A comparative study on aseismic performances of base isolation systems for multi-span continuous bridge

Various base isolation systems (BISs) such as the pure-friction, laminated rubber bearing, lead rubber bearing, resilient-friction base isolator and electricité de France systems, which have been used or are considered to have considerable potential for wide applications, are systematically compared and discussed for aseismic performances of multi-span continuous bridge in this study. Sensitivity analyses of the bridge employed the devices are carried out to choose the appropriate design parameters of various devices. It is possible to recommend the appropriate ranges of the natural period and the friction coefficient of the various BISs. Therefore, the recommended ranges of the design parameters are presented in this study. The design parameters such as the first natural period of the isolated bridge and the friction coefficient of the bearing are determined by the reciprocal relationship between the peak deck displacement and the peak overturning moment of the bridge in the recommended ranges, and then the relative effectiveness of the bearings is described for the selected design parameters under the different ground motions. The peak responses of the bridge with the friction-type bearing are less sensitive to substantial variations in the frequency range and the intensity of the ground excitation than those with the rubber-type bearing due to characteristics of the friction element within the range of this study.