STUDY ON SEISMIC RESPONSE CHARACTERISTICS OF ISOLATED CONTINUOUS BRIDGES UNDER LONG-PERIOD GROUND MOTION

The seismic response of Five-span isolated continuous bridges under far field and near field long-period ground motions are discussed. Lead rubber bearings (LRB) or friction pendulum bearings (FPB) are used in the bridges and the ground motions have significant pulse impacts. Comparing with an aseismic structure, the isolation effects of two isolated bridges are declined, and the seismic performance of an FPB structure is better than that of an LRB structure. Furthermore, the far field long-period ground motion has an adverse effect on an isolated continuous bridge with LRB in view of the larger displacement and internal force comparing with FPB bridges.