As the main method of calculating reinforced concrete structures for strength the modern Russian standards have been using the method of limiting equilibrium, which contains some contradictions. In recent years, a discussion has been developing on the transition to the deformation model of the resistance of reinforced concrete used by European code. However, there are a limited number of studies confirming the consistency of the proposed deformation model. We calculated the deformation of a slab on the basis of the Russian standards for theoretical and deformational model. The calculation was carried out by the finite element method using the model of nonlinear deformation of concrete. Then the analysis of the obtained results and their comparison with the results of calculation according to the theoretical provisions of the norms were performed.