Development of a Precast Bridge Deck Overhang System for the Rock Creek Bridge (0-6100-2)

Precast, prestressed panels are commonly used at interior beams for bridges in Texas. The use of these panels provides ease of construction, sufficient capacity, and good economy for the construction of bridges in Texas. Current practice for the overhang deck sections requires that formwork be constructed. The cost of constructing the bridge overhang is significantly higher than that of the interior sections where precast panels are used. The development of a precast overhang system has the potential to improve economy and safety in bridge construction. This research investigated the overhang and shear capacity of a precast overhang system for potential use in the Rock Creek Bridge in Parker County, Texas. Grout material characteristics for the haunch and constructability issues were also addressed. Results indicate that the capacity of the precast overhang system is sufficient to carry factored AASHTO loads with no or very limited cracking. Results from the shear study indicate that the shear capacity of threaded rods and threaded rods with couplers is lower than the conventional R-bar system. However, modifications of the initial design and layout for the end panels should provide sufficient capacity. A commercial grout has been identified for use in the haunch zone. A recommendation for the haunch form system for use on the bridge is also provided.