Earthquake Resilience of Spatially Distributed Building Clusters: Methodology and Application

Abstract

Interest in earthquake resilience has increased in recent years, and the use of building cluster performance objectives has been shown to be an effective method for evaluating the resilience of a built environment. A building cluster is a portfolio of buildings that share the same role in a community; its performance objectives are defined by considering earthquake scenarios, hazard levels, and individual building performance. The methodology presented in this paper employs performance-based assessments to estimate the probability of achieving building cluster performance objectives immediately following a seismic event. It can be used to assess the immediate post-earthquake community resilience in five steps: (1) hazard analysis; (2) conditional assessment of individual building performance; (3) conditional assessment of building cluster performance; (4) building cluster performance assessment by aggregation; and (5) earthquake resilience assessment of building clusters considering all hazard levels of interest. The design and extreme hazard levels are formulated using ground motion records selected based on the conditional spectra considering characteristics of earthquake scenarios and spatial correlation. Three performance objectives are defined for individual buildings and building clusters: (1) functionality; (2) safe and usable during repair; and (3) collapse prevention. Two engineering demand parameters, i.e., the maximum transient and the permanent interstory drift indices, are used to estimate individual building performance. The probability of achieving building cluster performance objective is calculated using the total probability theorem. The application of the proposed methodology is demonstrated using two clusters of reinforced concrete buildings, corresponding to ASCE 7 Risk Category II and IV structures, in San Francisco, California.