Evaluating Fiber Reinforced Polymer Repair Method for Cracked Prestressed Concrete Bridge Members Subjected to Repeated Loading Phase 2

US Transportation Collection2007PDFResearch PaperLarson, Kyle H.Rasheed, Hayder A.Peterman, Robert J.Kansas State UniversityKansas. Department of Transportation. Bureau of Materials and ResearchKansas. Department of Transportation. Bureau of Materials and ResearchKansasT beamsBeamsFiber reinforced polymersCarbonPrestressed concretePrestressed concrete bridgesConcrete bridgesCarbon Fiber reinforced polymersFRPCFRPKTRAN: KSU-02-3C1331This research is intended to investigate the fatigue performance of pre-cracked prestressed concrete T-beams for a specific strand stress range and its relationship to the level of strengthening gained. Controlling the strand stress range is accomplished by iterative cycles of nonlinear analysis to determine the amount of external carbon Fiber Reinforced Polymers (FRP) reinforcement needed for that purpose. Five pre-tensioned prestressed concrete T-beams were cast at a prestressed concrete plant in Newton, Kansas. Beam 1 was tested under static loading up to failure as a control specimen. Beams 2 and 3 were strengthened with Carbon Fiber Reinforced Polymers (CFRP) to have a design stress range of 18 ksi under service load condition. Beams 4 and 5 were also strengthened to have a higher stress range of 36 ksi. Beams 2 and 4 were loaded monotonically to failure while Beams 3 and 5 were cycled over a million times before they were brought to failure. The design yielded one layer of flexural CFRP wrapped around the web sides up to 2.25\u201d from the bottom for the 18 ksi stress range design. It also resulted in two layers of longitudinal CFRP for the 36 ksi stress range design, the inner layer wrapped around the web sides up to 0.5\u201d and the outer layer went up 3\u201d on the web sides. External CFRP stirrups were used to prevent the longitudinal CFRP from premature separation. Beams 2 and 4 successfully reached their target strengthening design levels and Beams 3 and 5 performed very well in fatigue.125