Experimental Research On Flexural Behavior Of RC Beams Strengthened With BFRP Sheets

In recent years, since the earthquake, environmental erosion, overloading andother factors, there are different degrees of damage exists in many bridges andabroad.For defective bridge, with fiber-reinforced composites reinforced them is aneconomical and reasonable solution. In comparison with the traditional reinforcementmethod, there is little increase of section mass when sticking to strengtheningcomponent of Fiber Composites material. Also, considering its machinability andoperability, it has distinct advantage in structural strengthening.BFRP, as a new fiberreinforced composite, has special properties compared to other fibers and is higherthan carbon fiber in ductility, corrosion resistance and high temperature resistance,wide sources of the raw materials and low cost. Therefore, the experimental researchof BFRP sheet reinforced concrete members has the important economic and socialefficiency.This paper conducts experimental study for concrete beam with load damage,using a series of contrast experiments on BFRP bond layers, concrete surfacetreatments and the number and type of anchorage schemes as parameters.The main contents are as follows:(1)Loaded on two test beams to failure, getting it cracking loads and ultimate loads,loaded on the other test beams to cracking.(2)Conducting the static loading experiment on the reinforced beam with stickingto different layer (1~5layer)BFRP Sheets, analyzed the influence of the layer numberto reinforcement effect.(3)First,chiseling the concrete surface, second, sticking to the same layer BFRPSheets on the test beam bottom,then analyzed the influence of reinforcement effect.(4)Conducting the experiment on strengthening of reinforced concrete beam ofBFRP sheets by changing the number and type of end anchorage, analyzed theinfluence of end anchorage to the reinforcement effect.The conclusions of this study are mainly as follows:(1)Ultimate bearing capacity of test beam increases as the increasing BFRP bondlayers, however their relationship is not of linear type. The improvement of ultimatebearing capacity is the most remarkable when sticking to2-4layer BFRP sheets,while the fiber sheets start to appear bond failure when over4layers.(2)Chiseling processing can avoid the bond failure of sticking interface, increasing the sticking effect of BFRP sheets.(3)End anchorage is one of the key factors which effect the bearing capacity ofreinforced beam. the more reliable is the anchorage, the better is strained condition ofreinforced beam. Meanwhile the ultimate bearing capacity had improved, the spancentre deflection decreased accordingly. When there are enough numbers ofanchorage, the reinforcement effect is little by continuing to increase the number ofanchorage or changing the type of end anchorage.(4) BFRP Sheets have the inhibition effect and retardation, increasing the wholebending rigidity of test beams and decreasing mid-span deflection.(5) Concrete mid-span section with CFRP strengthening accords withapproximately plane-section assumption...