Seismic Performance of Reinforced Concrete Frames Strengthened with Buckling-Restrained Bracing Steel Frames

This research evaluates the seismic performance of two reinforced concrete (RC) frames strengthened with WT steel frames and buckling-restrained braces (BRBs). High strength mortar bearing blocks are made at four inner corners of the RC frame in order to transfer forces of BRBs. BRBs are adopted in the proposed strengthening system to improve the structural strength, stiffness and energy dissipation efficiency. Test results show the lateral strength of strengthened frame continues to increase until reaching a drift ratio of 3% rad, and the lateral shear capacity is 2.6 times as that of the bare RC frame. The BRB core cracks at a drift ratio of 5% rad. This study concludes that the proposed method is capable of increasing the strength and stiffness of original RC frames, and also achieving good ductility and energy-dissipating capacities.