Development, characterization, and seismic application of a shape memory alloy-based self-centering damper

Shape memory alloys (SMAs) have been around for a while, but their applications in controlling dynamic response of structures are relatively new. This paper presents a conceptual development of a novel selfcentering damper (SCD), which uses superelastic Nickel-Titanium SMA wires for recentering and energy dissipation and a friction mechanism in parallel for additional damping. The concept is validated through quasi -static characterization tests on a laboratory -scaled model of the SCD. A numerical model of the SCD is then created for nonlinear dynamic analysis of steel braced frame buildings outfitted with SCDs. A series of analyses is conducted considering several ground motions scaled to match the target design spectra for the design basis earthquake (DBE) and maximum considered earthquake (MCE) levels. The results show that the buildings have negligible median residual drifts at both levels and median peak story drifts within the target of 1.5% and 2% at the DBE and MCE levels, respectively. Thus, the proposed SCD is promising for seismic response control of steel braced frame buildings.