Investigation of panel-to-panel connections and block-outs for full-depth precast concrete bridge decks.

PDFTech ReportFHWA/VCTIR 15-R582670Precast concreteBridge decksStructural connectionPanelsPosttensioningSurface treatingTensile strengthCrackingGroutLaboratory testsLoad testsVirginiaVirginia Center for Transportation Innovation and ResearchSwenty, Matthew K.Cousins, Thomas E.RobertsWollmann, Carin L.Virginia Center for Transportation Innovation and ResearchVirginia. Dept. of TransportationUnited States. Federal Highway AdministrationUS Transportation CollectionExperimental tests were performed at Virginia Tech to investigate transverse panel-to-panel connections and horizontal shearconnector block-outs for full-depth precast concrete bridge deck panels. The connections were designed for a deck replacementproject for a rural three-span continuous steel beam bridge in Virginia. Two reinforced and four post-tensioned connections weredesigned and tested in cyclical loading. Each connection was tested on a full-scale, two-beam setup in negative bending with asimulated HS-20 vehicle. The block-outs for the horizontal shear connections were also scrutinized during construction and testing.Several surface treatments were investigated to determine the best strategy to limit cracking and leakage at the grout-concreteinterface. The strain profile, cracking patterns, and ponding results are presented for all specimens.The reinforced connections and two post-tensioned connections with 167 psi initial stress experienced cracking and leakedwater by the end of the cyclic loading regime. In two connections post-tensioned with an initial compressive stress of 340 psi, thetensile stress in the deck under full live load remained below approximately 3\ue2\u2c6\u161(f'c). These transverse connections did not leak water,did not have full-depth cracking, and maintained a nearly linear strain distribution throughout the design life. Full-depth deck panelsmay be effectively used on continuous bridges if post-tensioning force is applied to the transverse connections to keep the totaltensile stress (remaining prestress minus live load stress) below 3\ue2\u2c6\u161(f'c) .The block-outs with a sand-blasted surface or an epoxy primer combined with a grout that met the requirements recommendedby Scholz et al. (2007) had only slight water leakage, and had smaller cracks at the grout-concrete interface than the control samples.These surface treatments are recommended for best long-term performance