Design formulas for channels subject to combined compression, shear and major axis bending

Abstract

In this work, analytical formulas are presented for channel design subject to multiple load combinations. Common design procedures found in the North American and Eurocode ignore the rotational and lateral restraints. Furthermore, limited design rules are available to predict buckling of channels subject to combination of compression, shear and major axis bending. The proposed formulas account for rotational and lateral restraints and result in significant weight reduction. Comparisons are made with other numerical procedures to confirm accuracy and suitability of the proposed expressions to use in practice. Influence of channel parameters on buckling behaviour of cold form steel (CFS) channels is also highlighted. It is shown that shear buckling stress (τcr) decreases by increasing (h/b) ratio. The difference in (Δτcr) reaches 14% for (h/D) = 25. Furthermore, much of the decrease in (τcr) values occurs for (h/b) between 2 and 4. It is also shown that a decrease in (τcr) up to 18.2% is attained by fully restraining the web edges against lateral movement.