This paper presents an innovative self-centering buckling-restrained brace (SC-BRB) composed of a shape memory alloy (SMA) cables based self-centering system and an all-steel BRB. This study commences with cyclic tests on individual SMA cable to understand the influence of annealing schemes and pre-tension procedures on their fundamental mechanical properties, such as strength, stiffness, self-centering capability, energy dissipation, as well as their degradation of the properties during cyclic loading. Based on the test results, the desired annealing scheme and training procedure for the SMA cables in the proposed SC-BRB were presented. The configuration and working principle of the proposed SMA-cables-based SC-BRB were subsequently described, followed by theoretical studies on hysteretic models of the proposed brace. Numerical simulations and parametric studies were carried out to investigate the mechanical performance of the proposed SC-BRB. The results show that the investigated SMA cable can reasonably scale up the satisfactory properties of the SMA wire. The initial elastic stiffness and the 'residual' self-centering force strength of the SMA cables, which are essential for the proposed SC-BRB application, can be greatly enhanced by inflicting certain pre-stress. The initial strain and area ratio of the pre-tensioned SMA cables are suggested to be designed as about 2.5% and in the range of 60%-71.4%, respectively, to achieve appropriate energy dissipation, residual deformation, and material cost of the proposed SC-BRB.

To improve the seismic performance of coupled shear walls in high‐rise buildings and to eliminate the problems of large residual deformation and relatively small initial stiffness and damping properties of the traditional viscoelastic coupling beam damper (TVCBD), an innovative shape memory alloy (SMA)‐cable‐controlled self‐centering viscoelastic coupling beam damper (SVCBD) with energy dissipation and self‐centering capabilities was designed and investigated in this study. The construction form and operating principles of the SVCBD were proposed, relevant material performance tests of the cables were performed, and good results were obtained. Finally, the contribution of the SVCBD to seismic mitigation of a 10‐story reinforced concrete coupled shear wall structure was verified by seismic time‐history analyses. The results indicated that compared with TVCBD, SVCBD possesses fuller hysteretic curves, showing stronger energy dissipation capacity, higher initial stiffness, and much smaller residual deformation. The initial strain and cross‐sectional area of the SMA cables and the shear area of the viscoelastic plates affect the energy dissipation and self‐centering performance of SVCBD significantly. The seismic response and post‐earthquake residual deformation of the coupled shear wall structure and the plastic damage of the main components can be effectively controlled by utilizing the proposed SVCBD.

No abstract

No abstract

No abstract