Investigating an alternative to exhumed grey cast iron water pipes for small-scale fatigue tests

Abstract

[EN] Reducing and preventing leakage is a priority for water distribution network managers in many countries, including the UK. Understanding the mechanisms that cause leaks to form, and developing the ability to model these processes, will enable proactive replacement of water pipes before they start to leak. Smaller diameter Grey Cast Iron (GCI) water pipes are understood to experience biaxial, repeating loads, so fatigue cracking may be a cause of leakage for these pipes. To investigate this fatigue cracking mechanism a small-scale biaxial fatigue experiment is under development at The University of Sheffield. A large number of small diameter, un-corroded GCI pipes are needed to serve as specimens for this experiment. Therefore, in this work off-the-shelf BS416-2 DN 50 mm soil pipes are explored as an alternative to using exhumed pipes, which are often corroded and ≥76.2 mm diameter. The graphite microstructure and tensile stress-strain behaviour of a BS416-2 pipe were characterised and compared with literature data for exhumed spun-cast GCI water pipes, and a good agreement was found. This work concluded that BS 416-2 soil pipes can be used to represent spun-cast GCI water pipes in small-scale destructive experiments.