Self-Centering and Energy Dissipation Behavior of Fe-SMA Prestressed Segmental Column Systems

Abstract

Major seismic events can result in large residual displacements in conventional monolithic bridge columns, causing serviceability problems and expensive repair costs. In contrast, post-tensioned segmental columns exhibit excellent self-centering behavior and low residual drifts. However, such structures have limited energy dissipation capacity and require heavy mechanical equipment for prestressing using conventional tendons. This study proposes a novel self-centering segmental column system where prestressing is achieved by exploiting the unique shape memory effect (SME) characteristic of iron-based shape memory alloy (Fe-SMA) bars. A 3D finite element (FE) model was developed in ABAQUS and validated against the experimental results to evaluate the seismic performance of the proposed system. The model incorporated the experimentally validated material behavior of Fe-SMA bars under tension-compression reversals using the combined isotropic/kinematic hardening model. The validated model was used to conduct a parametric study to investigate the effect of five parameters, including total axial load ratio at constant post-tensioning force, relative contributions of post-tensioning force and gravity force to total axial load ratio, ratio of energy dissipating (ED) bars to Fe-SMA bars, confinement of concrete segments, and configuration of Fe-SMA bars, on the self-centering and energy dissipation behavior of the Fe-SMA prestressed segmental columns. The results showed that Fe-SMA bars are capable of providing both adequate self-centering and energy dissipation capacity to segmental columns owing to their self-prestressing and high ductility. The paper is concluded by evaluating the applicability of the existing self-centering criteria to Fe-SMA prestressed columns