Background and Purpose Acknowledgments. 1.1 Background The Architect s Role in Seismic Design Contents The Bottom Line 1-8

Size: px

Start display at page:

Download "Background and Purpose Acknowledgments. 1.1 Background The Architect s Role in Seismic Design Contents The Bottom Line 1-8"

Cody Poole
5 years ago
Views:

1 FOREWORD AND ACKNOWLEDGMENTS Background and Purpose Acknowledgments i iii CHAPTER 1 INTRODUCTION Christopher Arnold 1.1 Background The Architect s Role in Seismic Design Contents The Bottom Line 1-8 CHAPTER 2 - NATURE OF EARTHQUAKES AND SEISMIC HAZARDS Bruce Bolt and Douglas Dreger 2.1 Introduction Observations of Earthquakes Plate Tectonics and Seismicity Earthquake Fault Types Earthquake Effects Seismic Waves and Strong Motion Seismic Instrumental Recordings and Systems Types of Earthquake Waves Seismic Sources and Strong Motion Earthquake Magnitude Elastic Rebound and its Relationship to Earthquake Strong Motion Source Directivity and its Effect on Strong Ground Motions Strong Ground Motion Duration of Strong Shaking Estimating Time Histories Seismic Hazard 2-32 v

2 2.7 Conclusions Acknowledgments Cited and Other Recommended References Web Resources 246 CHAPTER 3 - SITE EVALUATION AND SELECTION Richard Eisner 3.1 Introduction Selecting and Assessing Building Sites in Earthquake Country Performance Criteria, Site Selection and Evaluation Building Program and Site Evaluation The Importance of having the Right Team- Using Geotechnical Engineering Expertise The Site Assessment Process Geotechnical Report Content Additional Investigations to Determine Landslide and Liquefaction Information Sources for the Assessment Process Local Government Hazard Assessment DMA Tools for Getting Started Understanding Regional Earthquake Risk- the Big Picture of Expected Ground Motion ` Earthquake Hazards to Avoid Earthquake Fault Zones Ground Failure due to Liquefaction Areas of Intensified Ground Motion Ground Failure, Debris Flows and Land Slides Off-Site Issues that Effect Site Selection Access and Egress Infrastructure Adjacency 3-26 vi

3 3.8 Earthquake and Tsunami Hazards Special Considerations for Coastal Area Site Assessment Conclusion 3-31 CHAPTER 4 EARTHQUAKE EFFECTS ON BUILDINGS Christopher Arnold 4.1 Introduction Inertial Forces and Acceleration Duration, Velocity and Displacement Ground Amplification Period and Resonance Natural Periods Ground Motion and Building Resonance Site Response Spectrum Damping Dynamic Amplification Higher Forces and Uncalculated Resistance Ductility Strength, Stiffness, Force Distribution and Stress Concentration Strength and Stiffness Force Distribution and Stress Concentration Torsional Forces Nonstructural Components Construction Quality 4-25 vii

4 4.14 Conclusion References To Find Out More 4-27 CHAPTER 5 SEISMIC ISSUES IN ARCHITECTURAL DESIGN Christopher Arnold 5.1 Introduction The Basic Structural Systems The Vertical Lateral Resistance Systems Diaphragms-the Horizontal Resistance System Optimizing the Structural/Architectural Configuration The Effects of Configuration Irregularity Stress Concentrations Torsion Configuration irregularity in the Seismic Code Four Serious Configuration Conditions Soft and Weak Stories Discontinuous Shear Walls Variations in Perimeter Strength and Stiffness Re-entrant Corners Other Architectural/Structural Issues Overturning: Why Buildings Fall Down, Not Over Perforated Shear Walls Strong Beam, Weak Column Setbacks and Planes of Weakness Irregular Configurations: A Twentieth Century Problem A New Vernacular: the International Style and its Seismic Implications 5-33 viii

5 5.8 Designing for Problem Avoidance Use of Regular Configurations Designs for Irregular Configurations Beyond the international Style: Towards a Seismic Architecture? The Architect s Search for Forms Symbolic and Metaphorical New Architectural Prototypes Today Towards an Earthquake Architecture Expressing the Lateral Force Systems The Earthquake as a Metaphor Conclusion References To Find Out More 5-53 CHAPTER 6 THE REGULATION OF SEISMIC DESIGN Christine Theodoropoulos 6.1 Introduction Earthquakes and Code Action Early Twentieth Century The 1920 s and the First Seismic Code Mid century Codes and the Introduction of Statewide Regulations Late Twentieth Century: the Move toward New Model Building Codes Current State of Seismic Code Development Code Intent The Purpose of Code Provisions Conflicts between Intent, Expectations and Performance Performance Based Seismic Design Prescriptive Design, Performance Design and the Code Definitions of Performance Based Seismic Design Implementing Performance Based Seismic Design 6-18 ix

