Local Damage Control of Unconstrained Gusset Connections for Buckling Restrained Braces in RC Frames

An unconstrained gusset connection for buckling restrained braces in reinforced concrete frame structures is proposed and tested as an effort to mitigate the complicated and harmful interactions between the steel gusset plate and the adjoining reinforced concrete components. A local damage control scheme is also proposed to enhance the gusset connection performance by moving the potential plastic hinge at the beam end away from the connection region. Two different connecting methods, one with post-tensioned steel rods and the other embedded stud group, were tested. The results of the cyclic loading tests on the gusset connection subassemblies confirmed that the proposed damage control scheme is effective in controlling the locations of the beam hinges and thus preventing the BRBs from being dislocated from the entire structural system as a result of the beam end failure at extreme earthquake scenarios.