Theory And Finite Element Analysis Of Bending Ability Of RC Beams Glued With Steel Plate In Consideration Of Secondary Load

Bonded steel reinforcement technology has been widely used due to the advantages of effectively improving the bearing capacity of original structure, simple technics and short construction period. The component pasted steel plate without removal of the load will appear the phenomenon of secondary stress, strain of steel will be lagging behind the original strain of the structure and the component failure when the steel plate is often short of yield strength, causing the loss of bearing capacity of concrete structures and steel utilization. For this problem, the paper focuses on the effective utilization of the bonded steel plates and carrying capacity study of beams.In this paper, firstly, it is discussed about the basic theory and calculation formula of bearing capacity and stiffness of the reinforced beam. Secondly, it focuses on analysis of the finite element modeling method and the characteristics and the results of ABAQUS compared with experiment and theory analysis are verified. According to the beams at bottom pasted with steel plate,11specimens were analyzed for the strain of steel bar, steel plate and bearing capacity of components and the utilization ratio of steel plate under different reinforcement ratio, Stress level indicators, the strength of steel plate and quantity of steel plate. Results show that it is close to8b,max without considering the secondary stress of reinforcement beams, this article suggests that should try to uninstall. It is better to make β≤0.8for Q235steel and make β≤0.5for Q345steel. It can effectively utilize the strength of the steel plate by this way. The beam bottom and beam side bonded steel plate were analyzed and compared. Specimen are designed to ensure flexural failure and avoid component shear and bending shear failure, then6components were studied in different stress level indicators in accordance with the specifications. The results show that, when the β value is too high (greater than0.91), the bearing capacity of the strengthened beams side is significantly reduced. So, it is appropriate as far as possible to paste steel plate after unloading.