NCEER-ATC Joint Study on Fragility of Buildings

Abstract

This report provides improved damage-motion relationships that can be used in regional earthquake damage and loss studies. Three main areas for modification of the existing ATC-13 damage probability matrices were investigated. The first was to develop detailed descriptions of the original 40 building classes defined in ATC-13. These descriptions clarified assumptions made regarding the load carrying system and the standard design practices. The second approach for modifying the motion damage relationships was through collecting existing data. It was found that these data are not particularly useful because they were collected under different formats and with different interpretations by the individuals gathering the data. In addition, ground motions were not available for the majority of the data. The third modification considered the development of fragility formulations based on the information from the ATC-13 damage probability matrices. For that purpose, the original mean and 90% expert opinion values of damage at each intensity level were used to develop fragility curves for all 40 building classes. Then a lognormal function was fitted through the fragility curve to enable easy implementation of these fragility curves. These curves can be easily implemented in large regional damage and loss estimation studies.<BR>