Parametric study of RC bridge columns actively confined with shape memory alloy spirals under lateral cyclic loading

This paper focuses on studying numerically the cyclic behavior of RC bridge columns that are seismically retrofitted using thermally prestressed shape memory alloy (SMA) spirals, an innovative active confinement technique that has been validated experimentally. A fiber-based model of the actively confined column is first developed and is validated using experimental results. Comparing the numerical and experimental behaviors shows that the developed model is satisfactorily capable of describing the hysteretic behavior and damage states of the experimental column. The developed model is then used in a parametric study to investigate the effects of the interactions between active confinement pressure and other important design and geometrical parameters of the columns, such as axial load, volumetric ratio of longitudinal reinforcement, and slenderness ratio. The results of this parametric study provide practical information that is useful in setting a design guideline for retrofitted bridge columns using the newly developed SMA active confinement technique.