Finite Element Analysis Of Concrete Column Confined By CFRP Under Sustained Load

In recent years, using of the fiber material reinforced technology is increased in engineering, which is considered as a new highly technological method to strengthen the architecture. Especially from the WenChuan Earthquake, using FRP to strengthen the frame structures based on the anti-seismic would be the hotspot of the study in the near future. Researchers all around the world have been completed large amounts of tests and studies on FRP. Because of the limitations, strain lags of the strengthened structure under sustained load were not considered in researching methods based on the experiment. But it cannot be unloaded completely in practical reinforced engineering. So, it would be variable and widely used in the future to do the research on concrete structures confined by FRP under sustained load. There are so many factors influencing mechanical properties of the concrete component, including the discreteness and nonlinearity of the concrete, it is unrealistic and uneconomic to do amounts of tests. It is relatively easy and effective to solve this problem, using computer to do the model analysis. As the FEM technology developed, especially the reinforced concrete FEM, the entire process analysis on reinforced concrete structures under load is available, using FEM. This paper focuses on the analysis of concrete columns confined by CFRP under sustained load, which using the technology of the element of birth and death in ANSYS. The prime works has been done are as follows:(1) Numerical simulation on test processes of high-strength concrete square columns confined by CFRP under sustained axial load, using the technology of FEM in ANSYS. At the end, we got the critical bearing capacity, the fiber strain distribution of square columns, the stress-strain diagram and the strain curve of the CFRP influencing by the section height variation under ultimate loads. Comparing results from ANSYS to experiments, it is presented that the two are well matched.(2) Numerical simulation is done to every specimen under eccentric compression in test by the finite element program of ANSYS. Some valuable formations can be obtained, such as ultra carrying capacity, distribution of concrete crack at some time, equivalent stress contour of concrete and fiber-reinforced polymer at failure point, the loading-strain curve of bearing concrete, the loading-strain curve of steel bar and loading-deflection curve of specimens. From these analysis we can see that the two results are well matched. It is also presented that the finite element model and the analytical method using in this paper are both available, and the conclusions obtained in this paper are valuable in practical strengthening engineering.