Effect of steel bar corrosion on flexural behaviour through bond

Abstract

Steel reinforcing bar corrosion is a major concern in reinforced concrete (RC) structures. Two problems have to be tackled: determining the rate of corrosion and determining the effect of corrosion on the behaviour of the RC structure, not just at the serviceability limit but also at the ultimate limit. This paper deals with the latter, that is, the quantification of the effect of a known amount of corrosion on the flexural capacity of RC beams at the ultimate limit state. A partial interaction numerical procedure is described for quantifying the effect of corrosion at the ultimate limit state. The procedure quantifies: the flexural capacity and ductility prior to debonding – that is, while the corroded bars are still acting as reinforcement; the onset of debonding; and the flexural capacity and ductility after debonding while the corroded bars are acting as tendons. It is shown through mechanics that the onset of debonding due to corrosion is not necessarily a major or catastrophic problem as the RC beam can still have significant strength and ductility, both of which are quantifiable.