This paper presents a unified method for the torsion and shear design of prestressed and non-prestressed concrete flexural members, and provides an alternative method to the provisions of the ACI Building Code. The method applies to rectangular, box and flanged sections such as L-beams. The approach depends on subdividing the given section into component rectangles. Equations are given for the shear and torsion web reinforcement of beams as well as expressions for the minimum reinforcement and required amount of longitudinal steel. The design method is illustrated with a fully worked numerical example of a spandrel beam. The shear and torsion provisions in the Sixth Edition of the PCI Design Handbook are based on the principles outlined in this paper, which will also be referenced in ACI 318-05. The design method has been shown to be reliable, accurate and easy to use.
