How To Design and Build More Earthquake-Resistant and Cost

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					  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
 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
 Earthquake Risk is Well Recognized by Experts,
But Often Overlooked by Public Until It Is Too Late
         Perspective: EQ Risk Mitigation



•   Earthquakes Remain An Important National Hazard to Life And Property ($4B/Yr)
     –   Affect Our Homes, Work, Commerce, Economy, Social Fabric, & National Prestige

•   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
  Much Has Been Accomplished …
                                         Modern Ductile Details
                                            • Initial Failure at ~0.6g




                  Courtesy of Caltrans


Older Brittle Details
   • Total Failure at ~0.2g
   • Retrofit Priority                                 Courtesy of Caltrans
... and Continues To Be Accomplished




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




Courtesy of University of Nevada, Reno
        … Much Still Remains To Be Done
  Extreme Loading Conditions                   Performance-Based Design
        • Near-Fault Directivity                    • Quantitative Risk Assessment
        • Fault Crossing – Large Offset             • Account for Variability & Uncertainty
        • Liquefaction – Lateral Spread             • Multiple Performance Objectives
        • Landslide                                 • Cost-Effectiveness
                         Socio-Economic Impact
                            • System & Network Functionality
                            • Consequences on Commerce/Individuals/Society
Goals

Tools
                         Innovative Technologies
                            • Devices: Base Isolation, Energy Absorption, etc.
                            • Details: Materials, Connections, Systems, etc.

   Post-Yield Behavior                          Reliable Simulation
        • Highly Non-Linear Problem                  • System vs. Component Performance
        • Controlled Sequence of Yield               • Compounding Error & Uncertainty
        • Requires Large-Scale Testing               • Fault-to-Rebar for Variability
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
       Example: Verification to Deployment
        Innovative Bridge Application of Very Large Friction Pendulum Bearings




Courtesy of Caltrans
NEES Shared-Use Infrastructure




          [Operated by NEESinc]
 V      Example: Applied Engr. Research
                   V                  V

     Experimental Validation & Refinement of “Zipper Frame System” Concept
                                                         Add
                                                    Members
 Conventional Steel Braced Frame                                    Zipper Frame




                                                                                       Strengthens After
                                       Weakens After                                       First Yield
                                                       V               V   Yield        V
 V                 V    Yield         V First Yield




                                                                                               



     Behavior controlled by brace buckling -               Zipper struts tie all brace-to-beam
     system is unable to redistribute forces               intersection points together and force
     efficiently                                           all the compression braces to buckle
                                                           simultaneously (Khatib, Mahin, Pister)


Courtesy of Prof. Roberto Leon,
Georgia Tech.
                                                       V               V                V
                  NEES Testing of Zipper Frame
       Fast-Hybrid Component Test (Colorado)    Dynamic Frame-System Test (Buffalo)




    Simultaneous Substructure Test (Berkeley)    Static Frame-System Test (GaTech)




Courtesy of Prof. Roberto Leon,
Georgia Tech.
                 NEES Testing of Zipper Frame




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




Courtesy of Prof. Andrei Reinhorn
University of Buffalo
                     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