Self-Centering of RC Columns with Prestressed Fe-SMA Reinforcement

Abstract

Severe seismic events often lead to detrimental residual displacements in traditional monolithic bridge columns, resulting in serviceability issues and substantial repair costs. Conversely, post-tensioned segmental columns display beneficial self-centering behavior and minimal residual drifts owing to the post-tensioning force and rocking behavior at segment joints. Despite these advantages, such structures exhibit limited energy dissipation capacities and require heavy mechanical equipment for prestressing through conventional tendons. This paper discusses the feasibility of using prestressed Fe-SMA reinforcement for self-centering of existing and new bridge columns. Firstly, the results of an experimental study on the self-centering of existing monolithic columns are presented, followed by a numerical study on the feasibility of using Fe-SMA for the self-centering of segmental columns. A 3D finite element (FE) model, developed in ABAQUS, was validated against experimental results to evaluate the seismic performance of the proposed column system. The validated model was then utilized for a focused investigation into the influence of the ratio of energy dissipating (ED) bars to Fe-SMA bars, bond condition of Fe-SMA bars, and concrete confinement of segments on the self-centering and energy dissipation behavior of prestressed segmental columns. The results highlight the ability of Fe-SMA bars to provide effective self-centering and energy dissipation for existing and new bridge columns due to their self-prestressing and high ductility.