Seismic performance of steel frame structure adopting parallel spine frames with elastic braces

Abstract

Strong structural spines increase structural integrity and enhance the seismic performance of multistory buildings. However, they usually do not provide a resilient force, which may lead to large residual drifts after major earthquakes. To address this problem, an earlier study by the authors proposed a super-elastic bracing system comprising parallel spine frames with buckling-restrained dampers and steel elastic braces. This study further investigated the seismic performance of the proposed system using a five-story building prototype. Evaluations of the lateral stiffness and strength of the elastic braces and dampers were first formulated and validated using pushover analysis. Extensive seismic response analyses were then performed for models with different brace configurations and sections, damper yield strengths, and ground motion intensities. The analyses showed that adding elastic braces efficiently reduced the peak and residual drifts and had no significant influence on the story drift distribution. The demand for brace stiffness to reduce the residual drift to a particular level has been suggested.