Progress of buckling restrained braces and buckling restrained braced frames

The Buckling Restrained Brace (BRB), usually being composed of core steel brace and lateral resisting member, is a kind of effective lateral force resisting members in engineering. The large amplitude of global and local buckling of core steel brace can be avoided because the clearance between core steel brace and outer restraining member is designed appropriately and the restraining member has sufficiently lateral stiffness and strength. As a result, the core steel brace can approximately support axial compressive loading until yielding with higher buckling modes. The BRBs and buckling restrained braced frames (BRBFs) designed properly have been of stable hysteretic character, excellent ductility and energy dissipation capacity according to past relevant research. Lots of factors such as core steel brace mechanical character, flexural stiffness and strength of outer restraining member, clearance between core steel brace and outer restraining member, mechanical behavior of unbonded material and some detail constructions have great effects on the mechanical behavior of the BRBs. In order to improve the overall working behavior of BRBs and BRBFs as well as promote their application, the problems need to further exploring are proposed.