| With the development of high-strength steel, the use of high-strength steel has been increasing rapidly in building construction. The research on the stability of high-strength steel under axial compression seems more urgent. When the wide compressive plate of columns occurs local buckling, the component bearing capacity will not disappear. It will save steel by using the post-buckling strength. The effective width method is adopted in considering the post-buckling strength of the web in Chinese code†Code for design of steel structures(GB50017-2003)†which also have defects in considering the post-buckling strength of the web. In this paper, the main research contents and results are as follows:(1)6 axial compression experiments of Q460 high-strength welded I-section columns were conducted and the results were analyzed. Mechanical data of steel columns and ultimate bearing capacity are obtained. Through the study on the curves of load to displacement, it can be concluded that overall buckling occurred after local buckling.(2)Finite element analysis by ABAQUS was performed in this paper, where the residual stresses and the initial geometric imperfections of component were accurately described. And the finite element analysis results are compared with the test results to verify the reliability of finite element model.(3)By using the validated finite element model, the finite element parametric analysis is conducted on the I-section columns under axial compression, including the ratio of width to thickness of steel plate, the member slenderness ratio, the thickness of steel plate, the yield strength of steel plate. Finite element parametric analysis obtained the following conclusions: With the increase of the width thickness ratio limit of the component carrying capacity has improved, but the ratio of width to thickness should not be too big; With the increase of slenderness ratio, ultimate bearing capacity will decrease; Increasing the thickness of plates will improve the bearing capacity of the members; The steel yield strength increase, a corresponding increase of ultimate strength will occur..(4)Based on the finite element analysis, the author put forward the suggestion formula of direct strength method to the stability capacity of high strength steel I-section columns. The suggested calculation results are coincided with results of finite element analysis. But for the other section and other yield strength components, whether the suggestion formula is valid remains to be further study.In this paper, through the combination of experiment and finite element, the author studied the bearing capacity of high strength steel I-section columns under axial compression, analyzed the influence of the ratio of width to thickness of steel plate, the member slenderness ratio, the thickness of steel plate and the yield strength of steel plate. In the end of the paper, the author put forward the direct strength method formula to provide reference for the structure design of high strength steel. |
