Experimental Study And Finite Element Analysis Of Terminal Embedded Prestressed CFRP Reinforced Concrete Beams

During long-term operation,bridge structures are affected by the natural environment and human activities,which can cause different degrees of damage and disease,seriously threatening the reliability of bridge structures.Therefore,there is an urgent need for their reconstruction or strengthening.Bridge strengthening can restore the bridge load-bearing performance in a short period of time,and has gradually become a popular industry in the current market and a focus of research for many scholars.Fiber Reinforced Plastic(CFRP)is widely used in the field of bridge reinforcement due to its high strength,light weight,corrosion resistance,fatigue resistance,etc.Externally Bonded(EB)and Near Surface Mounted(NSM)CFRP reinforcement techniques have made a lot of progress in recent years.However,the problems of interface peeling and anchor failure in EB reinforcement and the problems of end peeling and grooving in NSM reinforcement have led to unsatisfactory structural reinforcement results.In view of this,this paper proposes a new reinforcement method-End Embedded CFRP reinforcement.Combining experimental research and finite element analysis,the interfacial bonding performance and flexural performance of end-embedded CFRP reinforced concrete structures are discussed,mainly including the following aspects.(1)The feasibility of the end-embedded CFRP reinforcement method was verified.Six prisms were designed for single shear pullout tests and four reinforced beams for flexural performance tests,and the effects of different bond length combinations on the interfacial bonding and reinforcement performance were investigated.The test results showed that the endembedded CFRP reinforcement method can effectively improve the bonding and load-bearing capacity of the reinforced members with less slotting,and delay and inhibit the occurrence of peeling damage at the beam ends.(2)A nonlinear finite element model of the end-embedded CFRP reinforced concrete prismatic body and reinforced beam was established.Based on the finite element analysis software ABAQUS,the bonding between concrete and CFRP was realized by using Spring2 nonlinear spring element,and the parametric modeling was realized by using Python language.By comparing with the test results,it can be obtained that the finite element model can better simulate the whole process of stressing the end-embedded reinforcement members,and effectively predict the load bearing capacity and damage mode of the structure.(3)The mechanism of different factors on the performance of end-embedded CFRP reinforcement was investigated.Using the verified three-dimensional nonlinear finite element models of end-embedded CFRP-reinforced concrete prisms and end-embedded CFRPreinforced concrete beams,the whole process of force deformation of the specimens was analyzed,and the effects of concrete strength and slot size on the interfacial bonding performance as well as the effects of bond length and prestressing level on flexural performance were investigated,and the optimum bond length of the end-embedded section was obtained.