Romashko-Maistruk O. Resistance of reinforced concrete elements to the multilevel formation of normal cracks

Thesis is devoted to the development of a general method of calculating the fracture resistance of structural reinforced concrete elements, taking into account the multilevel formation and the opening of normal cracks. The object of research – the process of multilevel formation and opening of normal cracks in reinforced concrete elements based on a model that takes into account the reinforcement to concrete adhesion; goal – to develop a general model and engineering methods for calculating the normal cracks multilevel formation in reinforced concrete elements based on a generalized model of reinforcement to concrete adhesion; methods – analysis of the experimental and theoretical studies results related to crack resistance of reinforced concrete elements; physical and mathematical modeling of SSS parameters of reinforced concrete elements; methods of numerical analysis, probability theory and mathematical statistics for processing the results of experimental and theoretical research; results – for the first time a force criterion of local adhesion disorder of reinforcement with tensioned concrete was proposed and a model and method for determining the energy resource of reinforced concrete elements based on deformation parameters was developed, the deformation-force model of the reinforced concrete elements resistance to force effects in the formation and development of normal cracks and a general method for calculating the normal cracks opening width were improved from the standpoint of sequential multilevel accumulation of concrete and reinforcement mutual displacements, a model of reinforcement-concrete adhesion was developed through the use of a nonlinear function of average stresses of the specified adhesion and a model of normal cracks multilevel formation in reinforced concrete elements, taking into account local adhesion disorder of reinforcement to concrete; introduced – in the design of load-bearing structures of reinforced concrete floors of residential and public buildings; area of use - in design practice for the calculation of reinforced concrete structural elements, in research institutions in the development and improvement of national regulations and in the educational process in the development of methodological support for disciplines related to reinforced concrete structures.