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Design of Structural ElementsThird EditionConcrete, steelwork, masonry and timber designs toBritish Standards and Eurocodesi9780415467193 A0119/3/09, 12:35 PM

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Design ofStructuralElementsThird EditionConcrete, steelwork, masonry andtimber designs to British Standardsand EurocodesChanakya Aryaiii9780415467193 A0139/3/09, 12:35 PM

First published 1994 by E & FN SponSecond edition published 2003 by Spon PressThis edition published 2009by Taylor & Francis2 Park Square, Milton Park, Abingdon, Oxon OX14 4RNSimultaneously published in the USA and Canadaby Taylor & Francis270 Madison Avenue, New York, NY 10016, USATaylor & Francis is an imprint of the Taylor & Francis Group, an informa businessThis edition published in the Taylor & Francis e-Library, 2009.To purchase your own copy of this or any of Taylor & Francis or Routledge’scollection of thousands of eBooks please go to www.eBookstore.tandf.co.uk. 1994, 2003, 2009 Chanakya AryaAll rights reserved. No part of this book may be reprinted or reproduced orutilised in any form or by any electronic, mechanical, or other means, nowknown or hereafter invented, including photocopying and recording, or inany information storage or retrieval system, without permission in writingfrom the publishers.The publisher makes no representation, express or implied, with regardto the accuracy of the information contained in this book and cannot accept anylegal responsibility or liability for any errors or omissions that may be made.British Library Cataloguing in Publication DataA catalogue record for this book is available from the British LibraryLibrary of Congress Cataloging in Publication DataArya, Chanakya.Design of structural elements : concrete, steelwork, masonry, and timber designsto British standards and Eurocodes / Chanakya Arya. – 3rd ed.p. cm.Includes bibliographical references and index.1. Structural design – Standards – Great Britain. 2. Structural design – Standards –Europe. I. Title. II. Title: Concrete, steelwork, masonry, and timber designto British standards and Eurocodes.TA658.A79 2009624.1′7–dc222008043080ISBN 0-203-92650-1 Master e-book ISBNISBN10: 0-415-46719-5 (hbk)ISBN10: 0-415-46720-9 (pbk)ISBN10: 0-203-92650-1 (ebk)ISBN13: 978-0-415-46719-3 (hbk)ISBN13: 978-0-415-46720-9 (pbk)ISBN13: 978-0-203-92650-5 (ebk)iv9780415467193 A0149/3/09, 12:35 PM

ContentsPreface to the third editionPreface to the second editionPreface to the first editionAcknowledgementsList of worked examplesPART ONE: INTRODUCTION TOSTRUCTURAL DESIGN1 Philosophy of design1.1 Introduction1.2 Basis of design1.3 SummaryQuestions22.12.22.32.42.52.62.7Basic structural concepts andmaterial propertiesIntroductionDesign loads acting on structuresDesign loads acting on elementsStructural analysisBeam designColumn 62728PART TWO: STRUCTURAL DESIGN TOBRITISH STANDARDS3 Design in reinforced concreteto BS 8110313.1 Introduction313.2 Objectives and scope313.3 Symbols323.4 Basis of design333.5 Material properties333.6 Loading353.7 Stress–strain curves363.8 Durability and fire resistance373.9 Beams443.10 Slabs933.11 Foundations1153.12 Retaining walls1213.133.14Design of short braced columnsSummaryQuestionsDesign in structural steelworkto BS 59504.1 Introduction4.2 Iron and steel4.3 Structural steel and steelsections4.4 Symbols4.5 General principles and designmethods4.6 Loading4.7 Design strengths4.8 Design of steel beams and joists4.9 Design of compression members4.10 Floor systems for steel framedstructures4.11 Design of connections4.12 237Design in unreinforced masonryto BS 5628239Introduction239Materials240Masonry design245Symbols245Design of vertically loaded masonrywalls246Design of laterally loaded wallpanels263Summary276Questions277Design in timber to BS 5268IntroductionStress gradingGrade stress and strength classPermissible stresses279279280280282v9780415467193 A0159/3/09, 12:35 PM

