Efficient SMA–Steel Bar Mechanical Connection for Seismic‐Resilient Structures: Experimental Evaluation

ABSTRACT Shape memory alloys (SMAs) have attracted increasing attention in recent years for their application in self‐centering (SC) seismic structures. To take full advantage of their recovery capability and energy dissipation (ED) potential, SMAs are typically incorporated into plastic hinge regions of reinforced concrete components as longitudinal reinforcement or utilized in high‐performance seismic protection devices. However, for widely used nickel–titanium SMAs, their smooth surface and poor machinability present significant challenges for the design of reliable mechanical connections with conventional steel reinforcement. To address this issue, this study proposes an efficient SMA–steel bar connection strategy that integrates swaged sleeves on SMA bars with straight‐threaded couplers, enabling reliable force transfer and rapid specimen assembly. The structural configuration and key design considerations of the proposed connection system were first presented. Experimental investigations were then conducted to evaluate its mechanical performance, with particular emphasis on the effects of sleeve length and bar diameter. Test results demonstrate that the proposed connection system provides a stable mechanical splice and reliable load transfer under various loading conditions, while maintaining the characteristic flag‐shaped hysteretic response of SMAs. Although the ED capacity of SMAs is lower than that of conventional hysteretic dampers, their primary function is to provide substantial SC capability to structural systems, which makes them highly attractive for seismic design. This study provides an efficient and reliable connection solution for SMA bars, supporting their wide application in seismic‐resilient structural systems.