Shaking Table Test of a High-Speed Railway Bridge with Combined Seismic Isolation Systems in a Nine-Degree Seismic Region

In order to investigate the feasibility and adaptability of a type of combined seismic isolation system in high-speed railway simply supported bridges in nine-degree seismic regions, a series of shaking table tests with a 1/10-scaled model are carried out in this paper. Firstly, a type of combined seismic isolation system is presented on the basis of seismic prevention principles of high-speed railway bridges in nine-degree seismic regions. Then, a 1/10-scaled full-bridge model with combined seismic isolation systems is designed and constructed by using a three-span high-speed railway simple supported box girder bridge as a prototype. Finally, fifteen near-fault seismic waves are input to obtain and analyze the damage state and seismic responses of the key components on the bridge model under different seismic waves. The test results show that the bridge model is in the elastic state under frequent seismic waves. The transverse and vertical accelerations of the main girders are within 0.375 g and 0.625 g. Under design seismic waves, the relative displacements of the piers and main girders and the displacement ductility ratios of the piers are less than 20 mm and 1.5. Under rare seismic waves, the main girders do not drop, and the displacement ductility ratios of the piers are less than 3.0. Therefore, the combined seismic isolation system meets the seismic prevention principles. It is expected to be an effective seismic isolation measure for high-speed railway simply supported bridges in nine-degree seismic regions.