Six approaches to the solution of the Saint-Venant torsion problem are considered and their effectiveness for the analysis of typical concrete sections is assessed. The use of the stress, warping and conjugate function formulations are evaluated in respect of their ease of application and relative accuracy when implemented in finite element systems based either on linear triangular or quadratic isoparametric elements. It is shown that the stress function approach is inferior to the other two formulations when linear triangular elements are employed. All three functions are shown to perform well when utilised with quadratic isoparametric elements but it is suggested that the warping function is the most versatile.

The other three methods which are considered are approximations which may be used for the preliminary assessment of torsional properties. The methods are based on both thin- and thick- walled models of the section and also on a modification of the thick-walled model which is such as to give better correspondence with the membrane analogy for the section. It is shown that the thin- and thick-walled approximations can result in errors of up to 50% for typical concrete sections but that this can be reduced to the order of 10% by judicious use of the membrane adjustment. It is, however, further demonstrated that compact sections, such as prestressed concrete bridge beams, are not accurately assessed by the membrane model and require the use of one of the finite element formulations for effective analysis.

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