Experimental Investigation of the Dynamic Response of Two Bridges Before and After Retrofitting with Elastomeric Bearings

Keywords: Quick release tests. Highway bridges. Full scale tests. Transverse loads. System identification. Elastomeric bearings. Snap back tests. Lead rubber bearings. Base isolation.

Abstract: Two bridges were subjected to transverse quick-release testing, which simulated transverse seismic loading. This report presents the results of a study of these two bridges before and after replacement of the original steel bearings: one with ordinary neoprene elastomeric bearings and the other with laminated rubber seismic isolation bearings. Test results indicate that steel bearings have considerable intrinsic strength and are able to withstand strong ground motions, primarily due to the frictional resistance of the bearings. The use of seismic isolation bearings, for these specific bridges, resulted in marginal performance improvement.