Earthquake Engineering Theory and Implementation, Second Edition

548 Pages·2006·8.25 MB·English

by  Nazzal Armouti

CONTENTS

FOREWORD xi

1. INTRODUCTION 1

2. CHARACTERISTICS OF EARTHQUAKES 7
2.1 Causes of Earthquakes 7
2.2 Plate Tectonic Theory 8
2.3 Measures of Earthquakes 10
2.3.1 Magnitude 11
2.3.2 Intensity 11
2.3.3 Instrumental Scale 13
2.3.4 Fourier Amplitude Spectrum 15
2.3.5 Power Spectral Density 15
2.3.6 Response Spectrum 16

3. LINEAR ELASTIC DYNAMIC ANALYSIS 17
3.1 Introduction 17
3.2 Single Degree of Freedom System 17
3.2.1 System Formulation 17
3.2.2 Response Spectrum of Elastic Systems 20
3.2.3 Design Response Spectrum 24
3.3 Generalized Single Degree of Freedom 27
3.4 Multiple Degrees of Freedom System (MDOF) 35
3.4.1 Multiple Degrees of Freedom System in
2-D Analysis 35
3.4.2 Multiple Degrees of Freedom System in
3-D Analysis 63
3.5 Shear Beam 77
3.6 Cantilever Flexure Beam 85
3.7 Simple Flexure Beam 92
3.8 Axial Beam 95
3.9 Finite Element Methods 96
3.9.1 Finite Element Concept in Structural Engineering 97
3.9.2 Stiffness Matrix (Virtual Work Approach) 98
3.9.3 Mass Matrix (Galerkin Approach) 102
3.9.4 Other Matrices 105
3.9.5 Mass Matrix in 2-D 106
3.9.6 Application of Consistent Mass Matrix 107
3.10 Incoherence 108
Problems 116
v
4. NONLINEAR AND INELASTIC DYNAMIC ANALYSIS 123
4.1 Introduction 123
4.2 Single Degree of Freedom System 125
4.3 Numerical Methods 126
4.3.1 Central Differences Method 126
4.3.2 Newmark- Methods 128
4.3.3 Wilson- Method 129
4.4 Multiple Degrees of Freedom System 135
4.5 Equivalent Linearization 145
Problems 151

5. BEHAVIOR OF STRUCTURES UNDER SEISMIC
EXCITATION 153
5.1 Introduction 153
5.1.1 Force Reduction Factor, R 154
5.1.2 Ductility 155
5.1.3 Energy Dissipation Capacity 157
5.1.4 Self-Centering Capacity 158
5.1.5 Frequency Shift 158
5.2 Relationship Between Force Reduction
and Ductility Demand 159
5.2.1 Equal Displacement Criterion 160
5.2.2 Equal Energy Criterion 160
5.2.3 General Relationship Between R and  161
d
5.3 Relationship Between Global Ductility and
Local Ductility 168
5.4 Local Ductility Capacity 170
5.5 Evaluation of Monotonic Local Ductility Capacity 170
5.5.1 Monotonic Behavior of Concrete 170
5.5.2 Monotonic Behavior of Steel 172
5.5.3 Idealized Strain Compatibility Analysis 173
5.5.4 General Strain Compatibility Analysis 185
5.6 Evaluation of Cyclic Local Ductility Capacity 192
5.6.1 Cyclic Behavior of Concrete 192
5.6.2 Cyclic Behavior of Steel 193
5.6.3 Cyclic Strain Compatibility Analysis 194
5.7 Precast Concrete Structures 195
5.8 Effect of Structure Configuration on Ductility 197
5.9 Second Order Effect on Ductility 198
5.10 Undesirable Hysteretic Behavior 198
5.11 Effect of Axial Load on Hysteretic Behavior 200
5.11.1 Rigid Bar Idealization 201
5.11.2 Energy Dissipation Factor ( ) 205
N
5.12 Design Considerations 207
5.13 Capacity Design 209
vi
5.14 Pushover Analysis 212
5.15 Recommended Versus Undesirable Structural
Systems 213
5.16 Strain Rate 215
Problems 217

