Earthquake Engineering

Transcription

1 Earthquake Engineering

2 Earthquake Engineering Theory and Implementation with the 2015 International Building Code Nazzal S. Armouti, Ph.D., P.E. Professor of Civil Engineering University of Jordan International Director International Code Council, ICC Third Edition New York Chicago San Francisco Athens London Madrid Mexico City Milan New Delhi Singapore Sydney Toronto

3 Cataloging-in-Publication Data is on file with the Library of Congress. McGraw-Hill Education books are available at special quantity discounts to use as premiums and sales promotions, or for use in corporate training programs. To contact a representative please visit the Contact Us page at Earthquake Engineering: Theory and Implementation with the 2015 International Building Code, Third Edition Copyright 2015 by McGraw-Hill Education. All rights reserved. Printed in the United States of America. Except as permitted under the United States Copyright Act of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a data base or retrieval system, without the prior written permission of the publisher QVS/QVS ISBN MHID The pages within this book were printed on acid-free paper. Sponsoring Editor Lauren Poplawski Editorial Supervisor Donna M. Martone Project Manager Namita Gahtori, Cenveo Publisher Services Production Supervisor Lynn M. Messina Copy Editor Cenveo Publisher Services Proofreader Cenveo Publisher Services Composition Cenveo Publisher Services Art Director, Cover Jeff Weeks Information contained in this work has been obtained by McGraw-Hill Education from sources believed to be reliable. However, neither McGraw-Hill Education nor its authors guarantee the accuracy or completeness of any information published herein, and neither McGraw-Hill Education nor its authors shall be responsible for any errors, omissions, or damages arising out of use of this information. This work is published with the understanding that McGraw-Hill Education and its authors are supplying information but are not attempting to render engineering or other professional services. If such services are required, the assistance of an appropriate professional should be sought.

4 Contents Foreword... xv Acknowledgment... xvii 1 Introduction Characteristics of Earthquakes Causes of Earthquakes Plate Tectonic Theory Measures of Earthquakes Magnitude Intensity Instrumental Scale Fourier Amplitude Spectrum Power Spectral Density Response Spectrum Linear Elastic Dynamic Analysis Introduction Single Degree of Freedom System System Formulation Response Spectrum of Elastic Systems Design Response Spectrum Generalized Single Degree of Freedom Multiple Degrees of Freedom System Multiple Degrees of Freedom System in 2D Analysis Modal Analysis Orthogonality of Mode Shapes Caution Importance of Modes Multiple Degrees of Freedom System in 3D Analysis Combination Effect of Different Ground Motions Mass Participation in Buildings Shear Beam Cantilever Flexure Beam Comparison between Shear Beam and Cantilever Flexure Beam Simple Flexure Beam v

5 vi Contents 3.8 Axial Beam Finite Element Method Finite Element Concept in Structural Engineering Stiffness Matrix (Virtual Work Approach) Mass Matrix (Virtual Work Approach) Stiffness and Mass Matrices (Galerkin Approach) Other Matrices Mass Matrix in 2D Application of Consistent Mass Matrix Incoherence Problems Nonlinear and Inelastic Dynamic Analysis Introduction Single Degree of Freedom System Numerical Methods Central Differences Method Newmark-a Methods Wilson-p Method Multiple Degrees of Freedom System Equivalent Linearization Problems Behavior of Structures under Seismic Excitation Introduction Force-Reduction Factor, R Ductility Energy Dissipation Capacity Self-Centering Capacity Frequency Shift General Note Relationship between Force Reduction and Ductility Demand Equal Displacement Criterion Equal Energy Criterion General Relationship between R and m d Relationship between Global Ductility and Local Ductility Local Ductility Capacity Evaluation of Monotonic Local Ductility Capacity Monotonic Behavior of Concrete Monotonic Behavior of Steel Idealized Strain Compatibility Analysis Curvature at First Yield Curvature at Ultimate State

