Development of a Structurally Optimized Ultra-High Performance Decked Bridge Girder
The characteristics of ultra-high performance concrete (UHPC) are particularly well suited to the structural and environmental challenges that are placed on every highway bridge. Specifically, the compressive strength allows for high levels of prestressing, and the tensile strengths allow for reduction or elimination of mild (i.e., shear, shrinkage, temperature) steel reinforcement. The durability allows for long-lasting concrete structures, which is especially important for bridge decks. The FHWA's research into optimal uses of UHPC in bridges is focusing on methods of economically and efficiently using this concrete to produce long-lasting, very durable bridges that can be fabricated and constructed quickly. A first-generation superstructure/deck combination has been developed and tested. In general terms, the structural member is a prestressed girder with a bulbed double-tee cross section that was designed to meet the structural and environmental loading demands of a standard highway bridge while also significantly reducing erection and overall construction times. The knowledge gained from the fabrication and testing of the first-generation girder has led to the design of a second-generation solution. Physical testing of the structural behavior of this next-generation solution is pending.