Earthquake-Resistant Behavior Of All-Steel Buckling-Restrained Braces

The buckling-restrained braces (BRBs) are a new kind of braces that can achieve the yield stress of the material in both tension and compression. They can reduce the seismic response of the structure by dissipation the vibration energy. But different types of the BRBs have different performances. This paper studies the all-steel BRB that consists of a steel core and buckling-restrained steel tube. Finite element method is adopted to simulate the earthquake-resistant behavior of the steel buckling-restrained brace. The main research contents of this paper are as follows.1. Through the stability analysis of the entire brace and the inner core, the corresponding critical loads and the critical width to thickness ratio of the core plate are got.2. The static cyclic test of the steel buckling-restrained brace consisting of a steel flat bar encased in square steel tube was carried out. The result from the test demonstrates that this kind of brace not only has stable hysteretic behavior and super energy dissipation capacity, but also has large deformation capacity. The initial curvature is a main factor influencing the performance of the brace.3. The effects of restraining ratio, width to thickness ratio of core, the restraining ring on the capability of the brace are analyzed through the finite element software. The comparison of the BRBs with cruciform core and rectangular core indicates that the brace with cruciform core has better earthquake-resistant behavior. The analysis of a buckling-restrained braced frame shows that the gusset plate of the brace needs tube stiffened.