Development of medium- and low-rise reinforced concrete building fragility curves based on Chi-Chi Earthquake data

In this paper, a grid-based cluster division procedure, in combination with a novel maximum likelihood estimate based on multinomial distribution, is proposed to derive fragility curves for medium- and low-rise reinforced concrete (RC) buildings in Taiwan. This new grid-based method generates higher-quality vulnerability data for reducing the dispersion of datasets than does the district-based method. The medium- and low-rise RC buildings are classified into six typologies according to both the number of floors and the design code, based on the complete building damage records collected after the 1999 Chi-Chi Earthquake in Taiwan. The results of the grid-based method show that the fragility curves are more stable and convergent than those from the district-based method. The numerical results demonstrate that the proposed method can reasonably be implemented for fragility analysis and can be used for assessing seismic risk in the future.