Predicting long term mild-steel weld capacity loss due to climate change influenced marine corrosion

Maritime infrastructure is usually designed for decades however, long-term structural integrity (serviceability and safety) may be compromised by increased rates of corrosion in aggressive marine environments when available mitigation techniques either fail or cease effectiveness. This is of particular concern for weld heat affected zones as they are known for their higher rate of localized corrosion. Moreover, increasingly environmental changes such as possible rise of seawater surface temperatures and increased seawater nutrient pollution is causing some concern regarding the integrity of commercial and industrial structures in marine exposed environment. These changes may affect abiotic and biotic (microbial) corrosion. In this paper structural reliability theory is used to model the long-term structural capacity loss of welds for mild-steel based on data obtained from mild-steel piling exposed for 33 years in a seawater harbour and on relevant empirical climate change reports. The results show that structural reliability is more sensitive to likely nutrient pollution than to predicted increases in surface seawater temperature, noting that increased seawater temperatures also could increase nutrient pollution from anthropological sources.