Research On Bearing Capacity Of Rectangular Section Columns Strengthened With CFRP

Theoretical analysis and numerical simulation of the bearing capacity of concrete columns strengthened with CFRP were presented on a foundation of the existed theory and test results. The contents are as follows:1. The relationship between stresses and strains can be simplified as the three broken line for the concrete column confined by CFRP. The ultimate strength models established by this relationship have nine typical ones. The calculated values of these models were compared to 103 sets of collected data. However, the results were not ideal. So, a new model was obtained by the fitting method. The comparison results indicated that the model was effective.2. The distribution of the radial constraint stress along the circumferential direction of the rectangular concrete column strengthened with CFRP was not uniform. Based on the previous studies, three aspects were developed. Firstly, the relationship between the corner radius and the reduction degree of the tensile strength of CFRP was studied. Secondly, the commonly used models of the effectively confined area were compared. Thirdly, the equivalent diameter was selected in the indirect methods on the basis of previous studies, and a new ultimate strength model was put forward for the rectangular concrete column strengthened with CFRP. Finally, the comparison with 92 sets of the experimental data indicated that the proposed model was effective.3. The bearing property of the concrete column strengthened with CFRP belongs to secondary load. In order to make the study conclusions close to practice, the ultimate strength model was modified by a lag coefficient. The new model was compared with test data and the results show that the model was high reliable,so that a reference was provided for the design of the rectangular column concrete strengthened with CFRP.4. The distribution law of the stress and strain along the longitudinal and the diffusion of cracks in the square concrete column with different packing layers of CFRP and strength grades of the concrete were analyzed by the finite element analysis software called ANSYS and the mechanism of increasing the bearing capacity of the concrete column strengthened with CFRP was summarized.