Performance-Based Earthquake Engineering EERI Seminar 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 Perform.-Based Approach Scientifically-defined seismic hazard Direct design approaches Defined outcomes with probabilities of achieving them Many newcomers to this field think that earthquake engineering has always been about design of structures for performance. This slide is partly to explain that that is not the current situation, and partly to define our vision of where we want to go. Deierlein

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

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

Damage Assessment: Nonstructural Fragilities EERI Seminar Damage Assessment: Nonstructural Fragilities Severe damage to gypsum board and distorsion of metal frame Small cracks only Small cracks only (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 Deierlein

Performance-Based Methodology EERI Seminar Performance-Based Methodology Collapse & Casualties Direct Financial Loss Downtime Decision Variable Damage Measure drift as an EDP Engineering Demand Parameter Intensity Measure Deierlein

Incremental Dynamic Analysis – Collapse EERI Seminar Incremental Dynamic Analysis – Collapse 44 Ground Motion Records Be sure to mention that the behavior at the GM levels near 2%in 50 yrs is really what we care about – not the median! GROUND MOTION INTENSITY STRUCTURAL RESPONSE (DRIFT) Deierlein

Mean Annual Frequency of Collapse EERI Seminar 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 Deierlein

Nonstructural Damage and Losses (Caltech) EERI Seminar Nonstructural Damage and Losses (Caltech) Deierlein

PBEE Methodology: IM-EDP-DM-DV EERI Seminar 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 Deierlein

Performance Assessment Components EERI Seminar Performance Assessment Components Decision Variable Relating Performance to Risk Decision Making Quantifying Damage Measures Simulation of System Response Earthquake Hazard Characterization Damage Measure Major accomplishment is formalization of modular framework -- many elements are common sense, but need for rigorous shared vision to define and articulate process, modules (data handoff), and terminology -- concepts are catching on, evidenced by adoption by ATC 58 effort, terminology used in research papers and presentations (students being reared on this framework). -- framework both for PBEE practice, but also an organizational structure for research (e.g., NEES and related efforts worldwide) Engineering Demand Parameter Intensity Measure Deierlein

Integrative Testbeds Buildings UCB Campus Bridges EERI Seminar Integrative Testbeds Buildings - Van Nuys - UC Sciences - SRB UCB Campus Bridges - Humboldt Bay - I-880 Viaduct Bay Area Highway Network Deierlein

Performance Assessment Components EERI Seminar Performance Assessment Components Decision Variable Relating Performance to Risk Decision Making Quantifying Damage Measures Simulation of System Response Earthquake Hazard Characterization Damage Measure Major accomplishment is formalization of modular framework -- many elements are common sense, but need for rigorous shared vision to define and articulate process, modules (data handoff), and terminology -- concepts are catching on, evidenced by adoption by ATC 58 effort, terminology used in research papers and presentations (students being reared on this framework). -- framework both for PBEE practice, but also an organizational structure for research (e.g., NEES and related efforts worldwide) Engineering Demand Parameter Intensity Measure Deierlein

Performance Assessment Components EERI Seminar Performance Assessment Components Decision Variable DV: $ loss, functionality, downtime, casualties Damage Measure DM: physical condition & consequences/ramifications Mathematical rigor and specificity – translating concepts into data structures and models From exploration to consensus of least common denominator (minimum level of resolution/granularity in process) Common framework for discussions (e.g., recent exchange regarding characterization of damage and fragility functions for partition walls among PEER-ATC 58 group). 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 Deierlein

PBEE – Probability Framework Equation EERI Seminar PBEE – Probability Framework Equation Impact Performance (Loss) Models and Simulation Hazard n(DV) – Probabilistic Description of Decision Variable (e.g., Mean Annual Probability $ Loss > 50% Replacement Cost) IM – Intensity Measure EDP – Engineering Demand Parameter DM – Damage Measure DV – Decision Variable Representation of the underlying mathematical rigor Importance of characterizing all variables in terms of characteristic values (mean/median) and their uncertainty (standard deviation) Propagation of uncertainties Articulation of DV’s Deierlein

Comprehensive System Simulation EERI Seminar Comprehensive System Simulation REF: Yang, Conte, Elgamal (UCSD) SYSTEM SIMULATION Shared vision to recognize the importance and the value (e.g., soil-foundation- structure interaction). -Ability to conduct such simulations (compatible models and computational platform) Helps articulate the important issues that need attention (e.g., introduction of strong motion, impact of ground deformations on performance) - Here more about this particular study later REF: Boulanger (UCDavis) Deierlein

NS Components & Contents EERI Seminar NS Components & Contents Problem Insight – Small Equipment -Cascade approach -Transmissibility important IM = Sa(T1) EDP = PFA DM Comprehensive vision extends to nonstructural and contents, important components of losses and functionality Example of work completed at the end of last year to characterize fragility of lab benches (high value equipment and research specimens) and what structural parameters should serve as input. Hutchinson Deierlein

Integrated Simulation/Assessment Platform EERI Seminar Integrated Simulation/Assessment Platform Computation Information Technology Algorithms, Solvers, Parallel/distributed computing Software framework, Databases, Visualization, Internet/grid computation Models OpenSees Models, Computational algorithms, databases and other informational Technologies Been adopted as simulation platform for NEESgrid and being extended for hybrid testing applications. Simulation & Reliability Models for Materials, Components, and Systems http://opensees.berkeley.edu Deierlein

Integrative Testbeds Buildings Van Nuys UC Sciences UCB Campus Bridges EERI Seminar Integrative Testbeds Buildings Van Nuys UC Sciences UCB Campus Bridges Humboldt Bay I-880 Viaduct Bay Area Highway Network Testbeds – major focus of research over years 5-7. Two bridges, two buildings, and the network of which they are a part. Product oriented, interdisciplinary focus. Served to test and evaluate the methodology and tools, identify gaps, and begin packaging. Focus of many presentations at last year’s site visit, evolved into benchmarking and other projects, some of which will be discussed today. Deierlein

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