To determination of dependence of parameters of surface cracks in concrete and reinforced concrete volume elements

Abstract

To determine the dependences of the parameters of surface non-through cracks, the problem of tensile bulk concrete elements (in the form of prisms) was considered. One group of elements contained a crack normal to tensile forces, and the other was inclined (the problem was modeled using the finite element method in the Ansys software package). The stress intensity factors of three types were determined, for which a macro (subroutine) was written in the APDL language, the calculated coefficients of the 2nd and 3rd type (KI, KII) were used for the first time in the considered problems. On the basis of these coefficients, relations between the length, width of the opening, the penetration of cracks are established, the boundaries of the pre-fracture zone are found, and the residual bearing capacity of the elements with a crack is estimated. It is shown that the stress relief area around the crack has a diamond shape. The dependences obtained and the procedure for obtaining the numerical values of KI abd KII constitute a scientific novelty.