Theoretical And Test Studies On Width To Thickness Ratio Limitation Of Cut T-shape Web Subject To Axial Compression

Stipulations for Width to Thickness ratio limitation of cut T-shape web subject to axial compression in the Code for Design of Steel Structures (GBJ17-88) are revised in a new version of the Code (GB50017-2003). But assumptions for the theoretical deduction are somewhat unsafe. With consideration to the propagation of Cut T-shape, it is necessary to verify the rationality of the revision or provide a more rational equation for revising.Theoretical analyzing, testing and FEM calculating are included in this paper to study the local buckling and Width to Thickness ratio limitation of cut T-shape web subject to axial compression.Theoretical analysis shows that Width to Thickness ratio and buckling coefficient are the main influence of the local buckling of the web, and the relative thickness and the relative Width to Thickness ratio influence the buckling coefficient most. According to the principle of "Equal Stability", the Width to Thickness ratio limitation of the web with the assumption that local buckling does not occur before integral buckling in an element is deduced. To verify the rationality of the theoretical deduction, axial compression test and related material test of three different sections with each section having five varied slenderness have been adopted in the Structure Laboratory of Xi'an University of Architecture & Technology. A lot of FEM analyses have been carried out in terms of the martial test results to identify the perimeters adopted in analyzing 8 different representative sections. Corresponding conclusions have been drawn.By testing and FEM analyzing, the revision of the Width to Thickness ratio limitation in the new version Code is considered safe and rational in most condition except that slenderness is too small. Considering the safety of the stipulation, this paper suggested the following equation for the revision in the domestic Code for Design of Steel Structures (GB50017-2003) : h₀/t_w =(10 + 0.25λ) 235/f_y 30 ≤ λ ≤ 100 , where λ - slenderness with respect to symmetry axis .