Experimental study on seismic performance of buckling restrained braced-RC frames with different stiffness ratios

To study the influence of stiffness ratio on the seismic performance of buckling restrained braced (BRB)-reinforced concrete frames, three BRB frames with stiffness ratios of three, five, and seven were designed and tested. Based on low-cycle reversed loading, the energy dissipation capacity, failure mode, mechanical performance of BRB connection joint and gusset plate, rotational deformation performance of BRB, mechanism of bending moment at end of BRB were studied. Furthermore, the design method of beam and column connected to BRB was discussed. The test results show that all the specimens develop excellent hysteretic behavior with plump hysteretic curves and stable energy dissipation. With the increase of stiffness ratio, the yield capacity and ultimate capacity of the structure are improved, while the damage of the BRB connection joint is more serious. The location of the plastic hinge is transferred to the toe of the gusset plate from the end of the column due to the existence of gusset plate. Under horizontal load, additional bending moments are generated at the end of BRB due to the rotational deformation, and the relationship between the rotational deformation and the inter-story drift ratio is approximately linear. It is an effective way to achieve the full energy dissipation of BRB under large deformation by improving the ductility of the energy dissipating substructure.