Steel Designers' Manual -  - ebook

Steel Designers' Manual ebook

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Opis

In 2010 the then current European national standards for buildingand construction were replaced by the EN Eurocodes, a set ofpan-European model building codes developed by the EuropeanCommittee for Standardization. The Eurocodes are a series of 10European Standards (EN 1990 - EN 1999) that provide a commonapproach for the design of buildings, other civil engineering worksand construction products. The design standards embodied in theseEurocodes will be used for all European public works and are set tobecome the de-facto standard for the private sector in Europe, withprobable adoption in many other countries. This classic manual on structural steelwork design was firstpublished in 1955, since when it has sold many tens of thousands ofcopies worldwide. For the seventh edition of the SteelDesigners' Manual all chapters have been comprehensivelyreviewed, revised to ensure they reflect current approaches andbest practice, and brought in to compliance with EN 1993: Design ofSteel Structures (the so-called Eurocode 3).

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Table of Contents

Cover

Title page

Copyright page

Introduction to the seventh edition

Contributors

INTRODUCTION

Chapter 1 Introduction – designing to the Eurocodes

1.1 Introduction

1.2 Creation of the Eurocodes

1.3 Structure of the Eurocodes

1.4 Non-contradictory complementary information – NCCI

1.5 Implementation in the UK

1.6 Benefits of designing to the Eurocodes

1.7 Industry support for the introduction of the Eurocodes

1.8 Conclusions

Chapter 2 Integrated design for successful steel construction

2.1 Client requirements for whole building performance, value and impact

2.2 Design for sustainability

2.3 Design for overall economy

2.4 Conclusions

Chapter 3 Loading to the Eurocodes

3.1 Imposed loads

3.2 Imposed loads on roofs

3.3 Snow loads

3.4 Accidental actions

3.5 Combinations of actions

DESIGN SYNTHESIS

Chapter 4 Single-storey buildings

4.1 The roles for steel in single-storey buildings

4.2 Design for long term performance

4.3 Anatomy of structure

4.4 Loading

4.5 Common types of primary frame

4.6 Preliminary design of portal frames

4.7 Bracing

4.8 Design of portal frames to BS EN 1993-1-1

Chapter 5 Multi-storey buildings

5.1 Introduction

5.2 Costs and construction programme

5.3 Understanding the design brief

5.4 Structural arrangements to resist sway

5.5 Stabilising systems

5.6 Columns

5.7 Floor systems

Chapter 6 Industrial steelwork

6.1 Introduction

6.2 Anatomy of structure

6.3 Loading

6.4 Thermal effects

6.5 Crane girder / lifting beam design

6.6 Structure in its wider context

Chapter 7 Special steel structures

7.1 Introduction

7.2 Space frame structures: 3-dimensional grids based on regular solids

7.3 Lightweight tension steel cable structures

7.4 Lightweight compression steel structures

7.5 Steel for stadiums

7.6 Information and process in the current digital age – the development of technology

Case study project credits

Chapter 8 Light steel structures and modular construction

8.1 Introduction

8.2 Building applications

8.3 Benefits of light steel construction

8.4 Light steel building elements

8.5 Modular construction

8.6 Hybrid construction

8.7 Structural design issues

8.8 Non-structural design issues

Chapter 9 Secondary steelwork

9.1 Introduction

9.2 Issues for consideration

9.3 Applications

APPLIED METALLURGY

Chapter 10 Applied metallurgy of steel

10.1 Introduction

10.2 Chemical composition

10.3 Heat treatment

10.4 Manufacture and effect on properties

10.5 Engineering properties and mechanical tests

10.6 Fabrication effects and service performance

10.7 Summary

Chapter 11 Failure processes

11.1 Fracture

11.2 Linear elastic fracture mechanics

11.3 Elastic-plastic fracture mechanics

11.4 Materials testing for fracture properties

11.5 Fracture-safe design

11.6 Fatigue

11.7 Final comments

ANALYSIS

Chapter 12 Analysis

12.1 Introduction

12.2 The basics

12.3 Analysis and design

12.4 Analysis by hand

12.5 Analysis by software

12.6 Analysis of multi-storey buildings

12.7 Portal frame buildings

12.8 Special structural members

12.9 Very important issues

Chapter 13 Structural vibration

13.1 Introduction

13.2 Causes of vibration

13.3 Perception of vibration

13.4 Types of response

13.5 Determining the modal properties

13.6 Calculating vibration response

13.7 Acceptability criteria

13.8 Practical considerations

13.9 Synchronised crowd activities

ELEMENT DESIGN

Chapter 14 Local buckling and cross-section classification

14.1 Introduction

14.2 Cross-sectional dimensions and moment-rotation behaviour

14.3 Effect of moment-rotation behaviour on approach to design and analysis

14.4 Classification table

14.5 Economic factors

Chapter 15 Tension members

15.1 Introduction

15.2 Types of tension member

15.3 Design for axial tension

15.4 Combined bending and tension

15.5 Eccentricity of end connections

15.6 Other considerations

15.7 Cables

Chapter 16 Columns and struts

16.1 Introduction

16.2 Common types of member

16.3 Design considerations

16.4 Cross-sectional considerations

16.5 Column buckling resistance

16.6 Torsional and flexural-torsional buckling

16.7 Effective (buckling) lengths Lcr

16.8 Special types of strut

16.9 Economic points

Chapter 17 Beams

17.1 Introduction

17.2 Common types of beam

17.3 Cross-section classification and moment resistance Mc,Rd

17.4 Basic design

17.5 Laterally unrestrained beams

17.6 Beams with web openings

Chapter 18 Plate girders

18.1 Introduction

18.2 Advantages and disadvantages

18.3 Initial choice of cross-section for plate girders

18.4 Design of plate girders to BS EN 1993-1-5

Chapter 19 Members with compression and moments

19.1 Occurrence of combined loading

19.2 Types of response – interaction

19.3 Effect of moment gradient loading

19.4 Selection of type of cross-section

19.5 Basic design procedure to Eurocode 3

19.6 Special design methods for members in portal frames

Chapter 20 Trusses

20.1 Introduction

20.2 Types of truss

20.3 Guidance on overall concept

20.4 Selection of elements and connections

20.5 Analysis of trusses

20.6 Detailed design considerations for elements

20.7 Bracing

20.8 Rigid-jointed Vierendeel girders

Chapter 21 Composite slabs

21.1 Definition

21.2 General description

21.3 Design for the construction condition

21.4 Design of composite slabs

21.5 Design for shear and concentrated loads

21.6 Tests on composite slabs

21.7 Serviceability limits and crack control

21.8 Shrinkage and creep

21.9 Fire resistance

Chapter 22 Composite beams

22.1 Introduction

22.2 Material properties

22.3 Composite beams

22.4 Plastic analysis of composite section

22.5 Shear resistance

22.6 Shear connection

22.7 Full and partial shear connection

22.8 Transverse reinforcement

22.9 Primary beams and edge beams

22.10 Continuous composite beams

22.11 Serviceability limit states

22.12 Design tables for composite beams

Chapter 23 Composite columns

