Probabilistic Analysis of Corrosion Rates and Degradation of Weathering Steel Bridges

Corrosion of weathering steels in outdoor conditions has been observed since their pioneering applications in construction in the 1960s. Changing environmental conditions such as decreasing SO2 concentration and changes in temperature and relative air humidity affect the formation and development of a protective layer of corrosion products on the surface of these steels. The study compares the long‐term corrosion rates of weathering steels according to EN ISO 9224 with the measured rates for various environments in the Czech Republic and abroad, with a focus on sites with high concentrations of chlorides from de‐icing salts. When considering related uncertainties, the corrosion rate models provide estimates in a wide range, and in‐situ measurements can significantly improve corrosion loss predictions. The reliability of bridges made of weathering steels with a well‐developed protective layer is insignificantly affected by corrosion. However, low reliability levels may be experienced in critical details where for example leakage may damage the protective layer of patina.