Bayda D. Residual Load-Carrying Capacity of Reinforced Concrete Beams After Their Partial Failure

The dissertation suggests a solution of the problem of creating a method of evaluation of the residual load-carrying capacity of reinforced concrete beams which, while in service, underwent destructive loading. When inspected, the technical condition of such beams is considered invalid or damaged and, in practice, the beams are considered destroyed. The dissertation suggests to regard these structures partially failed, e. i. having a residual load-carrying capacity. Consideration of the values of the residual load-carrying capacity of partially failed structures, when increased, can prove economically expedient. Estimation of the residual load-carrying capacity of partially failed beam elements requires a mathematical simulation of the process of their failure. The research suggests an experiment-based method of estimation of stress and strain state of normal cross sections of reinforced concrete beam elements under concrete compressed zone failure. The suggested method is based on the principles of anaverage cross section model of NIISK (State Research Institute of Building Constructions, Kyiv). The method allows to receive "bending moment-curvature" dependences from the beginning of loading to complete failure under a short- and long-term loading. As preconditions for the calculation method the criteria of the beginning and complete failure of the concrete compressed zone were suggested. It allows to clearly separate failing concrete structures from those which do not fail.