Ground Motion Frequency Insensitivity of Bearing-Supported Pedestrian Bridge with Viscous Dampers

This work studies the dynamic responses of bearing-supported pedestrian bridges with Y-shaped piers and various deck widths under harmonic ground motions. To fulfill the immediate occupancy performance objective, the dynamic responses of bridges with linear or nonlinear viscous dampers are evaluated by performing nonlinear time-history analyses. The results show that the maximum transverse displacements of girder and pier top in original bridges are closely dependent on the characteristic period of ground motion. The installation of linear viscous dampers between steel girder and Y-shaped piers can effectively improve the seismic performance of bridges and hence reduce the corresponding shear demand of bearings. Further parametric studies show that, with optimal damping coefficient and velocity exponent, the seismic performances of bridges with viscous dampers can be insensitive to the characteristic period of ground motion.