6 Contents vii General Strain Compatibility Analysis Evaluation of Cyclic Local Ductility Capacity Cyclic Behavior of Concrete Cyclic Behavior of Steel Cyclic Strain Compatibility Analysis Precast Concrete Structures Effect of Structure Configuration on Ductility Second-Order Effect on Ductility Undesirable Hysteretic Behavior Undesirable Hysteretic Behavior Due to Material Deterioration Undesirable Hysteretic Behavior Due to Unfavorable Structural Configuration Effect of Axial Load on Hysteretic Behavior 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 Energy Dissipation Factor (α N ) Design Considerations Capacity Design Pushover Analysis Recommended versus Undesirable Structural Systems Strain Rate Problems Design of Earthquake-Resistant Buildings (IBC) Introduction Definition of Structural Components Seismic Base Seismic Design Category Zoning Classification Response Spectra Design Requirements of Seismic Design Categories Seismic Design Category A Seismic Design Category B and C Seismic Design Category D, E, and F Earthquake-Induced Forces Regularity of Structures Horizontal Types of Irregularity Vertical Types of Irregularity

7 viii Contents Simplified Lateral Force Analysis Procedure Vertical Distribution of Base Shear Equivalent Lateral Force Procedure Vertical Distribution of Base Shear Modal Response Spectrum Analysis Two-Stage Analysis Procedures Time-History Analysis Directional Effect Redundancy Factor (q) Load Combinations Definitions and Requirements of Structural Systems Special Topics Diaphragm Design Forces Torsional Effect Drift Limitations Structural Separation P-D Effect Problems APPENDIX Seismic Provisions of Reinforced Concrete Structures (ACI 318) Introduction Ordinary Moment Frames Ordinary Beams Main Reinforcement Development of Reinforcement Shear Reinforcement Ordinary Beam-Columns Main Reinforcement Development of Reinforcement Shear Reinforcement Intermediate Moment Frames Intermediate Beams Main Reinforcement Lateral Reinforcement Intermediate Beam-Columns Lateral Reinforcement Special Moment Frames Special Beams Design Shear, V e Dimension Limitations Main Reinforcement Lateral Reinforcement

8 Contents ix Special Beam-Columns Design Forces Dimension Limitations Main Reinforcement Lateral Reinforcement Details Minimum Lateral Reinforcement Concrete Cover Protection Special Joints Development of Reinforcement Confined Concrete Ordinary Shear Walls Force Requirements Reinforcement Requirements Special Shear Walls Special Shear Walls without Openings Force Requirements Reinforcement Requirements Boundary Element Requirements Detailing of Boundary Elements Special Shear Walls with Openings Coupling Beams Detailing of Coupling Beams with Diagonals Diagonals Coupling Beams Diaphragms and Trusses Structural System Shear Strength Diaphragm Chords and Truss Members Foundations Strength Requirements Detailing Requirements Precast Concrete Precast Special Moment Frames Precast Special Frames with Ductile Connections Precast Special Frames with Strong Connections Precast Intermediate Shear Walls Precast Special Shear Walls Nonseismic-Resisting Systems General Requirements (A) Beam Requirements Beam-Column Requirements

9 x Contents General Requirements (B) Rectangular Sections Circular and Spiral Sections APPENDIX Introduction to AISC Seismic Provisions for Structural Steel Buildings Introduction General Requirements Load Combinations Material Demand Critical Welds Slenderness Requirements Special Bracing at Plastic Hinge Locations Protected Zones Column Splices Structural Systems Ordinary Moment Frames FR Moment Connections Demand Critical Welds Regions Intermediate Moment Frames Slenderness of Beams Protected Zones Beam-to-Column Connections Demand Critical Welds Regions 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 Special Truss Moment Frames Dimension Limitations Special Segments Slenderness of Special Segments Protected Zones Bracing of Trusses Demand Critical Welds Regions Ordinary Cantilever Column Systems Demand Critical Welds Regions Special Cantilever Column Systems Slenderness of Columns Protected Zones Base Plate Demand Critical Welds Regions

