The Benefits of a Seismic Retrofit Program for Commercial Unreinforced Masonry Structures: Salt Lake County, Utah

This paper assesses the benefits of a seismic retrofit program for commercial unreinforced masonry structures (CURMs) in Salt Lake County, Utah. A comparative risk assessment embedded in a geographic information systems is the method used. A policy evaluation time horizon of twenty years is set. Future rates of demolition and rehabilitation, with and without a retrofit policy, are assumed. Damage functions for ordinary and retrofitted URMs are used to assess losses having a 10 percent chance of being exceeded over a 50-year exposure period. With a retrofit program, expected losses are reduced by 57 percent or more than a quarter billion dollars when compared to the no-policy scenario. Expected injuries and fatalities are reduced by more than 80 percent. These are minimal benefits expected from enforcement of the seismic provisions of the Uniform Code of Building Conservation.

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A GIS-Based Assessment of Earthquake Property Damage and Casualty Risk: Salt Lake County, Utah

Earthquake Spectra ◽

10.1193/1.1585703 ◽

1993 ◽

Vol 9 (1) ◽

pp. 11-33 ◽

Cited By ~ 8

Author(s):

Philip C. Emmi ◽

Carl A. Horton

Keyword(s):

Salt Lake ◽

Network Models ◽

Policy Implications ◽

Property Damage ◽

Damage Functions ◽

Lake County ◽

Ground Shaking ◽

Triangular Irregular Network ◽

Earthquake Casualty ◽

Wasatch Fault

This paper offers a probabilistic assessment of expected property damage and casualty risk due to the earthquake ground shaking hazard affecting Salt Lake County, Utah (population = 725,600). Salt Lake County is bisected by a segment of the Wasatch Fault. It is also at risk from twenty-one other nearby fault segments. Findings are based on (1) a microzonation of the earthquake ground shaking hazard, (2) an inventory of buildings by value, structural frame type and use, (3) earthquake damage functions defining the performance of buildings as a function of ground shaking intensity, (4) data on the density of residential and employee populations, and (5) earthquake casualty functions defining casualty risk as a function of building damage. The analysis is supported by the algebraic combination of digital map layers within a vector-based geographic information system. Triangular irregular network models show the expected distributions of casualties. Hazard mitigation policy implications are also considered.

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