ABSTRACT

ABSTRACT: Story failure mode is a structural failure pattern that should be avoided during earthquake excitations. In structural reliability analysis, the story failure mode with the highest occurrence probability is the most significant for its influence on the overall probability of structural failure. The object of this study is to search for the most likely undesirable story failure mode in a probabilistic way. The story failure modes are defined by three patterns: upper story failure pattern, middle story failure pattern and lower story failure pattern. The failure probabilities of story failure modes of multi-story frame structures designed with different column over-design factors are evaluated by FORM, and the comparison of these probabilities is conducted. It is found that for an n-story frame structure there are n story failure modes have likelihood to be the dominant story failure mode, and they are the upper failure mode with n − 1 failure stories and all the n − 1 lower story failure modes.