23.1 Introduction

23.2 Design of composite columns

23.3 Simplified design method

23.4 Illustrative examples of design of composite columns

23.5 Longitudinal and transverse shear forces

Chapter 24 Design of light gauge steel elements

24.1 Introduction

24.2 Section properties

24.3 Local buckling

24.4 Distortional buckling

24.5 Design of compression members

24.6 Design of members in bending

CONNECTION DESIGN

Chapter 25 Bolting assemblies

25.1 Types of structural bolting assembly

25.2 Methods of tightening and their application

25.3 Geometric considerations

25.4 Methods of analysis of bolt groups

25.5 Design strengths

25.6 Tables of resistance

Chapter 26 Welds and design for welding

26.1 Advantages of welding

26.2 Ensuring weld quality and properties by the use of standards

26.3 Recommendations for cost reduction

26.4 Welding processes

26.5 Geometric considerations

26.6 Methods of analysis of weld groups

26.7 Design strengths

26.8 Concluding remarks

Chapter 27 Joint design and simple connections

27.1 Introduction

27.2 Simple connections

Chapter 28 Design of moment connections

28.1 Introduction

28.2 Design philosophy

28.3 Tension zone

28.4 Compression zone

28.5 Shear zone

28.6 Stiffeners

28.7 Design moment of resistance of end-plate joints

28.8 Rotational stiffness and rotation capacity

28.9 Summary

FOUNDATIONS

Chapter 29 Foundations and holding-down systems

29.1 Types of foundation

29.2 Design of foundations

29.3 Fixed and pinned column bases

29.4 Pinned column bases – axially loaded I-section columns

29.5 Design of fixed column bases

29.6 Holding-down systems

Chapter 30 Steel piles and steel basements

30.1 Introduction

30.2 Types of steel piles

30.3 Geotechnical uncertainty

30.4 Choosing a steel basement

30.5 Detailed basement design: Introduction

30.6 Detailed basement designs: Selection of soil parameters

30.7 Detailed basement design: Geotechnical analysis

30.8 Detailed basement design: Structural design

30.9 Other design details

30.10 Constructing a steel basement: Pile installation techniques

30.11 Specification and site control

30.12 Movement and monitoring

CONSTRUCTION

Chapter 31 Design for movement in structures

31.1 Introduction

31.2 Effects of temperature variation

31.3 Spacing of expansion joints

31.4 Design for movement in typical single-storey industrial steel buildings

31.5 Design for movement in typical multi-storey buildings

31.6 Treatment of movement joints

31.7 Use of special bearings

Chapter 32 Tolerances

32.1 Introduction

32.2 Standards

32.3 Implications of tolerances

32.4 Fabrication tolerances

32.5 Erection tolerances

Acknowledgement

Chapter 33 Fabrication

33.1 Introduction

33.2 Economy of fabrication

33.3 Welding

33.4 Bolting

33.5 Cutting

33.6 Handling and routeing of steel

33.7 Quality management

Chapter 34 Erection

34.1 Introduction

34.2 Method statements, regulations and documentation

34.3 Planning

34.4 Site practices

34.5 Site fabrication and modifications

34.6 Steel decking and shear connectors

34.7 Cranes and craneage

34.8 Safety

34.9 Accidents

Chapter 35 Fire protection and fire engineering

35.1 Introduction

35.2 Building regulations

35.3 Fire engineering design codes

35.4 Structural performance in fire

35.5 Fire protection materials

35.6 Advanced fire engineering

35.7 Selection of an appropriate approach to fire protection and fire engineering for specific buildings

Chapter 36 Corrosion and corrosion prevention

36.1 Introduction

36.2 General corrosion

36.3 Other forms of corrosion

36.4 Corrosion rates

36.5 Effect of the environment

36.6 Design and corrosion

36.7 Surface preparation

36.8 Metallic coatings

36.9 Paint coatings

36.10 Application of paints

36.11 Weather-resistant steels

36.12 The protective treatment specification

Appendix

Elastic properties

European standards for structural steels

Introduction

Designation systems

Bending moment, shear and deflection

Second moments of area

Plastic moduli

Formulae for rigid frames

Explanatory notes on section dimensions and properties

1 General

2 Dimensions of section

3 Section properties

4 Effective section properties

5 Bolts and welds

Tables of dimensions and gross section properties

Bolt and Weld Data for S275

Bolt and Weld Data for S355

Extracts from Concise Eurocodes

1.5 Terminology

2.5 General requirements for the design of joints

3.2 Densities of construction materials

4.4 Concrete

5.5 Classification of cross-sections

6.3 Buckling resistance of members

7.2 Vertical deflections

7.3 Horizontal deflections

8.2 Bolted connections

8.3 Welded connections

Floor plates

Fire resistance

Section factors for fire design

Corrosion resistance

Basic data on corrosion

British and European Standards for steelwork

Loading: Summary of changes since 2003

Loading: Current standards

Design: Summary of changes since 2003

Design: Current standards

Steel fabrication and erection: Summary of changes since 2003

Steel fabrication and erection: Current standards

Foundations and piling: Summary of changes since 2003

Foundations and piling: Current standards

Structural steel: Current standards

Steel products: Current standards

Cold-rolled thin gauge sections and sheets: Summary of changes since 2003

Cold-rolled thin gauge sections and sheets: Current standards

Stainless steels: Current standards

Castings and forgings: Current standards

Steel construction components: Current standards

Welding materials and processes: Current standards

Processes and consumables: Current standards

Testing and examination: Current standards

Bolts and fasteners: Summary of changes since 2003

Fire resistance: Current standards

Corrosion prevention and coatings: Current standards

Quality assurance: Current standards

Environmental: Current standards

Index

This edition first published 2012 © 2012 by Steel Construction Institute

Blackwell Publishing was acquired by John Wiley & Sons in February 2007. Blackwell’s publishing program has been merged with Wiley’s global Scientific, Technical and Medical business to form Wiley-Blackwell.

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All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by the UK Copyright, Designs and Patents Act 1988, without the prior permission of the publisher.

Designations used by companies to distinguish their products are often claimed as trademarks. All brand names and product names used in this book are trade names, service marks, trademarks or registered trademarks of their respective owners. The publisher is not associated with any product or vendor mentioned in this book. This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold on the understanding that the publisher is not engaged in rendering professional services. If professional advice or other expert assistance is required, the services of a competent professional should be sought.

Library of Congress Cataloging-in-Publication Data

Steel designers’ manual / the Steel Construction Institute ; edited by Buick Davison, Graham W. Owens.. – 7th ed.

p. cm.

Includes bibliographical references and index.

