DESIGNERS’ GUIDE TO EUROCODE 3: DESIGN OF STEEL BUILDINGS

DESIGNERS’ GUIDES TO THE EUROCODESDESIGNERS’ GUIDE TO EUROCODE 3:DESIGN OF STEEL BUILDINGSEN 1993-1-1, -1-3 and -1-8Second editionLEROY GARDNER and DAVID A. NETHERCOTImperial College London, UKSeries editorHaig Gulvanessian

Published by ICE Publishing, 40 Marsh Wall, London E14 9TPFull details of ICE Publishing sales representatives and distributors can be found rst published 2005Second edition 2011Eurocodes ExpertStructural Eurocodes offer the opportunity of harmonised design standards for the European constructionmarket and the rest of the world. To achieve this, the construction industry needs to become acquaintedwith the Eurocodes so that the maximum advantage can be taken of these opportunities.Eurocodes Expert is a new ICE and Thomas Telford initiative set up to assist in creating a greaterawareness of the impact and implementation of the Eurocodes within the UK construction industry.Eurocodes Expert provides a range of products and services to aid and support the transition to Eurocodes.For comprehensive and useful information on the adoption of the Eurocodes and their implementationprocess please visit our website on or email omA catalogue record for this book is available from the British LibraryISBN 978-0-7277-4172-1# Thomas Telford Limited 2011All rights, including translation, reserved. Except as permitted by the Copyright, Designs and Patents Act1988, no part of this publication may be reproduced, stored in a retrieval system or transmitted in any formor by any means, electronic, mechanical, photocopying or otherwise, without the prior written permission ofthe Publishing Director, ICE Publishing, 40 Marsh Wall, London E14 9TP.This book is published on the understanding that the authors are solely responsible for the statements madeand opinions expressed in it and that its publication does not necessarily imply that such statements and/oropinions are or reflect the views or opinions of the publishers. While every effort has been made to ensurethat the statements made and the opinions expressed in this publication provide a safe and accurate guide,no liability or responsibility can be accepted in this respect by the authors or publishers.Typeset by Academic þ Technical, BristolIndex created by Indexing Specialists (UK) Ltd, Hove, East SussexPrinted and bound by CPI Group (UK) Ltd, Croydon

Designers’ Guide to Eurocode 3: Design of Steel Buildings, 2nd ed.ISBN 978-0-7277-4172-1ICE Publishing: All rights reserveddoi: 10.1680/dsb.41721.001IntroductionThe material in this introduction relates to the foreword to the European Standard EN 1993-1-1,Eurocode 3: Design of Steel Structures, Part 1.1: General Rules and Rules for Buildings. Thefollowing aspects are covered:ggggggBackground to the Eurocode programmeStatus and field of application of EurocodesNational standards implementing EurocodesLinks between Eurocodes and product-harmonised technical specifications (ENs and ETAs)Additional information specific to EN 1993-1UK National Annex for EN 1993-1-1.Background to the Eurocode programmeWork began on the set of structural Eurocodes in 1975. For structural steelwork, the responsiblecommittee, under the chairmanship of Professor Patrick Dowling of Imperial College London,had the benefit of the earlier European Recommendations for the Design of Structural Steelwork,prepared by the European Convention for Constructional Steelwork in 1978 (ECCS, 1978).Apart from the obvious benefit of bringing together European experts, preparation of this document meant that some commonly accepted design procedures already existed, e.g. the Europeancolumn curves. Progress was, however, rather slow, and it was not until the mid-1980s that theofficial draft documents, termed ENVs, started to appear. The original, and unchanged, maingrouping of Eurocodes, comprises ten documents: EN 1990, covering the basis of structuraldesign, EN 1991, covering actions on structures, and eight further documents essentially coveringeach of the structural materials (concrete, steel, masonry, etc.). The full suite of Eurocodes odeEurocodeEurocodeEurocodeEurocodeEurocode0: Basis of Structural Design1: Actions on Structures2: Design of Concrete Structures3: Design of Steel Structures4: Design of Composite Steel and Concrete Structures5: Design of Timber Structures6: Design of Masonry Structures7: Geotechnical Design8: Design of Structures for Earthquake Resistance9: Design of Aluminium StructuresStatus and field of application of EurocodesGenerally, the Eurocodes provide structural design rules that may be applied to complete structures and structural components and other products. Rules are provided for common forms ofconstruction, and it is recommended that specialist advice is sought when considering unusualstructures. More specifically, the Eurocodes serve as reference documents that are recognisedby the EU member states for the following purposes:gggas a means to prove compliance with the essential requirements of Council Directive89/106/EECas a basis for specifying contracts for construction or related worksas a framework for developing harmonised technical specifications for constructionproducts.1

