Review article: Review of fragility analyses for major building types in China with new implications for intensity–PGA relation development

Abstract

The evaluation of the seismic fragility of buildings is one key task of earthquake safety and loss assessment. Many research reports and papers have been published over the past 4 decades that deal with the vulnerability of buildings to ground motion caused by earthquakes in China. We first scrutinized 69 papers and theses studying building damage for earthquakes that occurred in densely populated areas. They represent observations where macroseismic intensities have been determined according to the official Chinese Seismic Intensity Scale. From these many studies we derived the median fragility functions (dependent on intensity) for four damage limit states of the two most widely distributed building types: masonry and reinforced concrete. We also inspected 18 publications that provide analytical fragility functions (dependent on PGA, peak ground acceleration) for the same damage classes and building categories. Thus, a solid fragility database based on both intensity and PGA is established for seismicity-prone areas in mainland China. A comprehensive view of the problems posed by the evaluation of fragility for different building types is given. Based on the newly collected fragility database, we propose a new approach in deriving intensity–PGA relations by using fragility as the bridge, and reasonable intensity–PGA relations are developed. This novel approach may shed light on new thought in decreasing the scatter in traditional intensity–PGA relation development, i.e., by further classifying observed macroseismic intensities and instrumental ground motions based on differences in building seismic resistance capability.