Seismic Design of Foundations: Concepts and applications

Contents Preface ix
Acknowledgements xi

1 Introduction to earthquake geotechnical engineering in
relation to foundation design 1
1.1 Introduction 1
1.2 Overview of earthquake engineering 1
1.3 What does earthquake geotechnical engineering cover? 1
1.4 Examples of geotechnical damage 4
1.5 Major topics in earthquake geotechnical engineering 4
1.6 Historical perspective: how engineers learnt from earthquakes 13
1.7 Complexity of earthquake geotechnical engineering 29
1.8 Summary 32
References 32

2 Basic concepts of engineering seismology and seismic hazard
analysis 33
2.1 Introduction 33
2.2 Theories of plate tectonics and elastic rebound 33
2.3 Types of faults 34
2.4 Evaluation of earthquake size 35
2.5 Hazards for the seismic design of foundations 38
2.6 Seismic hazard analysis 39
2.7 Case study: damage to the outlet tunnel of the second
Kakkonda hydropower station (This case study is based on
the seminal work of Prof Konagai, see for futher details
Konagai (2005), Johansson and Konagai (2007) 44
2.8 Case study: quantification of the PGA for locations in India
where strong-motion records are unavailable 46
2.9 Quantification of fault movement 56
2.10 Case study: hazard to pipelines due to permanent ground
deformations 56
2.11 Quantification of the duration of an earthquake 60
2.12 Summary 60
References 60

3 Selection of strong motion for foundation design 63
3.1 Introduction 63
3.2 Background to the problem 63
3.3 Criteria for the selection of earthquake records 65
3.4 Methods for spectral matching 67
3.5 Case study: application of spectrum-compatible input motion 69
3.6 Summary 77
References 77

4 Ground response analysis 79
4.1 Introduction 79
4.2 Seismic wave propagation in layered media 81
4.3 Methods of ground response analysis 83
4.4 Linear ground response analysis procedure 84
4.5 Equivalent linear and non-linear programs for ground
response analysis 94
4.6 Simplified method to obtain the natural period of the ground 101
4.7 Natural period of the ground for a layered soil 101
4.8 Summary 102
References 102

5 Seismic analysis methods related to foundation design 103
5.1 Introduction 103
5.2 Fundamental period of structures 103
5.3 Fundamentals modal analysis 104
5.4 The concept of response spectrum 106
5.5 Application of response spectra analysis in foundation design 110
5.6 Example calculations for the base shear of a three-storey building 115
5.7 Essentials of performance-based design 119
5.8 Beam on a non-linear Winkler foundation (SSI) 125
5.9 Summary 136
References 138

6 Liquefaction: theoretical aspects 141
6.1 Introduction 141
6.2 Concept of effective stress and dilatancy 141
6.3 Mechanism of pore pressure development 143
6.4 Laboratory undrained tests 145
6.5 Role of numerical modelling 152
6.6 Actual earthquake records as manifestations of in situ soil
liquefaction 161
6.7 Effects on the built environment 164
6.8 Summary 168
References 170

7 Liquefaction: practical aspects 173
7.1 Introduction 173
7.2 Liquefaction susceptibility 173
7.3 Liquefaction triggering 178
7.4 Evaluation of the effects of liquefaction 187
7.5 Codes of practice-specified methods 190
7.6 Liquefaction-induced ground displacements 194
7.7 Worked example 202
7.8 Planning and design of major project in seismic areas 207
7.9 Summary 210
References 210

8 Analysis and design of shallow foundations 215
8.1 Introduction 215
8.2 Seismic bearing capacity of shallow foundations 215
8.3 Case studies: observed settlements of building during
earthquakes 217
8.4 Case studies: settlements of footings in physical model tests 223
8.5 Factors affecting settlements of shallow foundations in
liquefied ground 230
8.6 Estimation of total and differential settlements 233
8.7 Seismic design of mat foundations 238
8.8 Summary 238
References 238

9 Pile foundations 241
9.1 Introduction 241
9.2 Why piled foundation are used 241
9.3 Pile foundations in seismic areas 241
9.4 Failure mechanisms of pile-supported structures 245
9.5 Criteria for the design of piles in seismic areas 253
9.6 Design checks and calculations required 255
9.7 Design codes of practice 261
9.8 Modelling of the problem 263
9.9 Raked or battered piles 282
9.10 Example: pile-supported LNG tanks 285
9.11 Example: Kandla Port tower building on piles 290
9.12 Summary 291
References 291

10 Analysis of foundations for major bridges 297
10.1 Introduction 297
10.2 Survey of the performance of bridge foundations in
seismic areas 297
10.3 Bridge foundations 305
10.4 Caisson foundations 306
10.5 Stiffness of deep foundations 308
10.6 Methodology for fundamental frequency estimations 316
10.7 Dynamic behaviour of pile-supported bridges 320
10.8 Performance comparison of bridges supported on pile and
caisson foundations in liquefiable soils 328
10.9 Summary 329
References 329

11 Foundations in slopes and for retaining walls 331
11.1 Introduction 331
11.2 Concept of seismic coefficients for slopes and retaining walls 331
11.3 Foundation considerations for buildings on slopes 334
11.4 Case studies: seismic performance of buildings on slopes 336
11.5 Earth pressure theory 341
11.6 Foundations for retaining walls 347
11.7 Worked example 350
11.8 Case studies: seismic performance of retaining walls 354
11.9 Summary 362
References 362

12 Liquefaction countermeasures 365
12.1 Introduction 365
12.2 Liquefaction countermeasures 365
12.3 Ground improvement methods 369
12.4 Analysis and design of typical ground improvement methods 377
12.5 Worked examples for typical methods 386
12.6 Case studies: ground improvement method application 389
12.7 Case studies: seismic performance of improved-ground sites 395
12.8 Methods to strengthen shallow foundations 409
12.9 Methods to strengthen pile foundations 414
12.10 Summary 417
References 417

Appendix Engineering correlations for the design of foundations 421

Index 451