Affecting of the Long-Term Deformation to the Stability of RC Frame-Bracing Structural Systems under Special Accidental Impacts

Abstract

The paper is devoted to investigation of the loading duration affecting to stability of structural elements of reinforced concrete building frames at post-critical states caused by the sudden removal of one of the load-bearing constructions. Modelling of strength and deformation characteristics of reinforced concrete under long-term loading was performed using the theory of plasticity of concrete and reinforced concrete proposed by G.A. Geniev. Following to this theory, the rheological model of long-term strength of concrete was presented by two elements connected in series, one of which characterizes the process of short-term loading, and the second viscous element corresponds to the Kelvin-Voigt model and takes into account the processes of long-term deforming. It was established that at long-term loads acting to operated reinforced concrete structural system the value of critical force corresponding to loss of stability of the structural element decreases. This fact should be taken into account when assessing the resistance of such building frames to progressive collapse under special accidental impacts caused by removal one of load-bearing elements of a structural system.