Designers’ Guide to Eurocode 3: Design of Steel Buildings, 2nd ed.National standards implementing EurocodesThe National Standard implementing Eurocodes (e.g. BS EN 1993-1-1) must comprise the full,unaltered text of that Eurocode, including all annexes (as published by CEN). This may then bepreceded by a National Title Page and National Foreword, and, importantly, may be followed bya National Annex.The National Annex may only include information on those parameters (known as NationallyDetermined Parameters (NDPs)) within clauses that have been left open for national choice;these clauses are listed later in this chapter.Links between Eurocodes and product-harmonised technicalspecifications (ENs and ETAs)The clear need for consistency between the harmonised technical specifications for constructionproducts and the technical rules for work is highlighted. In particular, information accompanying such products should clearly state which, if any, NDPs have been taken into account.Additional information specific to EN 1993-1As with the Eurocodes for the other structural materials, Eurocode 3 for steel structures isintended to be used in conjunction with EN 1990 and EN 1991, where basic requirements,along with loads (actions) and action combinations are specified. An introduction to the provisions of EN 1990 and EN 1991 may be found in Chapter 14 of this guide. EN 1993-1 is split into11 parts, listed in Chapter 1 of this guide, each addressing specific steel components, limit statesor materials. EN 1993-1 is intended for use by designers and constructors, clients, committeesdrafting design-related product, testing and execution standards and relevant authorities, andthis guide is intended to provide interpretation and guidance on the application of its contents.UK National Annex for EN 1993-1-1National choice is allowed in EN 1993-1-1 in the following clauses of the code:2UK NationalAnnex clauseEN (1)B6.3.2.4(2)B6.3.3(5)Actions for particular regional or climatic or accidental situationsMaterial propertiesMaterial properties – use of Table 3.1 or product standardsDuctility requirementsFracture toughnessFracture toughness for buildingsThrough thickness propertiesLimit on cr for analysis typeScope of applicationValue for relative initial local bow imperfections e0/LScope of applicationNumerical value for factor kNumerical values for partial factors Mi for buildingsOther recommended numerical values for partial factors MiImperfection factor LT for lateral torsional bucklingNumerical values for LT;0 and and geometric limitations for the methodValues for parameter fValue for the slenderness limit (1)B7.2.2(1)B7.2.3(1)BBB.1.3(3)BValue for the modification factor kflChoice between alternative methods 1 and 2 for bending andcompressionLimits of application of general methodVertical deflection limitsHorizontal deflection limitsFloor vibration limitsBuckling lengths Lcr

IntroductionREFERENCEECCS (1978) European Recommendations for Steel Construction. European Convention forConstructional Steelwork, Brussels.3

PrefaceNow that the UK has adopted the set of structural Eurocodes it is timely to produce revisedversions of the series of guides based on their technical content. For the design of steel structures,Eurocode 3: Design of Steel Structures, Part 1.1: General Rules and Rules for Buildings (EN 19931-1), together with its National Annex, is the master document. It is, however, complementedby several other parts, each of which deals with a particular aspect of the design of structuralsteelwork.GeneralThis text concentrates on the main provisions of Part 1.1 of the code, but deals withsome aspects of Part 1.3 (cold-formed sections), Part 1.5 (plated structures) and Part 1.8 (connections). It does this by presenting and discussing the more important technical provisions,often by making specific reference to actual sections of the code documents. In addition, itmakes comparisons with the equivalent provisions in BS 5950, and illustrates the applicationof certain of the design procedures with a series of worked examples. When dealing with loadsand load combinations it makes appropriate reference to the companion Eurocodes EN 1990and EN 1991.Layout of this guideThe majority of the text relates to the most commonly encountered design situations. Thus, theprocedures for design at the cross-sectional, member and frame level for various situations arecovered in some detail. Chapters 1–11 directly reflect the arrangement of the code (i.e. sectionnumbers and equation numbers match those in EN 1993-1-1), and it is for this reason that thechapters vary greatly in length. Guidance on design for the ultimate limit state dominates Part1.1; this is mirrored herein. In the case of Chapters 12–14, the section numbering does notmatch the code, and the arrangement adopted is explained at the start of each of these chapters.All cross-references in this guide to sections, clauses, subclauses, paragraphs, annexes, figures,tables and expressions of EN 1993-1-1 are in italic type, which is also used where text fromEN 1993-1-1 has been directly reproduced (conversely, quotations from other sources, including other Eurocodes, and cross-references to sections, etc., of this guide, are in roman type).Expressions repeated from EN 1993-1-1 retain their numbering; other expressions havenumbers prefixed by D (for Designers’ Guide), e.g. equation (D5.1) in Chapter 5.The Eurocode format specifically precludes reproduction of material from one part to another.The ‘basic rules’ of the EN 1993-1-1 therefore provide insufficient coverage for the completedesign of a structure (e.g. Part 1.1 contains no material on connections, all of which is givenin Part 1.8). Thus, in practice, designers will need to consult several parts of the code. It is forthis reason that we have elected to base the content of the book on more than just Part 1.1. Readers will also find several references to the UK National Annex. The National Annex providesspecific limitations and guidance on the use of a number of provisions. Since these overrulethe basic clauses for application in the UK, their use has been included throughoutthis text. Where appropriate, reference has also been made to sources of non-contradictorycomplementary information (NCCI).AcknowledgementsIn preparing this text the authors have benefited enormously from discussions and advice frommany individuals and groups involved with the Eurocode operation. To each of these we accordour thanks. We are particularly grateful to Charles King of the SCI, who has provided expertadvice on many technical matters throughout the production of the book.L. GardnerD. A. Nethercotv