Calibration of finite element model of bridge with pier retrofitted using Fe-SMA strips

The present study focusses on the development, calibration and validation of the 3D finite element model of an existing highway bridge in Tripura, India with rehabilitated pier, further retrofitted using three different schemes of Fe-based shape memory alloy (SMA) strips. For this purpose, four severely damaged bridge pier models were first rehabilitated by RC jacketing. Three schemes of Fe-SMA strips namely hoop (H), end-anchored (EA) and a combination of previous two approaches (EAH) were adopted. To compare the seismic performance of the various Fe-SMA retrofitted test specimens with respect to the control specimen, hybrid simulation of the bridge was carried out with the scaled bridge pier models as experimental elements. Comparison of experimental results with those obtained from the initial finite-element (FE) based numerical model highlighted the need for model calibration to improve the numerical response. The initial numerical model of the control specimen was first calibrated using the experimental force–displacement response obtained from hybrid simulation. The calibrated model approximately accounted for possible bond-slip effects and slip at the jacket-pier interface. The updated numerical model of the control specimen was then utilized for simulating different piers with various Fe-SMA retrofitting schemes. The material parameters of Fe-SMA strips used as EA were determined using cyclic tests on Fe-SMA coupon specimen after thermal activation. Stress–strain parameters of Fe-SMA confined plain and reinforced concrete in the numerical model were obtained from corresponding empirical models based on experimental and FE analyses based data, respectively. The results based on updated FE model of the retrofitted bridge were finally validated using the data from hybrid simulation.