Shake Table Test on a Long-Span Cable-Stayed Bridge with Viscous Dampers Considering Wave Passage Effects

Abstract

This work focused on the damping effectiveness of additional longitudinal viscous dampers employed for seismic control of long-span cable-stayed bridges considering wave passage effects. A 1/35-scale physical model scaled from a typical long-span cable-stayed bridge was designed, constructed, and tested on four shake tables. The seismic responses of the systems with and without viscous dampers, under different types of ground motions considering uniform or traveling wave excitations, were analyzed and compared. The test results show that the damping effectiveness of the additional longitudinal viscous dampers was significantly reduced under near-field ground motion. The wave passage had a great influence on the displacement responses of the towers and the deck and the relative variation amplitudes of the cable forces near the midspan. Positive damping effectiveness was commonly achieved from the additional longitudinal viscous dampers under the far-field ground motions when considering the wave passage effect, whereas negative damping effectiveness was observed under the near-field ground motion at certain wave velocities.