Calculation of deformations of concrete with indirect reinforcement according to limit state design

Abstract

Currently, the issue of increasing the efficiency of the use of traditional materials in building structures due to rational structural solutions and improving design methods and material models is relevant. The use of indirect reinforcement improves the strength and deformation characteristics of concrete. The article considers the influence of indirect reinforcement in the form of transverse welded meshes on the strength and ultimate compressibility of concrete. The main attention is paid to the determination of the strain values determining the stress-strain diagram for concrete with indirect reinforcement. It is known that with an increase in the strength of concrete, the value of its ultimate compressive strains decreases. Indirect reinforcement can significantly increase the ultimate compressibility of concrete and makes the difference in ultimate deformations even more significant for concrete of different strengths. In this context, when calculating structures in accordance with the limit state design and decreasing the strength values of concrete in order to obtain the necessary security, it is possible to overestimate the ultimate compressibility of concrete. This is unacceptable in calculations based on the deformation model, since the achievement of ultimate deformations of the material is the main criterion for structural failure. To confirm the hypothesis, the results of tests for central compression of concrete with indirect reinforcement in the form of transverse welded meshes were selected. The strain values at the peak of the diagram were calculated for the experimental samples. Calculations were also performed for the characteristic compressive strength values and the design values of strength. The results are compared with experimental data. A significant overestimation of the values of strain at the peak of the diagram was noted in the calculations based on the characteristic compressive strength values and the design values of strength.