DESIGN OF STEEL STRUCTURES ECCS EUROCODE DESIGN MANUALS ECCS EUROCODE DESIGN MANUALS ECCS EDITORIAL BOARD Luís Simões da Silva (ECCS) António Lamas (Portugal) Jean-Pierre Jaspart (Belgium) Reidar Bjorhovde (USA) Ulrike Kuhlmann (Germany) DESIGN OF STEEL STRUCTURES Luís Simões da Silva, Rui Simões and Helena Gervásio FIRE DESIGN OF STEEL STRUCTURES Jean-Marc Franssen and Paulo Vila Real DESIGN OF PLATED STRUCTURES Darko Beg, Ulrike Kuhlmann, Laurence Davaine and Benjamin Braun FATIGUE DESIGN OF STEEL AND COMPOSITE STRUCTURES Alain Nussbaumer, Luís Borges and Laurence Davaine DESIGN OF COLD-FORMED STEEL STRUCTURES Dan Dubina, Viorel Ungureanu and Raffaele Landolfo AVAILABLE SOON DESIGN OF COMPOSITE STRUCTURES Markus Feldman and Benno Hoffmeister DESIGN OF JOINTS IN STEEL AND COMPOSITE STRUCTURES Jean-Pierre Jaspart, Klaus Weynand DESIGN OF STEEL STRUCTURES FOR BUILDINGS IN SEISMIC AREAS Raffaele Landolfo, Federico Mazzolani, Dan Dubina and Luís Simões da Silva INFORMATION AND ORDERING DETAILS For price, availability, and ordering visit our website www. For more information about books and journals visit www.ernst-und-sohn.de DESIGN OF STEEL STRUCTURES Eurocode 3: Design of Steel Structures Part 1-1 – General rules and rules for buildings Luís Simões da Silva Rui Simões Helena Gervásio Design of Steel Structures 1st Edition, 2010 1st Edition, Revised second impression 2013 Published by: ECCS – European Convention for Constructional Steelwork publications@steelconstruct.com Sales: Wilhelm Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin All rights reserved. No parts 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, without the prior permission of the copyright owner.
ECCS assumes no liability with respect to the use for any application of the material and information contained in this publication. Copyright © 2010, 2013 ECCS – European Convention for Constructional Steelwork ISBN (ECCS): 978-92-9147-115-7 ISBN (Ernst & Sohn): 978-3-433-0309-12 Legal dep.: - Printed in Multicomp Lda, Mem Martins, Portugal Photo cover credits: MARTIFER Construction TABLE OF CONTENTS TABLE OF CONTENTS FOREWORD xiii PREFACE xv Chapter 1 INTRODUCTION 1 1. Codes of Practice and Normalization 3 1. Basis of Design 8 1.
Actions and environmental influences 13 1. Ultimate limit states 15 1. Serviceability limit states 16 1. Materials 21 TABLE OF CONTENTS 1.
Toughness and through thickness properties 25 1. Geometric Characteristics and Tolerances 28 Chapter 2 STRUCTURAL ANALYSIS 33 2. Choice of member axis 36 2. Influence of eccentricities and supports 38 2.
Non-prismatic members and members with curved axis 39 2. Influence of joints 44 _____ 2. Combining beam elements together with two and vi three dimensional elements 51 2. Global Analysis of Steel Structures 75 2.
Structural stability of frames 77 2. Elastic critical load 80 2. 2nd order analysis 86 2. Classification of Cross Sections 108 TABLE OF CONTENTS Chapter 3 DESIGN OF MEMBERS 115 3.
Resistance of cross sections 116 3. Buckling resistance of members 121 3. Behaviour in tension 121 3. Design for tensile force 123 3.
Laterally Restrained Beams 134 3. Design for bending 135 3. Elastic and plastic bending moment resistance 135 _____ vii 3. Bi-axial bending 138 3.
Net area in bending 139 3. Design for shear 139 3. Design for combined shear and bending 140 3. Non-uniform torsion 157 TABLE OF CONTENTS 3.
