Abstract：To study the in-plane seismic performance of reinforced concrete(RC) frame with steel-plate assembled buckling-restrained brace(BRB) and the interaction between BRB and RC frame in out-of-plane direction under bi-directional earthquake, quasi-static tests were conducted on four RC frames with steel-plate assembled BRB and one RC frames without steel-plate assembled BRB. The influence of the out-of-plane deformation of frames, the out-of-plane bending stiffness of gusset plates, and the out-of-plane stiffness of the BRB extension section were considered. It is found that the storey shear force and storey drift hysteresis curves of the RC frames with steel-plate assembled BRB are plump and stable with or without the influence of bi-directional seismic action, implying a good seismic performance. The out-of-plane deformation of frames reduced the in-plane initial horizontal stiffness and load-bearing capacity of the RC frames with steel-plate assembled BRB, but increased the out-of-plane deformation of the steel-plate assembled BRB. The increase of the out-of-plane bending stiffness of gusset plates increased the out-of-plane force on the frame; The increase of out-of-plane bending stiffness of the BRB extension section reduced its out-of-plane deformation, but decreased the out-of-plane force of the BRB to the RC frame.