 ISBN-13: 978-1-4051-8940-8 (hardback)

 ISBN-10: 1-4051-8940-1 ()

 I. Davison, Buick. II. Owens, Graham W. (Graham Wynford) III. Steel Construction Institute (Great Britain)

 TA685.G67 2011

 624.1'821–dc23

2011028324

A catalogue record for this book is available from the British Library.

This book is published in the following electronic formats: ePDF 9781444344844; ePub 9781444344851; Mobi 9781444344868

Although care has been taken to ensure, to the best of our knowledge, that all data and information contained herein are accurate to the extent that they relate to either matters of fact or accepted practice or matters of opinion at the time of publication, the Steel Construction Institute assumes no responsibility for any errors in or misinterpretations of such data and or information or any loss or damage arising from or related to their use.

Extracts from the British Standards are reproduced with the permission of BSI. Complete copies of the standards quoted can be obtained by post from BSI Sales, Linford Wood, Milton Keynes, MK14 6LE.

Introduction to the seventh edition

At the instigation of the Iron and Steel Federation, the late Bernard Godfrey began work in 1952 on the first edition of the Steel Designers’ Manual. As principal author, he worked on the manuscript almost continuously for a period of two years. On many Friday evenings he would meet with his co-authors, Charles Gray, Lewis Kent and W.E. Mitchell, to review progress and resolve outstanding technical problems. A remarkable book emerged. Within approximately 900 pages it was possible for the steel designer to find everything necessary to carry out the detailed design of most conventional steelwork. Although not intended as an analytical treatise, the book contained the best summary of methods of analysis then available. The standard solutions, influence lines and formulae for frames could be used by the ingenious designer to disentangle the analysis of the most complex structure. Information on element design was intermingled with guidance on the design of both overall structures and connections. It was a book to dip into rather than read from cover to cover. However well one thought one knew its contents, it was amazing how often a further reading would give some useful insight into current problems. Readers forgave its idiosyncrasies, especially in the order of presentation. How could anyone justify slipping a detailed treatment of angle struts between a very general discussion of space frames and an overall presentation on engineering workshop design?

The book was very popular. It ran to four editions with numerous reprints in both hard and soft covers. Special versions were also produced for overseas markets. Each edition was updated by the introduction of new material from a variety of sources. However, the book gradually lost the coherence of its original authorship and it became clear in the 1980s that a more radical revision was required.

After 36 very successful years, it was decided to rewrite and reorder the book, while retaining its special character. This decision coincided with the formation of the Steel Construction Institute and it was given the task of co-ordinating this activity.

A complete restructuring of the book was undertaken for the fifth edition, with more material on overall design and a new section on construction. The analytical material was condensed because it is now widely available elsewhere, but all the design data were retained in order to maintain the practical usefulness of the book as a day-to-day design manual. Allowable stress design concepts were replaced by limit state design encompassing BS 5950 for buildings and BS 5400 for bridges. Design examples are to the more appropriate of these two codes for each particular application.

The fifth edition was published in 1992 and proved to be a very worthy successor to its antecedents. It also ran to several printings in both hard and soft covers; an international edition was also printed and proved to be very popular in overseas markets. The sixth edition of 2003 maintained the broad structure introduced in 1992, reflecting its target readership of designers of structural steelwork of all kinds, and included updates to accommodate changes in the principal design codes, BS5400 and BS5950.

This seventh edition, while maintaining the same overall structure, has required a more radical review of the content. The most significant changes are:

The adoption of the Eurocodes, presenting relevant parts of their background in the chapters on element and connection design and using them for all worked examples.Recognition of the growing importance of light steel and secondary steelwork with separate chapters on types of light steel structure, the detailed design of light gauge elements and secondary steelwork.Recognition of both the greater importance of sustainability to the built environment and the associated need for holistic, integrated approaches to design and construction.A revised approach to analysis, recognising the growing importance of computer methods.

Because all these changes introduced more material into an already very large text book, it was decided to concentrate on building structures, removing all references to bridges.

Introduction: Chapters 1–3

An introduction to both design to the Eurocodes and the need for integrated design.

Introduction – design to the Eurocodes (Chapter 1)Integrated design for successful steel construction (Chapter 2)Loading to the Eurocodes (Chapter 3).

Design synthesis: Chapters 4–9

A description of the processes by which design solutions are formed for a wide range of steel structures.

Single storey buildings (Chapter 4)Multi-storey buildings (Chapter 5)Industrial steelwork (Chapter 6)Special steel structures (Chapter 7)Light steel structures (Chapter 8)Secondary steelwork (Chapter 9)

Applied metallurgy: Chapters 10–11

Background material sufficient to inform designers of the important issues inherent in the production and use of steel and methods of accounting for them in practical design and construction.

Applied metallurgy of steel (Chapter 10)Failure processes (Chapter 11)

Analysis: Chapters 12 and 13

A resumé of analytical methods for determining the forces and moments in structures subject to static or dynamic loads, both manual and computer-based.

Comprehensive tables for a wide variety of beams and frames are given in the Appendix.

Analysis (Chapter 12)Structural vibrations (Chapter 13)

Element Design: Chapters 14–24

A comprehensive treatment of the design of steel elements, singly, in combination or acting compositely with concrete.

Local buckling and cross-section classification (Chapter 14)Tension members (Chapter 15)Columns and struts (Chapter 16)Beams (Chapter 17)Plate girders (Chapter 18)Members with compression and moments (Chapter 19)Trusses (Chapter 20)Composite slabs (Chapter 21)Composite beams (Chapter 22)Composite columns (Chapter 23)Light gauge elements (Chapter 24)

Connection design: Chapters 25–28

The general basis of design of connections is surveyed and amplified by consideration of specific connection methods.

Bolting assemblies (Chapter 25)Welds and design for welding (Chapter 26)Joint design and simple connection (Chapter 27)Moment connections (Chapter 28)

Foundations: Chapters 29 and 30

Relevant aspects of sub-structure design for steel construction.

Foundations and holding down systems (Chapter 29)Steel piles (Chapter 30)

Construction: Chapters 31–36

Important aspects of steel construction about which a designer must be informed in order to produce structures which can be economically fabricated and erected, and which will have a long and safe life.

Design for movement (Chapter 31)Tolerances (Chapter 32)Fabrication (Chapter 33)Erection (Chapter 34)Fire protection and fire engineering (Chapter 35)Corrosion and corrosion prevention (Chapter 36)

A comprehensive collection of data of direct use to the practising designer is compiled into a series of Appendices.

Throughout the book, Eurocode notation has been adopted.

By kind permission of the British Standards Institution, references are made to British Standards, including the Eurocodes, throughout the manual. The tables of fabrication and erection tolerances in Chapter 32 are taken from the fifth edition of the National Structural Steelwork Specification. Both these sources are used with the kind permission of the British Constructional Steelwork Association, the publishers.

Finally, we would like to thank all the contributors and acknowledge their hard work in updating the content and their co-operation in compiling this latest edition. All steelwork designers are indebted to their efforts in enabling this manual to be maintained as the most important single source of information on steel design.

