Localized corrosion of steel sheet piling

• Accelerated low water corrosion (ALWC) also causes differential horizontal corrosion.
• Corrosion perforation is correlated with material imperfections.
• Imperfections are more common in the webs and near the flange junctions.
• Older steel piling has more imperfections and is more prone to localized perforation.

When steel sheet piling suffers accelerated low water corrosion the webs and flange-web regions of individual piles often perforate first, for reasons not fully understood. To investigate this, samples of the cross-sections of typical U and Z profile sheet piling were exposed to natural seawater for 1, 2 and 3 years. They showed localized corrosion in the central region and also near the flange-web junctions. These locations were found to have more material defects and segregation and show composition differences. It is proposed these observations are linked to localized sheet pile perforation after long exposure to seawater.