Development and experimental study of a novel steel brace with load-bearing adjustable capacity utilizing the buckling behavior of partial steel plates

To regulate the seismic failure mode of a structure, this paper proposes a novel steel brace with load-bearing adjustable capacity (NSB-LBAC) utilizing the buckling behavior of partial steel plates. The NSB-LBAC comprises an outer steel tube, a slidable force-transmission steel tube, two load-bearing adjustable steel plates (LBASPs), two force-transmission components, and connectors. The LBASP with buckling and buckling-restrained segments was designed to adjust the nonlinear load bearing of the NSB-LBAC. The nonlinear load-bearing capacity can be adjusted by controlling the proportion of buckling and buckling-restrained segments. Considering the influences of the adjustable area ratio and length of the un-strengthened zone, pseudo-static experiments were conducted on five NSB-LBAC specimens to investigate their mechanical properties, load-bearing capacity, and energy dissipation capacity. The experimental results demonstrated that the proposed NSB-LBAC can achieve a load-bearing adjustable capacity by utilizing the buckling behavior of partial steel plates. The increased adjustable area ratio and length of the un-strengthened zone can reduce the post-buckling load-bearing capacity, and increased adjustable area ratio can retard the growth of the post-buckling load-bearing capacity. The increased length of the un-strengthened zone can increase the ductility of the NSB-LBAC. The proposed NSB-LBAC can provide an excellent energy dissipation capacity, and the increase in the adjustable area ratio can increase the energy dissipation capacity of the NSB-LBAC. A theoretical analysis model considering the buckling behavior of partial steel plates is proposed to evaluate the initial stiffness, yield load, and ultimate load of the NSB-LBAC.