ВАРИАНТ ТЕОРИИ ПЛАСТИЧНОСТИ БЕТОНА ПРИМЕНИТЕЛЬНО К СТАТИКО-ДИНАМИЧЕСКОМУ РЕЖИМУ ДЕФОРМИРОВАНИЯ

Abstract

Abstract. The substantiation of the modes of static-dynamic loading of the operated reinforced concrete frames of multi-storey buildings under the out-of-design impact in the form of sudden removal of individual load-bearing elements is presented. Based on the theory of plasticity of concrete and reinforced concrete by G.A. Geniev, analytical dependences are constructed to determine the parameters of the static-dynamic deformation diagram of concrete under various modes of static loading and sequential dynamic loading. The advantage of the obtained refined variant of concrete deformation is that it contains two important parameters that take into account the influence of the loading speed and the level of static loading on the complex stress-strain state of concrete. Numerical studies have shown that the limiting static-dynamic strength of concrete under dynamic loading depends on the level of the initial stress state under static loading of concrete, from which dynamic loading is carried out to the limit state. The numerical analysis carried out using the model under consideration also confirmed the results of experimental studies that microcracking in concrete under static loading does not begin with a certain stress level, but practically from the moment of the beginning of concrete loading. The results obtained are of interest for solving applied problems related to the problem of survivability, protection of buildings and structures from progressive collapse, in particular when determining the criteria for the strength of concrete under special stress.