Determination of Static-Dynamic Deformation Parameters of Concrete

Abstract

A variant of the deformation model of static-dynamic deformation of concrete, when varying the level of initial static loading, is proposed. On the basis of the theory of plasticity of concrete and reinforced concrete by G.A. Geniev, analytical dependencies have been built to determine the parameters of the diagram of static-dynamic deformation of concrete under different loading modes, and deformation criteria of strength have been formulated in the assumption of a single-parameter connection "limit strains-limit stresses" not only from the type, but also from the level of stress state. Numerical studies on the example of uniaxial loading show that the maximum dynamic strength, the maximum deformability of concrete and the maximum permissible time of dynamic impact in case of dynamic loading depend on the level of initial stress state in case of static loading of concrete, from which dynamic loading to the limit state is performed. The numerical analysis of static-dynamic deformation of compressed reinforced concrete elements under different loading modes carried out using the considered model also confirmed the results of experimental studies that microcracking in concrete under the static loading starts not with some level value of stresses, but practically from the moment of concrete loading beginning. The obtained results are of interest for solving applied problems related to the problem of survival and protection of buildings and structures from progressive collapse, in particular when determining criteria of concrete strength under a particularly tense state.