Theoretical Study And Nonlinear Finite Element Analysis On Prestressed CFRP Strengthened R.C Beam Under Secondary Load

Carbon fiber reinforced concrete structures is a new and efficient structure reinforcement technology, more convenient than the traditional structure reinforcement technology which has been widely used in recent ten years. With a detailed study found that carbon fiber sheet on flexural strengthening of concrete beams there exist:①The CFRP sheet can not be fully utilized, when the CFRP sheet and steel work together, the CFRP only play less than 20% of the intensity while the steel play a full strength.②The reinforcement effect are not obvious on the using stage, the cracking load and yield load of the structure improvement degree is small and is difficult to suppress the crack development. When the carbon sheet applied prestressed, the CFRP already played a considerable strength before the structure bearing load. Effective use of the high-strength of CFRP, but also suppress the deformation and crack development and avoiding the conflict of elastic modulus and strength ratio is too low of the CFRP. The article mainly includes the following:1) Carry on the theoretical analysis about the force of the whole process based on the existing prestressed CFRP R.C beams test data and formulas and deduced the theoretical formula of beams bearing capacity under the secondary load .2) Using the derived theoretical formula to calculate the bearing capacity of prestressed CFRP sheet strengthened R.C beams under the secondary load in various factors , analyzed the results and analysis of the bearing capacity influence and rules under the secondary load in various factors. Analysis showed that: prestressed CFRP strengthened R.C beams carrying capacity has been significantly improved and the influence on bearing capacity is very small under the secondary load, it can be insignificant.3) Derived from the stiffness and deflection formula on the serviceability limit stage of the prestressed CFRP sheet strengthen R.C beams under the secondary load, and verified the derived formula. The results show that the experimental values and calculated values basic coincidence , it is proved that the scientific of the theoretical derivation.4) Numerical simulation the whole process of prestressed CFRP sheet strengthening R.C beam by finite element software entitled ANSYS and the numerical simulation compared with experimental value, analysis shows that: a) the result of bearing capacity between the finite element analysis ANSYS result and the experimental result are more consistent; b) the load-deflection curves of experimental result and ANSYS result match the extent of deviation after the steel yield, but also consistent with the law.