Influence of corrosion extension on the flexural cyclic behaviour of steel elements

Abstract

The study numerically investigates how corrosion rate, location, and extent affect the flexural cyclic behaviour of steel elements. Eleven uniform corrosion scenarios were analysed, from partial to full corroded plastic hinge region (PHR), considering both geometry‐only degradation and combined geometry–material deterioration. Nonlinear cyclic analyses were conducted for three member lengths and corrosion rates, and four response parameters were normalised against uncorroded baselines to isolate corrosion effects. Results show that corrosion near the fixed end of the cantilever beam governs flexural strength and ductility degradation; damage to the first 50–75% of the PHR causes reductions similar to full‐length corrosion. The most severe condition results in a 60% decrease in moment capacity, whereas corrosion confined to the farthest quarter has minimal effect. Material degradation further amplifies strength loss but has a limited effect on rotation capacity. Overall, corrosion location is more critical than extent in controlling cyclic flexural response. The findings provide quantitative guidance for prioritising inspection and rehabilitation near fixed supports, as well as for modelling corroded steel members in seismic performance assessments.