Simplified method for Euler buckling load of closely star-battened angle column about Y axis

The Euler buckling load of a column is an important parameter to decide its ultimate axial compressive capacity by the column curves. When the closely star-battened angle column under compressive force is designed as an integrated single column according to the British and Chinese Codes, its Euler buckling load about Y axis is greatly overestimated. To solve this problem, firstly, a basic element of this column is seen as a frame composed of beams and the formula of its shear stiffness is derived based on the principle of virtual work. The formulas show that: (1) The shear rigidity of the column is not infinitely large as the integrated single columns; (2) The inflection point is not in the middle of the chord angle as the not closely battened column. Secondly, the method to calculate the Euler buckling load including the two properties is proposed. Finally, the above two properties are demonstrated vividly by a finite element model of beam elements, and the accuracy of the proposed method is proven by another finite element model of shell elements.