Test Study Of Common Stickup And Non-stick Four Anchorages CFRP Sheet To Reinforce RC Beam

As we know,the CFRP is a sort of new material in civil engineering,and the CFRP depend on many excellences of ethereal weight,super strength,erodeing resistance and anti-fatigue applied abroad in reinforce engineering. However,both academic study and application prove of the CFRP to be sticked on the surface of the structure is a simple mode directly,it,s the strain-lag of CFRP.At the same time,debonding failure will occur between the CFRP sheet and the structure,and CFRP,s super strength do not play enough.So the reinforce effect of member is limited.For the CFRP sheet applying prestress to reinforce constructure,may delay expansion of crack,improve capability of member,advance reinfore effect greatly.This paper based on the production of last,make the testing contrast of non-stick external four anchorages CFRP sheet reinforcement and common sticking reinforcement.C ontrast the reinforceing and loading experimental study of the two concrete T beams,obtained several conclutions as follows:The reinforce beam by the common stickup CFRP sheet that deformation relation accorded with plane assumption of CFRP and concrete.But the CFRP sheet had hysteresis effect of strain during the loading time.Though used two layers CFRP U-shaped hoop of the common stickup,the debonding failure occured more early.The most strain of longitudinal CFRP is 4912μεat the debonding monment.It is more low 10000μεof the allowed value of the standard,so the reinforcing effect is limited of the common stickup of CFRP.It needs more credible anchoring measure. Moreover,common stickup don't have prestress,so the method can't eliminated the deformation of the member.And it is a passive reinforcing method, the CFRP bear the load started,only during the time the member be loaded angin.So the improving capability of member is limited.Non-stick external many anchorages prestressed CFRP sheet reinforcing concrete beam is a bran-new external prestressed technic,that do many anchorages for the non-stick CFRP sheet by the WSGG(wave-shape-gear-grip).This method not only gains upper prestress,but also increses coordination of the CFRP sheet and the member.Meanwhile,the technic can exert ultimate strength of CFRP sheet adequately,can improve and advance capability of member markedly. The test of paper adopts four points of external anchored and prestressed CFRP sheet reinforcement.First,should fasten the two WSGG in two ends of the beam,then fastening the two WSGG in mid-span of the beam.In this way,the WSGG in mid-span will compell CFRP sheet making geometrical protraction,then prestress be bringed.By testing the effective prestress is 526MPa of the experiment.Loading test for the prestressed reinforce member,the CFRP sheet be tensile failure and before this moment,the tension strain is 10703με, exceeding the allowable value of the criterion.The test of two members can be drawn: though the longitudinal CFRP sheet dosage of the two beams are same in the reinforcing test,prestressed reinforce makes effect markedly.It,s yield load higher 9% than common stickup and ultimate load higher 33% than common stickup.Contrast,by WSGG anchoring is a mechanical mode,can afford credible anchored force,and insureing the high strength exerted of CFRP.However the U-shape hoop is sniped more easily,do not provide well anchored force,the longitudinal CFRP is easy debonding failure too.Meanwhile,external four anchorages prestress CFRP sheet reinforcement is an active reinforcing method,the prestress action delay the appearance of the cracks,decrease tempo of the cracks,improve the member capability obvious.Finally,base on the experiment,this paper reference the calculation theory of external prestress concrete construction,and tries more measures calculateing flexual capacity of the prestressed CFRP external anchored reinforcement beam.