Elgin Area Primary Water Supply Project

Owner
City of London ON
Engineer
Blue-Con Construction and AECOM, Inc.
General Contractor
Jacking Sub Contractor
Pipe Size
  • More than 14,700 meters (48,000 LF) of 900mm (36”) diameter steel water transmission pipe
  • Cement mortar lined (CML) per AWWA C205
  • Dielectric tape coating per AWWA C214
  • A combination of O-ring rolled groove gasketed joints for unrestrained conditions and lap welded bell and spigot joints for restrained conditions
  • Pipe was designed to a project design and performance requirement of 180 psi working pressure

The Problem

The original Elgin Area primary transmission pipeline was constructed in 1966 and consists of more than 14.7 kilometers (48,000 LF) of 750mm (30”) concrete pressure pipe from the water treatment plant in the Municipality of Central Elgin to a terminal reservoir just east of the city of St. Thomas located in Central Elgin. The 14,700 meters (48,000 LF) of 900mm (36”) diameter Steel Water Transmission Pipe with a Cement Mortar Lined (CML) existing Elgin Middlesex Booster Pumping Station and Reservoir valve house. The Elgin Area Primary Water Supply System services the cities of St. Thomas, London, Aylmer, Bayham, Central Elgin, Port Burwell, Southwold and other surrounding areas, for a total population of 112,000 people.

The Solution

It was determined that twinning the existing 750 mm (30”) diameter transmission main was needed to maintain a water source that was secure and available to accommodate future growth. The project procurement was undertaken in a three step process where three (3) Design/Build teams were invited to submit proposals. Each Design/Build proposal required the water transmission line to be designed in accordance with the standard specifications of the Elgin Area Primary Water Supply System, AWWA Standards, the Ontario Provincial Standards and Specifications and the City of London Standard Specifications. Each proposal was based on using either Concrete Pressure Pipe per AWWA C301 or Steel Water Transmission Main Pipe per AWWA C200. Each proposal was evaluated on their technical merit and total cost of construction. The pipe design was determined by each Design/Build Team based on the 2007 preliminary design report prepared by Delcan Inc. The Blue-Con Construction proposal using Steel Water Transmission Pipe was selected based on the overall technical merit of the proposal and overall cost of construction versus the other two (2) proposals which were based on using Concrete Pressure Pipe. The Steel Water Transmission Pipe alternative offered numerous advantages to both the owner and the Design/Build teams. The Steel Pipe utilized a Dielectric Tape Coating which acts as a bonded “barrier” coating and will provide an anticipated service life of more than 100 years. The Steel Pipe was furnished in 17 m (50 ft) lengths which were 1/3 the weight of the concrete pressure allowing for the use of smaller excavation equipment and faster pipe-laying production rates. The O-Ring Rolled Groove joints provided a fast and bottle tight joint system for long-term performance.

The performance based design approach utilized on this project allowed the owner to maximize the benefits of using Steel Water Transmission. The use of Steel Pipe lowered overall project construction costs by more than $1,500,000 compared to Concrete Pressure Pipe

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