Buick Davison and Graham W. Owens

Contributors

David G. Brown

David Brown graduated from the University of Bradford in 1982 and worked for several years for British Rail, Eastern Region, before joining a steelwork contractor as a designer, and then technical director. He joined the Steel Construction Institute in 1994 and has been involved with connections, frame design, Eurocodes and technical training.

Michael Burdekin

Michael Burdekin graduated from Cambridge University in 1961. After fifteen years of industrial research and construction experience, during which he was awarded a PhD from Cambridge University, he was appointed Professor of Civil and Structural Engineering at UMIST in 1977. He retired from this post in December 2002 and is now an Emeritus Professor of the University of Manchester. His specific expertise is the field of welded steel structures, particularly in materials behaviour and the application of fracture mechanics to fracture and fatigue failure.

Katherine Cashell

Dr Katherine Cashell is a Senior Engineer at the Steel Construction Institute and a Chartered Member of the Institution of Civil Engineers. Previous to this, she worked as a research assistant at Imperial College London and a Design Engineer at High Point Rendel Consultants.

Kwok-Fai Chung

Professor K F Chung obtained a bachelor degree from the University of Sheffield in 1984 and a doctoral degree from Imperial College in 1988. He joined the Steel Construction Institute in 1989 and worked as a research engineer for six years on steel, steel-concrete composite and cold-formed steel structures as well as structural fire engineering. After practising as a structural engineer in a leading consultant firm in Hong Kong for approximately a year, he joined the Hong Kong Polytechnic University in 1996 as an Assistant Professor and was promoted to a full Professor in 2005. He has published about 150 technical papers in journals and conferences together with five SCI design guides. Moreover, he has taught about 30 professional courses to practising engineers in Hong Kong, Singapore, Malaysia and Macau. He was Chairman of the Editorial Board and Chief Editor of the Proceedings of the IStructE Centenary Conference 2008. Currently, he is the Founding President of the Hong Kong Constructional Metal Structures Association and Advisor to the Macau Society of Metal Structures.

Graham Couchman

Graham Couchman graduated from Cambridge University in 1984 and completed a PhD in composite construction from the Swiss Federal Institute of Technology in Lausanne in 1994. He has experience of construction, design and research, specialising in composite construction and light gauge construction. He first joined SCI in 1995 then, after a brief spell at BRE, became Chief Executive of SCI in 2007. He is currently chairman of the European committee responsible for Eurocode 4.

Buick Davison

Dr Buick Davison is a Senior Lecturer in the Department of Civil and Structural Engineering at the University of Sheffield. In addition to his wide experience in teaching and research of steel structures, he is a Chartered Engineer and has worked in consultancies on the design of buildings and stadia.

David Deacon

David Deacon qualified as a Coating Technologist in 1964 and after working for the British Iron and Steel Research Association and the Burma Castrol Group, he started in consultancy of coatings for iron and steel structures in 1970.

His first major consultancy was the protective coatings for London’s Thames Barrier, which is now some 28 years old and a recent major survey has extended the life of the coatings to first major maintenance from 25 to 40 years.

His consultancy and advisory activities has taken him to over 50 countries worldwide on a range of projects; he is currently working on the refurbishment of the Cutty Sark iron frame, the Forth Rail and Road Bridges and numerous other structures.

He has given many papers on his specialist coatings subjects and is a co-author of the book ‘Steelwork Corrosion Control’. He is a Past President of the Institute of Corrosion and last year was awarded a unique Lifetime Achievement Award by the Institute of Corrosion.

David Dibb-Fuller

David Dibb-Fuller started his career with the Cleveland Bridge and Engineering Company in London. His early bridge related work gave a strong emphasis to heavy fabrication; in later years he moved on to building structures. As technical director for Conder Southern in Winchester, his strategy was to develop close links between design for strength and design for production. He moved on to become a partner with Gifford and Partners in Southampton until his retirement; he remains a consultant to the partnership.

Richard Dobson

Richard Dobson graduated from the University of Cambridge in 1980. For the first eight years of his professional career, he worked for consulting engineers in areas of bridge design and off-shore steel jacket design for the North Sea and other parts of the world. Twenty-four years ago Richard joined CSC (UK) Ltd, designing and developing software solutions for structural engineers. For the last 12 years, Richard has been the technical director at CSC overseeing the global development of CSC’s range of software products – Fastrak, Orion and Tedds.

Leroy Gardner

Dr Leroy Gardner is a Reader in Structural Engineering at Imperial College London and a Chartered Civil and Structural Engineer. He leads an active research group in the area of structural steelwork, teaches at both undergraduate and postgraduate levels and carries out specialist advisory work for industry. He has co-authored two textbooks and over 100 technical papers, and is a member of the BSI committee responsible for Eurocode 3.

Jeff Garner

Jeff Garner has over 30 years industrial experience in fabrication and welding. He is a professional Welding Engineer with a Masters degree in Welding Engineering. Working in a range of key industry sectors including petrochemical, nuclear, steel making, railways and construction he has acted as a consulting welding engineer, delivered welding technology training courses and provided representation on a number of British and European welding code/standards committees. Jeff joined the British Constructional Steelwork Association in 2008 as Welding and Fabrication Manager, responsible for providing welding and fabrication technology support throughout the UK steel construction industry. In 2011 he moved to edf.

Martin Heywood

Martin Heywood has worked at the SCI since 1998. He currently holds the title ‘Associate Director Construction Technology’ and has responsibility for a portfolio of projects involving light gauge steel, modern methods of construction, floor vibrations and building envelope systems. Previously, Martin worked for several years in the SCI’s Codes and Standards division where he authored the SCI’s Guide to the amendments to BS 5950-1:2000 and BS 5950 worked examples. Prior to joining the SCI, Martin worked for 3 years in civil engineering contracting and obtained a PhD in structural dynamics from Birmingham University.

Roger Hudson

Roger Hudson studied metallurgy at Sheffield Polytechnic whilst employed by BISRA. He also has a Masters degree from the University of Sheffield. In 1968, he joined the United Steel Companies at Swinden Laboratories in Rotherham to work on the corrosion of stainless steels. The laboratories later became part of British Steel where he was responsible for the Corrosion Laboratory and several research projects. He became principal technologist for Corus . He is a member of several technical and international standards committees, has written technical publications, and has lectured widely on the corrosion and protection of steel in structures. He has had a longstanding professional relationship with the Institute of Corrosion.

Mark Lawson

Mark Lawson is part-time Professor of Construction Systems at the University of Surrey and a Specialist Consultant to the Steel Construction Institute. In 1987, he joined the newly formed SCI as Research Manager for steel in buildings, with particular reference to composite construction, fire engineering and cold-formed steel. A graduate of Imperial College, and the University of Salford, where he worked in the field of cold-formed steel, Mark Lawson spent his early career at Ove Arup and Partners and the Construction Industry Research and Information Association. He is a member of the Institutions of Civil and Structural Engineers and the American Society of Civil Engineers.

