Influence of depth thresholds and interaction rules on the burst capacity evaluation of naturally corroded pipelines

Abstract

Based on 14 naturally corroded full-scale pipe specimens, the present study investigates to what extent a corrosion depth threshold influences the burst capacity of naturally corroded pipelines predicted using the finite element analysis (FEA) and well-known RSTRENG model. The study also employs FEA and RSTRENG to investigate the accuracy and effectiveness of five representative interaction rules, namely the B31G, B31.4, CSA, DNV and CW rules, for combining individual naturally-occurring corrosion anomalies into clusters. The analysis results indicate that applying a corrosion depth threshold of 10% of the pipe wall thickness (t) (i.e. any corrosion depths < 10%t are ignored) has a negligible impact on the predicted burst capacity. Furthermore, the CSA interaction rule is considered the most effective among the five interaction rules investigated in that it captures the most critical region of a corroded area without resulting in very large corrosion clusters that are time-consuming to identify and analyze.