Sliding Isolation System for Bridges: Experimental Study

Abstract

A seismic isolation system for bridges has been tested on a shake table. The system consisted of Teflon disc bridge bearings and displacement control devices. These devices provided restoring force for re-centering the bridge during earthquake excitation, additional energy dissipation capacity and rigidity for service loading. The tests were carried out with a 51-kip model which was subjected to strong recorded earthquake motions with a wide range of frequency content and to simulated motions compatible with CalTrans 0.6g design spectra. In all tests the isolated deck responded with peak acceleration less than the peak table acceleration and peak bearing displacement less than the peak table displacement. Results from an analytical model show very good agreement with experimental results.