Ian Liddell

Ian Liddell was a Founding Partner of Buro Happold in 1976. He has been responsible for a wide range of projects with special innovatory structural engineering including Sydney Opera House, the Millennium Dome, Mannheim Gridshell Roof, and the concept and scheme for Phoenix Stadium Retractable Roof. He is one of the world’s leading experts in the field of lightweight tension and fabric structures. He is a Royal Academy of Engineering Visiting Professor at the University of Cambridge and was awarded the Institution of Structural Engineers Gold Medal in 1999.

Allan Mann

Allan Mann graduated from Leeds University and gained a PhD there. Since then he has over 40 years of experience in steel structures of all kinds over the commercial, industrial and nuclear sectors. He also has extensive experience in roller coasters and large observation wheels. Allan has authored a number of papers, won a number of prizes and been closely associated with the Institution of Structural Engineers throughout his career.

Fergus McCormick

Fergus McCormick is a specialist in cable, long-span, dynamic and moving structures and wind engineering and is a sector specialist in Sports Stadia. His past projects include the BA London Eye, the City of Manchester Stadium and the Infinity Footbridge. For Buro Happold he has been Structural Leader for Astana Stadium Retractable Roof; Kirkby Stadium, Everton Football Club; Aviva Stadium and currently leads the structural team for the London 2012 Olympic Stadium.

David Moore

Dr David Moore is the Director of Engineering at the British Constructional Steelwork Association. Dr Moore has over 20 years experience of research and specialist advisory work in the area of structural engineering and has published over 70 technical papers on a wide range of subjects. He has also made a significant contribution to a number of specialised design guides and best practice guides for the UK and European steel industry. Many of these publications are used daily by practising structural engineers and steelwork contractors.

David Nethercot

Since graduating from the University of Wales, Cardiff, David Nethercot has completed forty years of teaching, research and specialist advisory work in the area of structural steelwork. The author of over 400 technical papers, he has lectured frequently on post-experience courses; he is a past Chairman of the BSI Committee responsible for BS 5950, and is a frequent contributor to technical initiatives associated with the structural steelwork industry. Since 1999 he has been head of the Department of Civil and Environmental Engineering at Imperial College. He is a past president of IStructE, received the 2008 Charles Massonnet prize from ECCS and was awarded a Gold Medal by the IStructE in 2009.

Graham W. Owens

Dr Graham Owens has 45 years’ experience in designing, constructing, teaching and researching in structural steelwork. After six years’ practical experience and 16 years at Imperial College, he joined the Steel Construction Institute at its formation in 1986. He was Director from 1992 until his retirement in 2008. He was President of the Institution of Structural Engineers in 2009. He continues some consultancy interests in wave energy, New Nuclear Build and Education.

Roger Pope

Dr Roger Pope is a consulting engineer who specialises in steel construction. His career in steel and steel construction began with the Steel Company of Wales in 1964. He is currently chairman of CB/203 the technical committee responsible for British Standards dealing with the design and execution of steel structures. He is also chairman of the Codes, Standards and Regulations Committee established by the Steel Construction Industry Sector under the auspices of the UK Government.

Alan Rathbone

Alan Rathbone is Chief Engineer at CSC. His previous experience includes design, research and advice on reinforced concrete and masonry, together with the design of volumetric building systems, using all main structural materials. He has worked with his co-contributor, Richard Dobson, for almost 25 years in the development of software solutions for structural engineers. He is a member of the BSI Committee CB/203 which is responsible for many of the steelwork design codes. A long-time member of the BCSA/SCI Connections Group, he has made a significant contribution to their efforts in producing the ‘Green Book’ series and is currently the Chairman. He is a Fellow of the Institution of Civil Engineers.

John Roberts

John Roberts graduated from the University of Sheffield in 1969 and was awarded a PhD there in 1972 for research on the impact loading of steel structures. His professional career includes a short period of site work with Alfred McAlpine plc, following which he has worked as a consulting engineer, since 1981 with Allott & Lomax/Babtie Group/Jacobs. He is an Executive Director of Operations at Jacobs Engineering UK Limited and has designed many major steelwork structures. He was President of the Institution of Structural Engineers in 1999-2000 and has served as a council member of both the Steel Construction Institute and the BCSA.

Alan Rogan

Alan Rogan, sponsored by British Steel (now TATA), obtained a PhD at the University of the West of England, Bristol, focusing on the steel sector. He then went on to be the Corus sponsored Reader at Oxford Brookes University in the school of Architecture. Alan is currently Managing Director of Metek Building Systems, a leading company involved in the design and construction of Light steel framing. The company, under Alan’s leadership, are now involved in the building of up to 7 storey high buildings. Alan has over 40 years of steel construction experience from bridge building to structures of all sizes and shapes. Alan continues to have a close relationship with TATA through a manufacturing agreement between the companies at Llanwern Steelworks, South Wales.

Michael Sansom

Michael Sansom has 19 years experience of environmental and sustainability work in consultancy, research and research management roles in the construction sector.

After completion of his PhD in nuclear waste disposal at Cardiff University in 1995, he worked for the UK Construction Industry Research and Information Association (CIRIA) managing construction research projects. He then worked for a large US consultancy working on contaminated land investigation and remediation.

Michael joined the SCI in 1999 where he now leads the Sustainability Division. He is involved in a range of sustainable construction activities including life cycle assessment, carbon foot-printing, BREEAM assessments and operational carbon emissions assessment and reduction.

Ian Simms

Ian Simms is currently the manager responsible for the fire engineering and composite construction departments at the Steel Construction Institute. Ian joined the SCI in April 1998 to work as a specialist in Fire Engineering, after completing his PhD at the University of Ulster.

Andrew Smith

Andy Smith worked for the Steel Construction Institute for four years after graduating from the University of Cambridge. He was involved in many projects relating to floor vibration and steel-concrete composite construction, and regularly presented courses on both these subjects. He is the lead author of SCI P354 on the design of floors for vibration and participated in an ECSC funded European project on the subject. Andy now lives and works as a consulting structural engineer in Canada.

Colin Taylor

Colin Taylor graduated from Cambridge in 1959. He started his professional career in steel fabrication, initially in the West Midlands and subsequently in South India. After eleven years he moved into consultancy where, besides practical design, he became involved with drafting work for British Standards and later for Eurocodes. Moving to the Steel Construction Institute on its formation, he also became involved with BS EN 1090-2 Execution of Steel Structures.

Colin contributed to all 9 parts of BS 5950, including preparing the initial drafts for Parts 1 and 2, compiled the 1989 revision of BS 449-2 and then contributed to all the 17 parts of the ENV stage of Eurocode 3, besides other Eurocodes. His last job before retiring from SCI was compiling and correcting BS 5950-1:2000.