6. DESIGN OF EARTHQUAKE-RESISTANT BUILDINGS (ICC) 223
6.1 Introduction 223
6.2 Definition of Structural Components 224
6.3 Seismic Design Category 226
6.4 Zoning Classification 227
6.5 Response Spectra 228
6.6 Design Requirements of Seismic Design Categories 229
6.7 Earthquake-Induced Forces 230
6.7.1 Regularity of Structures 232
6.7.2 Simplified Lateral Force Analysis Procedure 234
6.7.3 Equivalent Lateral Force Procedure 240
6.7.4 Modal Response Spectrum Analysis 247
6.7.5 Time-History Analysis 257
6.7.6 Directional Effect 262
6.8 Load Combinations 265
6.9 Definitions and Requirements of Structural Systems 276
6.10 Special Topics 276
6.10.1 Diaphragm Design Forces 276
6.10.2 Torsional Effect 277
6.10.3 Drift Limitations 277
6.10.4 Building Separation 278
6.10.5 P- Effect 279
Appendix 6-1: Tables 280

7. SEISMIC PROVISIONS OF REINFORCED CONCRETE
STRUCTURES (ACI 318) 285
7.1 Introduction 285
7.2 Ordinary Moment Frames (OMF) 286
7.2.1 Ordinary Beams 286
7.2.2 Ordinary Beam-Columns 295
7.3 Intermediate Moment Frames (IMF) 309
7.3.1 Intermediate Beams 309
7.3.2 Intermediate Beam-Columns 311
7.4 Special Moment Frames (SMF) 321
7.4.1 Special Beams 323
7.4.2 Special Beam-Columns 326
7.4.3 Special Joints 331
7.5 Ordinary Shear Walls (OSW) 343
vii
7.6 Special Shear Walls (SSW) 355
7.6.1 Special Shear Walls without Openings 356
7.6.2 Special Shear Walls with Openings 366
7.7 Coupling Beams 368
7.8 Diaphragms and Trusses 370
7.9 Foundations 373
7.10 Precast Concrete 374
7.10.1 Precast Special Moment Frames 375
7.10.2 Precast Intermediate Shear Walls 376
7.10.3 Precast Special Shear Walls 377
7.11 Nonseismic-Resisting Systems 377
Appendix 7-1: Design Charts 380

8. INTRODUCTION TO THE AISC SEISMIC PROVISIONS
FOR STRUCTURAL STEEL BUILDINGS 389
8.1 Introduction 389
8.2 General Requirements 390
8.3 Structural Systems 392
8.3.1 Ordinary Moment Frames (OMF) 392
8.3.2 Intermediate Moment Frames (IMF) 393
8.3.3 Special Moment Frames (SMF) 394
8.3.4 Special Truss Moment Frames (STMF) 396
8.3.5 Ordinary Concentrically Braced Frames (OCBF) 398
8.3.6 Special Concentrically Braced Frames (SCBF) 399
8.3.7 Eccentrically Braced Frames (EBF) 401
8.4. Allowable Stress Design Approach 405
Appendix 8-1: Tables 407

9. DESIGN OF EARTHQUAKE-RESISTANT BRIDGES
(AASHTO CODE) 409
9.1 Introduction 409
9.2 AASHTO Procedures for Bridge Design 411
9.3 Response Spectra 413
9.4 Single-Span Bridges 415
9.5 Bridges in Seismic Zone 1 415
9.6 Bridges in Seismic Zone 2 417
9.7 Bridges in Seismic Zones 3 and 4 417
9.8 Methods of Analysis 418
9.8.1 Uniform Load Method 419
9.8.1.1 Continuous Bridges 419
9.8.1.2 Discontinuous Bridges 429
9.8.2 Single-Mode Spectral Method 430
9.8.2.1 Continuous Bridges 430
9.8.2.2 Sinusoidal Method for Continuous Bridges 438

viii
9.8.2.3 Discontinuous Bridges 443
9.8.2.4 Rigid Deck Method for
Discontinuous Bridges 448
9.8.3 Multiple Mode Spectral Method 455
9.8.4 Time History Method 456
9.8.5 Directional Effect 457
9.9 Load Combinations 457
9.10 Design Requirements 458
9.11 Design Requirements of Reinforced Concrete
Beam-Columns 459
9.11.1 Bridges in Seismic Zone 1 459
9.11.2 Bridges in Seismic Zone 2 460
9.11.3 Bridges in Seismic Zones 3 and 4 464
9.12 Design Requirements of Reinforced Concrete
Pier Walls 465
9.13 Special Topics 467
9.13.1 Displacement Requirements (Seismic Seats) 467
9.13.2 Longitudinal Restrainers 468
9.13.3 Hold-Down Devices 468
9.13.4 Liquefaction 468

