Experimental Study on Coldforming Effect of Coldformed Thickwalled Steel with Lipped Channel Sections

Abstract:

In order to investigate the coldforming effect on yield strength distribution of coldformed thickwalled steel with open section, coupon test and axial compression test were carried out. Firstly, 5 types of coldformed lipped channel sections with thickness of 3, 8, 12 and 16mm, and two yield strength grades of Q235, Q345 were chosen to conduct coupon test for the web, flange, curling, corner parts, respectively, and a corresponding distribution model for the yield strength distribution of coldformed thickwalled steel with lipped channel section was put forward. Then, the axial compression tests of 5 stub columns with the same section as the coupon test were carried out for further investigation on the coldforming effect. Finally, the results of stub column test, the results based on the proposed yield strength distribution model, and the results based on the related codes in various countries were compared. It is shown that, the yield strength distribution of coldformed thickwalled steel with open section is greatly influenced by the coldforming effect, and mainly depends on the width to thickness ratio of the plate involved; the estimation based on the proposed yield strength distribution model is close to that based on of the codes in various countries, as well as the test results, although the latest is slightly larger. Moreover, among them, the results based on the Chinese code, GB 50018—2002, is closest to the experimental values with smallest variation coefficient, which means a best applicability.