Experimental study on open core hybrid buckling restrained braces with different debonding layer geometries

This study evaluates performances of newly developed open core hybrid buckling restrained braces (OC‐HyBRB) with debonding layers of two geometries. OC‐HyBRB has an axial load‐carrying steel core, two steel restrainers and two 3‐mm‐thick highly deformable rubber debonding layers. Debonding layer is continuous in first specimen and discontinuous in second specimen. OC‐HyBRB is designed to dissipate energy at lower strain levels through shear deformation of debonding layers. However, restrained local buckling of core first about weak axis and then about strong axis after threshold axial strain (∼2%) contributes to energy dissipation at higher strain levels. Thus, OC‐HyBRB is capable of dissipating energy in a wide range of core strain levels. Both types of OC‐HyBRBs are investigated using a specially designed test setup under a cyclic loading protocol, applied using a servo‐hydraulic actuator. Experimental force‐displacement hysteretic behaviour are found to be stable for both the specimens with enhanced stiffness at higher axial strain. This would reduce the residual deformation of the OC‐HyBRB. Thus, newly developed OC‐HyBRB would provide a simple yet efficient energy‐dissipation device for seismic response control of structures.