Advanced Modelling Techniques in Structural Design

Transcription

1 Advanced Modelling Techniques in Structural Design

2 Advanced Modelling Techniques in Structural Design Feng Fu City University London

3 This edition first published by John Wiley & Sons, Ltd. Registered office: John Wiley & Sons, Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, United Kingdom. Editorial offices: 9600 Garsington Road, Oxford, OX4 2DQ, United Kingdom. The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, United Kingdom. For details of our global editorial offices, for customer services and for information about how to apply for permission to reuse the copyright material in this book please see our website at The right of the author to be identified as the author of this work has been asserted in accordance with the UK Copyright, Designs and Patents Act 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. Limit of Liability/Disclaimer of Warranty: While the publisher and author(s) have used their best efforts in preparing this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. It is sold on the understanding that the publisher is not engaged in rendering professional services and neither the publisher nor the author shall be liable for damages arising herefrom. 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 Fu, Feng (Engineer) Advanced modelling techniques in structural design / Feng Fu, City University London. pages cm Includes bibliographical references and index. ISBN (cloth) 1. Structural analysis (Engineering) Mathematics. 2. Structural frames Mathematical models. I. Title. TA647.F dc A catalogue record for this book is available from the British Library. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books. Set in 10/12pt Minion by Laserwords Private Limited, Chennai, India

4 Contents About the Author Preface Acknowledgements xi xiii xv 1 Introduction Aims and scope Main structural design problems Introduction of finite element method Finite element methods Finite element types Conclusion 8 References 8 2 Major modelling programs and building information modelling (BIM) Fundamentals of analysis programs Selection of correct analysis packages Basic analysis procedures Building information modelling (BIM) Main analysis programs in current design practice Abaqus ANSYS SAP ETABS Autodesk robot structural analysis professional STAAD.Pro Major draughting program AutoCAD Autodesk Revit Rhino3D Bentley MicroStation Method to model complex geometry Import geometry into SAP Import geometry into ETABS Import geometry into Abaqus Set up model with Revit 25 References 25 Software and manuals 25

5 vi Contents 3 Tallbuildings Introduction Structural systems of tall buildings Gravity load resisting systems Lateral load resisting systems Lateral resisting systems and modelling examples Moment resisting frames (MRF) Shear walls Bracing systems Outrigger structures Tube structures and modelling example of the Willis Towers Diagrid structures and modelling example of the Gherkin Super frame (mega frame) structures and modelling example Modelling example of the Burj Khalifa Model set up Analysis and result Modelling example of Taipei 101 with tuned mass damper (TMD) TMD modelling TMD modelling result Conclusion 60 References 60 4 Earthquakeanalysisofbuildings Introduction Basic earthquake knowledge Categories of earthquake waves Measurement of earthquake Basic dynamic knowledge SDOF SDOF under earthquake MDOF under earthquake Response spectrum Modal analysis Response spectrum from Eurocode Ductility and modified response spectrum Modelling example of the response spectrum analysis using SAP Time history analysis and modelling example using SAP Fundamentals of time history analysis Modelling example of time history analysis using SAP Push-over analysis and modelling example using SAP Introduction Modelling example of push-over analysis using SAP References 97

6 Contents vii Codes and building regulations 97 Software and manuals 97 5 Progressive collapse analysis Introduction Design guidance for progressive collapse analysis Risk assessment Design and analysis method Indirect design method Direct design method Selection of design method Structural analysis procedures and acceptance criteria Modelling example of progressive collapse analysis using SAP2000 nonlinear dynamic procedure 104 References 112 Codes and building regulations Blast and impact loading Introduction Fundamentals of blast loading Basic design principles Major blast attack regimes Blast load characteristics Principle of the scaling law Simplification of the blast load profile Material behaviours at high strain-rate Dynamic response and pressure impulse diagrams Introduction of SPH theory Modelling examples of impact loading analysis using the coupled SPH and FEA method in Abaqus Modelling technique Modelling example 120 References 139 Codes and building regulations 139 Software and manuals Structural fire analysis Introduction Basic knowledge of heat transfer Fire development process Fire protection method Active system control Passive system control Fire temperature curve Determination of the thermal response of structural members 145

