Performance Analysis Of Carbon Fiber Reinforced Concrete Bridge Beam Based On Ukrainian Code (DBN B.2.3-22:2009)

Carbon Fiber Reinforced Polymer(CFRP)are now widely used to repair or strengthen bridge structures.CFRP advantages are: high strength,light weight,good corrosion resistance and ease of on-site construction,making it a good alternative to traditional reinforced bridge materials.During the reinforcement and repair of the reinforced concrete structures,CFRP is adhered to the surface of the reinforcement zone as an additional external reinforcement.Short-term experimental results of CFRP reinforcement show that these materials can improve the bending or shear strength.Since the 1980 s,countries including Japan,the United States,Germany,and Canada have attached great importance to the application of CFRP in engineering,and have gradually applied it to the repair and reinforcement of concrete structures,achieved remarkable results and economic benefits.In China,CFRP reinforced concrete structure research began in 1996 and now has become a common reinforcement material for reinforced concrete structures.There are 17,000 bridges in Ukraine about 9,000 of them are in emergency.In Ukraine,CFRP is gradually being used for the enhancement of normal sections.However,the study on the mechanical properties and reinforcement effect of CFRP-reinforced concrete structures is still insufficient.This article based on the Ukrainian Code for Reinforced Design(DBNB.2.3-22:2009).With a span of 4.0m and rectangular cross-section reinforced concrete beams with crosssection of 250×500mm as the research object,CFRP studied using the normative formula and finite element method.Strengthen the mechanical performance of concrete flexural members.The main research work and conclusions are as follows:(1)Summarize existing problems in CFRP reinforced concrete structures,general design requirements and reinforcement techniques.Through the study was obtained theoretical method for evaluating the effectiveness of composite CFRP-reinforced beams.(2)Based on the Ukrainian design code for reinforcement(DBNB.2.3-22:2009),was compared the influence of the three types of concrete stress-strain relations on the bearing capacity of the double-reinforced concrete rectangular simple beam.The results show that the maximum bearing capacity of the simply supported beam with the parabolic-rectangular pattern stress-strain relation increases to 100.55%,while the maximum bearing capacity of the simply supported beam with the bilinear stress-strain relation decreases to 93.56%.(3)For analyzing the nonlinearity of a rectangular reinforced concrete simply supported beam with a span of 4.0m and a cross section of 250×500mm used the finite element software ANSYS.Under the effect of 140 kN concentrated load,the maximum deformation of concrete beams is 0.79 mm,and the maximum equivalent stress of 6 A400-grade steel bars in reinforced concrete beams is 96.23 MPa.(4)Using Composite PrepPost module to create composite materials in Ansys Workbench,calculated the stress and displacement state of CFRP-reinforced reinforced concrete beams under the action of 140 kN concentrated load.The calculation results show that the maximum deflection of beams reinforced with CFRP composites is 0.57 mm,and the maximum equivalent stress of steel bars in reinforced concrete beams is 64.49 MPa.Ultimate load in the beams,strengthened by CFRP,reduced by 33%.Deformation is reduced by 22%.Stress is redistributed within the bending elements,and concrete in the compression zone has a bigger amount of stress.