Cross section resistance in torsion 161 3. Design for torsion 164 3. Elastic critical load 172 3. Effect of imperfections and plasticity 177 3.
Design for compression 183 3. Laterally Unrestrained Beams 197 3. Lateral-torsional buckling 197 3. Elastic critical moment 198 3.
Effect of imperfections and plasticity 208 _____ 3. Lateral-torsional buckling resistance 210 viii 3. Cross section resistance 224 3. Worked examples 242 TABLE OF CONTENTS Chapter 4 ELASTIC DESIGN OF STEEL STRUCTURES 271 4.
Simplified Methods of Analysis 273 4. Amplified sway-moment method 275 4. Sway-mode buckling length method 277 4. Member Stability of Non-prismatic Members and Components 288 4.
Non-prismatic members 288 4. Members with intermediate restraints 293 4. Design Example 1: Elastic Design of Braced Steel-Framed Building 317 _____ ix 4. Description of the structure 318 4.
General safety criteria, actions and combinations of actions 321 4. General safety criteria 321 4. Summary of basic actions 329 4. Load arrangement 334 TABLE OF CONTENTS 4.
Linear elastic analysis 336 4. Susceptibility to 2nd order effects: elastic critical loads 336 4. 2nd order elastic analysis 338 4. Cross section resistance 341 4.
Buckling resistance of beams 342 4. Buckling resistance of columns and beam-columns 342 Chapter 5 PLASTIC DESIGN OF STEEL STRUCTURES 343 5. General Rules for Plastic Design 343 5. Plastic limit analysis: method of mechanisms 344 x 5.
Code requirements for plastic analysis 349 5. Methods of Analysis 352 5. Approximate methods for pre-design 352 5. 2nd order effects 369 5.
Elastic critical load 369 5. 2nd order computational analysis 372 5. Simplified methods for analysis 373 5. Worked example 375 TABLE OF CONTENTS 5.
Member Stability and Buckling Resistance 385 5. General criteria for the verification of the stability of members with plastic hinges 385 5. Verification of the stability of members with plastic hinges 389 5. Prismatic members constituted by hot-rolled or equivalent welded I sections 390 5.
Haunched or tapered members made of rolled or equivalent welded I sections 392 5. Modification factors for moment gradients in members laterally restrained along the tension flange 395 5. Design Example 2: Plastic Design of Industrial Building 407 5. General description 408 _____ xi 5.
Quantification of actions, load combinations and general safety criteria 408 5. Summary of basic actions 415 5. Pre-design 418 TABLE OF CONTENTS 5. Linear elastic analysis 421 5.
2nd order effects 423 5. Elastic-plastic analysis 424 5. Cross section resistance 426 5. Buckling resistance of the rafters 426 5.
Buckling resistance of the columns 429 5. Synthesis 429 REFERENCES 431 _____ xii FOREWORD FOREWORD The development program for the design manuals of the European Convention for Constructional Steelwork (ECCS) represents a major effort for the steel construction industry and the engineering profession in Europe. Conceived by the ECCS Technical Activities Board under the leadership of its chairman, Professor Luis Simões da Silva, the manuals are being prepared in close agreement with the final stages of Eurocode 3 and its national Annexes. The scope of the development effort is vast, and reflects a unique undertaking in the world.
The publication of the first of the manuals, Design of Steel Structures, is a signal achievement which heralds the successful completion of the Eurocode 3 work and brings it directly to the designers who will implement the actual use of the code. As such, the book is more than a manual – it is a major textbook that details the fundamental concepts of the code and their practical application. It is a unique publication for a major construction market. Following a discussion of the Eurocode 3 basis of design, including the principles of reliability management and the limit state approach, the steel _____ material standards and their use under Eurocode 3 are detailed.
Structural xiii analysis and modeling are presented in a chapter that will assist the design engineer in the first stages of a design project. This is followed by a major chapter that provides the design criteria and approaches for the various types of structural members. The theories of behavior and strength are closely tied to the Eurocode requirements, making for a unique presentation of theory into practice. The following chapters expand on the principles and applications of elastic and plastic design of steel structures.
