Research On Axial Compression Bearing Capacity Of Multi-limbs Section Built-Up Cold-Formed Steel Stub Columns

Multi-limbs built-up cold-formed steel stub column is a mainly structural member consisting of a single C-sections and U-sections connected by self-drilling screws. This paper mainly describes the detailed study resulted on axial load carrying capacity of multi-limbs built-up cold-formed steel stub columns of three different sections forms by tests and numerical analysis, and the corresponding proposed design method is proposed.Firstly, this paper introduced the tests of multi-limbs built-up cold-formed steel stub columns detailedly; Including the test contents, material properties, test device, test process, and then full test course as well as the analysis of test result are introduced in details.Secondly, nonlinear finite element analysis is used to simulate test models under axial load in this paper. From the comparison of ANSYS and CUFSM analysis with experimental results, the finite element model is more accurate. The parametric study analysis was carried out to mainly determine the effect of the maximum width-thickness ratio of plate and spacing of screw. The results of the study indicate that the axial load bearing capacity of the multi-limbs built-up section stub column increases when the maximum width-thickness ratio of plate decreased, but the spacing of screw is not a main factor.Subsequently, based on the test and the finite element nolinear analysis, load bearing capacity of stub columns was caculated by the GB50018-2002, AISI2004. Then the results caculated by specification were compared with the test results and the ANSYS results. The comparision show that the GB50018-2002 could be used to calculate the he axial compression bearing capacity for the stub columns.Finally, based on the test and the numerical analysis, the design rule and the simple corresponding design method are brought forward.Compared with the current GB50018-2002 and the test results, the proposed methods indicate high degree of accuracy. Furthermore, the suggestion to the modifying is put out in this paper.