How To Design and Build More Earthquake-Resistant and Cost-Effective Structures

1. How To Design and Build More Earthquake-Resistant and Cost-Effective Structures Clifford J. Roblee, Ph.D., P.E Executive Director, NEES Consortium, Inc. Congressional Hazards Caucus Coalition Briefing Earthquakes: Mitigation Through Effective Design and Getting the Public Involved Room 2325 Rayburn Building, Washington, D.C. September 20, 2005

2. Earthquake Risk is Well Recognized by Experts, But Often Overlooked by Public Until It Is Too Late NHK Nagoya Office, Kobe, Japan, January 17, 1995 Courtesy Paul Somerville, URS There Is No Radar, No Intelligence, For Short-Term Warning Just Assurance of Long-Term Occurrence

3. Earthquake Risk is Well Recognized by Experts, But Often Overlooked by Public Until It Is Too Late

4. Earthquakes Remain An Important National Hazard to Life And Property ($4B/Yr) • Affect Our Homes, Work, Commerce, Economy, Social Fabric, & National Prestige Perspective: EQ Risk Mitigation • Engineering/Construction of Resilient Infrastructure is Best Mitigation Strategy • Complements Land Use, (Potential) Early Warning, and Emergency Response Strategies • 100% Effectiveness is Technically Feasible … Issues Surround Cost-Effectiveness • Success Requires: • Effective Design Tools for Hazard Identification • Cost-Effective Engineering Solutions for Varied: • Performance Objectives (Life Safety, Post-EQ Functionality, Life-Cycle Costs, etc.) • Hazard Types (Shaking, Fault Offset, Liquefaction, Landslide, Tsunami) and Levels of Hazard • Infrastructure Types (Buildings, Bridges, Lifelines, Dams, etc.) • Construction Materials (Steel, Concrete, Timber, Soil, etc.) • Construction Methods (Cast-in-Place, Pre-Fab Components, etc.) • Political Skill & Will: • Public-Interest Policies & Decisions (Market Alone Insufficient) • Smart Codes & Design Practices Applied by Knowledgeable Workforce • Good Construction & Maintenance Practices

5. Modern Ductile Details • Initial Failure at ~0.6g Courtesy of Caltrans Older Brittle Details • Total Failure at ~0.2g • Retrofit Priority Courtesy of Caltrans Much Has Been Accomplished …

6. ... and Continues To Be Accomplished Courtesy of University of Nevada, Reno

7. ... and Continues To Be Accomplished Courtesy of University of Nevada, Reno

8. Goals Tools … Much Still Remains To Be Done • Extreme Loading Conditions • Near-Fault Directivity • Fault Crossing – Large Offset • Liquefaction – Lateral Spread • Landslide • Performance-Based Design • Quantitative Risk Assessment • Account for Variability & Uncertainty • Multiple Performance Objectives • Cost-Effectiveness • Socio-Economic Impact • System & Network Functionality • Consequences on Commerce/Individuals/Society • Innovative Technologies • Devices: Base Isolation, Energy Absorption, etc. • Details: Materials, Connections, Systems, etc. • Reliable Simulation • System vs. Component Performance • Compounding Error & Uncertainty • Fault-to-Rebar for Variability • Post-Yield Behavior • Highly Non-Linear Problem • Controlled Sequence of Yield • Requires Large-Scale Testing

9. Advancing EQ-Resilient Infrastructure • Why Accelerate Innovation? • $100’s Billions in Annual US Construction in Seismic Areas • Typical Infrastructure Design Life: 30-100 Years • Retrofit is More Costly and Less Effective Than New Construction • The Innovation Process (10-30 Years) • Basic Research: Ideas & Discovery of Fundamental Concepts/Techniques • Applied Research (Development): Evaluation, Testing, Refinement, Design Models • Verification: Prototype/Trial Applications & Monitoring, Pre-Guidelines • Professional Acceptance & Adoption: Code & Standards Development • Deployment: Routine Application by Stakeholders • What’s Needed to Accelerate Innovation? • Strategic Plan for Research (including Development) • Balanced Portfolio of Basic and Applied Research • Stakeholder Involvement in Both Planning and Guiding Research • Advanced Testing Facilities & Knowledgeable Researchers (e.g. NEES) • Political Will (Public Support & $$$) for Research thru Deployment

10. Example: Verification to DeploymentInnovative Bridge Application of Very Large Friction Pendulum Bearings Courtesy of Caltrans

11. [Operated by NEESinc] NEES Shared-Use Infrastructure

12. Add Members Conventional Steel Braced Frame Zipper Frame Strengthens After First Yield Weakens After First Yield Yield Yield Behavior controlled by brace buckling - system is unable to redistribute forces efficiently Zipper struts tie all brace-to-beam intersection points together and force all the compression braces to buckle simultaneously (Khatib, Mahin, Pister) Example: Applied Engr. ResearchExperimental Validation & Refinement of “Zipper Frame System” Concept Courtesy of Prof. Roberto Leon, Georgia Tech.

13. Fast-Hybrid Component Test (Colorado) Dynamic Frame-System Test (Buffalo) Simultaneous Substructure Test (Berkeley) Static Frame-System Test (GaTech) NEES Testing of Zipper Frame Courtesy of Prof. Roberto Leon, Georgia Tech.

14. NEES Testing of Zipper Frame Courtesy of Prof. Andrei Reinhorn University of Buffalo

15. NEES Testing of Zipper Frame Courtesy of Prof. Andrei Reinhorn University of Buffalo

16. Closing Perspective “We are not about to predict earthquakes. As one door closes, another opens. If we can’t predict earthquakes, then let’s learn to live safely with them. Isn’t it better if we can build buildings that don’t fall down. Then, rather than try to evacuate populations and then come back to a destroyed city, we don’t have to leave, and our cities survive. It seems to me that this really is the best solution, and the way to do that is to begin to identify buildings that are collapse risks and begin to improve them or get rid of them.” Dr. Ross Stein, Geophysicist, USGS Menlo Park “Science Friday” Interview, June 24, 2005