Local buckling coefficients for thin-walled lipped channels under bending about asymmetrical axis

• A parametric study was performed on thin-walled channel cross-section members subjected to bending about the asymmetrical axis with the web in compression. • A piecewise function was calibrated that can accurately reveal the nature of the dependence of the buckling coefficient on the flange width. • New proposed expressions are simpler, one of them is in a simple power form. • The result of the newly proposed expression is more accurate. • New proposed expressions take into account the influence of material properties and corner radius, which have not been addressed in previous studies. This paper aims to calibrate a formula for determining the buckling coefficient of thin-walled lipped channels subjected to bending about the asymmetrical axis when the web is in compression to modify the current analytical solution in AISI S100, which has been reported to have poor accuracy. A parametric study, combined with the exclusion method, was performed on results derived from the Finite Strip Method of 177 models simulated using THIN-WALL-2 software. Based on the finding that the local buckling mode of the web governs the buckling under the present loading condition, a novel set of expressions, using a piecewise function as the core, was proposed to calculate the buckling coefficient. These expressions result from a data regression. Compared to previous studies, the new expressions are simpler and more accurate. In the range of common commercial cross-sections, new formulas bring an error of only 1.83 %. The newly proposed expressions also consider the influence of material properties and corner radius, which were ignored in previous studies.