Long-Term Performance of Elastomeric Bridge Bearings

Abstract

The effects of long-term service on bridge bearings composed of steel plates laminated between elastomeric layers, as placed on twin structures carrying the Route 400 Aurora Expressway over Route 16 and Conrail tracks in New York’s Erie County, are summarized. Expansion-joint bearings replaced as part of a recent rehabilitation project were recovered for evaluation and were found to be in generally good condition. New York’s current accelerated aging test procedures were evaluated by comparing mean ratings for these bearings (after simulated aging in their original 1969 acceptance testing) with results of similar tests conducted from 1992 to 1995 (after their removal from these bridges). An analysis of mean ratings from other 1969 acceptance tests is included, with similar tests repeated to determine the effects of the years in service. As a final step, the recovered bearings underwent further testing for conformance with other current specifications. The bearings, as originally installed on these structures, had problematic design, construction, and material properties, but nevertheless performed very well in service and were insensitive to these deficiencies.