Evaluation of FRP repair method for cracked bridge members.

987792PDFResearch PaperRDT04-024RI02-008Bearing capacityCarbon fibersCost effectivenessDebondingFailure analysisFiber reinforced plasticsGirdersLaboratory testsPrestressed concreteScale modelsShear strengthStrengthening (Maintenance)United StatesMissouriKansasUniversity of Missouri--Rolla. Center for Infrastructure Engineering StudiesPhillis, Sarah E.Parretti, RenatoNanni, AntonioMissouri University of Science and Technology. Center for Infrastructure Engineering StudiesMissouri. Dept. of TransportationUS Transportation CollectionThis research program was undertaken to investigate the effects Carbon Fiber Reinforced Polymers (CFRP) have on the shear strength on under-reinforced, lab-scale prestressed concrete (PC) bridge girders. Many bridges in the states of Missouri and Kansas are structurally deficient and require either repair or replacement to ensure functionality. CFRP can offer a cost and time effective solution to these problems.For this purpose six (6) lab-scale PC bridge tee-girders were constructed for testing. Two girders were shear sufficient according to today\ue2\u20ac\u2122s standards. The remaining four (4) girders were shear deficient and required upgrade in order to achieve the same level of shear capacity as the "shear-sufficient girders". The shear strengthening of these girders was performed using CFRP laminates applied by manual lay-up and Near Surface Mounted (NSM) CFRP bars. All beams, with exception of the control one (i.e., a shear-deficient beam), were alsostrengthened in flexure using CFRP laminates.The observed failure mode of all strengthened beams was CFRP debonding. The flexural FRP laminate on each girder debonded before other failure modes could be experienced. Despite this, the three shearstrengthened girders did achieve a significant increase in load capacity over the control girder. Compared with the analytical prediction according to existing design guidelines, the shear-strengthened girders showed load carrying capacities equal to 1.01, 0.97 and 0.87 of the predicted value. Had flexural FRP laminate debonding not been the cause of failure, a closer match with prediction would have been possible