CALCULATION OF STRUCTURAL DEGRADATION DUE TO CORROSION OF REINFORCEMENTS

Abstract

Reinforced concrete structures can deteriorate due to corrosion of reinforcements. The main structural consequences due to corrosion are: a) loss of steel cross section which can be generalized or localized; b) loss of steel ductility, a phenomenon attributed to hydrogen generation due to acid production during the corrosion process; c) loss of steel/concrete bond due to the gap and cracks created by the steel section reduction and d) the cracking of concrete cover due the pressure generated by the oxide production, which aims in a loss of load-bearing cross section of concrete. All these effects influence the progressive loss in structural capacity. The loss rate is directly linked to the corrosion rate which in turn depends on the climate. Assuming that the corrosion rate is averaged at a yearly basis, the rate of structural deterioration can be predicted by considering residual load-bearing areas. Examples will be presented on corroded beams at different degrees, in order to illustrate de principle of recalculation based in the reduced cross section and the consideration of the bond loss.