CONTENTS Preface ix 1 Introduction 1 1.1 Opening 1 1.2 Failure incidents 2 1.3 State of research 5 1.4 Standards and guidelines 7 2 Typology of progressive collapse 11 2.1 General 11 2.2 Types of progressive collapse 12 2.2.1 Pancake-type collapse 12 2.2.2 Zipper-type collapse 14 2.2.3 Domino-type collapse 16 2.2.4 Section-type collapse 18 2.2.5 Instability-type collapse 20 2.2.6 Mixed-type collapse 23 2.3 Classes of progressive collapse 25 2.4 Collapse-promoting features 25 2.4.1 Dynamic action and force concentration 25 2.4.2 Brittle material behaviour 26 2.4.3 Overstrength and ductile material behaviour 26 2.4.4 Continuity or discontinuity 27 2.4.5 Series or parallel load transfer 28 2.4.6 Spatial orientation, size, and slenderness 28 2.4.7 Structuredness 29 2.5 Summary 30 3 Current design procedures 32 3.1 Inadequacy of current procedures 32 3.2 Possible improvements 34 4 Design against progressive collapse 37 4.1 General 37 4.2 Two definitions 38 4.2.1 Robustness 38 4.2.2 Collapse resistance 39 4.3 Design criteria 40 4.3.1 Design requirements 40 4.3.2 Design objectives 42 4.3.3 Design methods 47 4.3.4 Verification procedures 48 5 Design methods 52 5.1 General 52 5.2 Prevent local failure 55 5.2.1 Specific local resistance 55 5.2.2 Non-structural protective measures 55 5.2.3 Discussion and further remarks 56 5.3 Assume local failure 58 5.3.1 General 58 5.3.2 Alternative load paths 59 5.3.3 Isolation by segmentation 62 5.3.4 Redundancy versus segmentation 71 5.3.5 Interaction and progressive collapse 77 5.4 Local failure: prevent or assume? 80 5.5 Prescriptive design rules 83 6 Applications 86 6.1 General 86 6.2 Design of collapse-resistant bridges 87 6.2.1 General 87 6.2.2 Continuous girder bridges 88 6.2.3 Cable-stayed bridges 89 6.2.4 Suspension bridges 97 6.2.5 Arch bridges 99 6.3 Design of collapse-resistant high-rise buildings 99 6.3.1 General 99 6.3.2 Specific local resistance 100 6.3.3 Non-structural protective measures 112 6.3.4 Alternative load paths 113 6.3.5 Isolation by segmentation 114 6.3.6 Fire protection, fire fighting, and evacuation121 7 Measures of robustness and collapse resistance 123 7.1 General 123 7.2 Areas of application 123 7.3 Requirements 124 7.4 Present approaches 125 7.5 Stiffness -based measures of robustness 126 7.6 Damage-based measures of robustness 127 7.7 Energy-based measures of robustness 130 7.8 Summary and future directions 131 8 Conclusions 133 8.1 Synopsis 133 8.2 Outlook 137 References 139 Index 147