Experimental study on the hysteretic behavior of single-diagonal unbonded steel plate brace encased in reinforced concrete panel

Six quasi-static tests on single-diagonal unbonded steel plate brace encased in reinforced concrete panel, referred to as panel buckling-restrained brace(panel BRB), are conducted. The effects of the unbonded materials as well as the clearance between the panel and the core brace, the configuration of the reinforcement and the steel bars, the thickness of the panel and the concrete strength on the hysteretic behavior of panel BRBs are investigated. The results show that all panel BRBs exhibit stable hysteretic behavior without deterioration in load resistance and stiffness before failure of the panels, and the skeleton curves of all the specimens are close to the bilinear models. The lateral drifts of the specimens at failure are as high as 1/87-1/29. The tests also indicate that the specimens with more even and smaller clearance and reasonable steel bar configurations performed better, whereas where the clearance is slightly larger, the specimens fail earlier by either punching shear or local flexure. The braces still retain residual flexural deformation with multiple waves after the test, which testifies to that the stability capacity of the core brace has been enhanced to its yield strength by the buckling form with multiple waves.