The article presents the results of a numerical study of the deformation of concrete prisms under static loading. On the basis of experimental data, an average polynomial dependence was constructed that describes the diagram of concrete deformation. Using the obtained approximation function, a table of stress values and corresponding relative deformations is formed, used to set the law of concrete deformation in the LIRA-CAD 2022 PC in the form of a piecewise linear dependence (law 14). Finite element modeling of the concrete prism was performed using three-dimensional finite elements, taking into account the physical nonlinearity of the material and the step-by-step application of the load. The results of numerical modeling were compared with experimental data, which showed satisfactory coordination of the obtained stress-strain relationships.