The authors have been studied the buckling behaviour of axially compressed tubes with through-gusset connections. In order to obtain the buckling strength of the concentric system with the double shear connections, the precise analysis and the simple formula were proposed, and their accuracy was confirmed by the loading tests. But for the eccentric system with the single shear connections, only the precise analysis was established, and its accuracy was confirmed by the loading tests. In this analysis, the iterative calculation is necessary to obtain the buckling strength. This paper deals with the simple estimate of the buckling strength for the eccentric system for the sake of practical design. Through the use of simple mechanical models and the application of some simplifications, the buckling strength can be given as a root of the quadratic equation.
