РАСЧЕТНЫЕ МОДЕЛИ ДЕФОРМИРОВАНИЯ ЖЕЛЕЗОБЕТОННЫХ КОНСТРУКЦИЙ В ЗДАНИЯХ И СООРУЖЕНИЯХ ПРИ КРУЧЕНИИ С ИЗГИБОМ

Abstract

A computational model of the complex resistance of reinforced concrete structures in buildings and structures under torsion with bending is proposed, consisting of a support block (formed by a spatial crack and a compressed concrete zone closed on it, - spatial section k) and a second block formed by a vertical section I– I, passing perpendicular to the longitudinal axis of the reinforced concrete element along the edge of the compressed zone, closing the spatial spiral-shaped crack. Cases are considered when the torque effect has the greatest influence on the stress-strain state of structures. We have a design diagram A of the resistance of a reinforced concrete structure under the combined action of a bending moment, torque and shear force for a spiral-shaped spatial crack, as well as a design diagram B for a spatial X-shaped crack. In this case, as the design forces in the spatial section, the following are taken into account: normal and tangential forces in the concrete of the compressed zone; components of axial and thrust forces in the working reinforcement crossed by a spatial crack. Resolving equations are constructed that form a closed-loop system and the Lagrange function that unites them is written. Using the partial derivatives of the constructed function with respect to all the variables included in it and equating them to zero, an additional system of equations is compiled, from which, after the appropriate algebraic transformations, a dependence is obtained that allows one to find the projection of a dangerous spatial crack.