The many design examples that are presented throughout the book represent a significant part of the manual. These will be especially well received by the design profession. Without a doubt, the examples will facilitate the acceptance of the code and provide for a smooth transition from earlier national codes to the Eurocode. Reidar Bjorhovde Member, ECCS Editorial Board PREFACE PREFACE The General rules and rules for buildings of part 1-1 of Eurocode 3 constitute the core of the code procedures for the design of steel structures.
They contain the basic guidance for structural modeling and analysis of steel frameworks and the rules for the evaluation of the resistance of structural members and components subject to different loading conditions. According to the objectives of the ECCS Eurocode Design Manuals, it is the objective of this book to provide mix of “light” theoretical background, explanation of the code prescriptions and detailed design examples. Consequently, this book is more than a manual: it provides an all-in-one source for an explanation of the theoretical concepts behind the code and detailed design examples that try to reproduce real design situations instead of the usually simplified examples that are found in most textbooks. This book evolved from the experience of teaching Steel Structures according to ENV 1993-1-1 since 1993.
It further benefited from the participation in Technical Committees TC8 and TC10 of ECCS where the _____ background and the applicability of the various clauses of EN 1993-1-1 was xv continuously questioned. This book covers exclusively part 1-1 of Eurocode 3 because of the required level of detail. Forthcoming volumes discuss and apply most of the additional parts of Eurocode 3 using a consistent format. Chapter 1 introduces general aspects such as the basis of design, material properties and geometric characteristics and tolerances, corresponding to chapters 1 to 4 and chapter 7 of EN 1993-1-1.
It highlights the important topics that are required in the design of steel structures. Structural analysis is discussed in chapter 2, including structural modelling, global analysis and classification of cross sections, covering chapter 5 of EN 1993-1-1. The design of steel members subjected to various types of internal force (tension, bending and shear, compression and torsion) and their combinations is described in chapter 3, corresponding to chapter 6 of EN 1993-1-1. Chapter 4 presents the design of steel structures using 3D elastic analysis based on PREFACE the case study of a real building.
Finally, chapter 5 discusses plastic design, using a pitched-roof industrial building to exemplify all relevant aspects. Furthermore, the design examples provided in this book are chosen from real design cases. Two complete design examples are presented: i) a braced steel- framed building; and ii) a pitched-roof industrial building. The chosen design approach tries to reproduce, as much as possible, real design practice instead of more academic approaches that often only deal with parts of the design process.
This means that the design examples start by quantifying the actions. They then progress in a detailed step-by-step manner to global analysis and individual member verifications. The design tools currently available and adopted in most design offices are based on software for 3D analysis. Consequently, the design example for multi-storey buildings is analysed as a 3D structure, all subsequent checks being consistent with this approach.
This is by no means a straightforward implementation, since most global stability verifications were developed and validated for 2D structures. The authors are indebted to Prof. Reidar Bjorhovde who carried out a detailed technical review of the manuscript and provided many valuable comments and suggestions. Warm thanks to Prof.
David Anderson who carried out an additional detailed revision of the book and also made sure that the English language was properly used. Further thanks to Liliana Marques and José Alexandre Henriques, PhD students at the University of _____ Coimbra, for the help with the design examples of chapter 4. Additional xvi thanks to Prof. Tiago Abecasis who spotted innumerous “bugs” in the text.
Finally, thanks to Filipe Dias and the staff of cmm and ECCS for all the editorial and typesetting work, making it possible to bring to an end two years of work in this project. Luís Simões da Silva Rui Simões Helena Gervásio Coimbra, March 2010 Chapter 1 INTRODUCTION 1. GENERAL OBSERVATIONS Steel construction combines a number of unique features that make it an ideal solution for many applications in the construction industry. Steel provides unbeatable speed of construction and off-site fabrication, thereby reducing the financial risks associated with site-dependent delays.