Comparative study of strengthening strategies for reinforced concrete frame with soft ground story

Abstract

One of the common forms of reinforced concrete (RC) framed building is to provide parking facility at ground level which is created by not providing any infill masonry at parking floor level. Due to the presence of infill walls in the entire upper story except for the ground story makes the upper stories much stiffer than the open ground story resulting in their poor performance during earthquakes. So strengthening of such reinforced concrete (RC) frame buildings with an open ground story is indispensable. In the present study several Strengthening options were evaluated for their effectiveness in improving the performance of such building without disturbing the parking facility of ground story based on linear and nonlinear analysis. The strengthening techniques studied were changing column dimension, providing diagonal bracing, lateral buttresses, shear wall, and providing chevron. The Strengthened building results were compared with the results of the original structure to deduce the structural performance improvement and cost associated to each solution were determined to develop cost efficiency relation for different strengthening technique. Providing lateral buttresses in the open first story was found to be more feasible in both case of increase ground story strength and economic point of view among all strengthening options.