The In-Plane Stability of a Frame Containing Pin-Based Stepped Columns

This paper presents five graphs and a simple formula from which the in-plane buckling load of a pin based stepped column, forming part of a rigid-jointed frame, can be calculated. These analytical aids were derived from a parametric study of the problem using a proven finite-element stability analysis program. They account for the rotational and translational restraints within the frame system, and enable the designer to readily determine the most critical disposition of the crane loads. The method is illustrated by an example.