Fundamentals of Seismic Loading on Structures

Fundamentals of Seismic Loading on Structures......Page 4
Contents......Page 10
Preface......Page 18
Acknowledgements......Page 20
1.1 A Historical Perspective......Page 24
1.1.1 Seismic Areas of the World......Page 27
1.1.2 Types of Failure......Page 28
1.1.3 Fault Movement and its Destructive Action......Page 30
1.2 The Nature of Earthquakes......Page 31
1.3 Plate Tectonics......Page 32
1.3.1 Types of Plate Boundaries......Page 33
1.3.2 Convergent and Divergent Boundaries......Page 34
1.3.3 Seismicity and Plate Tectonics......Page 35
1.5 Seismic Waves......Page 37
1.5.1 Body Waves......Page 38
1.6 Seismometers......Page 40
1.6.1 Early Seismographs......Page 41
1.6.2 Modern Developments......Page 43
1.7 Magnitude and Intensity......Page 45
1.7.1 Magnitude Scales......Page 46
1.7.2 Seismic Moment......Page 47
1.7.3 Intensity Scales......Page 48
1.9 Significant Milestones in Earthquake Engineering......Page 50
1.10 Seismic Tomography......Page 51
1.11 References......Page 55
2.1 Introduction......Page 58
2.2 Free Vibration......Page 61
2.2.1 Equations of Motion with Damping......Page 63
2.2.2 Damping Ratio......Page 64
2.3 Periodic Forcing Function......Page 65
2.3.2 Damping......Page 69
2.3.3 Support Motion......Page 71
2.4.1 Duhamel Integral......Page 72
2.4.2 Numerical Evaluation......Page 73
2.4.3 Worked Example – Duhamel Integral......Page 75
2.5 References......Page 76
3.2 Lumped Parameter Systems with Two Degrees of Freedom......Page 78
3.3 Lumped Parameter Systems with more than Two Degrees of Freedom......Page 79
3.3.1 Free Vibration......Page 81
3.3.2 A Worked Example (Two degrees of Freedom System)......Page 83
3.3.3 Normalization of Mode Shapes......Page 85
3.3.4 Orthogonality of Mode Shapes......Page 86
3.3.5 Worked Example – Orthogonality Check......Page 87
3.4.1 Use of Normal or Generalized Coordinates......Page 88
3.5 Damping Orthogonality......Page 90
3.6.2 Incremental Integration Process......Page 91
3.6.3 Numerical Procedures for Integration......Page 92
3.6.4 Estimate of Errors......Page 94
3.6.5 Houbolt’s Method......Page 95
3.7 References......Page 96
4.1 Introduction......Page 98
4.2.1 Random Variable Space......Page 99
4.2.2 Gaussian or Normal Distribution......Page 104
4.2.3 Worked Example with Standard Normal Variable......Page 107
4.3.2 Fourier Series (Robson, 1963)......Page 108
4.3.3 Fourier Integrals (Robson, 1963, with permission)......Page 110
4.3.4 Spectral Density (Robson, 1963)......Page 112
4.4.1 Introducing Discrete Fourier Transform (DFT)......Page 114
4.5 A Worked Example (Erzincan, 1992)......Page 115
4.6 References......Page 118
5.1.1 Ground Motion Particulars......Page 120
5.1.2 After Shocks and Before Shocks......Page 122
5.1.3 Earthquake Source Model......Page 126
5.1.4 Empirical Relations of Source Parameters......Page 130
5.2 Ground Motion Parameters......Page 133
5.2.2 PGA and Modified Mercalli Intensity (MMI)......Page 137
5.2.3 Engineering Models of Attenuation Relationships......Page 139
5.2.4 Next Generation Attenuation (NGA) Models for Shallow Crustal Earthquakes in Western United States (2008)......Page 157
5.3 References......Page 159
6.1.2 A Practical Way Forward......Page 164
6.1.3 Constructing Tripartite Plots......Page 168
6.2 Design Response Spectra......Page 172
6.2.1 AWorked Example: An MDOF System Subjected to Earthquake Loading......Page 175
6.3 Site Dependent Response Spectra......Page 186
6.3.1 The Design Process......Page 187
6.3.2 Practical Example: Construction of a Site Dependent Response Spectrum......Page 189
6.4 Inelastic Response Spectra......Page 197
6.4.1 Response Spectra: A Cautionary Note......Page 199
6.5 References......Page 201
7.1 Introduction......Page 204
7.2 Basic Steps in Probabilistic Seismic Hazard Analysis (PSHA)......Page 206
7.2.1 Historical Seismicity......Page 208
7.2.4 Gutenberg-Richter Recurrence Law......Page 209
7.2.6 Why the Gutenberg-Richter Model?......Page 212
7.2.9 Temporal Model (or the arrival process)......Page 213
7.2.10 Poisson Model......Page 214
7.3.1 Multiple Point Sources......Page 215
7.3.2 Area Source......Page 216
7.3.3 Line Source......Page 217
7.4 PSHA as Introduced by Cornell......Page 218
