Elastic Buckling Of Web Plates In I-girders Under Combined Stresses Considering Of The Restriction From The Flange To The Web

Local buckling of web plates in I-girders steel composite beam subjected to combined bending, shear and patch loading is one of the key problems in steel structures design. In the steel structures design code (GB50017-2003), the correlative computational formula was made big changes with reference to British Code and Australian Code. However, the modified formula is lack of study and verification. In this paper, the finite element method is utilized to study the elastic buckling of transverse stiffened web panels in I-girders under combined stresses considering of the effects of various geometric parameters and stress combinations. Applicability and relative safety degree of the correlative formula are examined emphatically.In this paper, a parameter correlating the torsional stiffness of the flange and the flexural stiffness of the web is introduced to quantify the rotatonal restriction from the flange to the web plate.First of all, this paper studies the elastic buckling of the web plates subjected to combined bending and patch loading, or combined shear and patch loading, then subjected to combined stresses with the results of elastic buckling of the web plates under combined bending and shear.In this paper, it is verified that the dots of the buckling critical stresses don't match the curves of the formula in the code very well by the finite element method. So the formula is not applicable because of high relative safety degree. Another formula is proposed in this paper based on the results by ANSYS. Applicability and relative safety degree of this formula are also studied considering of the effects of parameters such as aspect ratio of web plates, length of patch loading and stress combinationsThis paper's work is modification and perfection to the formula in the code, and the base for a further study of local buckling of web plates in I-girders under combined stresses.