Seismic reliability of RC and steel-concrete composite buildings

सार

This study evaluates the seismic reliability of steel-concrete composite and RC-framed buildings considering vector-valued ground motion intensity measure. To efficiently predict the structural response of the structures, the appropriate choice of Intensity Measure (IM) and Damage Measure (DM) is crucial. In this study, the first modal spectral acceleration in conjunction with the measure of spectral shape is chosen as IM. The maximum inter-story drift is selected as the damage measure. The example model buildings are analyzed through Incremental Dynamic Analysis (IDA) subjected to a set of ten ground motion records. From IDA curves median curves are derived for example buildings and damage states are established from it. For the reliability analysis, a vector-valued IM is chosen, consisting of Sa(T1) and the ratio of Sa(T2) / Sa(T1), where T1 corresponds to the fundamental (first mode) time period of the structure, and T2 is selected to represent essential characteristics of the response spectrum profile. The drift hazard curves of example model buildings are developed using the reliability approach. Further, limit state probabilities are determined from drift hazard curves, and the values are compared for composite and RC-framed structures. From the reliability analysis, it is found that the composite building results in a decrease in the drift and hence increases in the reliability of the composite structure.