LAUSR

Existing research to predict seismic fragility of Reinforced Concrete Containment (RCC) buildings does not take into account the impact of its inelastic bidirectional interaction arising from bidirectional horizontal ground motions. Hence, this study attempts to present a reliable and feasible method for fragility of the RCC subject to bidirectional ground motions. Three bidirectional load histories due to inelastic bidirectional interaction are firstly introduced to determine displacement-based failure limits for this structure. Nine bidirectional earthquake Intensity Measures (IMs) are developed to perform the bidirectional Incremental Dynamic Analysis (IDA). For the selection of an optimum method for fragility under bidirectional earthquake excitations, three fragility analysis methods are conducted and their results are compared. Results show that the maximum likelihood method yields better fragility results than the other two methods. The safety factor method for fragility cannot get the aleatory randomness properly. Besides, the first-mode geometric mean spectral acceleration SaGM (T1) is found to strongly correlate with the demand measure for the RCC and is suggested for deriving fragility curves for such structures under bidirectional earthquake excitations.