Experimental Investigation of the Fatigue Strength and Leakage Failure Mode of Corroded Cast Iron Water Pipes

Controlled laboratory-based physical evidence is presented, showing how the type of fatigue loading impacts the remaining life and the failure mode of corroded GCI water pipes. Leak-before-burst behavior is shown for pipes experiencing internal water pressure fatigue loading but not for four-point bending fatigue. Sharp pits are shown to reduce fatigue strength by up to 5.4 times, with the degree of reduction dependent on alignment. Condition assessments of corroded GCI water pipes must consider both the three-dimensional shape of the corrosion pitting and the loading experienced by the pipe to give a true assessment of the damage caused by a corrosion pit.