TANGENTIAL STRESSES IN BENDING ELEMENTS UNDER THE TWO-QUADRATIC LAW OF CONCRETE DEFORMATION

Abstract

The tangential stresses in concrete and reinforced concrete beams under the combined action of bending moment and transverse force are determined in this work. The experimental and theoretical studies of the leading Ukrainian authors regarding the study of the work of compressed and bending concrete and reinforced concrete elements of structures under various force influences and an arbitrary shape of the cross-section are analyzed. Developed methods for assessing the stressstrain state based on real diaphragms of concrete deformation, taking into account physical and geometric nonlinearity. Derived dependences of normal stresses in bending elements under the two-quadratic law of concrete deformation. The authors analyzed the nature of the plot of tangential stresses in a concrete beam. The point where becomes extreme xy τ is determined. The maximum tangential stresses are determined. The tangential stresses under the two-fold law of concrete deformation are described. The maximum tangential stresses under the nonlinear law of deformation were analyzed, and it was shown that they have smaller values than under the linear law. It is shown that the proposed methods of determining stresses in concrete do not provide an opportunity to determine normal and tangential stresses, as well as to analyze the actual stress state in cross-sections along the wall and the height of the elements, therefore, the work continues the research of concrete and reinforced concrete structures to determine the tangential stresses of internal forces with nonlinear laws of deformation of concrete. It is stated that the formulas for the tangential stresses of the element, which take into account the nonlinear component of the law of deformation, in addition to the transverse force, contain the ratio of the bending moment acting in the section to the moment of the calculated concrete beam. On the basis of the obtained results, plots of tangential stresses in the stretched and compressed zones of the concrete cross-section were constructed. According to the research results, the formulas for determining tangential stresses for a reinforced concrete beam are derived, taking into account the variability of the given moment of inertia along its axis.