Elastic buckling of cellular columns under axial compression

Abstract

Abstract A calculation of the elastic buckling load for cellular columns with multiple circular openings is required to determine their axial load capacity. Due to the complexity of column geometry and shear effects, the available methods to analyze the elastic buckling load are limited. This study proposes a method of calculation the elastic buckling load about the major axis of a pin-ended cellular column. The analysis is based on simplification of the column geometry and uses an effective length of shear force transfer across openings in the columns. The shear force in the column causes additional deformations of the web-post and the Tee section of cellular columns. The buckling load is derived by using differential equations of total curvature of the buckling curve, which is the sum of curvatures due to moment and shear forces. The proposed buckling load estimate is validated by comparisons with finite element analysis. A parametric study of the column geometry effects on shear, such as the section ratios, the opening ratios, the spacing ratios and the slendernesses, was also conducted. The shear effects clearly increases with open area fraction in the web, and with the section ratios. It was found that the spacing ratio affects the buckling load more than the opening ratio. Overall, the shear effects degrade the buckling load by less than 20% when the slenderness exceeds 50 compared to the Euler buckling load.