Experimental Research On The Application Technique Of Prestressed CFRP Sheets In Strengthening RC Bridge Girders

A large number of existing bridges need to be strengthened andreinforced. In recent years, the method of using Carbon Fiber ReinforcedPolymer sheets for repairing and strengthening the reinforced concretestructures has gained an extensive application for strengthening of concretestructures. To make effectively use of high strength of CFRP sheets, theprestressed technical is used for the flexural strengthening of RC beams.The application technique of prestressed CFRP sheets is developed andresearched in this thesis. Seven RC T-beams strengthened with prestressedCFRP sheets were constructed and tested. The device to apply prestress inCFRP sheets and the construction method is developed. Based on theexperimental researches, following conclusions are obtained:⑴ The ultimate strength of the beam reinforced with prestressed CFRPsheets can be increased and the high strength of CFRP sheets can be fullyused.⑵ The prestressed CFRP sheets can delay the formation of cracks,increasing the stiffness, decreasing the strain in reinforcing bar, andincreasing yield load and ultimate load capacity. So it can be meet with thedemands of service states.⑶ the debonding between CFRP sheets and concrete can be preventedby "U" type anchorage during the cut-off of prestressed CFRP sheet.Based on the experimental results, loss of prestress in CFRP sheets,failure type and flexural strength were analyzed. And the design suggestionand calculation methods are put forward in the thesis finally.