Promoting Earthquake Risk Reduction for Wood-Frame Soft-Story Buildings: A Case Study of San Francisco's Seismic Retrofit Program

Published

June 27, 2022

Author(s)

Yating Zhang, Juan Fung, Katherine Johnson, Siamak Sattar

Abstract

Wood-frame soft-story buildings have been responsible for massive loss of life and property in past earthquakes. To reduce future earthquake losses, several cities in California passed ordinances that mandated seismic upgrades for buildings containing weak first stories. However, even with mandates, compliance with the ordinances has been less than complete, with implementation for commercial buildings as low as 50%. This study assesses the effectiveness of the mandatory approach employed by the City of San Francisco and the influence of individual, economic, and social factors on retrofit implementation. A two-level regression model is developed to predict retrofit probability for soft-story buildings. The results indicate that seismic retrofit is less likely to be taken for older, larger buildings that are located on higher-value land, and less likely to be taken in communities with lower median housing values, lower median gross rents, higher vacancy rates, lower population densities, and lower level of educational attainment. However, mandatory retrofit requirements may greatly motivate owners to strengthen buildings that are less desirable due to building characteristics or neighborhood socioeconomic conditions.

Proceedings Title

Proceedings of the 12th National Conference on Earthquake Engineering

Conference Dates

June 27-July 1, 2022

Conference Location

Salt Lake City, UT, US

Conference Title

The 12th National Conference on Earthquake Engineering

Pub Type

Conferences

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Keywords

seismic retrofit, risk mitigation, motivations, impediments, implementation

Citation

Zhang, Y. , Fung, J. , Johnson, K. and Sattar, S. (2022), Promoting Earthquake Risk Reduction for Wood-Frame Soft-Story Buildings: A Case Study of San Francisco's Seismic Retrofit Program, Proceedings of the 12th National Conference on Earthquake Engineering, Salt Lake City, UT, US, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=933464 (Accessed May 2, 2026)

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