Shake Table Tests of a Bridge Model with Different Seismic Isolation Devices

The importance of improving the surveillance and maintenance of road infrastructures has become an issue in most countries in the world. Actually, most bridges were built several years ago, when traffic loads were different from the current ones and seismic actions were often neglected. Today, one of the main goals is the identification of suitable seismic retrofit interventions for existing bridges. A scaled span of a real viaduct was tested on a shake table in order to study the efficiency of different isolation systems, composed of HDRBs and SDs or CSSs, in comparison with the original rubber support systems. Different sensors were used to measure accelerations and displacements of the structure under increasing seismic input and to point out the different experimental behavior of the seismically isolated configurations. HDRBs + SDs allowed to obtain significant reduction in accelerations and no residual displacements, while the performances of CSSs were improved by means of lubrication.