Stepwise Regression for LTB Strength Prediction of I-Beams Subjected to Different Loading Conditions

Lateral torsional buckling (LTB) is a highly investigated failure mode of beams due to their instability. Despite many studies, existing standard recommendations still have limitations to determine the ultimate capacity of such members subjected to LTB mode. Accordingly, in the current paper, an in-depth parametric study has attempted to study the effect of all major parameters, especially the influence of different types of loading on the ultimate capacity of steel I-beams. Moreover, using the provided reliable database, the stepwise regression (SR) method was employed, and an accurate formula was introduced to evaluate the LTB capacity of steel I-beams. To show the robustness of the developed formulation, a comparison was made against the existing equations. It was found that the proposed equation based on the SR consists of a strong accuracy among others and it can be utilized by engineers who are designing the I-beams against LTB.