Numerical investigations on bending and shear buckling interaction of I-Girders with slender WEB

Abstract Steel I-girders with slender web are commonly used in the engineering practice. Previous research results proved that the current bending and shear interaction (M-V) check of the EN1993-1-5 does not always provide safe side resistance. The current research work focuses on the analysis of the M-V interaction behavior of longitudinally unstiffened and stiffened I-girders with slender web. Applicability interval of the current EN1993-1-5 based M-V interaction resistance model is determined and based on the executed numerical investigation a refined M-V interaction equation is proposed to ensure safe and economic design. The results of the numerical parametric study also proved that the flange contribution in the shear buckling resistance does not match the current design rules of the EN 1993-1-5. In a specific parameter range (girders with light flanges) the current design rule underestimates the flange contribution to the shear buckling resistance leading to conservative resistances. However, for I-girders with heavy flanges the current design method gives unsafe results. Therefore, the current paper presents an improved formula to the flange contribution ensuring better approximation of the computed resistances.