Numerical and theoretical analysis of normal stress distribution in flanges of I-girders with trapezoidal corrugated webs under uniform bending

I-girders with corrugated webs (IGCWs) are a new type of structure that has been increasingly used in engineering. The normal stress distribution in flanges of IGCWs is quite complicated compared with that of conventional I-girders under in-plane loads. This study numerically and theoretically investigates the normal stress distribution rules and mechanisms in flanges of I-girders with trapezoidal corrugated webs (IGTCWs) under uniform bending in the elastic stage. First, finite element (FE) modelling was developed using ABAQUS software and verified by the available experimental results. Based on the verified FE models, a detailed analysis of the normal stress distribution in flanges of IGTCWs was performed. The results show that the normal stresses are nearly uniformly distributed over the flange in cross-sections with inclined web folds. Normal stresses in cross sections with parallel web folds are approximately linearly distributed along the flange width, with stresses away from the corrugated web side being much larger than those near it. Its mechanism is explored using a secondary transverse moment theory, which is improved and completed by considering the proposed effective cross-section coefficient and equivalent width coefficient for the action of shear flow. The reliability of this theory was verified through comparison with the normal stress difference and distribution results of the supplementary FE models. Finally, the formulae for calculating the normal stresses in flanges of different cross-sections of IGTCWs under uniform bending are presented. These formulae suggest that secondary normal stresses generated by secondary transverse moments in cross-sections with parallel web folds account for 7% to 13% of the total normal stresses and cannot be ignored in the stress analysis.