Development of a novel high-performance all-steel fish-bone shaped buckling-restrained brace

Based on investigation of recent strong earthquakes, there is a potential that BRBs may rupture during a strong earthquake or subsequent repeated aftershocks. This study aims to propose a novel type of light-weighted all-steel dismountable BRB with fish-bone shaped core plate, which is termed FB-BRB in this paper. The FB-BRB consists of a core plate, two filling plates, two restraining plates and unbonding material. Deformation capacity of the proposed FB-BRB is to be maximized by generating several necking locations at the core plate, and details to avoid strain concentration at stoppers are also proposed. Experimental study is carried out using four scaled specimens with different configurations. Favorable seismic performance is obtained through comparison with that of a conventional BRB. The failure mechanisms of the newly proposed FB-BRBs are also further verified through numerical study using a combination of a ductile fracture model and a cyclic plasticity model, where further improvement is required to fully achieve the expected deformation mechanism.