Efforts in beams subjected to torsion and bending Case: Analysis of steel beam bridge-crane

Abstract

In all structures stresses due to torsion are originated when the resultant of the forces doesn't cross by the shear center o f the section. Shear center as well has one double meaning: on the one hand it's the point where the resultant o f loads must be applied so that a structure moves without rotating and by another one, is the point with respect to which one structures rotate, when it's put under torsional moments. Normally, solicitations due to the Saint Venant Torsion and the Warping Torsion, occurring. The fundamental difference among them is in the form as the section is distorted. While first, they are characterized by the presence o f the shear stresses in the plañe of the section, in second appear in addition, displacements in the longitudinal direction that are translated in the presence o f normal stresses. In order to illustrate the characteristics o f the Warping Torsion a case o f design o f a bridge crane in metallic structure is reported in the present article, that is put under the action o f a train o f live loads. With this election, it's desired to show the application o f the theory o f the sectorial areas in the determination o f the stresses due to the Warping Torsion in a construction of the daily practice of an engineer designer o f structures.