Stability Analysis Of Biaxial Bending Of I-section Beam-columns With Slender Web

For I-section beam-columns, thin and high webs are adopted in the design method, and these design both fully develop bearing capacity of the section and save materials. This kind of design method can lead to local buckling of web, but this doesn't mean to lose bearing capacity.Firstly, this paper establishes the FEM model which can consider the local buckling of web with finite element program ANSYS. In order to simulate the practical situation, the original deformation and the residual stresses are considered. The finite element ANSYS calculated results agree well with the test data, which proves the model established by the FEM program ANSYS is reliable.Secondly, parametric analysis of the biaxial bending of I-section beam-columns with slender web is carried out. It is found that, when the slenderness ratio and the load eccentricity of members are large, the stability capacity will be varied slightly by changing the web width-thickness. With the same quantity of steel material, stability capacity can be improved by broadening the web. The bearing capacity of the members can be reduced by residual stress.Thirdly, this paper makes use of the formula of stability in "The Code for Design of Steel Structure"(GB 50017-2003), combining the effective width-method in GB 50017-2003 and CECS102:2002, to calculate the stability capacity and compare with the FEM calculated results. It is found that the effective width method in CECS102:2002 is more accurate than that in GB50017-2003, but both of them are conservative.