EXPERIMENTRAL STUDY ON SEIMEIC PERFORMANCE FOR AN INNOVATIVE SELF-CENTERING SMA BRACE

During rare earthquake, the effective improvement of the ductility and energy dissipation capacity and reduction of residual deformation of a brace is currently in higher demand to ensure the seismic safety and seismic resilience capacity. Based on the ideals of shape memory alloy (SMA) and friction slip, an innovative self-centering brace with low friction and SMA is developed, which has the advantage of good seismic performance, high self-centering capacity and zero damage. Low frequency cyclic tests were carried on five non-SMA brace specimens and six self-centering SMA brace specimens, thusly the hysteresis curves, skeleton curves, secant stiffness, energy dissipation capacity and self-centering ratio of these specimens can be investigated. The test results show that: the self-centering SMA braces proposed have excellent energy dissipation capacity, bearing capacity, ductility and self-centering capacity, while all the steel plates in the specimens remain elastic without any yielding during the test, and the SMA in the specimens can return to the initial state. In addition, hysteretic behavior of the brace can be idealized as a flag-shape with little residual deformation, and the self-centering ratio has reached 93.7%. Therefore, the innovative brace has excellent seismic performance, which can be used as a self-centering damper.