p Pure Torsion-Application of Model of Characteristic Failure Cross Sections

Torsion in structural concrete members is a discipline where in-depth research is still possible and desirable. Sophisticated computer programs have been developed that deliver the ultimate load-bearing capacities after following the whole loading/deformation process. This paper presents the model of the characteristic failure cross sections (MCFC) and the efficiency factor, psi, of the skew reinforcement and applies them to fundamental test series from the literature on beams with rectangular cross sections loaded in pure torsion. A simple design formula is proposed and validated on test results from the literature. Failure modes and the influence of concrete strength are discussed. Minimum and maximum rates of reinforcement are defined, and detailing recommendations are given