Experimental Study of Maintenance-Free Steel-Composite Buckling Restrained Braces

High-rise buildings are very flexible, have a small damping, and respond significantly under strong dynamic load. However, there is a lack of studies about buckling restrained braces (BRBs) used in high-rise buildings, towering steel structures, and bridge structures. In this paper, the authors put forward a new type of brace, the maintenance-free steel-composite buckling restrained brace (MFSC-BRB). The MFSC-BRB has a steel plate core, for which a ribbed glass fiber reinforced polymer (GFRP) rectangular tube is used as the restraint unit; the steel core is encapsulated by the GFRP rectangular tube. In this study, MFSC-BRBs were fabricated using a vacuum-infused molding process that enabled them to be integrally formed all at once. Four specimens were designed according to the vacuum-infused molding process; then, the failure mode, deformation capacity, and hysteretic behavior of the MFSC-BRBs were studied. The results showed that the new MFSC-BRB has good integrity and good energy dissipation capacity under the action of a low weekly repeated loading effect. When the axial displacement is large, the performance of the single wave section expansion joint is better than that of the double wave section expansion joint. The greater the restraint ratio of the restrained yield section, the greater the energy dissipation of the brace. The proposed MFSC-BRBs have good integrity and are lightweight compared with traditional BRBs.