Elastomeric Bearings for Steel Trapezoidal Box Girder Bridges

Abstract

Traditionally, bridge bearings supporting steel trapezoidal box girders (tub girders) consist of fabricator-designed mechanical devices, such as pot or disc bearings, that may be guided or unguided and are expensive to fabricate and place. Performance of these bearings has been mixed: some are maintenance-free and others require significant maintenance, repair, or replacement. In Texas, bridge bearings supporting concrete and steel superstructure types are typically steel-laminated elastomeric bearings that are tapered or have a constant thickness. Recently, the Texas Department of Transportation has used these structurally engineered elastomeric bearings for tub girders in place of mechanically engineered pot or disc bearings. This paper describes the rationale for the application of elastomeric bearings to tub girders and outlines design recommendations that are based on the use of elastomeric bearings for the tub girder direct connectors of the interchange of US-290 and I-35 built in Austin in the late 1990s and placed in service in 2001.