Seismic assessment of relatively tall bridge piers retrofitted with concrete jacketing

Seismic assessment of relatively tall bridge piers retrofitted with reinforced concrete jacketing is conducted in this paper on the basis of the current Japanese seismic design method. To check the rationality of retrofitting schemes, a-seismic performance of retrofitted piers is studied comparatively with varied major retrofitting parameters, such as the thickness of the concrete layer, the amount of longitudinal reinforcement and hoop in the jacket. From the comparison between nonlinear static and dynamic analysis, it is found that the current seismic design approach based on the equal energy assumption is too conservative for relatively tall piers. To improve the ductility of relatively tall piers, it will not be helpful to only increase the amount of longitudinal reinforcement and thickness of the retrofitting concrete layer.