Behaviour of concrete beams under torsion: NSC plain and hollow beams

A simple computation procedure is developed to predict the general behaviour of reinforced concrete beams under torsion. Both plain and hollow normal strength concrete beams are considered. Different theoretical models are used to reflect the actual behaviour of the beams in the various phases of loading. To pass from a phase to the following one, transition criteria need to be taken into consideration. Such criteria are explained. The theoretical predictions are compared with result from reported tests. Conclusions are presented. The main conclusion is that the calculation procedure described in this paper gives good predictions when compared with the actual behaviour of the plain and hollow beams.