A Simplified Empirical Model for Predicting Residual Flexural Capacity of Corroded Prestressed Concrete Beams

Prestressed concrete (PSC) beams are widely used in critical infrastructure but are highly susceptible to corrosion in aggressive environments, which can significantly compromise their structural performance. Accurate prediction of residual flexural capacity is crucial for evaluating the safety and serviceability of corroded PSC elements. This study presents a simplified empirical model for estimating the residual flexural strength of corroded PSC beams, with maximum strand mass loss serving as the key governing parameter. This approach is superior to existing models, which typically rely on average mass loss and fail to capture the localized stress concentrations induced by pitting corrosion. The model was developed from an experimental dataset of 31 corroded beams, covering maximum mass loss up to 90% using exponential regression. An extensive database of 124 test results from 19 independent studies was used for the purpose of verification and comparison with existing models. The proposed model was capable of effectively capturing the degradation trend and providing accurate and conservative predictions, with an average experimental-to-calculated capacity ratio of 1.04 and a coefficient of variation of 8.7%. Its direct reliance on maximum mass loss, which can be indirectly inferred from corrosion-induced crack widths, significantly enhances the practicality and safety of the model for field condition assessments and life-cycle management of PSC structures.