Torsional strength of reinforced concrete beams

A simple method for predicting the ultimate strength and mode of failure of reinforced concrete beams subjected to pure torsion is presented. This met hod is an extension of a recently developed method for predicting the stren gth of membrane elements subjected to pure shear that was also applied to b eams subjected to combined shearing forces, bending moments, and axial load s. The torsional strength is related to the amounts of transverse and longi tudinal reinforcement and to the concrete strength. To check the adequacy o f this simple method, the calculated strength and mode of failure are check ed against the experimental results of 66 beam tests available in the liter ature, and good agreement is found. The simplicity of the method is illustr ated by an example.