Author(s)

M. Saiidi & H. Wang

Abstract

Shape memory alloys (SMAs) are unique alloys that have the ability to undergo large deformation, but can recover deformations fully after the loads. The primary objective of this study was to investigate the seismic performance of RC columns with SMA longitudinal reinforcement in the plastic hinge area. Another target was to evaluate seismic performance and damage in a repaired SMA-reinforced column using engineered cementitious composites (ECC). Two quarter-scale spiral RC columns with SMA longitudinal reinforcement in the plastic hinge area were designed and constructed for shake table testing at the Large Scale Structure Laboratory of the University of Nevada, Reno. The shake table data showed that SMA RC columns were able to recover nearly all of the post-yield deformation and that the use of ECC reduced the concrete damage substantially, thus requiring minimal repair even after very large earthquakes. Keywords: shape memory alloy, seismic performance, deformation, engineered cementitious composites, plastic hinge. 1 Introduction Reinforced concrete structures in seismic regions are susceptible to collapse and severe damage due to excessive lateral displacements. The basis of conventional seismic design is to yield steel in order to dissipate energy while encountering permanent deformation due to plastic properties of post-yield steel reinforcements. Shape memory alloys (SMA) are unique alloys that have the ability to undergo large deformations, but can return to their undeformed shape by heating or through removal of the stress. Therefore if SMA can be used as reinforcement in seismic design, it can yield under strains caused by seismic loads but potentially recover deformations at the end of earthquakes. The University of Nevada, Reno (UNR) and others have conducted analytical and

Keywords

shape memory alloy, seismic performance, deformation, engineered cementitious composites, plastic hinge.