7 viii Contents 7.7 Structural fire design Fire safety design objectives Fire safety design framework Major modelling techniques for structural fire analysis Zone model CFD model Finite element method using the fire temperature 7.9 curve 147 Modelling example of heat transfer analysis using Abaqus Model set up Define the heat transferring parameters Analysis Model results Other type of slabs 164 References 166 Building codes and regulations Space structures Introduction Type of space structures Double layer grids Latticed shell structures Tensegrity domes Design load Dead load Live load Temperature effect Stability analysis of space structures Member buckling analysis Local buckling analysis Global buckling analysis Modelling example of a single layer dome using SAP2000 (including global buckling analysis Set up a 3D model in AutoCAD Import the 3D model into SAP Define load pattern Define load cases (including global buckling analysis) Run global buckling analysis Define load combination Analysis and result Auto-design module Nonlinear geometric analysis of Tensegrity structures The initial geometrical equilibrium (form finding) Static analysis Modelling example of Tensigrity dome using SAP2000 (nonlinear geometrical analysis Set up a 3D model in Rhino 187

8 Contents ix Import 3D model into SAP Nonlinear geometric analysis of Tensegrity using SAP Define the prestressed force Form finding (determination of initial geometrical equilibrium Static analysis 195 References 195 Building codes and regulations 196 Software and manuals Bridge structures Introduction Structural types of bridges Beam bridges and truss bridges Arch bridges Cantilever bridges Suspension bridges Cable-stayed bridges Structural design of bridge structure Design loading Dead loads Live loads Seismic effects on bridges Wind effects on bridges Accidental actions (impact loads) Modelling example of Milau Viaduct using CSI Bridge Model set up Defining abutments Define the vehicle loading Analysis and result Modelling example of Forth Bridge using SAP References 221 Codes and regulations Foot-induced vibration Introduction to vibration problems in structural design Characteristics of foot-induced dynamic loads Pace frequency Vertical loading Horizontal loads Loads induced by groups and crowds Acceptance criteria Footbridge Floor slabs Loading representation of foot-induced vibration Time-domain solution (time history analysis) Frequency-based solutions (random analysis) 228

9 x Contents 10.5 Modelling example of vibration analysis for the Millennium Bridge using SAP2000 (time-based method) Model set up Simulation of pedestrian loads Analysis of Millennium Bridge before retrofit Analysis of the Millennium Bridge after retrofit Modelling example of vibration analysis of hospital floor using Abaqus (frequency-based method) Prototype structure Modelling technique Analysis procedures and major Abaqus commands used in the simulation Analysis result interpretation 245 References 251 Codes and building regulations 251 Software and manuals 252 Index 253

10 About the Author Dr Feng Fu received his PhD from the University of Leeds and MBA from the University of Manchester. He is a Chartered Structural Engineer and Member of American Society of Civil Engineering. He is currently a Lecturer in Structural Engineering in City University London following his work at the University of Bradford in the same position. Prior to that, he worked for several world-leading consultancy companies and was involved in the design of several prestigious construction projects worldwide. HeworkedintheadvancedanalysisteamintheWSPGroupLtdLondon,following his work as a Structural Engineer in the Waterman Group Ltd London. Prior to commencing his PhD in the UK, he also worked as Structural Engineer for one of the best design companies in China, the Beijing Institute of Architectural Design and Research. During his industrial practice, he worked with several world-leading architects such as Zaha Hadid, Forster and SOM. He has designed and analysed all kinds of complex and challenging structures, such as tall buildings, long-span space structures and bridges. He has also gained extensive experience in designing buildings under extreme loadings, such as blast and fire, and designing buildings to prevent progressive collapse. Dr Fu has extensive research experience in the areas of progressive collapse, buildings under extreme loadings such as blast and fire, Tensegrity structures and composite joints. He has specialised in advanced numerical modelling and has developed several modelling programs using different languages such as FORTRAN and Visual Basic. He has also carried out several full-scale tests on composite joints. His recent research has focused on investigating the behaviour of high-rise buildings, bridges and offshore structures under extreme loads such as blast and fire using advanced 3D numerical modelling techniques. He has published a number of refereed journal papers as the first author and is also a reviewer for over 15 international journals and two books.

