Simulation Of Interfacial Bond Property FRP Reinforced Concrete Based On CZM

FRP bar are widely used in civil engineering with the characteristics of high strength and corrosion resistance.With the same as reinforced concrete structure,FRP-reinforced concrete structure needs to ensure a sufficient bond strength for interface,which slippage does not occur.Scholars at home and abroad,obtain various forms of bond-slip constitutive models through the testing of FRP-reinforced concrete structure.However,due to the limitations of the theoretical study and experimental conditions,specimen of existing test is limited to extreme pulling force and average bond strength;numerical calculation for existing,often couple public nodes of different materials or use spring elements to simulate failure of the interface.Cohesive Zone Model based on theory of fracture mechanics,properly reacts brittle process of bonding and separating through the interface bonding strength and fracture energy.This paper will be based on CZM model and use cohesive interfacial element to simulate the process of interface bonding and sliding failure in FRP-reinforced concrete.Not only the interface bond strength can be verified,but the distribution and processes of interfacial stress in FRP reinforced concrete can be got.Main content and conclusions are as follows:(1)Study on the theory of interfacial bond properties of FRP reinforced concrete.Bilinear model which represents bond stress-slip relation of FRP reinforced concrete is proposed for theoretical analysis and numerical calculation,and interfacial bond-slip control equations based on elastic theory can get solutions of interfacial bond stress and slip distribution anywhere.Results shows that bilinear model with simple form and parameters easy to determine is reasonable to describe the interface of FRP-reinforced concrete bond.(2)Using bilinear model proposed in this paper to analyze pull-out test and beam test considering bond-slip of FRP-reinforced concrete.It is proved that bilinear model is feasible through comparision of ultimate pulling capcity between FEA and test.Analyze the change of interfacial bond stress and slip with different load,which reveals the process of adhesive interfacial failure.Scope of the interfacial bond strength of FRP-reinforced concrete as well as range of slip under different bond length are given based on experimental and numerical analysis results.(3)Analyze FRP-reinforced concrete beams considering interfacial bond-slip.It shows that bearing capactiy of simulation conincides with experimental results on condition of minimum bond strength.But Interfacial slippage does not occur because that the deformation of beams is relatively small.Therefore,we continue to study the influence of bonding parameters on the mechanical properties of FRP-reinforced concrete beam,and idntify that the critical bond stress when an interfacial slippage occurs is 3MPa.Fracture energy has little effect on bearing capacity.Finally,study the influence of concrete crack on interface bonding properties,found that bonding performance decreased significantly near cracks in concrete.