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The development and implementation of full-depth, precast overhang panel systems has the potential to improve constructibility, productivity, and make bridges more economical. Recently, various shear connector systems have been proposed to provide shear-transfer resistance between girders and the precast overhang panels. There is, however, limited information and guidance on the design for shear-transfer capacities for full-depth, precast overhang panel systems. This research performed experiments and assessed the results to estimate the shear-transfer capacities of four types of shear connectors systems. The confinement system of the shear pocket was varied with the hopes of enhancing the shear-transfer capacity. Results indicate that five stages of shear-transfer and failure mechanisms occur during testing. These stages include initial adhesion loss, shear key action, shear key action failure, dowel action of the shear connectors at a sustained load, and final failure of the system. Results from this research indicate that steel reinforcing hoops placed in the shear pocket and shear reinforcing hoops placed in the overhang panel around the opening of the shear pocket provide limited or no improvement in capacity of the shear connector/coupler system. When comparing energy absorption capacities, however, the shear connector systems evaluated can provide improved performance when compared with the conventional R-bar system. A new equation is proposed based on this research.
Keywords: full depth; precast overhang panel system; shear friction; shear-transfer mechanism.
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INTRODUCTION
Early applications of structural composite systems have been mostly limited to the steel stringers or girders and precast concrete deck systems (Issa et al. 1995). More recently, precast girders and precast deck panels have been more widely investigated and used for the rapid construc- tion of bridges. Figure 1 shows a new design for a full-depth overhang system developed for the construction of the Rock Creek Bridge in Parker County, TX. The advantage of a full- depth overhang is that it minimizes construction activities under the bridge that are typically less safe and more costly, and it can eliminate and significantly reduce the need for formwork on the overhang. During the design of the over- hang panels and overall bridge, it was identified that there was minimal information and guidance on the shear connec- tors and connector capacity. Thus, research was performed to provide guidance...