Guidelines for the Use, Design, and Construction of Bridge Approach Slabs

About the report:

Differential settlement at the roadway/bridge interface typically results in an abrupt grade change, causing driver discomfort, impairing driver safety, and exerting potentially excessive impact traffic loading on the abutment. Bridge approach slabs are used to keep the effects of this differential settlement within tolerable limits. In many cases, however, the final magnitude of settlement exceeds the working range of an approach slab, necessitating costly roadway and slab repairs. Many state DOTs regard the settlement of bridge approach slabs as a substantial maintenance problem. Guidelines affecting the use, design methodology, material specifications, and construction techniques vary greatly from state to state. The purpose of this study was to provide a literature review on the subject and to conduct a survey on the state of the practice. Thirty-nine state DOTs responded to the survey. Summary findings were compiled, and a comparison with current VDOT practices was made. Recommendations for a new set of guidelines, aimed at mitigating bridge approach settlement, were formulated.

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