RESEARCH PROGRESS OF BUCKLING RESTRAINED BRACES: TYPES, DESIGN METHODS AND APPLICATIONS

This paper summarizes the development of buckling restrained braces (BRBs) for the last 40 years since they were invented. The development trend of BRB designs tends to make BRBs more lightweight, to have higher load-carrying capacity and complex functional capabilities. This paper particularly proposes a number of newly developed BRBs including all-steel assembled BRB, shuttle-shaped BRB, core-separated BRB, latticed BRB with multiple chords and truss-restraining (cable-truss and rigid-truss) BRB. The composition, structural mechanism, failure mode, elastic buckling load, load-carrying capacity under monotonic compressive load, hysteretic and low-cycle fatigue performance under cyclic load of each type of BRB are described respectively. In addition, the corresponding experimental results are obtained. The design theories of the external restraining stiffness, lower limit of restraining ratio, external connecting strength and constructional details of projections are of major concerns. The relevant design specifications in China and other countries are reviewed, and two design methods based on the restraining ratio and normalized slenderness ratio of BRBs are introduced.