Earthquake Engineering

1 Introduction
2 Characteristics of Earthquakes
2.1 Causes of Earthquakes
2.2 Plate Tectonic Theory
2.3 Measures of Earthquakes
2.3.1 Magnitude
2.3.2 Intensity
2.3.3 Instrumental Scale
2.3.4 Fourier Amplitude Spectrum
2.3.5 Power Spectral Density
2.3.6 Response Spectrum
3 Linear Elastic Dynamic Analysis
3.1 Introduction
3.2 Single Degree of Freedom System
3.2.1 System Formulation
3.2.2 Response Spectrum of Elastic Systems
3.2.3 Design Response Spectrum
3.3 Generalized Single Degree of Freedom
3.4 Multiple Degrees of Freedom System
3.4.1 Multiple Degrees of Freedom System in 2D Analysis
Modal Analysis
Orthogonality of Mode Shapes
Caution
Importance of Modes
3.4.2 Multiple Degrees of Freedom System in 3D Analysis
Combination Effect of Different Ground Motions
3.4.3 Mass Participation in Buildings
3.5 Shear Beam
3.6 Cantilever Flexure Beam
Comparison between Shear Beam and Cantilever Flexure Beam
3.7 Simple Flexure Beam
3.8 Axial Beam
3.9 Finite Element Method
3.9.1 Finite Element Concept in Structural Engineering
3.9.2 Stiffness Matrix (Virtual Work Approach)
3.9.3 Mass Matrix (Virtual Work Approach)
3.9.4 Stiffness and Mass Matrices (Galerkin Approach)
3.9.5 Other Matrices
3.9.6 Mass Matrix in 2D
3.9.7 Application of Consistent Mass Matrix
3.10 Incoherence
3.11 Problems
4 Nonlinear and Inelastic Dynamic Analysis
4.1 Introduction
4.2 Single Degree of Freedom System
4.3 Numerical Methods
4.3.1 Central Differences Method
4.3.2 Newmark-β Methods
4.3.3 Wilson-θ Method
4.4 Multiple Degrees of Freedom System
4.5 Equivalent Linearization
4.6 Problems
5 Behavior of Structures under Seismic Excitation
5.1 Introduction
5.1.1 Force-Reduction Factor, R
5.1.2 Ductility
5.1.3 Energy Dissipation Capacity
5.1.4 Self-Centering Capacity
5.1.5 Frequency Shift
General Note
5.2 Relationship between Force Reduction and Ductility Demand
5.2.1 Equal Displacement Criterion
5.2.2 Equal Energy Criterion
5.2.3 General Relationship between R and μd
5.3 Relationship between Global Ductility and Local Ductility
5.4 Local Ductility Capacity
5.5 Evaluation of Monotonic Local Ductility Capacity
5.5.1 Monotonic Behavior of Concrete
5.5.2 Monotonic Behavior of Steel
5.5.3 Idealized Strain Compatibility Analysis
Curvature at First Yield
Curvature at Ultimate State
5.5.4 General Strain Compatibility Analysis
5.6 Evaluation of Cyclic Local Ductility Capacity
5.6.1 Cyclic Behavior of Concrete
5.6.2 Cyclic Behavior of Steel
5.6.3 Cyclic Strain Compatibility Analysis
5.7 Precast Concrete Structures
5.8 Effect of Structure Configuration on Ductility
5.9 Second-Order Effect on Ductility
5.10 Undesirable Hysteretic Behavior
Undesirable Hysteretic Behavior Due to Material Deterioration
Undesirable Hysteretic Behavior Due to Unfavorable Structural Configuration
5.11 Effect of Axial Load on Hysteretic Behavior
5.11.1 Rigid Bar Idealization
Case 1: Rigid Bar under Axial Load and without Springs
Case 2: Rigid Bar with Springs and without Axial Load
Case 3: Rigid Bar with Springs and under Axial Load
5.11.2 Energy Dissipation Factor (αN)
5.12 Design Considerations
5.13 Capacity Design
5.14 Pushover Analysis
5.15 Recommended versus Undesirable Structural Systems
5.16 Strain Rate
5.17 Problems
6 Design of Earthquake-Resistant Buildings (IBC)
6.1 Introduction
