SIMULATION OF STRESS-STRAIN DIAGRAM OF COMPRESSED CONCRETE UNDER LONG-TERM LOADS

Abstract

This article is devoted to the modeling of the deformation diagram of compressed concrete under the action of a long-term load. The specified modeling is carried out by transforming the standard deformation diagram of compressed concrete obtained under the action of a static load. The main attention is paid to the effect of low loading rate on the determining parameters (strength and "critical" deformations) of the concrete deformation diagram. A critical analysis of currently known studies of the levels of long-term strength and "limit" deformability of compressed concrete is given. It is shown that the long-term strength of compressed concrete and its deformability are dependent not only on the strain rate of the concrete itself, but also on the level of its elastic-plasticity (class).

The functional relationship between the above-mentioned characteristics of compressed concrete under the action of static and long-term loads is established using the law of conservation of the specific potential energy of deformation of the material. It is demonstrated how it can be used to relate the strength of compressed concrete under three different loading modes. An analytical dependence was also obtained, which connects the elastic-plasticity coefficients of compressed concrete under the action of static and long-term loads. It is also shown that the coefficients of elastic-plastic properties of concrete under long-term and static loads are also related to each other with the help of the initial modulus of elasticity. The expediency of using in practical methods of calculating concrete and reinforced concrete elements and structures, not the normative, but the initial modulus of elasticity (deformations) of concrete is substantiated