지진하중을 받는 철골 모멘트 골조의 전체붕괴 예측을 위한 근사적 방법

Abstract

The global collapse of steel moment resisting frames under seismic excitations is predicted by performing incremental dynamic analysis (IDA) as a function of the selected intensity measure, IM. This procedure requires nonlinear response history analysis (NL-RHA) of the structure for an ensemble of ground motions, each scaled to many intensity levels, selected to cover a wide range of structural response - all the way from elastic behavior to dynamic instability. Recognizing that IDA of practical structures is computationally extremely demanding, an approximate procedure based on the first mode equivalent single degree of freedom (SDF) system is developed. The global collapse of 9- and 20-story steel moment resisting frames are computed by the exact and the approximate procedure. By using the proposed approximate procedure, this study estimates the probability of collapse as a function of the IM and compares the results with the exact values, from which the accuracy of the proposed procedure is verified.