1. 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

2. 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

3. 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% % %
Downtime, days
Casualty rate
0.0
Deierlein

4. 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

5. 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

6. 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

7. 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 (0.5% in 50 years)
2.7 5%
Hazard Curve
2/50
Deierlein

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

9. 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

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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

16. 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

17. 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
Deierlein

18. 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

19. 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