Since then Colin has worked as a consultant for SCI and for DCLG and continued on numerous BSI committees and as convenor for EN 1993-6 Crane supporting structures. His main interest now is serving in local government as an elected member of two councils.

Richard Thackray

Richard Thackray graduated from Imperial College London with a degree and PhD in the field of Materials Science, and joined the University of Sheffield as Corus Lecturer in Steelmaking in 2003. His particular expertise is in the areas of clean steel production, continuous casting, and the processing of next generation high strength steels. He is currently the Chairman of the Iron and Steel Society, a division of the Institute of Materials, Minerals and Mining.

Mark Tiddy

Mark Tiddy is the Technical Manager of Cooper & Turner, the UK’s leading manufacturer of fasteners used in the construction industry. He spent the first part of his career as a graduate metallurgist in the steel industry and for the past twenty five years has worked in the fastener industry. He is the UK expert on CEN/TC 185/WG6 the European committee responsible for structural bolting.

Andrew Way

After graduating from the University of Nottingham, Andrew Way has spent his career in the field of steel construction design and research. In 1996 he joined the Steel Construction Institute where he now holds the position of Manager of Light Gauge Construction. He is a Chartered Engineer and is also responsible for the management of the SCI Assessed third party verification scheme.

Richard White

Richard White is an Associate Director of Ove Arup and Partners. He has worked in their Building Engineering office in London since graduating from Newcastle University in 1980. During that time he has both contributed to and led the structural design of a wide range of building projects. His experience includes the design and construction of offices, airports, railway stations and art galleries. These projects embrace a broad range of primary structural materials and incorporate a variety of secondary steel components including architecturally expressed metalwork.

Richard was a member of the structures working party for the British Council for Offices Design Guide 2000 and 2005 and is a member of the Institutions of Civil and Structural Engineers.

Erica Wilcox

Erica Wilcox worked as a civil and geotechnical engineering designer at Arup for many years, after graduating from the University of Bristol. Her experience covers a wide range of geotechnical design, including the design of numerous embedded retaining walls. Her research MSc at the University of Bristol covered the monitoring and back analysis of a steel sheet pile basement.

John Yates

John Yates was appointed to a personal chair in mechanical engineering at the University of Sheffield in 2000, after five years as a reader in the department. He graduated from Pembroke College, Cambridge in 1981 in metallurgy and materials science and then undertook research degrees at Cranfield and the University of Sheffield, before several years of post-doctoral engineering and materials research. His particular interests are in developing structural integrity assessment tools based on the physical mechanisms of fatigue and fracture. He is the honorary editor of Engineering Integrity and an editor of the international journal Fatigue and Fracture of Engineering Materials and Structures. John moved to the University of Manchester in August 2010 as Professor of Computational Mechanics and Director of the Centre for Modelling and Simulation.

Ralph B.G. Yeo

Ralph Yeo graduated in metallurgy at Cardiff and Birmingham and lectured at the University of the Witwatersrand. In the USA he worked on the development of weldable high-strength and alloy steels with International Nickel and US Steel and on industrial gases and the development of welding consumables and processes at Union Carbide’s Linde Division. Commercial and general management activities in the UK, mainly with the Lincoln Electric Company, were followed by twelve years as a consultant and expert witness with special interest in improved designs for welding.

Commercial and general management activities in the UK, mainly with the Lincoln Electric Company, were followed by twelve years as a consultant and expert witness with special interest in improved designs for welding before retirement and occasional lectures on improvements in design for welding.

Andrew Oldham

The illustrations in this Seventh edition of the manual are the careful work of senior CAD technician Andrew Oldham. Andrew has over fifteen years experience in architectural, civil and structural drawing working with Arup, Hadfield Cawkwell and Davidson, and SKM in Sheffield. The editors gratefully acknowledge his excellent contribution to the much improved quality of the illustrations in this edition.

Chapter 1

Introduction – designing to the Eurocodes

GRAHAM COUCHMAN

1.1 Introduction

For more than twenty years, the design of steel framed buildings in the UK, including those where composite (steel and concrete) construction is used, has generally been in accordance with the British Standard BS 5950. This first appeared in 1985 to replace BS 449 and introduced designers to the concept of limit state design. However, BS 5950 was withdrawn in March 2010 and replaced by the various parts of the Structural Eurocodes.

Bridge design in the UK has generally been in accordance with BS 5400, which was also introduced in the early 1980s and was also replaced in 2010.

The Structural Eurocodes are a set of structural design standards, developed by the European Committee for Standardisation (CEN) over the last 30 years, to cover the design of all types of structures in steel, concrete, timber, masonry and aluminium. In the UK, they are published by BSI under the designations BS EN 1990 to BS EN 1999. Each of the ten Eurocodes is published in several parts, and each part is accompanied by a National Annex that adds certain UK-specific provisions to go alongside the CEN document when it is implemented in the UK.

In England, implementation of these Standards for building design is achieved through Approved Document A to the Building Regulations. In Scotland and Northern Ireland, corresponding changes will be made to their regulations. It is expected that adoption of the Eurocodes by building designers will increase steadily from 2010 onwards.

As a public body, the Highways Agency is committed to specifying the Eurocodes for the design of all highway bridges as soon as it is practicable to do so. British Standard information reflected in the numerous BDs and BAs will be effectively replaced, and a comprehensive range of complementary guidance documents will be produced.

1.2 Creation of the Eurocodes

The Structural Eurocodes were initiated by the Commission of the European Communities as a set of common structural design standards to provide a means for eliminating barriers to trade. Their scope was subsequently widened to include the EFTA countries, and their production was placed within the control of CEN. CEN had been founded in 1961 by the national standards bodies in the European Economic Community and EFTA countries. Its Technical Committees and Sub-Committees managed the actual process of bringing appropriate state-of-the-art technical content together to form the Eurocodes.

The size of the task, and indeed the difficulty of reaching agreement between the member states, is evident not only from the length of time it has taken to produce the final ENs, but also from the need for interim ENV documents (pre-norms) and a mechanism to allow national variations. ENVs appeared in the early 1990s and were intended to be useable documents that would permit feedback from ‘real use’. In the UK this did not really happen as most designers, largely driven by commercial pressures, did not change ‘until they had to’.

During the past fifteen years or so, the ENVs have been developed into EN documents. For each Eurocode part, a Project Team of experts was formed and duly considered national comments from the various member states. The UK was well represented on all the major Project Teams, which is a very positive reflection of our national expertise and ensured that the UK voice was heard.

1.3 Structure of the Eurocodes

There are ten separate Structural Eurocodes, as noted in Table 1.1.

