Experimental study of bridge seismic sliding isolation systems

An experimental study of a seismically isolated and a comparable nonisolated bridge is presented. The bridge model featured flexible and stiff piers and, in certain cases, different isolation system properties at the two piers. Designs for application in areas of low to moderate seismic activity and designs for application in areas of strong seismic activity and all types of soil conditions were tested. All systems consisted of sliding bearings and rubber restoring force devices. Moreover, fluid viscous dampers were utilized in a system specifically designed to withstand the strong and long period level 2 Japanese design motions while transferring a force to the substructure not more than one-third of the deck weight and allowing bearing displacements less than 200 mm in prototype scale. The analytical modelling of the systems and a design example are presented.