A model of stress concentration factors for external corrosion patches on large-diameter underground cast iron pipes

ABSTRACT

Field evidence revealed that buried cast iron water pipes can deteriorate through large localized corrosion patches with lengths greater than 1 m, formed by a cluster of small pits. This study investigated the effect of large corrosion patches on the performance of large-diameter cast iron pipes. Although large corrosion patches are highly irregular in nature, they were idealized as semi-ellipsoids. To validate the approximation of corrosion patch geometries with semi-ellipsoids, comparison of finite element models of scanned corroded pipe geometries with the approximated semi-ellipsoidal patches on the same pipes were conducted. Following this validation, parametric studies were performed, which covered a wide range of the pipe and patch dimensions. Based on the finite element analysis, an equation for stress concentration factors was derived and is presented in this paper. This development will significantly assist the pipe engineers and asset managers in the condition assessment of corroded cast iron pipelines.

KEYWORDS:

• Pitting corrosion
• large corrosion patch
• stress concentration
• cast iron pipes

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This publication is supported through the activities of the Advanced Condition Assessment and Pipe Failure Prediction project, which was funded by the consortium of Australian water utilities lead by Sydney Water Corporation, Water Research Foundation (United States), Water Industry Research Ltd. (United Kingdom), the Smart Water Fund project funded by South East Water, City West Water, Yarra Valley Water, and Melbourne Water, and the Implementation Phase Project with Sydney Water.

Notes on contributors

Guoyang Fu

Guoyang Fu is a research fellow in Civil Engineering at Monash University. His research focuses on life-cycle analysis of deteriorated infrastructure.

Chunshun Zhang

Chunshun Zhang is a lecturer in Civil Engineering at Monash University. His research focuses on infrastructure geomechanics.

Ravin Deo

Ravin Deo is a research fellow in Civil Engineering at Monash University. His research is in engineering geophysics.

Suranji Rathnayaka

Suranji Rathnayaka is an engineer in City West Water, Melbourne and visiting lecturer at Monash University. He specializes in asset management.

Benjamin Shannon

Benjamin Shannon is a research associate in Civil Engineering at Monash University. His research focuses on pipe design and renovation.

Jayantha Kodikara

Professor Jayantha Kodikara is the Deputy Head in the Department of Civil Engineering, Monash University and the Director of ARC Smart Pavements Hub.