TEST ON RESILIENCE CAPACITY OF SELF-CENTERING BUCKLING RESTRAINED BRACE WITH DISC SPRINGS

Abstract

The properly constructed buckling restrained braces (BRBs) usually have good ductility and energy dissipation capacity and therefore can be used in braced steel frames. However, large residual plastic deformation of the BRBs deteriorates their resilience capacity and hence results in large residual deformation of the buckling restrained braced steel frames (BRBFs) under large drifts. To reduce the residual deformation of BRB while keeping good ductility and energy dissipation capacity, a new self-centering buckling restrained brace (SCBRB), letting both BRB part and self-centering part work in parallel, is proposed. The self-centering capacity of SCBRB is provided by a combination of pre-compressed disc springs, which provides restoring forces and facilitates reduction of the residual deformation of the BRB. The BRB is composed of a core steel plate brace, a restraining member formed by the circular steel tube filled with mortar, and debonding materials between them. By quasi-static tests, one self-centering buckling restrained brace specimen (SCBRB) and one pure BRB specimen were tested to mainly examine the constructional details and hysteretic behavior of SCBRB. The material and configuration details of core steel plate brace in both the SCBRB and the pure BRB are the same for comparison. The test results show that, compared with the pure BRB which still exhibits large residual deformation, the SCBRB presents a flag-shape hysteretic performance and its residual deformation decreases significantly. The hysteretic curves of both the SCBRB and the pure BRB are stable before tension fracture of plate brace due to low cyclic fatigue, and the other components remained intact.