Section Method for Critical Local Buckling Stresses of Cold-Formed Steel C-Sections with Centered Rectangular Web Holes

The objective of the study is to develop a suite of closed-form local buckling stress equations for cold-formed steel (CFS) C sections with centered rectangular web holes. Finite strip analyses are performed over a representative collection of over 1000 CFS C-sections under four loading conditions to generate data. Closed-form equations of buckling coefficients are developed in the simple forms of ratios of polynomials with modification factors used to consider the influence of holes. The suite of equations is named as the section method. The proposed section method has excellent accuracy over the C-sections considered in this study (mean ∈ [1.00, 1.01], COV ∈ [0.02, 0.06] for holed sections) and far exceeds the performance of the existing closed-form equations in the AISI S100 known as element method (mean = [1.55, 3.64], COV = [0.32, 0.51] for holed sections). The section method provides an alternative method for practicing engineers not using finite strip analyses and will lead to a more streamlined CFS design workflow.