Structural integrity assessment of aging steel water pipelines subjected to corrosion degradation and traffic loads

Purpose Aiming at the aging steel water pipelines buried under urban intersections, a predictive reliability assessment framework is proposed by considering the combined effects of internal corrosion and traffic-induced fatigue to provide the decision support for pipeline maintenance and management. Design/methodology/approach The proposed framework evaluates the corrosion effects and then integrates the corrosion and fatigue damage for reliability assessment. The effects of corrosion, considering the material performance deterioration and pipe stress concentration, are first evaluated. A novel strain energy density-based approach is proposed for integrating damage induced by corrosion and fatigue, whereby a new limit state function considering the combined action of corrosion and fatigue is proposed based on strain energy density failure criteria. Finally, reliability assessment has been conducted on the aging water pipelines under urban intersections. A DN500 steel water pipeline buried at an urban intersection is taken as a case study to demonstrate the engineering practicality of the proposed framework. Findings The predicted fatigue life degradation induced by corrosion is consistent with the corresponding fatigue testing results of the corroded specimens in literature, which verifies the effectiveness of the proposed limit state function. And the case study of a DN500 pipeline has demonstrated the feasibility and engineering practicality of the reliability assessment framework. Originality/value This study proposes a novel strain energy density-based approach for integrating corrosion and fatigue effects in pipeline reliability assessment. The limit state function considering the combined effects of fatigue loading and corrosion is then developed based on the approach.