Superposition principle as the fundamental error of the creep theory and standards of the reinforced concrete

The errors in the foundations of the modern theory of creep of reinforced concrete caused by the use of the principle of superposition, which is an expansive interpretation of the principle (scheme) of the linear superposition of Boltzmann, are revealed and investigated. Extensive interpretation arises from the following circumstances: the phenomenon of aging of concrete; changes in the short-term properties of concrete with age τ at the time of its loading; nonlinearity of creep deformation, starting from the lowest loading levels; the use of “chain models” in the form of a series connection of several bodies, for example - the theory of Maslov, the theory of aging, a viscous element; addition of short-term properties of concrete to the properties of its creep; expanding interpretation of the compliance function for difference kernels. In the international norms of creep of reinforced concrete only linear creep of concrete and instantaneous linear properties are taken into account; their authors call their developments “a new advanced format developed in recent decades by international standards institutions”. However, these format estimates are erroneous. According to the Eurocode, a short-term diagram of concrete σ-ε has a descending section and a limited extent; and the floor-duchit of concrete is nonlinear. The founders of the theory are A.A. Gvozdev, N.Kh. Harutyunyan, S.V. Aleksandrovsky, P.I. Vasilyev - repeatedly indicate: “creep-concrete deformations are non-linearly dependent on stresses, starting from the lowest levels”. The results of the analysis published by the authors in the journal of Structural Mechanics of Engineering Constructions and Buildings No. 6 of 2017 and No. 3 of 2016 are supplemented. The article was written in accordance with the recommendations of the round table held in the RUDN University on June 9, 2016, under the direction of the D.Sc., prof. S.N. Krivoshapko.