Experimental Research On Mechanical Property Of Reinforced Concrete Beams Strenghtened

Currently,the overloading of highway bridges is very common,which made the reinforcedconcrete bridge crack and injury,then proceeded to affect the bearing capacity of thebridges,aswell as the urgent need to bridge strengthening.People have done many studies on strengtheningof structures,some studies also need to do continually,there are structure strengthened not workingwell even failure.This paper chose structure strengthening with externally bonded CFRP andsteel plate which are commonly used mathoses in structure strengthening project.the problem ofreinforced section internal force distribution will be researched,by laboratory testing combinedwith theoretical analysis,and further understand the working mechanism of compound crosssection,providing a reference for reinforcement design.There are total 32 precast concrete beams for testing,these test beams are overloaded 20times with 0.85,1.0,1.2times of ultimate loading capacity desigen values before strengthening.theinternal force distribution will be researched, and test result proved that the compound crosssection work following section assumption,we can analyse the internal force by elastic theory.thedistribution of inner force for strengthening material will fall down with overloading levelincreasing,and the ratio of reinforcement,quantity of strengthening matetials,method ofstrengthening are all the influence factors for inner force distribution.The performance of bending rsistance before strengthening and after are also reseached,andthe results indict that reinfore concrete beams can rsist overloading which is relative high;sectionstrain distribution,deflection,ultimate loads,crack distribution and the distuction afterstrengthening with CFRP are all influened by the degree of overloading,quantity of CFRP,ratioof reinforcement and the mode of strengthening.the flexual capacity will not reduce with highlevel overloading.beams damaged Seriously then strengthened with CFRP, are liable to peel offmore,we should emphasize on the anchorage more.