6 6.5 Seismic Design Provisions Code-defined Parameters Performance Levels Performance Based Seismic Engineering Engineering Analysis Methods Nonstructural Codes Conclusion References 6-32 CHAPTER 7 - SEISMIC DESIGN: PAST, PRESENT AND FUTURE Eric Elsesser 7.1 Introduction A Brief Summary of 100 Years of Structural Seismic Design Historic and Current Structural-Seismic Systems Early Structural Systems- Pre-1906 San Francisco Earthquake The Early Years ( ) The Middle years ( ) The Mature Years ( ) The Creative Years ( ) Background and Progression of Structural-Seismic Concepts Development of Seismic Resisting Systems Pictorial History of Seismic Systems Commentary on Structural Frameworks Steel Building Frameworks Concrete Building Frameworks System Characteristics Elastic Design-Linear Systems 7-35 x

7 7.6.2 Post Elastic Design-Nonlinear Drift Cyclic Behavior Performance Based Seismic Design Nonlinear Performance Comparisons Energy Dissipation The Design Approach - Force vs. Energy The Search for the Perfect Seismic System Structural Mechanisms Semi-Active and Active Dampers Cost Effective Systems Avoiding the Same Mistakes Configurations are Critical Common Sense Structural Design-Lessons Learned Conclusions References 7-51 CHAPTER 8 EXISTING BUILDINGS: EVALUATION & RETROFIT William Holmes 8.1 Introduction Contents of Chapter Reference to other Relevant Chapters Background Changes in Building Practice and Seismic Design Requirements Resulting in Buildings that are Currently Considered Inadequate Philosophy Developed for Treatment of Existing Buildings Code Requirements Covering Existing Buildings The FEMA Program to Reduce the Seismic Risk from Existing Buildings FEMA Sponsored Activity for Existing Buildings The FEMA Model Building Types Seismic Evaluation of Existing Buildings Expected Performance by Building Types 8-32 xi

8 8.4.2 Evaluation of Individual Buildings Other Evaluation Issues Seismic Retrofit of Existing Buildings Categories of Retrofit Activity Conceptual Design of a Retrofit Scheme for an Individual Bldg Other Retrofit Issues Examples Special Issues with Historic Buildings Special Seismic Considerations Common Issues of Tradeoffs Examples of historical Buildings Conclusion References References from Text To Learn More 8-74 CHAPTER 9 NONSTRUCTURAL DESIGN PHILOSOPHY Gary McGavin 9.1 Introduction What is Meant by the Term Nonstructural? Architectural Components Mechanical and Electrical Components Consequences of Inadequate Design Nonstructural Seismic Design and Normal Seismic Design Effects of Improper Nonstructural Design Damage to Nonstructural Systems and Components Design Details for Nonstructural Damage Reduction Precast Concrete Cladding Panels Suspended Ceilings Lighting Fixtures 9-17 xii

9 9.6.4 Heavy (masonry) Full-height Non-Load Bearing Walls Partial-height Masonry Walls Partial-height Metal Stud Walls Parapet Bracing Sheet Metal Ductwork Piping Vibration-isolated Equipment Emergency Power Equipment Tall Shelving Gas Water Heaters The Need for Systems Design Who is Responsible for Design? Nonstructural Codes Methods of Seismic Qualification Design Team Judgment Prior Qualification Mathematical Analysis and other Qualification Methods Some Myths regarding Nonstructural Design What can the Architect do to Decrease Nonstructural Damage? The Complexity of Retrofitting Existing Buildings Conclusions References 9-31 CHAPTER 10 DESIGN FOR EXTREME HAZARDS Christopher Arnold 10.1 Introduction Multi-hazard Design System Interactions 10-2 xiii

Contents. Tables. Terminology and Notations. Foreword. xxi

Contents. Tables. Terminology and Notations. Foreword. xxi Tables x Terminology and Notations xi Foreword xxi 1 Aim and scope 1 1.1 Aim 1 1.2 The Eurocode system 2 1.3 Scope of Manual 3 1.3.1 General 3 1.3.2 Basis of the Manual 5 1.3.3 Other general requirements