6.2 Definition of Structural Components
6.2.1 Seismic Base
6.3 Seismic Design Category
6.4 Zoning Classification
6.5 Response Spectra
6.6 Design Requirements of Seismic Design Categories
Seismic Design Category A
Seismic Design Category B and C
Seismic Design Category D, E, and F
6.7 Earthquake-Induced Forces
6.7.1 Regularity of Structures
Horizontal Types of Irregularity
Vertical Types of Irregularity
6.7.2 Simplified Lateral Force Analysis Procedure
Vertical Distribution of Base Shear
6.7.3 Equivalent Lateral Force Procedure
Vertical Distribution of Base Shear
6.7.4 Modal Response Spectrum Analysis
6.7.5 Two-Stage Analysis Procedures
6.7.6 Time-History Analysis
6.7.7 Directional Effect
Redundancy Factor (Ï)
6.8 Load Combinations
6.9 Definitions and Requirements of Structural Systems
6.10 Special Topics
6.10.1 Diaphragm Design Forces
6.10.2 Torsional Effect
6.10.3 Drift Limitations
6.10.4 Structural Separation
6.10.5 P-Î" Effect
6.11 Problems
APPENDIX 6-1
7 Seismic Provisions of Reinforced Concrete Structures (ACI 318)
7.1 Introduction
7.2 Ordinary Moment Frames
7.2.1 Ordinary Beams
Main Reinforcement
Development of Reinforcement
Shear Reinforcement
7.2.2 Ordinary Beam-Columns
Main Reinforcement
Development of Reinforcement
Shear Reinforcement
7.3 Intermediate Moment Frames
7.3.1 Intermediate Beams
Main Reinforcement
Lateral Reinforcement
7.3.2 Intermediate Beam-Columns
Lateral Reinforcement
7.4 Special Moment Frames
7.4.1 Special Beams
Design Shear, Ve
Dimension Limitations
Main Reinforcement
Lateral Reinforcement
7.4.2 Special Beam-Columns
Design Forces
Dimension Limitations
Main Reinforcement
Lateral Reinforcement Details
Minimum Lateral Reinforcement
Concrete Cover Protection
7.4.3 Special Joints
Development of Reinforcement
Confined Concrete
7.5 Ordinary Shear Walls
Force Requirements
Reinforcement Requirements
7.6 Special Shear Walls
7.6.1 Special Shear Walls without Openings
Force Requirements
Reinforcement Requirements
Boundary Element Requirements
Detailing of Boundary Elements
7.6.2 Special Shear Walls with Openings
7.7 Coupling Beams
7.7.1 Detailing of Coupling Beams with Diagonals
Diagonals
Coupling Beams
7.8 Diaphragms and Trusses
7.8.1 Structural System
7.8.2 Shear Strength
7.8.3 Diaphragm Chords and Truss Members
7.9 Foundations
7.9.1 Strength Requirements
7.9.2 Detailing Requirements
7.10 Precast Concrete
7.10.1 Precast Special Moment Frames
Precast Special Frames with Ductile Connections
Precast Special Frames with Strong Connections
7.10.2 Precast Intermediate Shear Walls
7.10.3 Precast Special Shear Walls
7.11 Nonseismic-Resisting Systems
7.11.1 General Requirements (A)
Beam Requirements
Beam-Column Requirements
7.11.2 General Requirements (B)
Rectangular Sections
Circular and Spiral Sections
APPENDIX 7-1
8 Introduction to AISC Seismic Provisions for Structural Steel Buildings
8.1 Introduction
8.2 General Requirements
Load Combinations
Material
Demand Critical Welds
Slenderness Requirements
Special Bracing at Plastic Hinge Locations
Protected Zones
Column Splices
8.3 Structural Systems
8.3.1 Ordinary Moment Frames
FR Moment Connections
Demand Critical Welds Regions
8.3.2 Intermediate Moment Frames
Slenderness of Beams
Protected Zones
Beam-to-Column Connections
Demand Critical Welds Regions