10 Contents xi Ordinary Concentrically Braced Frames Slenderness of Columns V-braced and Inverted V-braced Frames Diagonal Brace Connections Demand Critical Welds Regions 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 Eccentrically Braced Frames Strength Requirements Slenderness Requirements Protected Zones Beam-to-Column Connections General Link Requirements Demand Critical Welds Regions Buckling-Restrained Braced Frames Special Plate Shear Walls (SPSW) Strength Requirements Slenderness Requirements Protected Zones Demand Critical Welds Regions Allowable Stress Design Approach APPENDIX Design of Earthquake-Resistant Bridges (AASHTO Code) Introduction AASHTO Procedures for Bridge Design Response Spectra Single Span Bridges Bridges in Seismic Zone Bridges in Seismic Zone Bridges in Seismic Zones 3 and Methods of Analysis Uniform Load Method Continuous Bridges Discontinuous Bridges

11 xii Contents Single-Mode Spectral Method Continuous Bridges Sinusoidal Method for Continuous Bridges Discontinuous Bridges Rigid Deck Method for Discontinuous Bridges Multiple Mode Spectral Method Time-History Method Directional Effect Load Combinations Design Requirements Design Requirements of Reinforced Concrete Beam-Columns Bridges in Seismic Zone Bridges in Seismic Zone Bridges in Seismic Zones 3 and Detailing of Transverse Reinforcement Design Requirements of Reinforced Concrete Pier Walls Special Topics P-D Requirements Displacement Requirements (Seismic Seats) Longitudinal Restrainers Hold-Down Devices Liquefaction APPENDIX Geotechnical Aspects and Foundations Introduction Wave Propagation Ground Response Liquefaction Equivalent Uniform Cyclic Shear Stress Method Slope Stability Lateral Earth Pressure Foundations APPENDIX Synthetic Earthquakes Introduction Fourier Transform Power Spectral Density Stationary Random Processes Random Ground Motion Model Implementation of Ground Motion Model Validity of Synthetic Earthquakes

12 Contents xiii 12 Seismic Isolation Introduction Concept of Seismic Isolation Lead-Rubber Bearing Isolators Analysis of Seismically Isolated Structures Design of Seismically Isolated Structures Allowable Compressive Stress Allowable Shear Deformation (Shear Strain) Allowable Rotation Stability Requirements Lead Core Dimensions Shear Stiffness APPENDIX Bibliography Index

13 Foreword This is the third edition of a one-of-a-kind textbook. This book explains the fundamental concepts of structural dynamics and earthquake engineering with an exceptional clarity and an unprecedented quantity of numerical examples that help the reader fully understand the concepts being discussed. Professor Armouti has done a phenomenal job of explaining the difficult concepts of linear and nonlinear dynamics and structural response to earthquake excitations. The presentation style, simplicity of language, and the vast number of examples help make the concepts presented easily understandable even to those who face them for the first time. This is an ideal textbook for teaching a first undergraduate or graduate course in earthquake engineering. It not only explains the structural dynamics 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. The provisions of ASCE 7 standard as well as those in the International Building Code (IBC), ACI-318, and AISC seismic provisions are clearly explained and illustrated through numerical examples. Students of the subject will find this book easy to follow and will appreciate the wealth of numerical examples presented for every small and large issue discussed. The instructors will find this book useful because of the simplicity of the presentation, the extensive number of solved examples, and the problems contained at the end of the first five chapters. To aid instructors in using the book effectively for teaching the subject, an Instructor s Manual containing solutions to end of chapter problems and a set of Powerpoint presentation slides are made available to qualified instructors. Last, but not the 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 the first edition of this book by the International Code Council, which was seeking my opinion regarding potential publication in the United States, 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. xv

14 xvi Foreword I did strongly recommend publication of the first and second editions of this textbook for the U.S. market and I am very pleased to have done the same for this third edition of the book. Farzad Naeim, Ph.D., S.E., Esq. President, Farzad Naeim, Inc. Irvine, California Past President, Earthquake Engineering Research Institute

15 Acknowledgment I gratefully acknowledge the help, support, and encouragement received from my family, friends, and colleagues throughout Jordan and abroad which have converted my exhaustion into motivation. THANK YOU ALL!!! xvii