Metro Line Drainage Projects: Double Barrel Tunnel
Helping the City of Edmonton to successfully manage the Metro Line LRT’s impacts to drainage
This project rerouted and augmented drainage for Edmonton’s new Metro Line LRT, by relocating a large double-barrel tunnel in the project area.
Because the proposed LRT tunnel alignment would intersect with an existing double barrel tunnel, the project managers had to resolve the conflict. This entailed a complex rerouting of flows by connecting existing tunnels with new hand tunnels and closing off the original double barrel in places where it conflicted with the LRT alignment.
The downtown location of the tunnels meant encountering abandoned I-beams and concrete pilings as well as wet and sticky ground conditions. The project’s location also meant challenges such as LRT coordination and traffic management. Likewise, schedule adherence was important because of coordination with the LRT project and the impact of delays to the downtown area.
The closely-monitored alignment of the Metro Line could not be altered without enormous redesign work. SMA’s intensive value engineering and constructability reviews identified and mitigated the points of conflict with the existing drainage system.
We created a monthly system for reporting cost and progress for a holistic view of project status. Incorporation of sophisticated methods such as the Analytic Hierarchy Process with value engineering as well as customized simulation modeling provided a detailed methodology for meeting the specific needs of each drainage project.
The decision to relocate the double barrel by connecting existing tunnels to a new hand tunnel was safer and posed less environmental risk.
SMA’s services also helped the projects to finish earlier than planned, which alleviated concerns over working in a high-traffic area. This approach resulted in cost savings and schedule adherence on this publicly funded project.
SMA’s innovative use of lean production in this project had a direct impact on its ability to stay on schedule, despite delays caused by the major geotechnical issues confronting this project.
Our work on this project garnered a 2014 Consulting Engineers of Alberta award of Excellence for Project Management as well as an award of Merit for Small Firm-Big Impact