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To transform earthquake engineering assessment and design ...

Perform.-Based Approach Scientifically-defined seismic hazard Direct design approaches Defined outcomes with probabilities of achieving them. Performance-Based Earthquake Engineering. To transform earthquake engineering assessment and design. Traditional Approach

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To transform earthquake engineering assessment and design ...

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  1. Perform.-Based Approach • Scientifically-defined seismic hazard • Direct design approaches • Defined outcomes with probabilities of achieving them Performance-Based Earthquake Engineering To transform earthquake engineering assessment and design ... • Traditional Approach • Non-scientifically defined seismic hazard • Indirect design approaches • Undefined and uncertain outcomes

  2. Base Shear Demand Joe’s Beer! Food! Very rare events (2%/50yrs) Joe’s Beer! Food! Rare events (10%/50yrs) Occasional events (20%/50yrs) Structurally Stable Frequent events (50%/50yrs) Operational Life Safe Lateral Deformation Assessment by Static Pushover Analysis (FEMA 273/356 and ASCE 41) Ref: R.O. Hamburger

  3. O P E N O P E N O P E N $, % replacement 25% 50% 100% 0 Downtime, days 1 7 30 180 0 Casualty rate 0.0001 0.001 0.01 0.25 0.0 Performance-Based Earthquake Engineering Collapse Onset Damage Threshold Base Shear Deformation PBEE today FEMA 356 Performance Levels IO LS CP PBEE tomorrow

  4. Small cracks only Small cracks only Damage Assessment: Nonstructural Fragilities Severe damage to gypsum board and distorsion of metal frame (Replace partition) Probability of Damage State Wide cracks in gypsum boards Wide cracks in gypsum boards (Replace gypsum boards) Small cracks only (Patch, Retape & Paint) Interstory Drift Ratio Ref: E. Miranda

  5. Collapse & Casualties • Direct Financial Loss • Downtime Decision Variable Damage Measure Engineering Demand Parameter drift as an EDP Intensity Measure Performance-Based Methodology

  6. Incremental Dynamic Analysis – Collapse 44 Ground Motion Records GROUND MOTION INTENSITY STRUCTURAL RESPONSE (DRIFT)

  7. Mean Annual Frequency of Collapse Collapse CDF Collapse Performance • Margin: Sa,collapse = 2.7 MCE • 5% Probability of collapse under design MCE = 5% • Mean Annual Frequency: MAFcol = 1.0 x 10-4 (0.5% in 50 years) 2.7 5% Hazard Curve 2/50

  8. Nonstructural Damage and Losses (Caltech)

  9. PBEE Methodology: IM-EDP-DM-DV • Ground Motion Hazard Characterization • IM Definition (Sa, …) • Selection and Scaling of Ground Motions • Simulation: IM – EDP • Choice of EDPs (Drift, Floor Accel., other …) • Fidelity of simulations to model collapse • Damage Modeling: EDP – DM • Taxonomy of components • Definition of conditional EDP-DM “damage function” • Loss Modeling: DM – DV • Definition of conditional DM-DV loss functions • Downtime and injuries/fatalities are a challenge

  10. Relating Performance to Risk Decision Making Quantifying Damage Measures Simulation of System Response Earthquake Hazard Characterization Performance Assessment Components Decision Variable Damage Measure Engineering Demand Parameter Intensity Measure

  11. Integrative Testbeds • Buildings - Van Nuys - UC Sciences - SRB • UCB Campus • Bridges - Humboldt Bay - I-880 Viaduct • Bay Area Highway Network

  12. Relating Performance to Risk Decision Making Quantifying Damage Measures Simulation of System Response Earthquake Hazard Characterization Performance Assessment Components Decision Variable Damage Measure Engineering Demand Parameter Intensity Measure

  13. Performance Assessment Components DV: $ loss, functionality, downtime, casualties Decision Variable Damage Measure DM: physical condition & consequences/ramifications Engineering Demand Parameter EDP: Drift Ratio (peak, residual), Floor Acceleration, Local Indices (Qp, strain, …) Intensity Measure IM: Sa(T1), multiple Sa’s, epsilon, Sdinelastic, duration

  14. n(DV) – Probabilistic Description of Decision Variable (e.g., Mean Annual Probability $ Loss > 50% Replacement Cost) PBEE – Probability Framework Equation Hazard Performance (Loss) Models and Simulation Impact IM – Intensity Measure EDP – Engineering Demand Parameter DM – Damage Measure DV – Decision Variable

  15. Comprehensive System Simulation REF: Yang, Conte, Elgamal (UCSD) REF: Boulanger (UCDavis)

  16. DM EDP = PFA -Cascade approach -Transmissibility important IM = Sa(T1) NS Components & Contents Problem Insight – Small Equipment Hutchinson

  17. InformationTechnology Computation Models http://opensees.berkeley.edu Integrated Simulation/Assessment Platform Algorithms, Solvers, Parallel/distributed computing Software framework, Databases, Visualization, Internet/grid computation Simulation & Reliability Models for Materials, Components, and Systems

  18. Integrative Testbeds • Buildings • Van Nuys • UC Sciences • UCB Campus • Bridges • Humboldt Bay • I-880 Viaduct • Bay Area Highway Network

  19. Evolution of PBEE Concept • Groups of Buildings: • Portfolio Analysis • Regional Loss Studies • Mitigation Studies • e.g., ATC 13, HAZUS • Building Ratings: • Probable • Maximum Loss • Other • e.g., ST-RISK • Individual Buildings: • Evaluation • Retrofit • e.g., FEMA 273/356 Casualties Repair Costs Downtime Percentage or Dollars Performance Objectives Ref. W. Holmes

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