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.

Findings

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 pipe had intactmortar.
  • Soil testing along the feedermain showed significantly aggressive soils in certain areas, predominantly due tohigh chloride concentrations.
  • Laboratory testing confirmed that some distressed pipes did have chlorides penetrate the mortar, while otherpipes showed no evidence of chloride penetration.
  • Severe pitting and corrosion of the prestress wires was present, as well as significant quantities of brittle wirefailure. Laboratory testing determined that prestress wires were prone to splitting.
  • Evidence of Hydrogen Embrittlement and Stress Corrosion Cracking of the prestress wires was found. Both inthis 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.

Final Pipe Investigation report can be found here

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

Executive summary and findings
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