COMPARATIVE STUDY OF RETROFITTING OF RC FRAME USING SHEAR WALL AND STEEL BRACING

Abstract

Most of the existing buildings located in seismic zone do not fulfil current seismic requirements and suffer extensive damage during a severe ground motion. The seismic capacity of such earthquake vulnerable buildings or earthquake damaged buildings should be assessed for the future use of the buildings. An adequate knowledge of different retrofitting techniques is necessary to make such structures earthquake resistant. The objective of the present study is to study the inelastic behavior of reinforced concrete structures. A 5 storey RC frame has been selected and different retrofitting techniques have been employed for the structure. The performance of the selected frame with two different retrofitting techniques has been investigated under nonlinear static (pushover) analysis. Due to its simplicity, professionals are more attracted to non linear static (NSP) or pushover analysis. Modeling for such analysis requires the determination of nonlinear properties of each component in the structure. The response of the structure mainly depends on the assumption made in the modeling process; therefore, care has to be given to get reasonable result. It has been seen that incorporating retrofitting techniques, such as, adding shear wall or adding steel braces to the frame improves the performance of the frames considerably. The parameters including yield base shear, yield displacement, ductility, over strength factor are extracted from pushover curves or capacity curves obtained from inelastic pushover analyses of the bare frame, brace-frame system and shear wall-frame system. These pushover analyses have given conservative results.