Torsion: from theory to practice

This paper deals with the basic torsion analysis of members with thin-walled open cross-section from the point of view of influence of the pure ( Saint-Venant) torsion rigidity to the member behaviour under mixed torsion, combined of pure and warping torsion effects. The attention to the practical understanding of torsion problems is given. Comparing to the bending problems the torsion analysis is more laborious and complicated for practical design even in very simple cases of boundary condition and loading. In this connection an approximate design procedure for torsion members based on the modified analogy between bending and torsion is being presented.