Experimental Research on ColdFormed ThickWalled Steel Box Stubs and Comparison of Results with Related Codes

Abstract:

Sixteen specimens were tested under axial compression to investigate the effect of coldforming process on the behavior of stub columns. The main parameters varied in the tests were the widththickness ratio of steel tubes. The test results indicate that the shape of loaddisplacement curves depends mainly on the widththickness ratio of crosssections. When the widththickness ratio is relatively small, the axial load decreases slowly after the peak ponit of the curve and the total axial displacement is relatively large before failure. On the contrary, the effect of local buckling on the loaddisplacement curves is significant, which results in the sharp declining of curves after the peak point when the withthickness is rather large. Meanwhile, the calculation results of related standards considering the coldforming effects were compared with the experimental results. The comparison show that the formula for calculating the yielding strength of coldFormed thinWalled sections considering the coldforming effects in Chinese Technical Code of ColdFormed ThinWalled Steel Structures(GB500182002) is suitable for those coldformed thickwalled steel stubs with local buckling restrained.

Key words:coldformed thickwalled tube; stub column; coldforming effect; specification formula; widththickness ratio