Hysteretic response and failure behavior of an SMA cable-based self-centering brace

This study explores the experimental response and failure behavior of an SMA cable brace. The kernel of the developed SMA brace consists of four SMA cables with a diameter of 8 mm. The cables are configured within bracing system in a way that they are only subjected to tensile loads regardless of the loading direction of the bracing itself. A mechanical anchorage system that can satisfactorily anchor SMA cables of the bracing system was first described, and its performance was validated. Then, the design and fabrication process of the SMA brace was discussed. Two SMA cable braces were manufactured and tested under different loading conditions. The first SMA brace was subjected to increasing displacement amplitude loading protocol until all SMA cables within the bracing system failed. The evolution of various parameters such as equivalent viscous damping and residual deformations with the displacement loading amplitude was quantitatively evaluated. The second SMA brace was tested for consistency verification and to study the effects of loading frequency and number of loading cycles on the response of the SMA brace. Results obtained from the experimental tests revealed the excellent self-centering behavior of SMA brace with an ultimate force capacity of 125 kN and a displacement capacity of 65 mm. The equivalent viscous damping for the developed brace was about 5%. The complete failure of the brace was gradual, and the SMA brace was able to carry large loads even after one or two SMA cables ruptured.