The Cfrt Force Performance Analysis

The test data of 28 short eccentric CFST columns and 13 short cantilever columns was analyzed thoroughly in this paper. The parameters of confinement index and eccentric ratio to eccentric column (or axial load ratio to cantilever column) were the most significant effect factors. For the CFST member, the more confinement index was, the better mechanical behavior was shown, which included the more significant confined force, larger ultimate load, better ductility. In the early research, the effect of the confinement index was paid enough attention, but the effect of the eccentric ratio was analyzed by few people. The eccentric ratio to the eccentric columns and the axial load ratio to the cantilever columns was another important factor. It was indicated that the confined force and the ultimate load decreased with the increment of eccentric ratio, the eccentric ratio not only lowed down the ultimate load, but also weakened the confined force of the steel tube in the concrete compressed area. The more the eccentric ratio was, the later the confinement of the steel tube played role, and the less the area was, the less the confined force was. The axial load ratio influenced the cantilever columns behaviors significant, the larger axial load ratio was, the lower ultimate load and worse ductility was shown. Thus, according to the analysis result the eccentric ratio was considered as the parameter to modify the concrete material constitutive law, and the Craston method was used to analyze cross section, and the steel material constitutive law was explained with 4 lines. According to these, a finite element program based on the presented model and double nonlinear was compiled, and the calculated results agree with the test results well, this was the basis of the analysis of the CFST arch bridges.In the paper, the ultimate load of CFST member was calculated according to 8 design codes about CFST, the calculated results compared with the test results and each other, some useful conclusion was drawn to carry out the codes in practice.