Scientific journal
Scientific Review. Technical science
ISSN 2500-0799
ПИ №ФС77-57440

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CONCERNING THE ISSUE OF CALCULATION OF THE COMPRESSED REINFORCED CONCRETE ELEMENTS WITH REGARD TO THE INSTANTANEOUS NONLINEARITY AND NONLINEAR CREEP BEHAVIOUR OF CONCRETE

Elistratov V.N. 1
1 Saint-Petersburg State University of Architecture and Civil Engineering
The article specifies a problem related to the neglect of analytical dependence that approximates a nonlinear diagram with a falling section of the instantaneous deformation of concrete when making the concrete creep equations, as well as the stability calculation of the compressed reinforced concrete elements at high stresses, when the nonlinear creep deformations occur. It was found out that the use of Hooke’s law to describe the connection between the instantaneous deformation and stresses inside the concrete at the stress level of more than 0,45R leads to a mismatch of theoretical calculations and the experiments held. This research paper presents a method to resolve this problem by bringing in the Sargin formula to describe the relationship “σb – εb”, given in Eurocode 2, to a convenient form for practical use (quintic polynomial), and integrate them into the existing creep equations instead of Hooke’s law. Subsequently, it has enabled the obtaining of analytical equation to determine the coefficient of concrete creep, which is regulated by the Russian and European design codes for concrete and reinforced concrete structures and is used in calculation of compressed concrete elements for continuous stress.