MAIN FEATURES OF CONCRETE DEFORMATION UNDER THE ACTION OF DYNAMIC LOADS

Abstract

This article is devoted to the features of the general model of compressed concrete deformation in concrete and reinforced concrete elements and structures under the dynamic loads action. The proposed model is a further in-depth development of the previously developed generalized deformation and force model of concrete and reinforced concrete resistance to force effects. It is based on the hypothesis of invariability and independence from the loading mode of the specific potential energy of concrete ultimate deformation (destruction) in a standard sample. A critical analysis of the research results by other authors published today on the above-mentioned subject has been performed. The main attention is paid to the well-known dynamic increase factor (DIF). The main advantages and disadvantages of the currently existing methods and ways of its determination have been classified and analyzed. An analytically justified function of its maximum possible values under the dynamic loads action was obtained. The various factors influence on the DIFu limit values for compressed concrete is taken into account using an integrated parameter – the well-known coefficient of elastic-plastic concrete properties k. The dependence of intermediate DIF values on the compressed concrete deformation rate under the different intensity dynamic loads action is proposed. The effectiveness of the developed method of determining the DIF coefficient for compressed concrete according to the proposed dependence was evaluated by comparing the theoretical calculations results with individual researchers experimental data. Similar comparisons were also made with the calculations results performed according to well-known European methods of the CEB FIB.