11 Preface Analysis of complex structures has become increasingly important and impressive progress has been made over the last two decades. Thanks to the advent of computers and the development of different numerical modelling methods, engineers are capable of designing more challenging buildings, such as Buji Khalifa, Taipei 101, Millau Viaduct and so on. Ihaveworkedinboththeindustryandacademiaformanyyearsandhavenoticed that many engineers lack knowledge of the theories and modelling techniques in analysis of complex structures, as well as some special design problems such as vibration, fire, blast and progressive collapse. There is also a large knowledge gap for students, in addition to which most have difficulty designing and analysing real construction projects. The motivation behind this book is to provide engineers with an understanding of the featured design problems for different types of structures, with an effective way to model these types of structures using conventional commercial software and with the theories and design principles that underpin the relevant analysis. WhileIworkedintheadvancedanalysisteamintheWSPgroup,Igainedexperience in different kinds of structural analysis problems and modelled many complex structures, from tall buildings to long-span structures. I worked out many methods to effectively model them, using just continental analysis programs, and I feel it is necessary to share these methods with readers. WhileteachingattheUniversityofBradfordandCityUniversityLondon,Istarted to teach my final year and Masters students how to model existing complex buildings around the world in their graduation projects, such as Buji Khalifa and the Millau Viaduct.Itisgreattoseethatthesehavebecomethemostpopularprojects.Thestudents learnt both design principles and modelling methods through these projects. Therefore, another objective of this book is to provide civil engineer students with detailed knowledge in design and analysis of complex structures. Thus, this book has been written to serve not only as a textbook for college and university students, but also as a reference book for practising engineers. This book covers almost all the structural design problems an engineer may face, such as lateral stability analysis for tall buildings, earthquake analysis, progressive collapse analysis, structural fire analysis, blast analysis, vibration analysis, nonlinear geometric analysisandbucklinganalysis.anotherfeatureofthisbookisthatmostoftheseanalysis methods are demonstrated using existing prestigious projects around the world, such as Buji Khalifa, the Willis Towers, Taipei 101, the Gherkin, the Millennium Bridge, the Millau Viaduct, the Forth Bridge and so on. This is to help develop understanding of

12 xiv Preface effective ways to model complex structures. In addition, this book also introduces the latest Building Information Modelling system, which is a new way forward in design and analysis of modern projects. The features of major commercial programs used in the industry are also introduced, which provides guidance for readers on the selection of analysis programs. Feng Fu

13 Acknowledgements I would like to express my gratitude to Computer and Structures Inc., Dassault Systems and/or its subsidiaries, Autodesk Inc. and Robert McNeel & Associates for granting me permission to use images of their product. I would also like to thank the BSI Group in the UK and the National Institute of Building Sciences in the USA for allowing me to reproduce some of the tables and charts from their design guidance. I also would like to express my gratitude toward Foster + Partners for providing some of the architectural drawings of the projects I demonstrate in this book, namely the Gherkin, the Millau Viaduct and the Millennium Bridge. Iamgratefultoallthereviewerswhoofferedcomments.SpecialthankstoDrPaul Sayer and Ms Harriet Konishi from Wiley Blackwell for their assistance in preparation of this book. Someofthemodelsusedinthisbookhavebeenbuiltbymeandsomearebased on models set up by MSc and final-year students under my supervision. Therefore, I am very appreciative of my final-year and MSc students: Mr Aftab Ahsan, Mr Tariq Khan, Mr Ahmedali Khan, Mr Hussain Jiffry, Mr Moundhir Baaziz, Mr Eftychios Sartzetakis, Mr Georgios Sergiou, Mr Ismail Gajia and Mr Zmanko Ahmad and indeed all my other students not mentioned here. Thanks to my family, especially my father Mr Changbin Fu, my mother Mrs Shuzhen Chen and my wife Dr Yan Tan for their support in finishing this book.