Experimental research of assembled buckling-restrained braces wrapped with carbon or basalt fiber

Abstract

A new assembled buckling-restrained brace (ABRB) wrapped with carbon or basalt fiber cloth is proposed. It has the following advantages: 1) it can be disassembled by cutting the fiber cloth; 2) it is easy to inspect and repair the core plates after destructive earthquakes; 3) the outer fiber material also serves as a corrosion resistance to the outer steel tube. A total of eight ABRB specimens were tested under quasi-static axial loads. The test results indicate that the ABRB is capable to undergo fully-reverse yielding cycles without loss of stiffness and strength with sufficient ductility and energy absorption capacity. Multi-wave buckling occurred on the core plates of ABRBs resulting in “jumped” hysteretic curves in compression stage. ABRB specimens fractured in the middle of the core plate elements when a loading protocol included increasing deformation amplitudes with additional fatigue cyclic loading; while when the loading protocol consisted of increasing deformation amplitude cyclic loading without maximum amplitude limit, rupture of the ABRB specimens occurred at the junctions of yielding segments and non-yielding segments of core plate. When a pair of restraining members of an ABRB are connected and restrained with fiber cloth, the assembled constraint mechanics can resist the lateral thrust exerted by core plate. The nonlinear finite element analysis results show good agreement with the experimental data. Both the results from the experiment and numerical simulation show that the proposed ABRBs can satisfy the performance requirements for the BRB components and provide a beneficial alternative for BRB fabrication and application.