Influence of the Shape Memory Alloys on Endplate Connections and Residual Deformation

Abstract

Yielding in steel structures dissipates seismic energy, which results in residual deformations. Conventional lateral-resisting systems provide appropriate seismic safety. However, these systems undergo severe structural damage when exposed to strong ground motions. Seismic residual drifts make it difficult or impossible to fix damaged structures. Therefore, systems that can reduce seismic residual deformations are required. Superelastic shape memory alloys (SMAs) can withstand significant deformations and recover all plastic deformations upon unloading. They can significantly lessen seismic residual deformations in steel structures, making post-seismic retrofitting easier. This paper will compare the use of a superelastic Ni-Ti alloy and a Fe-based SMA in two endplate connections of NIST benchmark buildings (NIST Technical Note 1863-3). In addition, some features that lead to decreased residual deformation in these types of joints will be investigated.