11.37: Hybrid tests of a full‐scale two‐story buckling‐restrained braced RC frame

Abstract

A novel implementation of buckling-restrained braces (BRB) in new reinforced concrete (RC) frame construction is investigated. Seismic design and analysis methods for the use of the proposed steel cast-in anchor bracket (CAB) as the connection for the BRB and RC members are investigated. The steel CAB is designed to resist the normal and shear forces transferred from the BRB in order to secure the seismic performance of RC buildings. In this study, a full-scale two-story RC frame with BRBs (BRB-RCF) is tested using hybrid and cyclic loading test procedures. The BRBs are arranged in a zigzag configuration and designed to resist 70% of the story shear. The gusset design incorporates the BRB axial and RC frame actions, while the beam and column members comply with ACI 318-14 seismic design provisions. When the inter-story drift ratio for both stories reached 3.5%, the overall lateral force versus deformation response was still very stable. The hysteresis energy dissipation ratios in the four hybrid tests range from 60% to 94% in the two stories, indicating that BRBs can effectively dissipate seismic input energy. Test results confirm that BRBs enhanced the RC frame stiffness, strength and ductility, complied with performance-based seismic design. No failure of the proposed steel CABs and RC discontinuity regions was observed in the tests. This study demonstrates that the proposed design and construction methods for the CABs are effective and practical for real applications.