Combined Hurricane and Earthquake Hazard Component Vulnerability Analysis Terri R. Norton and Makola M. Abdullah, Ph.D. Florida A&M University - Florida State University Wind Hazard and Earthquake Engineering Lab
OUTLINE • Introduction • Fragility Curves • Research Objectives • Research Proposal • Vulnerability Analysis • Damage Estimation (USGS, 2004)
INTRODUCTION • Each year the United States is affected by natural hazards. • Hurricanes plague the east coast, while earthquakes affect the west. • These hazards have the potential to cause extensive property damage and create mass casualties. • Hurricane Andrew (1992), Hurricane Floyd (1999) • Northridge Earthquake (1994)
INTRODUCTION cont. • Understanding system vulnerability is essential to damage prediction. • Vulnerability = susceptibility of being damaged • System vulnerability can be approximated through the collection of component vulnerabilities. • Fragility curves are used to measure vulnerability.
FRAGILITY CURVES • Relate the probability of being in or exceeding a building damage state to a response parameter. f: is the standard normal probability integral mr:is the median fragility Br: is the logarithmic standard deviation and x is the peak (ground or spectral) acceleration (FEMA, 1999)
Extensive Complete Moderate Slight X Extensive Complete Moderate Slight X Top floor Beam Lower Corner Column X X Third Floor Bracing X Interior Walls Third Floor Slab FRAGILITY TYPES Component vs. System Fragility • System fragility is needed for input in most loss estimation software, like HAZUS. • Research considers a building as an assembly of components. • Unanwa (2000) • Shinozuka (2000) (Kishi, 2003)
OBJECTIVES • Develop generalized component fragilities for wood-framed residential structures. • Use fault tree analysis to identify component relationships • Determine system vulnerability based on weighted component fragility. • Estimate the economic loss of the structure.
USGS peak acceleration map ASCE wind speed map Demand Conversion Input Demand Damage Estimate Vulnerability PROPOSED APPROACH • Component fragility based on converted demand • Fault tree analysis • Compilation of component fragility into system fragility • Vulnerability converted into economic loss • Total loss based on system vulnerability
INPUT DEMAND • Earthquake loads • USGS peak acceleration map (% g) • Extreme wind loads • ASCE 7 wind speed design map (mph) • Loads converted to a generalized demand parameter
COMPONENT VULNERABILITY • Each component fragility will be a function of a specific demand parameter. • Windows may be a function of pressure • Wall may be a function of shear force • Existing research will assist in constructing component fragilities functions. • Maximum likelihood method may also assist in the estimation of the two-parameter lognormal distribution function.
MAXIMUM LIKELIHOOD where and F(x): probability of being damaged 1-F(x): Probability of not being damaged x: input demand a: 0 or 1, does not or does sustain damage (Shinozuka, 2000)
FAULT TREE ANALYSIS • Explains the logical sequence of damage propagation. • From direct to indirect damage
SYSTEM VULNERABILITY • A function of all the component fragilities combined.
SYSTEM VULNERABILITY • A function of all the component fragilities combined. (Shinozuka, 2000)
Vulnerability, % Input Demand DAMAGE APPROXIMATION $ Repair Cost
ECONOMIC LOSS • Repair Cost • Structural and Nonstructural damage • Damage of contents • Loss of Functionality
QUESTIONS? (FEMA, 1994)
CONTACT INFO • Terri R. Norton • Email: email@example.com • Makola M. Abdullah, Ph.D. • Email: firstname.lastname@example.org • http://www.eng.fsu.edu/departments/civil/index.html • http://www.wheel.eng.fsu.edu FAMU-FSU College of Engineering
FRAGILITY DEVELOPMENT • ATC-13 (1985): heuristic damage functions • estimates were based on the personal knowledge and experience of experts in the field • HAZUS (1997): a combination of heuristic and analytical damage function models • The focus of this assessment is the building’s response to ground motion • Unanwa (2000): heuristic and analytical damage functions • Consideration was given to damage propagation either through the direct impact of the wind or as a result of damage of other components
Roof covering Roof structure Beams and Columns Connections Slabs Partition walls Exterior wall Exterior doors & windows Exterior doors Interior Mechanical & Electrical Plumbing Foundation BUILDING COMPONENTS