Bridge Deck Overhang Construction

An experimental investigation was conducted at the Ferguson Structural Engineering Laboratory at the University of Texas at Austin to investigate the current bridge deck overhang construction practice as is relates to the use of the new Texas Igirders (Tx girders). Due to the wide and thin top flange of the Tx-girders, the Texas Department of Transportation funded a testing program to have the performance and behavior of the current systems for overhang forming investigated. The primary objectives of this investigation were to examine the performance of commercially available overhang forming products and provide recommendations for their use with Tx Girders. In order to achieve the goals set forth, four Tx-girders were fabricated in the laboratory and a total of thirteen load tests were performed on the overhang forming products and Tx girders. Recommendations for the use of overhang forming systems for the Tx girders were based on the results of the experiments and synthesis of those results.

At the completion of the testing of the currently available systems for overhang forming, a new concept was developed to use a precast overhang as an alternate solution to create the finished bridge deck overhang construction. The solution involved precasting a portion of the overhang after the fabrication of pretensioned girders and using the precast portion of the overhang as stay-in-place formwork.