A comparative study on cyclic performance of stainless steel (STS304) and carbon steel (SS275) buckling-restrained braces

Stainless steel has emerged as a promising structural material in seismic applications owing to its exceptional ductility, cyclic-hardening characteristics, and inherent resistance to corrosion and fire. This study presents the development and experimental evaluation of an all-stainless-steel assembled buckling-restrained brace (ASS-BRB), in which all components including core, restraining units, and bolts are fabricated entirely from stainless steel. The configuration is designed to enable rapid installation and straightforward replacement of cores, while leveraging the mechanical advantages of stainless steel to achieve enhanced post-yield performance and extended service life. Experimental tests were conducted on a total of six specimens, comprising two groups of three each fabricated from austenitic stainless steel STS304 and carbon steel SS275 with identical geometries, to evaluate and compare their cyclic performance. The failure modes, hysteretic behavior, energy dissipation capacities, strength adjustment factors, cumulative plastic deformation (CPD), and post-yield stiffness were systematically analyzed and compared. The STS304 BRBs exhibited superior hysteretic performance, with notably higher stiffness at 2% and 3% strain amplitudes compared to the SS275 BRBs. The findings demonstrate that STS304 BRBs offer a viable and high-performance alternative to conventional carbon steel BRBs, with greater post-yield stiffness and energy dissipation capacity, advancing the development of durable and corrosion-resistant seismic protective systems.