Theoretical Study And Numerical Simulation On Cfrp Strengthened R.c Two-way Slab Under Preload

CFRP was initially used to reinforce concrete structure in 1980's. Because of it's low weight (300g/m~2),high tensile strength (2300MPa-4450MPa),good corrosion-resistance and convenient constructed, CFRP has been widely used in structural reinforcement project recently. Both domestic and overseas investigations show that carrying capacity and stiffness reducing deformation of CFRP strengthened R.C bending members are improved. The ductility of the members is still outstanding with seismic reinforcement. However, due to the specificity of its mechanical performance and failure type, there are requirements of the researches on CFRP strengthened R.C two-way slabs, especially under load. This research analysis deeply on CFRP strengthened R.C two-way slabs under preload based on the former experimental studies. The main researches are as following:(1) According to the test phenomenons and theoretical analysis, this paper focus on the simple support reinforced two-way slab under concentrated load and derivates the formula of carrying capacity under preload.(2) Based on theoretical calculation formula, influences on carry capacity by load are analyzed under variety conditions including reinforcement ratio, concrete strength, paste volume etc.Analysis indicate that the carrying capacity of the R.C two-way slab strengthened by CFRP is improved significantly. Preload level almost has no impact on carrying capacity, which can be ignored.(3) The thesis derivates the formula of short-term stiffness,and then verifies its effectiveness. It is used afterward to calculate the deflection under different preload level. The results show that the preload level affects the stiffness obviously, which should not be ignored.(4) The numerical simulation of the whole process is set by means of the finite element software ANSYS and then the results of the simulation and theoretical calculation are compared. The results show as following: a) It is practicality to simplify the linear plastic hinge line. b) Carrying capacity calculation results coincide with the finite element analysis results. c) The results of deflection analysis have small quantity deviation from the calculated results; however, it accord with the discipline. The results of the numerical simulation also demonstrate the validity of the theory and the results.