1

Specification

158

8.4.2

Arrangement of space deck

158

8.4.3

Approximate analysis and design

158

8.4.4

Computer analysis

159

8.4.5

Computer results

162

8.4.6

Member design

162

8.5

Framed domes

163

8.5.1

Types

163

8.5.2

Dome construction

164

8.5.3

Loading

165

8.5.4

Analysis

166

8.5.5

Stability

166

8.6

Schwedler dome

166

8.6.1

Specification

166

8.6.2

Loading for statical analysis

167

8.6.3

Statical analysis

167

8.6.4

Member design

171

x

8.6.5 8.7

Membrane analysis Retractable roof stadium

172 172

8.7.1

Introduction

172

8.7.2

Proposed structure

173

8.7.3

Preliminary section sizes

174

8.7.4

Problems in design and operation

175

Bibliography

177

Index

179

Preface

The main purpose of the second edition is again to present principles, relevant considerations and sample designs for some of the major types of steel-framed buildings. All buildings can be framed in different ways with different types of joints and analysed using different methods. Member design for ultimate conditions is specified. Projects are selected to show alternative designs for the same structure. Designs are now to conform to limit state theory—the British steel code and the new Eurocode. Design principles are set out briefly and designs made to the British code only. Reference is made to the Eurocode in one special case. Many more design calculations and checks are required for the limit state code than for the previous elastic code and thus not all load cases or detailed checks can be carried out for every design project. However, further necessary design work is indicated in these cases. Though computer methods, mainly for analysis, but also increasingly used for member and connection design are now the design office procedural norm, approximate, manual methods are still of great importance. These are required mainly to obtain sections for computer analysis and to check final designs. The book, as in the case of the first edition, is aimed at final year students, candidates on master’s degree courses in structural engineering and young engineers in industry. Fundamental knowledge of the methods of structural analysis and design from a basic design course is assumed.

Preface to the First Edition

The purpose of the book is to present the principles and practice of design for some of the main modern structures. It is intended for final year degree students to show the application of structural engineering theory and so assist them to gain an appreciation of the problems involved in the design process in the limited time available in college. In such a presentation many topics cannot be covered in any great detail. Design is a decision-making process where engineering judgement based on experience, theoretical knowledge, comparative design studies etc., is used to arrive at the best solution for a given situation. The material in the book covers the following: (a) discussion of conceptual design and planning; (b) presentation of the principles and procedures for the various methods of analysis and design; (c) detailed analysis and design for selected structures. Preliminary design studies are made in other cases where the full treatment of the problem is beyond the scope of this book. In detailed design, the results are presented in the form of sketches showing framing plans, member sizes and constructional details. Although the book is primarily concerned with the design of steel structures, ...