Numerical Investigation of Energy Dissipation Device to Improve Seismic Response of Existing Steel Buildings with Soft-First-Story

Retrofitting buildings in densely populated areas with a soft story configuration on the first floor can pose a daunting challenge to the community. Against this backdrop, this study set out to evaluate the seismic retrofit strategy's adequacy in enhancing the seismic performance of buildings with a soft story. The proposed strategy utilizes an earthquake energy dissipation device consisting of a combination of a diagonal brace and a metallic-yielding damper at the ground story level. Two prototype buildings, one with five and the other with ten floors, were chosen to assess the proposed retrofit strategy's seismic response through nonlinear static and dynamic analyses. The seismic capacity, lateral displacement response, maximum inter-story drift ratio, energy dissipation, and collapse fragility are the major response parameters used to compare original and retrofitted buildings. The nonlinear static analysis results revealed that the seismic capacity for buildings equipped with a yielding damper was higher than that of the original buildings. It was also found that retrofitted frame buildings had a desirable structural behavior with a higher value of dissipated energy and a lower value of residual displacements and inter-story drift ratio, in turn reducing the likelihood of soft-story failure.