Evaluation of Seismic Strengthening Techniques for High-Rise RC Masonry Infill Frame with Soft Ground Story

Abstract

In the seismically active regions, the reinforced concrete frame short, medium, and high rise buildings with masonry infill story and soft ground story are the most common type of construction. For this type of building there is not much information in the design codes for the analysis and design because of the non-linear behavior of the masonry infill panel and soft story. Structural engineers considering masonry as a non-structural element which means that the stiffness and strength of masonry are not taken into account during the design process, because masonry is much more brittle than the other frame elements. The most common and vulnerable problem arising from masonry infill reinforced concrete frame is the building with soft ground story as there is a discontinuity in the stiffness and strength along with the height of the building. To cope with this issue, the lateral strength and stiffness of such ground story column or overall building should be enhanced. Now, this modification in stiffness and strength can be achieved by increasing the shear capacity and moment capacity of first story columns and beams by changing the shear reinforcement the longitudinal reinforcement and changing sections of first story elements. The present study is focused on finding out a solution for the shear capacity and moment capacity of first story of the frames.