Table 1.1 The structural Eurocodes

ENEurocodeEN 1990Eurocode: Basis of structural designEN 1991Eurocode 1: Actions on structuresEN 1992Eurocode 2: Design of concrete structuresEN 1993Eurocode 3: Design of steel structuresEN 1994Eurocode 4: Design of composite steel and concrete structuresEN 1995Eurocode 5: Design of timber structuresEN 1996Eurocode 6: Design of masonry structuresEN 1997Eurocode 7: Geotechnical designEN 1998Eurocode 8: Design of structures for earthquake resistance (depending on the location)EN 1999Eurocode 9: Design of Aluminium Structures

Each Eurocode comprises a number of Parts, which are published as separate documents, and each Part consists of:

the main body of textnormative annexesinformative annexes.

CEN publish the full text of each Eurocode Part in three languages (English, French and German) with the above EN designations. National standards bodies may translate the text into other languages but may not make any technical changes. The information given in each part is thus the same for each country in Europe.

To allow national use, the EN document is provided with a front cover and foreword by each national standards body, and published nationally using an appropriate prefix (for example EN 1990 is published by BSI as BS EN 1990). The text may be followed by a National Annex (see below), or a National Annex may be published separately.

The structure of the various Eurocodes and their many parts has been driven by logic. Thus the design basis in EN 1990 applies irrespective of the construction material or the type of structure. For each construction material, requirements that are independent of structural form are given in General Parts (one for each aspect of design) and form-specific requirements are given in other Parts. Taking Eurocode 3 as an example, indeed one where this philosophy was taken to an extreme, the resultant parts are given in Table 1.2.

Table 1.2 The parts of Eurocode 3 (titles given are informative, not necessarily as published)

ENEurocodeEN 1993-1-1Eurocode 3: Design of Steel Structures – Part 1-1: General rules and rules for buildingsEN 1993-1-2Eurocode 3: Design of Steel Structures – Part 1-2: General rules – structural fire designEN 1993-1-3Eurocode 3: Design of Steel Structures – Part 1-3: General rules – cold formed thin gauge members and sheetingEN 1993-1-4Eurocode 3: Design of Steel Structures – Part 1-4: General rules – structures in stainless steelEN 1993-1-5Eurocode 3: Design of Steel Structures – Part 1-5: General rules – strength and stability of planar plated structures without transverse loadingEN 1993-1-6Eurocode 3: Design of Steel Structures – Part 1-6: General rules – strength and stability of shell structuresEN 1993-1-7Eurocode 3: Design of Steel Structures – Part 1-7: General rules – design values for plated structures subjected to out of plane loadingEN 1993-1-8Eurocode 3: Design of Steel Structures – Part 1-8: General rules – design of jointsEN 1993-1-9Eurocode 3: Design of Steel Structures – Part 1-9: General rules – fatigue strengthEN 1993-1-10Eurocode 3: Design of Steel Structures – Part 1-10: General rules – material toughness and through thickness assessmentEN 1993-1-11Eurocode 3: Design of Steel Structures – Part 1-11: General rules – design of structures with tension componentsEN 1993-1-12Eurocode 3: Design of Steel Structures – Part 1-12: General rules – supplementary rules for high strength steelsEN 1993-2Eurocode 3: Design of Steel Structures – Part 2: BridgesEN 1993-3-1Eurocode 3: Design of Steel Structures – Part 3-1: Towers, masts and chimneys – towers and mastsEN 1993-3-2Eurocode 3: Design of Steel Structures – Part 3-2: Towers, masts and chimneys – chimneysEN 1993-4-1Eurocode 3: Design of Steel Structures – Part 4-1: Silos, tanks and pipelines – silosEN 1993-4-2Eurocode 3: Design of Steel Structures – Part 4-2: Silos, tanks and pipelines – tanksEN 1993-4-3Eurocode 3: Design of Steel Structures – Part 4-3: Silos, tanks and pipelines – pipelinesEN 1993-5Eurocode 3: Design of Steel Structures – Part 5: PilingEN 1993-6Eurocode 3: Design of Steel Structures – Part 6: Crane supporting structures

Within each part the content is organised considering physical phenomena, rather than structural elements. So whereas BS 5950-1-1 includes Sections such as ‘compression members with moments’, EN 1993-1-1 contains Sections such as ‘buckling resistance of members’ and ‘resistance of cross-sections’. The design of a structural element will therefore entail referring to numerous Sections of the document.

Another key aspect of the formatting logic is that there can be no duplication of rules, i.e. they can only be given in one document. A consequence of dividing the Eurocodes into these separate parts, and not allowing the same rule to appear in more than one part, is that when designing a steel structure many separate Eurocode documents will be required. Logical yes, but not very user friendly.

The Eurocode Parts contain two distinct types of rules, known as Principles and Application Rules. The former must be followed if a design is to be described as compliant with the code. The latter are given as ways of satisfying the Principles, but it may be possible to use alternative rules and still achieve this compliance (although how this would work in practice is yet to be seen).

Within the text of each Eurocode Part, provision is made for national choice in the setting of some factors and the adoption of some design methods (e.g. when guidance is given in an Informative Annex, a national view may be taken on the applicability of that ‘information’). The choices are generally referred to as Nationally Determined Parameters (NDPs), and details are given in the National Annex to the Part. In many cases the annex will simply tell the designer to use the recommended value / option (i.e. there will be no national deviation). In addition, the National Annex may give references to publications that contain so-called non-contradictory complementary information (NCCI) that will assist the designer (see below).

This facility for national variations was adopted to provide regulatory bodies with a means of maintaining existing national levels of safety. The guidance given in a National Annex applies to structures that are to be constructed within the country of its publication (so, for example, a UK designer wishing to design a structure in Germany will need to comply with the National Annexes published by DIN, not those published by BSI). The National Annex (NA) is therefore an essential document when using a Eurocode Part.

1.4 Non-Contradictory Complementary Information – NCCI

The Eurocodes are design standards, not design handbooks. This is reflected in their format, as discussed above. They omit some design guidance where it is considered to be readily available in textbooks or other established sources. It is also accepted that they cannot possibly cover everything that will be needed when carrying out a design. For building design, the SCI has been collating some of the additional information that designers will need, some of which was contained in BS 5950. For highway bridges, the Highways Agency has led a thorough examination of the Eurocodes to determine what additional requirements will be needed to ensure bridges will continue to be safe, economic, maintainable, adaptable and durable.

The Eurocode format allows so-called non-contradictory complementary information (NCCI) to be used to assist the designer when designing a structure to the Eurocodes. According to CEN rules, a National Annex cannot contain NCCI but it may give references to publications containing NCCI. As the name suggests, any guidance that is referenced in the National Annex must not contradict the principles of the Eurocode.

The steel community has established a website that will serve as an up-to-date repository for NCCI, primarily aimed at steel and composite building design (www.steel-ncci.co.uk). This is referenced in the appropriate National Annexes. Additionally, BSI is publishing NCCI guidance in the form of Published Documents (PDs). These documents are only informative and do not have the status of a Standard. They include a number of background documents to the UK National Annexes. It is the intention of the Highways Agency that most additional guidance will be published as BSI PDs.

