Proactive pipe management: multiaxial fatigue of water pipe grey cast iron

The UK’s water distribution networks contain large numbers of decades-old grey cast iron (GCI) water pipes which are well known to deteriorate in service, develop leaks and ultimately burst. Reducing leakage has become a priority for UK water companies to provide a resilient water service in the face of climate change, population growth and other pressures. The huge number of GCI water pipes still in service coupled with very low pipe replacement rates mean the remaining GCI pipes cannot be replaced wholesale. This paper makes use of recently published multiaxial fatigue data for GCI pipes to investigate whether the multiaxial combination of loads experienced by a GCI water pipe could be used to identify pipes at a greater risk of failure. Based on a comparison of loading scenarios, this study concluded that considering the multiaxial combination of loads applied to a pipe does have the potential to help inform pipe replacement decisions, enabling high-risk pipes to be prioritised for replacement.