Torsion of structural cores on deformable foundations

An approximate method is presented for assessing the influence of foundation deformations on the warping stresses of a shear core subject to torsional loading. The core is assumed supported on elastic foundations such that the vertical displacements are proportional to the imposed forces. Solutions have been derived for two general forms of loading, a concentrated torque at any level, and a distributed twisting moment whose intensity is defined as any polynomial in the height coordinate. A numerical example is given to illustrate the reduction in warping stresses which can occur as a result of relative foundation deformations.