8.3.3 Special Moment Frames
Column-Beam Moment Ratios
Slenderness of Beams
Protected Zones
Beam-to-Column Connections
Lateral Support of Column Flanges
Demand Critical Welds Regions
8.3.4 Special Truss Moment Frames
Dimension Limitations
Special Segments
Slenderness of Special Segments
Protected Zones
Bracing of Trusses
Demand Critical Welds Regions
8.3.5 Ordinary Cantilever Column Systems
Demand Critical Welds Regions
8.3.6 Special Cantilever Column Systems
Slenderness of Columns
Protected Zones
Base Plate
Demand Critical Welds Regions
8.3.7 Ordinary Concentrically Braced Frames
Slenderness of Columns
V-braced and Inverted V-braced Frames
Diagonal Brace Connections
Demand Critical Welds Regions
8.3.8 Special Concentrically Braced Frames
Slenderness of Columns
Protected Zones
Strength Requirements
Beam-to-Column Connections
Brace Connections
Diagonal Braces
V- and Inverted V-Type Braces
Demand Critical Welds Regions
8.3.9 Eccentrically Braced Frames
Strength Requirements
Slenderness Requirements
Protected Zones
Beam-to-Column Connections
General Link Requirements
Demand Critical Welds Regions
8.3.10 Buckling-Restrained Braced Frames
8.3.11 Special Plate Shear Walls (SPSW)
Strength Requirements
Slenderness Requirements
Protected Zones
Demand Critical Welds Regions
8.4 Allowable Stress Design Approach
APPENDIX 8-1
9 Design of Earthquake-Resistant Bridges (AASHTO Code)
9.1 Introduction
9.2 AASHTO Procedures for Bridge Design
9.3 Response Spectra
9.4 Single Span Bridges
9.5 Bridges in Seismic Zone 1
9.6 Bridges in Seismic Zone 2
9.7 Bridges in Seismic Zones 3 and 4
9.8 Methods of Analysis
9.8.1 Uniform Load Method
Continuous Bridges
Discontinuous Bridges
9.8.2 Single-Mode Spectral Method
Continuous Bridges
Sinusoidal Method for Continuous Bridges
Discontinuous Bridges
Rigid Deck Method for Discontinuous Bridges
9.8.3 Multiple Mode Spectral Method
9.8.4 Time-History Method
9.8.5 Directional Effect
9.9 Load Combinations
9.10 Design Requirements
9.11 Design Requirements of Reinforced Concrete Beam-Columns
9.11.1 Bridges in Seismic Zone 1
9.11.2 Bridges in Seismic Zone 2
9.11.3 Bridges in Seismic Zones 3 and 4
Detailing of Transverse Reinforcement
9.12 Design Requirements of Reinforced Concrete Pier Walls
9.13 Special Topics
9.13.1 P-Î" Requirements
9.1 3.2 Displacement Requirements (Seismic Seats)
9.13.3 Longitudinal Restrainers
9.13.4 Hold-Down Devices
9.13.5 Liquefaction
APPENDIX 9-1
10 Geotechnical Aspects and Foundations
10.1 Introduction
10.2 Wave Propagation
10.3 Ground Response
10.4 Liquefaction
Equivalent Uniform Cyclic Shear Stress Method
10.5 Slope Stability
10.6 Lateral Earth Pressure
10.7 Foundations
APPENDIX 10-1
11 Synthetic Earthquakes
11.1 Introduction
11.2 Fourier Transform
11.3 Power Spectral Density
11.4 Stationary Random Processes
11.5 Random Ground Motion Model
11.6 Implementation of Ground Motion Model
11.7 Validity of Synthetic Earthquakes
12 Seismic Isolation
12.1 Introduction
12.2 Concept of Seismic Isolation
12.3 Lead-Rubber Bearing Isolators
12.4 Analysis of Seismically Isolated Structures
12.5 Design of Seismically Isolated Structures
Allowable Compressive Stress
Allowable Shear Deformation (Shear Strain)
Allowable Rotation
Stability Requirements
Lead Core Dimensions
Shear Stiffness
APPENDIX 12-1
Bibliography
Index