Structural instability of bars

When compressed over all or part of their cross-section, bar-type structural elements are likely to see their load-bearing capacity affected by instability phenomena. In the case of an axially compressed element (column), such a phenomenon is referred to as "buckling". For an element subjected to bending (beam) around the axis of high inertia of its cross-section, under the action of end moments and/or transverse loads, it is referred to as "tilting". The greater the bar's slenderness, the greater the instability.

This dossier introduces the basic principles that led to the development of dimensional buckling and torsional buckling curves. The practical application of these curves in the context of regulatory verifications is developed elsewhere, more specifically in the files dealing with compressed or bent structural steel components.