The effect of the warping deformation on the structural behaviour of thin-walled open section shear walls

Thin-walled open section beams are carefully analysed by Vlasov's theory of the sectorial areas. It allows to take into account their peculiar warping deformation which appears in presence of torsional actions. This behaviour determines a further stress state along the axis of the element which is rarely considered in structural analyses. The aim of the present paper is the evaluation of the warping deformation of thin-walled open section beams subjected to torsion. Firstly, the analytical theory proposed by Vlasov is verified through an experimental test on a steel specimen defined by a U profile. Specific analyses are performed with the aim of a sophisticated optical device in order to assess the transverse distortion of the section. Then, the results obtained experimentally and confirmed by a Finite Element (FE) program permit to validate a computer program based on the analytical theory and devised to study the structural behaviour of high-rise buildings stiffened by thin-walled open section shear walls. In order to evaluate the effectiveness of the program, an example which highlights the benefits provided by the present method compared to FE program is carried out.