Cyclic Tension–Compression Behaviors of Large-Dimensional Superelastic Shape Memory Alloy Buckling-Restrained Plates

This study proposed novel designs for achieving self-centering (SC) behavior using superelastic shape memory alloy (SMA) buckling-restrained plates (BRPs). Compared with previous studies relying on small-diameter SMA bars, this study employed large-dimensional SMA plates that could provide sufficient strength for real construction projects. The design concept and configurations of SMA-BRPs were first introduced. Corresponding tests were then conducted. Three specimens were tested, including one that was unsatisfactory and two that were acceptable. Based on the initial examination of the behavior and failure mode of the unsatisfactory trial specimen, the corresponding modifications were made to achieve the improved performance of two acceptable specimens. Subsequently, the hysteresis and SC behaviors, energy dissipation capacity, and yielding strength degradation of the two acceptable specimens were investigated. Both specimens exhibited high-quality flag-shaped behaviors in their tension–compression cycles, with their strengths reaching around 200 kN under tension and more than 310 kN under compression, representing one of the largest strength values shown by a single SMA element in the literature. Asymmetric behavior was observed under tensile and compressive loadings, primarily due to the asymmetric behavior of the SMA base material, high-mode inelastic buckling under compression and friction between the SMA core plate and buckling-restraining device. After the tests, finite element models were developed to obtain an in-depth understanding of the detailed behavior of SMA-BRPs. The studies showed that SMA-BRPs successfully achieved the SC buckling-restraining design target. The design incorporating end restrainers was preferred due to its flexibility, which reduces application restraints.