Contents6.56.66.76.86.96.10Timber designSymbolsFlexural membersDesign of compression membersDesign of stud 109.119.129.1310PART THREE: STRUCTURAL DESIGNTO THE EUROCODES7 The structural Eurocodes:An introduction3097.1 Scope3097.2 Benefits of Eurocodes3097.3 Production of Eurocodes3107.4 Format3107.5 Problems associated with draftingthe Eurocodes3107.6 Decimal point3127.7 Implementation3127.8 Maintenance3127.9 Difference between nationalstandards and .19.29.39.49.59.69.7Eurocode 2: Design of concretestructuresIntroductionStructure of EC 2SymbolsMaterial propertiesActionsStress–strain diagramsCover, fire, durability and bondDesign of singly and doublyreinforced rectangular beamsDesign of one-way solid slabsDesign of pad foundationsDesign of columnsEurocode 3: Design of steelstructuresIntroductionStructure of EC 3Principles and Application rulesNationally DeterminedParametersSymbolsMember axesBasis of onsMaterialsClassification of cross-sectionsDesign of beamsDesign of columnsConnectionsEurocode 6: Design ofmasonry structuresIntroductionLayoutPrinciples/Application rulesNationally DeterminedParametersSymbolsBasis of designActionsDesign compressive strengthDurabilityDesign of unreinforced masonrywalls subjected to verticalloadingDesign of laterally loaded wallpanelsEurocode 5: Design oftimber structuresIntroductionLayoutPrinciples/Application rulesNationally DeterminedParametersSymbolsBasis of designDesign of flexural membersDesign of columnsAppendix A Permissible stress and loadfactor designAppendix B Dimensions and propertiesof steel universal beams andcolumnsAppendix C Buckling resistance ofunstiffened websAppendix D Second moment of area of acomposite beamAppendix E References and furtherreadingIndexvi9780415467193 A0169/3/09, 12:35 7

Preface to thethird editionSince publication of the second edition of Designof Structural Elements there have been two majordevelopments in the field of structural engineeringwhich have suggested this new edition.The first and foremost of these is that theEurocodes for concrete, steel, masonry and timberdesign have now been converted to full EuroNorm(EN) status and, with the possible exception of thesteel code, all the associated UK National Annexeshave also been finalised and published. Therefore,these codes can now be used for structural design,although guidance on the timing and circumstancesunder which they must be used is still awaited.Thus, the content of Chapters 8 to 11 on, respectively, the design of concrete, steel, masonry andtimber structures has been completely revised tocomply with the EN versions of the Eurocodes forthese materials. The opportunity has been used toexpand Chapter 10 and include several workedexamples on the design of masonry walls subject toeither vertical or lateral loading or a combinationof both.The second major development is that a numberof small but significant amendments have beenmade to the 1997 edition of BS 8110: Part 1 onconcrete design, and new editions of BS 5628:Parts 1 and 3 on masonry design have recentlybeen published. These and other national standards, e.g. BS 5950 for steel design and BS 5268for timber design, are still widely used in the UKand beyond. This situation is likely to persist forsome years, and therefore the decision was takento retain the chapters on British Standards andwhere necessary update the material to reflect latestdesign recommendations. This principally affectsthe material in Chapters 3 and 5 on concrete andmasonry design.The chapters on Eurocodes are not self-containedbut include reference to relevant chapters on BritishStandards. This should not present any problemsto readers familiar with British Standards, but willmean that readers new to this subject will have torefer to two chapters from time to time to get themost from this book. This is not ideal, but shouldresult in the reader becoming familiar with bothBritish and European practices, which is probablynecessary during the transition phase from BritishStandards to Eurocodes.vii9780415467193 A0179/3/09, 12:35 PM

