Kearney Lake Road Slipline

Facing a deteriorating Prestressed Concrete Cylinder Pipe (PCCP) water transmission main, Halifax Water needed to select rehabilitation or replacement for a water transmission main located under Kearney Lake Road, a main high traffic level corridor on the west side of Halifax. After extensive research on rehabilitation technologies, Halifax Water—the municipal water, wastewater, and stormwater utility serving the residents of the Halifax region in Nova Scotia, Canada—selected sprialweld steel pipe for the permanent repair of a structurally deficient PCCP transmission water main.

Engineers determined that a major contributor to the cause of PCCP failure is the high use of road salts and the resulting concentration of chlorides within the pipeline backfill along the highly traveled route. As a result, it was determined that a 100-year pipe design life is necessary for this project.

Northwest Pipe manufactured a spiralweld steel pipe with a unique O-Ring rubber gasket joint to rehabilitate 4,920 linear feet of a 48-inch host PCCP primary transmission main by sliplining the steel pipe into the PCCP. We manufactured the joints by welding a Carnegie double-gasket groove joint ring to the inside of one end of each pipe. We sized the spigot ring to perfectly match the interior of the main pipe body so that a swedged bell would not be required. The use of double gasket Carnegie joint rings, allow each joint to be individually air-tested immediately upon installation and ensure that the OD of the steel pipe liner sections remained constant throughout the entire length of the pipeline.

The result is a completely rehabilitated pipeline with a structural independent lining system that not only allows for the maximum internal flow within a 42-inch steel pipe liner, but is also designed to last 100 years.