Pipe Investigation

The purpose of the Pipe Investigation, undertaken by Associated Engineering and Pure Technologies is to understand the factors that led to the deterioration of the feeder main and its failure on June 5, 2024.

From these findings, the report indicated that there was not one specific factor that led to the failure of the feeder main in June.

The  findings indicate that several different factors may have contributed to the feeder main failure, including:

• Some pipes showed visible mortar cracking and delamination upon excavation, while other pipes had intact mortar.
• Soil testing along the feeder main showed significantly aggressive soils in certain areas, predominantly due to high chloride concentrations.
• Laboratory testing confirmed that some distressed pipes did have chlorides penetrate the mortar, while other pipes showed no evidence of chloride penetration.
• Severe pitting and corrosion of the pre-stress wires was present, as well as significant quantities of brittle wire failure. Laboratory testing determined that pre-stress wires were prone to splitting.
• Evidence of Hydrogen Embrittlement and Stress Corrosion Cracking of the pre-stress wires was found. Both in this case appear to be due to chloride penetration of the mortar and/or microcracking.

The review of the design and operations also confirmed the original design of the pipe was consistent with the proper guidelines of the time and operations of the pipeline were well within the design parameters of the pipe.

Note: Due to extensive report findings, it is best to download on a desktop computer.