Evaluation of seismic performance of RC columns retrofitted by SMA wire jackets through fragility analysis

Abstract

The goal of this study is to provide seismic fragility curves of reinforced concrete columns retrofitted by shape memory alloy wire jackets and thus assess the seismic performance of the columns against earthquakes, comparing them with the reinforced concrete columns with lap-spliced and continuous reinforcement. For that purpose, this study first developed analytical models of the experimental results of the three types of columns, 1) lap-spliced reinforcement, 2) continuous reinforcement and 3) lap-spliced reinforcement and retrofitted by SMA wire jackets, using OpenSEES program, which is oriented to nonlinear dynamic analysis. Then, a suit of ten recorded ground motions was used to conduct dynamic analyses of the analytical models with scaling of peak ground acceleration from 0.1g to 1.0g with increase of 0.1g. From the static experimental tests, the column retrofitted with SMA wire jackets had larger displacement ductility by 2.3 times than the lap-spliced column, which was 6% larger compared with the ductility of the continuous reinforcement column. In the fragility analyses, the SMA wire jacketed column had a median value similar to the continuous reinforcement column for the yield damage state. However, for the complete damage state, the SMA wire jacketed column showed 1.33 times larger median value than the continuously reinforcement column.