Performance Testing and Cyclic Behavior of Buckling-Restrained Braces with H Cross Section Unrestrained Segments

The hysteretic behavior of four buckling-restrained braces (BRBs) with H cross section unrestrained segment was tested under cyclic load. The transformation of the unrestrained segment's section from crisscross shape to H shape can improve the moment-resistance capacity of unrestrained segment significantly and avoid buckling instability of unrestrained segment effectively due to evident stiffness enhancement. BRBs were designed according to Chinese codes, the load-carrying elements of BRBs were fabricated with Chinese Q235 steel. In the process of experiment, BRBs did not buckle, BRBs could undergo fully-reversed axial yielding cycles without loss of stiffness and strength, the ductility and energy absorption capacity of BRBs are large enough to withstand major earthquake. The resilience model can be simplified to a symmetrical bilinear resilience model. The ratio of width to thickness of inner core has a little influence on the mechanical behavior and energy-dissipation capacity of BRBs. A suggestion fo...