Carbon Fiber Reinforced Polymer Grids for Shear and End Zone Reinforcement in Bridge Beams

dc.contributorVirginia Transportation Research Councilen
dc.contributorVirginia Tech Transportation Instituteen
dc.contributor.authorWard, Johnen
dc.contributor.authorMagee, Mitchen
dc.contributor.authorRoberts-Wollmann, Carin L.en
dc.contributor.authorCousins, Thomas E.en
dc.contributor.departmentCivil and Environmental Engineeringen
dc.date.accessioned2019-10-06T00:59:28Zen
dc.date.available2019-10-06T00:59:28Zen
dc.date.issued2018-01en
dc.description.abstractCorrosion of reinforcing steel reduces life spans of bridges throughout the United States; therefore, using non-corroding carbon fiber reinforced polymer (CFRP) reinforcement is seen as a way to increase service life. The use of CFRP as the flexural reinforcement in bridge girders has been extensively studied. However, CFRP transverse reinforcement has not been investigated as rigorously, and many of those studies have focused on carbon fiber composite cable (CFCC) stirrups. The use of C-Grid or NEFMAC grid as options for transverse reinforcing has not been previously investigated. This testing program first determined the mechanical properties of C-Grid and NEFMAC grid and their respective development lengths. Five 18-ft long, 19-in deep beams were fabricated to test the C-Grid and NEFMAC, as well as conventional steel and CFCC stirrups. The beams were loaded with a single point load closer to one end of the beam to create a larger shear load for a given moment. Overall beam displacement was measured, and beams were fitted with rosettes and instrumentation to capture initiation of shear cracking. Test results were compared to theoretical shear capacities calculated using four different methods. The design method which provided the best prediction of shear strength was the AASHTO modified compression field theory, using equations for β and θ. The manufacturer’s guaranteed tensile strength should be used for design, as long as that strength is the average strength, as determined by at least five tests, reduced by three standard deviations. Shear cracks were controlled to a similar width as in beams with steel stirrups when at least two layers of grid were in place. An additional study was undertaken to determine if CFRP grids, either alone or in combination with traditional steel stirrups, could be used to control cracking in the end zones of pretensioned I-beams. Unfortunately, it was determined that, due to its low modulus, the amount of CFRP grid required to control cracking in the end zones was not economically feasible. Nevertheless, this study concluded that C-Grid and NEFMAC grid are both viable shear reinforcement options outside of the end regions. This report presents the initial recommendations for design.en
dc.description.notesFinal Contracten
dc.description.sponsorshipVirginia Department of Transportationen
dc.description.sponsorshipFederal Highway Administrationen
dc.description.sponsorshipContract or Grant No. 107830en
dc.format.extent73 pagesen
dc.format.mimetypeapplication/pdfen
dc.identifier18_R17_Carbon_Fiber_Reinforced_Polymer_Grids_for_Shear.pdfen
dc.identifier.citationWard, J. E., Magee, M., Roberts-Wollmann, C. L., & Cousins, T. E. (2018). Carbon Fiber Reinforced Polymer Grids for Shear and End Zone Reinforcement in Bridge Beams (No. FHWA/VTRC 18-R17; VTRC 18-R17). Virginia Transportation Research Council.en
dc.identifier.govdocFHWA/VTRC 18-R17en
dc.identifier.urihttp://hdl.handle.net/10919/94371en
dc.identifier.urlhttp://www.virginiadot.org/vtrc/main/online_reports/pdf/18-r17.pdfen
dc.language.isoenen
dc.publisherVirginia Transportation Research Councilen
dc.rightsCreative Commons CC0 1.0 Universal Public Domain Dedicationen
dc.rights.urihttp://creativecommons.org/publicdomain/zero/1.0/en
dc.subjectCFRPen
dc.subjectShearen
dc.subjectPrestressed beamsen
dc.subjectEnd zone reinforcementen
dc.titleCarbon Fiber Reinforced Polymer Grids for Shear and End Zone Reinforcement in Bridge Beamsen
dc.typeTechnical reporten
dc.type.dcmitypeTexten

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