Numerical Simulation Of Fatigue Behavior Of RC Beams Strengthened With Prestressed CFRP Under High Humid And Temperature Environment

Prestressed CFRP(Carbon Fibre Reinforced Polymer)reinforcement technology has been widely used in engineering due to its advantages of light weight while high strength.It also has the advantages of closing structural cracks and corrosion resistance and so on.In this paper,RC beams(reinforced concrete beams)strengthened with CFRP serving in the subtropical zone are studied.The effects of temperature,humidity,prestress and load on fatigue properties of the strengthened beams are considered.The model of RC beams strengthened by Prestressed CFRP under high temperature and humidity environment is established by using Abaqus commercial calculation software,and the fatigue performance of strengthened beams under that environment is explored.The main research contents and conclusions are as follows:(1)According to the characteristics of components and materials of RC beams strengthened by CFRP,and this paper also considering the degradation of material properties of strengthened beams under constant amplitude cyclic load and high humid and thermal environment。In this paper a numerical analysis model of fatigue properties of RC beams strengthened by prestressing CFRP under high humid and thermal environment is established.The calculation of fatigue cycle number is simplified according to the degradation rule of each component of reinforced beam under cyclic load.(2)In this paper,the calculation model of RC beams strengthened by non-prestressing CFRP under constant amplitude cyclic load is established by Abaqus commercial calculation,and the validity of the finite element model is verified by the previous experimental study of this group.The experimental and computational results show that the finite element model can accurately simulate the static response of the strengthened beam structure,and the deflectionload cycle curve and life of the strengthened beam under fatigue cyclic load are in good agreement with the calculated results.(3)In this paper,the finite element model is used to calculate the fatigue deformation and damage of reinforced beams under different Prestressed degrees,different humid and thermal environments,and different loads.The fatigue properties of RC beams strengthened with CFRP are studied and the life of structures is predicted.The results show that: 1).The high temperature and humidity environment has a great influence on the deflection of RC beams strengthened by CFRP during fatigue cycle.The increase rate of deflection and deflection increases with the increase of temperature and humidity,and the stress and damage of the main bars in the middle span have the same rule.2).the Increasing of Prestressed degree can reduce the deflection of the structure and the stress of the stress and it also can reduce damage of the steel bar.However,with the increase of the degree of prestressing,the damage growth rate of CFRP-concrete interface will also increase.In the low temperature and humidity environment(38 ℃,78% R·H),increasing the degree of prestressing can improve the life of the structure,but when the temperature and humidity are high(50 ℃,95% R·H),the fatigue life of the beams strengthened with 22% degree of prestressing is lower than that strengthened with 10% degree of prestressing...