Research On The Axially Compressed Behavior Of Triple-limbs Box Section Built-up Cold-formed Steel Columns

In this paper, the bearing capacity of the triple-limbs box section built-up cold-formed axially compressed and eccentric compressed steel column is reaserched by experiment and finite element analysis, according to the study, the suggested calculation method of the bearing capacity of the triple-limbs box section built-up cold-formed steel column in the China specification is proposed.First of all, the experiment of the bearing capacity of the triple-limbs box section built-up cold-formed column is began. Then the purpose and content of the test, the specimen and the test equipment, the test procedure and method, test phenomenon, the failure mode and the analysis of test results are introduced in detail.In the next place, simulating the nonlinear finite element numerical simulation of the triple-limbs box section built-up cold-formed column of analysis by the software ABAQUS in this paper. The characteristics of the model and the process of establishing the model are introduced, and the finite element analysis results are compared with the experimental results, which verifies the correctness of the finite element model and the modeling method. By using the finite element program to analyze the bearing capacity with the slenderness ratio, the ratio of web height to thickness, the eccentric direction and eccentricity.Then the bearing capacity is calculated that refer to the provisions of the specification GB50018-2002 in China and the United States AISI specification(Effective Width Method and Direct Strength Method) method, and the calculated results, the experiment and the finite element analysis results are compared and analyzed. The results show that the axial compression specimens, the results of the long column which are calculated by effective width method in the China specification is safe, while the results of the short column is unsafe. The calculation results of the United States AISI effective width method is safe, while the direct strength method is not. Those results are all less than the results of finite element analysis. For the eccentric compression specimens, the calculation results of the specification in China and the United States AISI specification are both less than the experimental results and the finite element analysis results, the calculation results of the United States AISI specification is too conservative.At last, on the basis of the comparative analysis of the experiment results, the finite element analysis results and the theoretical calculation results, the suggestive calculation method is proposed for the axial compression and the eccentric compression.