Prediction of fatigue failure of corrosion affected riveted connections in steel structures

Corrosion of steel is now a worldwide issue, threatening the safety of steel structures. Literature suggests that little research has been conducted on the prediction of fatigue failures of connections subjected to simultaneous fatigue and corrosion. This paper proposes a new method to predict the failure of connections subjected to fatigue and corrosion. A model is developed to determine the effect of corrosion on S-N curve of corroded steel. The fatigue damage to corroded connections is modelled as a stochastic process which considers the corrosion effects on both stress range and S-N curve. The first-passage probability method is used to determine the time-dependent probability of fatigue failure of connections subjected to fatigue and corrosion. A case study is then provided to demonstrate the application of the proposed methodology. It is found in the paper that not considering the effect of corrosion on S-N curve can lead to 15.45% reduction of the probability of fatigue failure of corroded connections over 150 years, which can be catastrophic. It has also been found, through sensitivity analysis, that corrosion rate can considerably affect the probability of fatigue failure in longer term. The methodology proposed in this paper can help structural engineers and asset managers in making decisions regarding the repair and/or maintenance of connections subjected to the combined effects of corrosion and fatigue.