Recent progress in buckling restrained braces: A review on material development and selection

Passive energy dissipation devices are a widely accepted solution used to improve the response of the structures under seismic conditions. While several types of passive energy dissipation elements have been proposed for replaceable elements, buckling restrained braces (BRB) was one of the most effective replaceable elements which has been used to retrofit frame structures in the past few years. A traditional BRB consists of a steel brace core with a cruciform cross section that is surrounded by a stiff steel tube (restraining unit) and unbonded materials to ensure the brace to move freely. The region between the tube and brace is filled with concrete-like materials. In recent years, a significant amount of research has been carried out on new types of BRBs which are more efficient and inexpensive. This paper presents an overview of recent advances in the development of BRB materials and buckling mechanism, with an emphasis on the material development for the restraining unit. The application of fibre-reinforced polymer (FRP) as restraining unit in BRB is highlighted.