Experimental results of a NiTi shape memory alloy (SMA)-based recentering beam-column connection

A half-scale interior beam-column connection incorporating superelastic nickel-titanium shape memory alloy (SMA) tendons was designed, fabricated, and tested to assess the feasibility of such a connection in a moment-resisting frame. This connection was compared to three other connections utilizing tendons made of steel, martensitic nickel–titanium, and superelastic nickel–titanium paralleled with aluminum. The connections with steel and martensitic nickel–titanium tendons rapidly lost their stiffness after being cycled beyond their elastic drift levels. The two tests with the superelastic nickel–titanium tendons showed significant recentering capabilities; they recovered a large portion of the post-elastic drift and showed promise for a material-based recentering moment connection. This novel connection was intended as a proof of concept that can be further developed in terms of practicality, ease of installation, and cost.