Deformation of box-sectional structures during torsion with bending

The article is devoted to the problem of complex stress state of reinforced concrete under the action of torsion with bending, taking into account axial and transverse forces. The existing calculation models remain imperfect, despite a significant number of publications in the world on this problem. They are fragmentary and sometimes contradictory and consider individual special cases of stress. The proposed version of the deformation model is based on physical relations for reinforced concrete, static equations and conditions for compatibility of deformations in the design section at the stage after the crack formation. The calculation model takes into account all the components of external forces in the rod element, the spatial nature of cracks, various cases of the location of the compressed concrete zone or its absence, depending on the ratio of the acting forces in the design structure. The obtained analytical dependences allow one to determine interconnected design parameters, such as stresses in the concrete of the compressed zone, the height of the compressed concrete, stresses in axial and transverse rods, deformations in concrete and reinforcement, curvature and twisting angle of a reinforced concrete element, while simultaneously applying a twisting and bending moments, axial and transverse forces to the element. The deformation model obtained in the article can be used in the design of a wide class of reinforced concrete structures under the action of torsion with bending taking into account axial and transverse forces in the calculated element.