Torsional rigidity of reinforced concrete bars with arbitrary sectional shape

In this paper, the torsional rigidity of arbitrarily shape bar made of diff erent materials is studied on the basis of theory of elasticity and finite element approach. With additional boundary conditions for the common bounda ries of different materials from the continuous conditions of deformation a nd traction across the interior boundary, the torsion function can be solve d numerically from the second boundary-value problem of potential theory. T he traction jump boundary conditions across the interior surfaces are enfor ced in the alternate finite element approach. Several examples are shown to check the computational approach proposed, and the approach, at last, is a pplied to calculate the torsional rigidity of reinforced concrete bar and s ome multiply connected cross sections such as tower leg section of the Tsin g Ma Bridge and other engineering structures. (C) 2000 Elsevier Science B.V . All rights reserved.