Self-centering steel beam-to-column connections with novel superelastic SMA angles

This paper proposed a novel type of self-centering (SC) steel beam-to-column connection using superelastic shape memory alloy (SMA) angles and steel angles. Unlike conventional post-tensioned SC connections, the proposed SC connection utilized SMA angles to provide SC ability and moderate energy dissipation, enabling easy installation and replacement. Experimental and numerical studies were conducted to investigate the cyclic behavior of the connection. Two types of steel connections with different configurations were tested: one equipped with SMA angles only and the other with a combination of SMA and steel angles. The cyclic behavior of the SC steel beam-to-column connections was investigated through a series of experiments. A numerical study was also conducted to provide more insight into the mechanical behavior of the connections and the local strain condition of SMA angles. Numerical results were validated with experimental results. Comparative results demonstrated that both connections exhibited desirable flag-shaped hysteresis behavior with SC and energy dissipation. No obvious damage and residual deformation were observed in SMA angles after cyclic loads in both the experiments and numerical simulations, indicating that the SC connection using SMA angles can be reused for successive mainshocks and aftershocks without replacement. Therefore, the proposed SC connection can help achieve the goal of earthquake resilience in structural design.