Torsion of Perforated Concrete Shafts

A simple method of analysis is presented for torsionally loaded perforated shafts. This difficult topic is presented for the first time in a manner suitable for use in engineering offices. The internal forces, the twist and the period of the free torsional vibrations are found to depend on a single, dimensionless, parameter, which is denoted as torsional stiffness parameter of the shaft. The use of dimensionless coefficients makes it possible to find the general solution and to express it in explicit form. Moreover, it is recognized that there exists a complete mathematical analogy between the torsionally loaded shaft and the laterally loaded shear wall. This, it is expected, will simplify future research in the theory of building structures.