Comparative review of corrosion assessment methods in exposed galvanised steel structures

Accurate estimation of atmospheric and soil corrosion is fundamental to the design and longevity of steel structures, particularly those exposed to elements such as rain, wind, sunlight, and temperature fluctuations. This research compares five widely used methodologies for assessing atmospheric corrosion rates: ISO 9223:2012, ISO 9224:2012, ISO 14713-1:2017, empirical data provided by the Galvanizers Association (UK), and the galvanising specification ISO 1461:2022. Their theoretical underpinnings, applicability, and conservative margins are evaluated. By analysing their approaches to corrosivity classification, corrosion rate calculation, and protective coating specifications, this study highlights their strengths, limitations, and design lifespans, offering guidance on how to apply these tools effectively in engineering practice. To ensure the durability of steel structures underground, the chemical parameters of the soil, such as electrical resistivity, acidity, alkalinity, and sulphate content, should be considered. The DIN 50929-1:2017 standard is analysed as a comprehensive guideline for assessing corrosiveness. The methodologies address atmospheric corrosion and soil corrosion and provide a comprehensive corrosion justification for exposed steel structures in a case study in the UK. The findings underscore the complementary nature of these methodologies in ensuring effective corrosion management for steel structures in various environmental contexts, providing insights into effective corrosion management strategies.