Strength of transversally stiffened I-girders under combined shear and compression

Steel plate girders of cable-stayed bridge decks are frequently subjected to high compression in addition to shear and bending. Therefore, this paper presents a numerical study of combined shear and compression interaction (N-V interaction), assessing the buckling and ultimate strength of steel slender plates and I-girders. Using the effective width method given in EN 1993-1-5, moderate axial compressions are not directly considered to reduce the shear capacity of the steel members when checking the overall bending, shear and compression resistance. However, numerical results show that the shear capacity is reduced in presence of compression, even if considerable stress shedding occurs for small ratio between the areas of web and flanges. An assessment of the influence of the equivalent geometric imperfections is also given to identify the worst-case shapes and amplitudes. Moreover, different finite element models varying the boundary conditions are used to analyse the (N-V) interaction and differences are shown and discussed. The basicmodels are validated by recalculating the EN 1993-1-5 buckling curves. Finally, parametric studies are carried out running Geometric Material and Non-Linear Imperfect Analysis (GMNIA) models and results compared against a newly derived N-V interaction. Following the results, a new resistance model is proposed, and a statistical assessment is carried out. (C) 2020 Elsevier Ltd. All rights reserved.