THE PROBLEM OF CRACK OPENING WIDTH AND STIFFNESS OF REINFORCED CONCRETE STRUCTURES, BUILDINGS AND CONSTRUCTIONS

The article defines the main results for the development of reinforced concrete mechanics. In the isotropic medium between the cracks is used "first object - flows-blocks", "second object - main cracks" and the effect of reinforced concrete, the physical essence of which is the non-uniformity of concrete and continuous reinforcement. Reactions arise in the concrete for deformation of the reinforcement from the bonding of the compressed concrete in the tensile region. The average resistance of the tensile concrete and the "average total force of the working reinforcement," the third object, are transmitted through the effect of reinforced concrete and the "dowel" effect. The crack opening widths are the relative mutual displacements of reinforcement and concrete, determined from the boundary conditions and the Thomas-Author hypothesis. A new classification of cracks has been developed: regular cracks (anisotropic medium of reinforced concrete) and main cracks based on the effect of reinforced concrete (origins - concentrations) and maximum opening in the closed equations of mechanics of reinforced concrete from the Lagrange function. The author has proposed hypotheses, theorems of linear and angular deformations, functionals for deplanation of cross section of reinforced concrete element from elastic-plastic stage, jumps - cracks and stiffness matrix in a single compound strip which allow to reduce the order of differential equations. The resistance design model method for reinforced concrete mechanics is used for the rod, wall, and slab of the "envelope" of cracks. Hybrid from Lira (finite element method of reinforced concrete from anisotropy) developed in the form of two finite element effect of reinforced concrete of "flat and spatial cantilever" for external and internal displacements. The general principle from Loleith to the "opening - closing" of cracks, the stiffness of the mechanics of reinforced concrete is obtained in the form of the method of the computational model of resistance.