Abstract: The current AASHTO specifications impose a penalty on the strengths corresponding to the compression flange in slender-web
cross sections due to bend-buckling of the web in flexural compression. This web bend-buckling factor (Rb) does not account for any potential
benefits from the influence of web longitudinal stiffening. In a companion paper, the authors developed a cross-section model that can be used
to estimate the flexural capacity of I-girders at the yield limit state. In this paper, an improved handling of combined web bend-buckling and
lateral torsional buckling (LTB) of longitudinally stiffened I-girders is proposed based on finite-element test simulations. Results from the proposed
prediction model are compared to available experimental tests. In addition, the Rb calculated from the proposed model, used in conjunction
with the current specification flange local buckling (FLB) equations, is shown to provide an improved characterization of the FLB
capacity of these types of members