Dynamic performance of soft-storey structures with gap elements at beam-column joints

Abstract

Soft-storey structures are more susceptible to failure for seismic vibrations, which is well-known to the world. But, in multi-storey apartments, it is a practice to provide a parking place at the ground storey, inducing soft-storey effects. In the present study, an effort is made to reduce the soft-storey effect on the structure's dynamic performance by introducing an arrangement of gap elements at beam-column joints. To that context, a numerical assessment is carried out to check the performance of the RC structure. The gap element is modelled as a spring either in a beam or in a column or both.The research has been performed in two parts; the first part of the analysis is focused on optimizing the gap element pattern. Diagonal compressive struts replace the infill walls, and the ground storey is modelled as an open ground storey without infill walls, which is considered a soft-storey. From the first part, an optimal gap element pattern from five different arbitrary patterns is obtained from the results of linear dynamic response spectrum analysis, depending upon the comparison of various seismic parameters. The second part of the analysis involves checking the effect of the gap element's optimized pattern for four levels of structures with vertically varied aspect ratios. Response spectrum analysis is performed, and a study is conducted to compare the seismic parameters for the four levels. The models with gap elements have shown an apparent reduction in storey displacements, inter-storey drift ratios, over-turning moments, and increment in storey stiffness when compared to the conventional models, thus exhibiting constructive outcomes.