Study On Interfacial Debonding Loadcarrying Capacity Between Prestressed CFRP Plate And Concrete

Carbon fiber composite materials are widely used in the field of bridge reinforcement due to their high strength and good durability.However,when ordinary carbon fiber sheets are used to reinforce the structure,its high-strength characteristics cannot be fully utilized.The use of pre-stressed carbon fiber materials can solve this problem well.When using prestressed carbon fiber sheets to reinforce components,the peeling failure of the prestressed carbon fiber sheet and concrete interface is an important failure form.Therefore,the peeling mechanism and peeling bearing capacity of the prestressed carbon fiber sheet and concrete interface become an important research Subject.This paper is based on the prestressed carbon fiber board and concrete in-plane shear test and the prestressed carbon fiber board reinforced rectangular beam test.The research content and results are as follows:(1)Based on the in-plane shear test of carbon fiber board and concrete,the influence of prestress size,thickness of adhesive layer and width of carbon fiber board on the interfacial bonding performance was discussed.By analyzing the strain distribution of carbon fiber board under different static loads,the interface stress transfer mechanism.Based on the bilinear model,the interface bond-slip curve and three important interface mechanical behavior indicators are studied.After a large number of numerical regression analysis and trial calculations,a suggested bond-slip constitutive relationship model is proposed.(2)The proposed bond-slip constitutive relationship is set into the interface element,and the ANSYS model of the prestressed carbon fiber board and the concrete in-plane shear specimen is established.The calculation results of the numerical model are compared with the experimental results.The two are in good agreement,which shows that this thesis The proposed interface constitutive relationship is more reasonable and can be used to study the interface between prestressed carbon fiber board and concrete.Based on the interface bond-slip constitutive relationship and the results of finite element analysis proposed in this thesis,and the influence of various factors such as the size of the prestress,the thickness of the adhesive layer,and the width of the carbon fiber board on the interface peeling bearing capacity,it is proposed that it can be applied to the prestress The calculation model of the interface peeling bearing capacity of the in-plane shear peeling failure of the carbon fiber board.(3)Through the bending test of reinforced concrete beam with prestressed carbon fiber board,the influence of different prestress on the strengthened beam was studied.It is found that the use of pre-stressed carbon fiber board to strengthen the concrete beam can effectively increase its cracking load and peeling load,inhibit the occurrence and development of cracks,and reduce the deflection and deformation of the specimen.At the same time,the use of prestressed carbon fiber board to strengthen the concrete beam can give full play to the high strength characteristics of carbon fiber board.(4)The peeling failure process and causes of the prestressed carbon fiber board reinforced beam under concentrated load and the interface stress are studied,and the mechanical mechanism and stress state of the peeling failure caused by the central bending main crack are analyzed.On the basis of the research in Chapter 3,the calculation method of the peeling bearing capacity of reinforced beams when the middle crack peeling failure occurs is given.After comparing the calculation results of the formula with the test results,it is found that the average error is within 10%.Using the interface constitutive relationship proposed in this thesis,a finite element model of the reinforced beam considering the bond-slip between the carbon fiber board and the concrete is established.The finite element calculation results are in good agreement with the experimental results,indicating that the established in this paper is limited in considering the interface bond-slip The meta-model can better simulate the test process of prestressed carbon fiber board strengthened beams.