DYNAMIC ANALYSIS OF RC FRAMED BUILDING WITH INFILL

Abstract

Reinforced concrete Frame with masonry is practiced in major part of world (predominantly in India) due to its low cost and easily availability of material and skilled labour. If masonry is added in reinforced concrete frame, as practiced it increases strength and stiffness to structure but performance decreases due to low ductility of brick and mortar which constitutes masonry. In-filled panel made up of masonry constitute as an integral entity of reinforced concrete frame and can be idealized as a strut element in in-plane action and as a single degree of freedom system in out of plane action. Combined interaction in in-plane and out of plane is a complex phenomenon and an iterative relationship to compute has been presented. Collective study has been carried out to calculate width of diagonal strut. Equations as proposed by different researchers for finding the equivalent width of strut under cracked and uncracked section, different modes of failure in in-plane and out of plane action, modeling of surrounding frame and the interface has been presented. Building has been designed as SMRF as per Indian codal provision for earthquake, thereafter in-plane action of bare and infilled frame is compared by responses spectrum analysis and pushover analysis is performed. Further incremental dynamic time history analysis is performed by scaling the ground motion (up and down) till the collapse of structure occurs. Time history is converted into spectral acceleration v/s period plot .Then spectral acceleration corresponding to fundamental mode of vibration is noted for different scaled ground motion. This process is repeated for different ground motion and a plot for spectral acceleration and inter-storey drift is drawn. Inter-storey drift corresponding to different damage states is defined. At last fragility curve is drawn between the probability of exceedance and spectral acceleration.