Buckling Of Transverse And Longituded Stiffened Web Under Combined Stresses

Local buckling capacity of steel composite beam subjected to combined bending,shear and patch loading is one of key problem in steel structures design.The computational formula for local stability of web was based on the assumption of infinite-elastic perfect plates in the steel structures design code (GBJ17-88).But in the revised code (GB50017-2003), this formula was made big change with reference to British code (BS5950,Partl) and Australian code (AS4100),the related research result of our country was included as well.In the modified formula , influence of early geometric imperfection and elastic-plastic buckling stage were considered, which is compatible with both actual circumstance of engineering and the strength formula of beams under bending stresses (considering partial plasticity of the section).In this paper ,the preceding problem is deeply analyzed and studied ,considering the effects of various geometric parameters and stress combinations on buckling critical stress of web,the revised local buckling correlative formula for transverse and longituded stiffened web panels under combined stresses is analyzed and verified by finite element method. Relative safety degree of the correlative formula is examined emphatically.