Study On Load-carrying Performance Of Axially-loaded Short Column Cold-formed Steel

The current Chinese Specification"Technical Code of Cold-Formed Thin-Wall Steel Structures"(GB50018-2002)prescribes that the section of cold-formed thin-wall steel members are simple section and lattice section primarily, but other compound sections lack relative design method. So in order to verify the suitability of it, it is necessary to carry out relative experimental and theoretical study on this subject.A total of 7 cold-formed thin-wall steel stub columns were tested on the axial compression characteristic. The parameters of columns were sections dimensions, thickness and space of joint plate. The experimental results show that the ultimate failure mode is the local and whole of members related buckling. It is not conservative for designing the compression stub column's ultimate load according to the method in the specification GB50018-2002. So, through the analysis, according to the effective width method of our country specification to calculate the cold-formed thin-walled steel combination section members bearing capacity, the correction coefficient to consider board group related situation influencing bearing capacity take account.The effective width method which is widely used in designing cold-formed thin-wall steel in the world has its shortcoming, another method in the field of cold-formed thin-wall steel named Direct Strength Design Method (DSM) is introduced in the paper. And the ultimate load of the stub columns using DSM and effective width method were calculated. The results show that DSM is more close to the experimental results than effective width method. Then a suggested formula about cold-formed thin-wall steel compound section members was put forward.Finally, cold-formed thin-walled steel axial compressive short column were simulated using ANSYS. ANSYS can determine the elastic buckling and the nonlinear buckling of members. Simulation results are in good agreement with the test results.