7.4.1 Line Source Illustration Problem (Cornell, 1968)......Page 222
7.5 Monte Carlo Simulation Techniques......Page 223
7.5.1 Monte Carlo Simulation Process – An Insight......Page 226
7.5.2 Example: Point Source (extracted from Cornell, 1968)......Page 227
7.6 Construction of Uniform Hazard Spectrum......Page 230
7.6.1 Monte Carlo Simulation Plots for Peak Ground Acceleration......Page 231
7.6.2 Procedure for Construction of Uniform Hazard Response Spectrum......Page 232
7.7.1 De-aggregation – An Introduction......Page 235
7.7.2 Computational Scheme for De-aggregation......Page 236
7.7.3 Logic-Tree Simulation – An Introduction......Page 238
7.8 References......Page 239
8.1 Introduction......Page 242
8.1.1 Historical Development......Page 244
8.2.1 Base Shear Method......Page 257
8.3.2 Dynamic Analysis Procedures......Page 262
8.4 Eurocode 8......Page 267
8.4.1 A Worked Example......Page 269
8.5.1 General......Page 272
8.5.2 Design Criteria......Page 273
8.5.4 Gravity Loads and Load Combinations......Page 276
8.5.5 Gravity Load Analysis......Page 279
8.5.7 Equivalent Lateral Force Procedure (1617.4)......Page 280
8.5.9 Lateral Analysis......Page 281
8.5.10 Modification of Approximate Period......Page 282
8.5.11 Revised Design Base Shear......Page 283
8.5.13 Storey Drift Limitation......Page 284
8.5.15 Redundancy Factor, ρ, (1617.2)......Page 286
8.5.17 Mode Shapes......Page 288
8.5.20 Modal Seismic Design Coefficients, Csm......Page 290
8.5.21 Base Shear using Modal Analysis......Page 291
8.5.23 Scaling of Elastic Response Parameters for Design......Page 292
8.5.25 Lateral Analysis......Page 293
8.5.26 Storey Drift Limitation......Page 298
8.6 References......Page 299
9.1 Introduction......Page 302
9.2 Behaviour of Beam Columns......Page 303
9.2.2 Long or Intermediate Length Beam Column......Page 305
9.3 Full Scale Laboratory Tests......Page 306
9.3.2 Mode of Failure......Page 308
9.3.3 Experimental Plots......Page 309
9.4 Concepts and Issues: Frames Subjected to Seismic Loading......Page 312
9.5 Proceeding with Dynamic Analysis (MDOF systems)......Page 313
9.5.2 Column Strength Curves......Page 314
9.5.3 Dynamic Analysis......Page 315
9.6 Behaviour of Steel Members under Cyclic Loading......Page 316
9.6.1 FE Analysis......Page 317
9.6.3 A Note on the Factors Affecting the Strength of Columns......Page 318
9.7.2 Current Practice......Page 319
9.7.3 Damping Devices in Use......Page 321
9.8 References......Page 326
10.2 Definition of the Problem......Page 328
10.2.1 Important Features of Soil-Structure Interaction......Page 329
10.3.1 Mexico City (1985) Earthquake......Page 331
10.3.2 Loma Prieta (1989) Earthquake......Page 333
10.4 Damaging Effects Due to Liquefaction......Page 339
10.4.1 Design Implications for Piles due to Liquefaction......Page 343
10.5 References......Page 344
11.1.1 Geotechnical Aspects of Liquefaction......Page 346
11.2.1 Analytical Procedure – Empirical Formulation (Seed and Idriss, 1971)......Page 348
11.2.2 A Simplified Method (Seed and Idriss, 1971)......Page 350
11.3.1 Problem Definition......Page 355
11.3.2 Case Study – Using Field Data......Page 358
11.4.1 Current State of the Art......Page 361
11.4.2 Most Recent Work......Page 367
11.4.3 Worked Example with SPT Procedure (Idriss and Boulanger, 2004)......Page 369
11.5 Influence of Fines Content......Page 371
11.6.1 Fresh Evidence of Liquefaction of Cohesive Soils......Page 372
11.7 Construction of Foundations of Structures in the Earthquake Zones Susceptible to Liquefaction......Page 373
11.8 References......Page 376
12.1 Preamble......Page 380
12.2 Background to Current Developments......Page 381
12.2.2 Efforts in Japan......Page 382
12.3 Performance-Based Methodology......Page 383
12.3.1 Performance Objectives......Page 384
12.3.2 Performance Levels......Page 385
12.3.3 Performance Objectives......Page 386
12.3.4 Hazard Levels (design ground motions)......Page 387
12.4 Current Analysis Procedures......Page 388
12.4.1 ATC Commentary......Page 390
12.4.2 Displacement Design Procedures......Page 392
12.5.1 Targets for ‘Second Generation Tools’......Page 393
12.5.2 Prognosis......Page 394
12.6 References......Page 395
Index......Page 398