Variability in Section Loss and Maximum Pit Depth of Corroded Prestressing Wires

In the last years, chloride-induced corrosion damage has been recognized as a primary cause of deterioration in infrastructures. In this context, structural durability of prestressed concrete (PC) bridges results to be strictly affected by pitting corrosion, causing detrimental effects in terms of stress concentration and residual strength capacity. In this paper, the pitting corrosion of twenty-three seven-wire strands belonging to naturally corroded PC beams exposed to wet-dry cycles for 10 years is discussed. All strand samples were scanned using a structured light 3D scanner of the GOM ATOS series in order to obtain information about pit depth, mass loss and wire section loss. Correlation between strand section loss and wire section loss is proposed. Finally, the paper describes a probabilistic model for the prediction of the maximum pit-depth distribution of prestressing wires by using the Lognormal distribution function.