Stability of eccentrically compressed reinforced concrete elements under special impacts with account taken of shear deformations

Introduction. When structural models of reinforced concrete frameworks of buildings and structures are designed, bars and plates simulate structural elements. As rule, such an approach entails rigid cohesion between reinforcement bars and concrete; thus, it fails to simulate the true nature of their joint action in the areas having high stress gradients, for example, beam-column junctions. In this regard, it’s necessary to plot analytical dependencies and develop a methodology for the stability analysis of the strain state of bar elements of reinforced concrete frameworks of buildings and structures with account taken of shear deformations at the interface between a reinforcement bar and concrete. Materials and methods. The Rzhanitsyn composite bar theory was applied to design a stress-strain model of an eccentrically compressed reinforced concrete bar. The Kelvin-Voigt model is proposed as a rheological stress-strain model of static and dynamic resistance of concrete. Results. Analytical dependencies needed to analyze the stress-strain state and stability of an eccentrically compressed reinforced concrete bar exposed to dynamic loading, were plotted. These dependencies take account of shear deformations at the interface between reinforcement bars and concrete. A nonlinear calculation algorithm was developed; it took account of the elastoplastic behavior of concrete and steel bars, when the stability problem of an eccentrically compressed dynamically loaded reinforced concrete bar was solved. Conclusions. Analytical dependencies, obtained by the author, allow to take account of shear deformations at the interface between reinforcement bars and concrete in eccentrically compressed reinforced concrete elements of frameworks of buildings and structures for the purpose of analyzing the stability of such elements exposed to special impacts caused by the unexpected failure of one bearing element of a structural system.