10. GEOTECHNICAL ASPECTS AND FOUNDATIONS 469
10.1 Introduction 469
10.2 Wave Propagation 470
10.3 Ground Response 472
10.4 Liquefaction 474
10.5 Slope Stability 478
10.6 Lateral Earth Pressure 479
10.7 Foundations 481
Appendix 10-1: Tables 487

11. SYNTHETIC EARTHQUAKES 491
11.1 Introduction 491
11.2 Fourier Transform 492
11.3 Power Spectral Density 495
11.4 Stationary Random Processes 496
11.5 Random Ground Motion Model 497
11.6 Implementation of Ground Motion Model 503
11.7 Validity of Synthetic Earthquakes 503
ix
12. SEISMIC ISOLATION 509
12.1 Introduction 509
12.2 The Seismic Isolation Concept 510
12.3 Lead-Rubber Bearing Isolator 511
12.4 Analysis of Seismically Isolated Structures 513
12.5 Design of Seismically Isolated Structures 513
Appendix 12-1: Design Tables and Charts 523

BIBLIOGRAPHY 525

INDEX 531

UNIT CONVERSION TABLE 537
x
FOREWORD

This one of a kind book explains the fundamental concepts of structural
dynamics and earthquake engineering with exceptional clarity and an un-
precedented quantity of numerical examples that help the reader fully
understand the concepts being discussed.

Professor Armouti has done a phenomenal job of explaining the dif-
icult concepts of linear and nonlinear dynamics and structural response to
earthquake excitations. The presentation style, simplicity of language,
and many examples make these concepts readily understandable even to
those who face them for the first time.

This ideal textbook for teaching a first undergraduate or graduate
course in earthquake engineering not only explains the structural dyn-
mics theories necessary for understanding linear and nonlinear response
to earthquake excitations, but also covers the basic design of earthquake
resistant steel and reinforced concrete buildings, bridges and isolated
systems, in accordance with the latest codes of the United States.

Students will appreciate the wealth of numerical examples presented
for every small and large issue discussed. Instructors will appreciate the
simplicity of the presentation, the extensive number of solved examples
and the problems contained at the end of the first five chapters. Last, but
not least, engineering practitioners will find this book to be an invaluable
source of information regarding response of various systems and
components to earthquake excitations.

When I was first presented with the manuscript of this book by the In-
ternational Code Council, the first thought that crossed my mind was: an
earthquake engineering book from Jordan for the U.S. market? This initial
reaction, however, rapidly faded when I went over the contents and the
presentation of the book. I did strongly recommend publication of this
textbook for the U.S. market. I am very pleased that this unique book is
now available to students and practitioners of earthquake engineering in
this country.

Farzad Naeim, Ph.D., S.E., Esq.
President Elect,
Earthquake Engineering Research Institute

Vice President and General Counsel
John A. Martin & Associates, Inc.
Los Angeles, California
xi
xii
1

INTRODUCTION

Earthquake engineering is the science that studies the behavior of
structures under earthquake excitation and provides the rules on how to
design structures to survive seismic shocks. Earthquakes are wild and
violent events that can have
dramatic effects on structures. In
fact, many structures have
n,
collapsed during earthquakes o
because earthquake-induced ati
er
forces or displacements ex- el
c
ceeded the ultimate capacity of c
A Time, t
the structures. Therefore, the
study of structural behavior at
full capacity is a necessary FIGURE 1-1
EARTHQUAKE RECORD
element of earthquake en-
gineering.

Earthquakes are extremely random and oscillatory in nature (as shown in
Fig. 1-1). Because earthquakes cause structures to largely deform in
opposite directions, earthquake en-
F
gineering also requires an under-
standing of structural behavior under Hysteresis Fy
cyclic loading. Figure 1-2 shows an Loop
example of cyclic loading in the

y
inelastic range. Furthermore, the
extreme randomness and uncertain
Cyclic
occurrence of earthquakes also Structure Loading
require the use of a probability
approach in the analysis and design FIGURE1-2
CYCLIC BEHAVIOR
of structures that may experience
seismic excitation.
1