Modeling of Reinforced Concrete in the “LIRA” Intelligence for the Problem of Crack Opening

In most of the world-famous computing complexes, when designing reinforced concrete structures, is not taken into account the current development of a finite element model, where it is necessary to adequately take into account the nature of the development and opening of cracks in them. The criterion for the disclosure of cracks in reinforced concrete structures is carried out using the achievement of completely different criteria. Completely different criteria should be used when analyzing the appearance and development of discrete cracks for modeling discrete cracks, taking into account the effect of violation of the discontinuity of concrete and the reaction of reinforcement from the mechanics of destruction of two elements and the development of cracks in reinforced concrete. The physical essence of which is the additional deformation effect of the reaction of reinforcement and concrete in the form of an ellipsoid for an alternative kinematic crack, from a universal two-console element in reinforced concrete. At the same time, in the stretched area of concrete for the distance between cracks and the width of the opening has in these local zones adjacent to the crack adhesion and importantly compressed concrete tensions. A classification of the basic spatial cracks in spatial reinforced concrete composite structures is constructed for discrete levels,—cracks that develop to zones of concentration of geometric, force, deformation loading or the inter-environment region, where the full picture of various types of cracks. Based on the basic cracks, a complete scheme of spatial cracks is applied by finding adjacent cracks with the involvement of the deformation criterion of their formation and the method of finding the extremum of the function of many variables using Lagrange multipliers. Nevertheless, the method of modeling discrete cracks, including using most of the world’s well-known, has not been developed by the intelligence of computing complexes. The development of spatial cracks is carried out on special bilinear surfaces. Then approximating spatial finite elements are inserted into them, which are “expanded”, modeling a spatial crack, the disclosure of which is set in the form of a deformation effect, taking into account the effect of reinforced concrete continuity violation. When solving the inverse problem of determining the width of crack opening, the deformation effect is not set, and with the help of “stitching”, only the presence of a gap of the minimum possible width is modeled, its opening under appropriate loading and determines the width of crack opening as the divergence of the banks of this gap. The article considers the pairs of finite elements adjacent to such a crack from opposite sides—a special calculated two-element console model. These pairs are considered in two states: before their “stitching” and after their “stitching”, taking into account the deformation effect and the effect of breaking the continuity of concrete. To find the level distance between cracks and the width of their opening from a reinforced concrete structure, which allows determine the desired parameters, tools or modules of the LIRA program.