Tables x Terminology and Notations xi Foreword xxi 1 Aim and scope 1 1.1 Aim 1 1.2 The Eurocode system 2 1.3 Scope of Manual 3 1.3.1 General 3 1.3.2 Basis of the Manual 5 1.3.3 Other general requirements 5 1.3.4 Other exclusions from the scope of this Manual 6 1.4 Contents 7 2 Reference documents 8 2.1 Other Eurocodes 8 2.2 National Forewords and Annexes 8 2.3 AFNOR and BSI supporting documentation 8 2.4 Other Eurocode manuals 9 2.5 Other sources of information 9 2.5.1 Designers guides to the Eurocodes 9 2.5.2 Websites 9 2.5.3 AFPS guides 10 3 National Annexes and Nationally Determined Parameters 11 3.1 Purpose of the National Annexes 11 3.2 Treatment of Nationally Determined Parameters 11 3.3 French National Annexes 11 3.4 UK National Annexes 12 4 Performance objectives 13 4.1 Introduction 13 4.2 No collapse requirement 13 4.3 Damage limitation requirement 14 5 Design fundamentals 15 5.1 Desirable characteristics of earthquake resistant buildings 15 5.2 Primary and secondary elements 16 5.3 Dissipative structures and zones 16 v
5.4 The behaviour factor q 16 5.5 Ductility classes 17 5.6 Capacity design method 19 5.7 Flow charts of the design process 20 6 Regularity in plan and elevation 23 6.1 Introduction 23 6.2 Consequences of regularity classification 24 6.3 Assessment of regularity in plan 25 6.3.1 Introduction 25 6.3.2 Preliminary assessment of regularity in plan 25 6.3.3 Detailed assessment of regularity in plan 28 6.3.4 Moderate irregularity in plan 31 6.3.5 High irregularity in plan 32 6.3.6 Determining the centres of stiffness, radii of gyration and torsional radii 32 6.4 Assessment of regularity in elevation 34 6.4.1 Regular elevations 34 6.4.2 Moderately irregular elevations 36 6.4.3 Highly irregular elevations 36 7 Geotechnical aspects 38 7.1 Influence of site conditions on seismic design 38 7.1.1 Principal hazards 38 7.1.2 Active faults 38 7.1.3 Slope stability 39 7.1.4 Topographical effects 40 7.1.5 Potentially liquefiable soils 40 7.1.6 Settlement of soils 43 7.2 Site investigation 43 7.2.1 Strength parameters 43 7.2.2 Determination of ground type 44 7.2.3 Soil stiffness and damping 44 8 Design ground motions 47 8.1 Introduction 47 8.2 Importance classes 51 8.3 Ground type 52 8.4 Horizontal elastic response spectrum 54 8.5 Horizontal design spectra 57 8.6 Near source effects 57 9 Seismic analysis 58 9.1 Choice of analysis method 58 9.2 General assumptions for seismic analysis 60 9.2.1 Modelling 60 9.2.2 Mass to be included in the seismic analysis 62 9.2.3 Torsion 64 vi
9.2.4 Combination of the effects of the horizontal seismic components 66 9.2.5 Combinations of seismic loads with other loads 66 9.3 Equivalent linear analysis, using a q (behaviour) factor 67 9.3.1 Choice of linear analysis method 67 9.3.2 Use of planar models in buildings with irregularity in plan 68 9.3.3 Lateral force method 69 9.3.4 Modal combinations in multimodal response spectrum analysis 72 9.3.5 Calculation of displacement 73 9.4 Non-linear methods 74 9.4.1 Introduction 74 9.4.2 Modelling issues 74 9.4.3 Safety verification 75 9.4.4 Non-linear static (pushover) analysis 75 9.5 P-D effects 77 10 Concrete buildings 79 10.1 Overview of main differences between seismic and non-seismic design 79 10.2 Design to Eurocode 2 (DCL design) 79 10.3 Ductile design (DCM and DCH design) 80 10.4 Design strength of materials 80 10.4.1 Material properties 80 10.4.2 Partial factors for material properties 80 10.5 Types of reinforced concrete buildings and behaviour factors 81 10.6 Moment resisting frames (beams, columns and joints) 83 10.6.1 General conditions for frames 83 10.6.2. Columns 84 10.6.3 Beams 95 10.6.4 Beam-column joints 101 10.7 Walls 104 10.7.1 Definitions 104 10.7.2 Dimensions 104 10.7.3 Ductile walls and coupled walls 104 10.7.4 Large lightly reinforced walls 112 10.7.5 Further information on reinforced concrete wall design 117 10.8 Detailing of confinement reinforcement 117 10.9 Laps and splices 118 10.10 Design and detailing of secondary elements 119 10.11 Provisions for concrete floor diaphragms 120 10.12 Local effects due to masonry or concrete infills 121 10.13 Precast frames and precast floor systems 124 10.13.1 Introduction 124 10.13.2 Precast frames 124 10.13.3 Precast concrete floors 127 Contents vii
11 Steel buildings 129 11.1 Scope 129 11.2 Material specification 129 11.2.1 Material properties 129 11.2.2 Partial factors for materials 131 11.3 Design to Eurocode 3 (DCL Design) 132 11.4 Ductile Design (DCM and DCH Design) 132 11.5 Types of steel buildings and behaviour factors 135 11.5.1 Moment resisting frames 135 11.5.2 Concentrically braced frames 135 11.5.3 Behaviour factors 135 11.6 Requirements for compactness of sections in dissipative zones 138 11.7 General rules for connection design 138 11.8 Moment resisting frames (beams, columns and joints) 140 11.8.1 General 140 11.8.2 Dissipative regions 140 11.8.3 Beams 140 11.8.4 Connections 142 11.8.5 Columns 145 11.8.6 Web panels 147 11.9 Design of concentrically braced frames 148 11.9.1 General 148 11.9.2 Distribution of bracing strength 148 11.9.3 Columns and beams 149 11.9.4 Connections 149 11.9.5 Additional rules for specific types of concentrically braced frames 149 11.10 Unbraced frames with masonry infill 153 12 Foundations 154 12.1 General principles 154 12.2 Capacity design of foundations 154 12.3 Seismic capacity for shallow foundations 155 12.3.1 Ultimate limit state conditions 155 12.3.2 Sliding 156 12.3.3 Bearing capacity 157 12.4 Structural design of shallow concrete foundations 157 12.4.1 Design actions effects 157 12.4.2 Tie beams and foundation beams 158 12.5 Design of piled foundations 159 12.5.1 Seismic analysis 159 12.5.2 Design and detailing 161 Contents viii
13 Seismic joints 162 14 Damage limitation 163 15 Non-structural elements 165 15.1 General considerations 165 15.2 Protection of acceleration-sensitive non-structural elements 165 15.2.1 Introduction 165 15.2.2 Simplified procedure 165 15.2.3 Seismic coefficient 166 15.2.4 Importance factors 167 15.2.5 Behaviour factors 167 15.3 Protection of drift-sensitive non-structural elements 168 15.3.1 General 168 15.3.2 Masonry infill in contact with concrete and steel moment resisting frames 169 References 171 Appendix A: Example calculations of torsional radii and radius of gyration 175 ix