The dissertation is devoted to solving an important scientific and technical problem of developing the foundations of the general strain and force model of concrete and reinforced concrete resistance, based on the reinforced concrete elements sections real state diagrams and aimed at the disclosure of their internal static uncertainty, while ensuring the methodological unity of all calculations by the boundary states. In this work, the continuity dependence of the reinforced concrete elements state diagram the "moment-curvilinear", which has functional unity with the concrete deformation diagram the "strain-deformations", transforms into it and provides the methodological unity of reinforced concrete elements calculations, is obtained. The method of disclosing the internal static uncertainty of reinforced concrete elements sections at any stage of their deformation is proposed by completing the system of static, geometric and physical relations of the element with the state diagram the "moment-curvilinear" and the five-parameter function of the compressed concrete boundary deformations, which provides a significant reduction of iterative operations in calculations. The method for determining the reinforced concrete elements curvature directly from the state diagrams the "moment-curvilinear" is proposed, which substantially increased the efficiency of the energy methods application for deflections calculating and improved the calculating method of their crack resistance with the avoidance of the influence of a number of empirical parameters and coefficients. Research results develop a general theory of concrete and reinforced concrete elements deformation, improve methods of their calculation by the boundary states and promote the use of common methodological prerequisites for their implementation. The obtained dependence of the state diagram the "moment-curvilinear" provides an integral estimation of the stress and deformed state of the reinforced concrete elements cross sections at any stage of their deformation. The analytical solutions of the integral dependences the "moment-curvilinear", obtained by the extreme Fermat criterion, allow us to predict not only the boundary curvature or limiting deformations of the compressed concrete boundary fibers in reinforced concrete elements, but also their stress and deformed state in general. The curvature determination directly from the state diagrams the "moment-curvilinear" ensures the closure of the solutions "stiffness-curvilinear-deflection" in the reinforced concrete elements calculations at the boundary states. Together, the solutions obtained can serve as the basis for the further development of concrete and reinforced concrete the general theory. The developed methods of calculating the normal cross sections of reinforced concrete elements at the boundary states are realized by compact algorithms in both engineering and programmatic interpretations, and the recommendations on the reinforced concrete elements of structures calculation prepared on their basis are adopted by RIBS (Kyiv) for use in the development and improvement of national normative documents. The research results have found practical application in the engineering organizations of Rivne, Volyn and Lviv regions in the construction objects design for residential, public and agricultural purposes. Research materials are introduced into the educational process of higher education institutions in the preparation of specialists in the construction profile. Key words: reinforced concrete elements, resistance model, stiffness, state diagrams, limit deformations, bearing strength, crack resistance, deflections.