1.5 Implementation in the UK

The stated aim of the Eurocodes is to be mandatory for European public works, and become the ‘default standard’ for private sector projects. However, for buildings, this aim must be understood within the context of the UK regulatory system, which does not oblige designers to adopt any particular solution contained within an Approved Document. At the time of writing, Approved Document A to the Building Regulations (England and Wales) states that ‘These Eurocodes … when used in conjunction with their National Annexes and when approved by the Secretary of State, are intended to be referenced in this Approved Document as practical guidance on meeting the Part A Requirements’. Approved Document A will be updated in due course to make specific reference to the Eurocodes. Regulations in Scotland and Northern Ireland will also be updated to refer to the Eurocodes.

This means that, in principle, British Standards can be widely used to design buildings for the foreseeable future, assuming clients and / or insurers are happy with the use of ‘out-of-date’ guidance. Over time, the information contained within these BSs will suffer from a lack of maintenance (they will not be maintained beyond 2010).

For bridges the situation is somewhat different, because as a public body the Highways Agency will specify Eurocodes for the design of all highway structures as soon as it is practicable to do so. The Agency has indeed been preparing for the introduction of the Eurocodes for some time.

1.6 Benefits of Designing to the Eurocodes

At a purely technical level, the benefits of the Eurocodes can only be due to either more ‘accurate’ rules, or rules that cover a broader scope than previous standards and therefore facilitate the use of a broader range of solutions. Benefits will therefore be greater in countries where existing national rules were either out-of-date or limited in their scope. Not surprisingly, this means that the technical benefits to the UK are limited (a few examples are however given below).

However, to consider only the technical benefits is to miss the point of the Eurocodes. They were always intended to be more about removing trade barriers than advancing the state-of-the-art beyond the best practice present in the best national standards. Indeed, the Eurocodes are now a permanent feature so a fundamental benefit they possess is that they represent the future. Designers rely heavily on design guides, training courses and software. In future these will all be based on the Eurocodes, indeed one could envisage significant improvements in software given the vastly improved ratio between development cost and sales value that pan-national rules will bring.

A further conclusion from the studies carried out by the Highways Agency, and one which may be of general application, was that the less prescriptive approaches adopted in the Eurocodes will allow greater scope for innovation and encourage designers to use advanced analysis techniques.

Some specific benefits of the Eurocodes are considered below.

1.6.1 Clarity and Style

In the UK we tend to be rather pragmatic in our approach to design, and this is often considered by our continental colleagues, mistakenly, to show a lack of rigour. One of the manifestations of our approach is our liking for lookup tables, perhaps based on empirical information. The Eurocodes tend to be much more transparent in the way they present the physics behind aspects of structural behaviour. Whilst less user friendly, this can only help to reduce the instances of information being used out-of-context, by enabling the intelligent user to appreciate better what the code writers were considering.

One of the conclusions from the extensive studies initiated by the Highways Agency was that the clauses were expressed in a more ‘mathematical’ style than found in British Standards. It was also noted that the design principles are generally clear (although it was also noted that it is not always obvious how they should be satisfied). Having climbed a ‘significant learning curve’ the trial designers found use of the codes to be different but not necessarily more difficult.

1.6.2 Scope

The scope of rules given in BS 5950 for the design of buildings is, not surprisingly, comparable with that of EN 1993. The most obvious exceptions to this cover-all statement come from the world of composite steel-concrete construction. EN 1994 extends the scope that was included in BS 5950-3-1 to include continuous beams and, perhaps more usefully, composite columns. In terms of the latter, both filled tubes and encased open sections are covered. There is also considerably more guidance given on connection design and behaviour than can be found in BS 5950, although this has, of course, been well covered in the past for UK designers by the SCI-BCSA ‘Green Books’.

Clearly the scope covered by the various parts of EN 1993 enables a consistent design approach to be adopted for buildings, bridges, silos, masts, etc.

1.6.3 Technical Improvements

As noted above, it would be unreasonable to expect the rules in the Eurocodes to represent a significant technical improvement over the content of current British Standards. According to the Highways Agency, trial calculations of highway bridges revealed that the Eurocodes ‘would make little difference to common forms of bridges and highway structures in terms of member sizes’ and, compared on a like-for-like basis, the Eurocodes generally resulted in sectional resistances that were within 10% of the results from the British Standards. Whilst the author is not aware of such thorough comparisons of building designs, a similar conclusion would be expected.

Perhaps the biggest benefit will come from the option to use lower load factors. The load combination equations given in EN 1990 mean that in the absence of wind loading, gravity loads on beams can be reduced. The factors for dead and imposed load drop from 1.4 and 1.6 to 1.25 and 1.5 respectively. Loads may therefore be reduced by between 5 and 10%.

In terms of member performance there are some significant gains to be had in a number of areas. Often it becomes clear that the price of having ‘simple’ rules in BS 5950 was their conservatism.

1.7 Industry Support for the Introduction of the Eurocodes

Whilst recognising that it would be inappropriate to ‘abandon’ the British Standards prematurely, the steel sector (in terms of the combined forces of Tata, SCI and BCSA) has nevertheless been busy preparing design guides since late 2007. This ensures that as the Eurocodes become available to use, designers have the help of high quality guidance. Ten guides were published in 2009, including explanatory texts, worked examples and design data (section and member properties). These and further publications will cover key aspects of both steel and composite design for buildings and bridges.

In addition to traditional design guides, comprehensive information is available through sector websites. Access Steel (www.access-steel.com) offers guidance on project initiation, scheme development and detailed design. Whilst initially populated with only harmonised information, new UK-specific information (reflecting the National Annexes) is being frequently added. The site includes many interlinked modules on the detailed design of elements, with step-by-step guidance, full supporting information and worked examples, to give a thorough understanding of how the Eurocodes should be used.

NCCI may be found on www.steel-ncci.co.uk. This website is referenced in the National Annexes to various parts of Eurocode 3 and 4 and serves as a listing of non-contradictory complementary information for the design of steel and composite structures. The NCCI references are associated with relevant clauses of the codes and provide links to other resources. Where the NCCI is a public electronic resource, hyperlinks are provided.

SCI and others have offered a range of courses covering design to various Eurocodes for some time. Uptake has been steadily increasing as design offices realise that the codes will not go away, and indeed begin to be asked to price for Eurocode-compliant designs.

All the major software houses have been developing Eurocode-compliant tools for some time, waiting for the right time to put them on the market. Similar to the purchase of design guides and attendance at courses, there is something of a ‘chicken and egg’ situation here – designers will only start using the Eurocodes once help is available, but there is no real market for that help until designers start to use the codes. Changes to the Building Regulations will force this situation in due course.

1.8 Conclusions

The production of the Eurocodes has occupied a very substantial part of the careers of some leading engineers across Europe. SCI has been associated with Eurocode development since its inception in 1986, and indeed the author first used an ENV version of Eurocode 4 to design one of the buildings at Sizewell B in the mid- to late eighties.