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Preface to thesecond editionThe main motivation for preparing this newedition was to update the text in Chapters 4 and 6on steel and timber design to conform with thelatest editions of respectively BS 5950: Part 1 andBS 5268: Part 2. The opportunity has also beentaken to add new material to Chapters 3 and 4.Thus, Chapter 3 on concrete design now includesa new section and several new worked examples onthe analysis and design of continuous beams andslabs. Examples illustrating the analysis and designof two-way spanning slabs and columns subjectto axial load and bending have also been added.The section on concrete slabs has been updated. Adiscussion on flooring systems for steel framedstructures is featured in Chapter 4 together with asection and several worked examples on compositefloor design.Work on converting Parts 1.1 of the Eurocodesfor concrete, steel, timber and masonry structuresto full EN status is still ongoing. Until such timethat these documents are approved the design rulesin pre-standard form, designated by ENV, remainvalid. The material in Chapters 8, 9 and 11 tothe ENV versions of EC2, EC3 and EC5 are stillcurrent. The first part of Eurocode 6 on masonrydesign was published in pre-standard form in1996, some three years after publication of the firstedition of this book. The material in Chapter 10has therefore been revised, so it now conforms tothe guidance given in the ENV.I would like to thank the following who haveassisted with the preparation of this new edition: Professor Colin Baley for preparing Appendix C; FredLambert, Tony Threlfall, Charles Goodchild andPeter Watt for reviewing parts of the manuscript.ix9780415467193 A0199/3/09, 12:35 PM

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Preface to thefirst editionStructural design is a key element of all degree anddiploma courses in civil and structural engineering.It involves the study of principles and procedurescontained in the latest codes of practice for structural design for a range of materials, including concrete, steel, masonry and timber.Most textbooks on structural design consider onlyone construction material and, therefore, the studentmay end up buying several books on the subject.This is undesirable from the viewpoint of cost butalso because it makes it difficult for the studentto unify principles of structural design, because ofdiffering presentation approaches adopted by theauthors.There are a number of combined textbooks whichinclude sections on several materials. However,these tend to concentrate on application of thecodes and give little explanation of the structuralprinciples involved or, indeed, an awareness ofmaterial properties and their design implications.Moreover, none of the books refer to the newEurocodes for structural design, which will eventually replace British Standards.The purpose of this book, then, is to describethe background to the principles and procedurescontained in the latest British Standards andEurocodes on the structural use of concrete, steelwork, masonry and timber. It is primarily aimed atstudents on civil and structural engineering degreeand diploma courses. Allied professionals such asarchitects, builders and surveyors will also find itappropriate. In so far as it includes five chapters onthe structural Eurocodes it will be of considerableinterest to practising engineers too.The subject matter is divided into 11 chaptersand 3 parts:Part Onecontains two chapters and explains theprinciples and philosophy of structuraldesign, focusing on the limit stateapproach. It also explains how theoverall loading on a structure andPart TwoPart Threeindividual elements can be assessed,thereby enabling the designer to sizethe element.contains four chapters covering thedesign and detailing of a number ofstructural elements, e.g. floors, beams,walls, columns, connections andfoundations to the latest British codesof practice for concrete, steelwork,masonry and timber design.contains five chapters on the Eurocodes for these materials. The first ofthese describes the purpose, scope andproblems associated with drafting theEurocodes. The remaining chaptersdescribe the layout and contents ofEC2, EC3, EC5 and EC6 for designin concrete, steelwork, timber andmasonry respectively.At the end of Chapters 1–6 a number of designproblems have been included for the student toattempt.Although most of the tables and figures fromthe British Standards referred to in the text havebeen reproduced, it is expected that the readerwill have either the full Standard or the publication Extracts from British Standards for Students ofStructural Design in order to gain the most fromthis book.I would like to thank the following who haveassisted with the production of this book: PeterWright for co-authoring Chapters 1, 4 and 9; FredLambert, Tony Fewell, John Moran, David Smith,Tony Threlfall, Colin Taylor, Peter Watt and PeterSteer for reviewing various parts of the manuscript;Tony Fawcett for the drafting of the figures;and Associate Professor Noor Hana for help withproofreading.C. AryaLondonUKxi9780415467193 A01119/3/09, 12:35 PM

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AcknowledgementsI am once again indebted to Tony Threlfall, formerly of the British Cement Association and nowan independent consultant, for comprehensively reviewing Chapter 8 and the material in Chapter 3on durability and fire resistanceI would also sincerely like to thank ProfessorR.S. Narayanan of the Clark Smith Partnershipfor reviewing Chapter