West Pine Creek Sanitary Trunk & Feedermain
Client:
City of Calgary
Location:
Calgary, Alberta
Year:
2018
Project Scope
The West Pine Creek Sanitary Trunk and Feedermain was the largest City of Calgary tunnelling project at the time of construction, delivered by Whissell as Prime Contractor in partnership with the City and private developers. The scope combined large-diameter microtunnelling and open-cut installation across a shared right-of-way, requiring precise coordination of two major pipeline systems advancing simultaneously.
- 3,000 m of 1800mm microtunnelled sanitary trunk; 1,000 m of 1650mm open-cut sanitary trunk; 2,000 m of 1500mm open-cut sanitary pipe
- 400 m of microtunnelled casing for 1050mm steel feedermain; 2,500 m of open-cut 1050mm steel feedermain
- 15 launch/reception shafts to maximum depths of 26 m
- Large cast-in-place thrust blocks and 4×4 m precast valve chamber construction
- All associated manholes, structures, and full surface restoration
Challenge & Mitigation
Extremely poor ground conditions required unique well-point dewatering solutions to facilitate open-cut construction and shaft installations. Bedrock and mixed face conditions were encountered at the tunnel face, and depths exceeded 20 m for open cut and 26 m for microtunnel. Crossings of major roadways and railways required continuous structural monitoring throughout construction.
Value Add Solution
Working collaboratively with Stantec, Whissell proposed switching from HDPE-lined concrete to HOBAS fiberglass pipe for the sanitary trunk. This eliminated the need for HDPE welding, improved hydraulic flow characteristics, generated a credit to the City of Calgary, and reduced overall installation duration, a signature example of Whissell's constructability expertise delivering measurable value on a flagship regional infrastructure program.
