Use of IDA to Estimate Variations in Drift Demands of Irregular RCC Buildings

Abstract

The paper describes incremental dynamic analysis (IDA) of 4 RCC building models (1 regular and 3 geometrically irregular) subjected to far-fault, near-fault, and fling-step ground motions. Identifying critical frames and storeys to predict the members where collapse initializes is emphasized. The objective of the paper is to show that the location of the critical storeys at which the inter-storey drift demands are more severe, depending on the kind of seismic excitation and the type of building. The results of interest are the height-wise variation of inter-storey drift demands. For different irregular configurations, storeys most vulnerable to damages were identified and their drift demands elaborated. Comparing the susceptibility of failure for different suits of ground motions for different plan and vertical geometric irregularities, the results showed a wide range of difference in the parts of the buildings experiencing significant drift demand. Near-field and fling-step ground motions affected the storeys with irregularities, the most and far-field ground motions affected the lower stories the most, irrespective of the presence or absence of any irregularities.