Project Overview
The Port Mann/ Highway 1 Improvement Project (PMH1) was executed as a design-build project. Its purpose was to mitigate traffic congestion, improve safety for vehicles and pedestrians, improve environmental habitat, and re-implement public transit in greater Vancouver.
The scope of work involved replacing the Port Mann Bridge with a 10-lane bridge, widening Highway 1, and upgrading its interchanges.
Part of the PMHI was the Latimer Creek and Leoran Brook Salmon Habitat Enhancement Culverts project to improve fish passage between habitats.
Three culverts would be installed from the median of the highway, alongside Latimar Creek. Native Coho Salmon and Cutthroat Trout had been unable to swim through the existing culverts for several decades. The new culverts would mimic a natural extension of the creek.
Challenges
• Installation of the culverts by open-cut methods was not a feasible because of the 20-ft. depths and environmental impacts
• Potential for risk of settlement as culverts crossed two lanes of traffic and ramps
• Project timing to ensure that native Coho Salmon and Cutthroat Trout had migrated before construction
• Strict line and grade tolerances – 0.54 – 2.42%
• Varied subsurface ground conditions
Solution
The subcontractor approached the project using their Akkerman Guided Boring Machine system as a means of achieving absolute accuracy. They used their auger boring machine to install the first stage reaming head, then followed it with their SCCI S150 horizontal pipe driving unit to advance the 120-in. steel casing.
Outcome
• All tolerance met with success
• Simple, efficient and cost effective solution to large diameter, on grade tunneling in unconsolidated ground
• Boulders were enveloped for removal
• This contractor’s first instance of combining hybrid methods of guided auger boring and horizontal pile driving unit
