Influence of Masonry Infill Panels on the Seismic Performance of Irregular Buildings

Abstract

RC buildings constructed on hills demonstrate diverse structural behaviour as compared to conventional buildings. Since these irregular buildings are asymmetric in elevation as well as plan at different floor levels, they exhibit different centre of masses and centre of stiffness at various floor levels. As a result of which, they are torsionally coupled in addition to the lateral loads, when subjected to seismic forces. Further, hill buildings have different column lengths at same storey because of steep slopes. Thus, the shorter column on uphill side has much higher stiffness and attracts more forces, and hence, it is more susceptible to damage as compared to the column on downhill side. Moreover, the unreinforced masonry infills often play a substantial role in the seismic performance of hill buildings. This study investigates the effect of masonry infills on the seismic behaviour of RC moment-resisting frames in two hill building configurations, viz. Stepback and Setback-stepback. All the configurations have been modelled using a finite element software and examined by response spectrum analysis and nonlinear static pushover analysis. The results obtained from the study have been discussed as variations in storey shear, base shear, time period, maximum top storey displacement values and plastic hinge development pattern in the building structure. At last, vulnerability and suitability of the different configurations against seismic excitations have been suggested.