Low Level Road project, Vancouver, showing multi-tiered retaining walls. Image: Stantec.
From the October-November 2016 print issue, p. 55
The project involved the realignment and elevation of approximately 2.6 kilometres of the Low Level Road in North Vancouver, B.C. The road parallels rail tracks along the north shore of the Burrard Inlet.
With international trade continuing to grow, the project was carried out to enhance rail and port operations. It was also designed to address long-standing community safety concerns and traffic congestion challenges in the area. Stantec was the principal consultant.
The work added space for two new CN mainline tracks that can accommodate 3,650-m (12,000-ft.) long trains. It also included the elimination of three existing road and rail crossings, and the provision of direct access to the port terminals. In addition, the engineers reconfigured three intersections and improved lanes for cyclists. Another component was an extension of the Spirit Trail pedestrian walkway.
As a sustainable solution for the community, this is the first transportation project in North America to achieve ISI Envision Platinum Certification. The certification covers five categories: community quality of life, sustainability leadership, resource allocation, natural world, and climate and risks.
Roadway realigned, stabilized with mult-tier retaining walls
Previously the roadway was vulnerable to rock falls, landslides, risks of seismic events (liquefiable soils, unstable slopes, etc.), and a predicted rise in the sea level. These hazards were mitigated by stabilizing the slopes with over 30,000 m² of multi-tier retaining walls. They incorporate seismic design and elevate the roadway above the 200-year predicted sea level rise.
The retaining wall types and configurations were optimized during detailed design development, which saved over $14.5 million in project costs.
The new road and pathway alignments maintain a green buffer zone between the community, roadway, and port terminals. The grade separation between the road and rail users also addressed the safety issues.
Three notable bridges
The project’s new bridge structures include the Spirit Trail Woodland Suspension Bridge, which is a 56-m clear span that offers a sensitive solution in the context of the surrounding vegetation. Another, the Spirit Trail Overpass, is a tilted steel tied arch superstructure that is an aesthetically pleasing 42-m span landmark in the community. The Neptune/Cargill Overpass is a 78-m long flared, two-span steel girder vehicle bridge that features integral support design (no joints or bearings) to minimize future maintenance costs.
Stakeholder engagement and First Nations involvement
The Port led a robust stakeholder engagement program, involving residents, businesses and the City of North Vancouver, to develop a design. It took into consideration local needs and resulted in multiple design iterations within difficult timeframes. Environmentally sensitive areas were protected. For examle, an eagle’s nest tree habitat was preserved directly adjacent to the Spirit Bridge. View impacts were addressed, noise and dust during construction were minimized, and access for local residents and businesses was maintained.
The Port of Vancouver awarded contracts with significant financial value to First Nations communities, while art installations along the project corridor recognize the cultural and historical significance of the area.
Low Level Road Project, North Vancouver, B.C.
Award-winning firm (prime consultant, design): Stantec (Kip Skabar, P.Eng., Emily Dunlop, Henrik Kristiansen, P.Eng., Garry Romanetz, P.Eng., Richard Lanyi, P.Eng., Lourette Swanepoel, Thys Fourie, P.Eng., Peter Brayford, Helen Zhang, P.Eng., Charter Chan, P.Eng., Adam McIntyre, P.Eng., Alberto
Owner/client: City of North Vancouver, Port of Vancouver
Project management: MMM Group (WSP)
General contractor: B&B Heavy Civil
Other key players: Delcan/Parsons (traffic management), Morrison Hershfield (woodland bridges design check), De Leur (road safety audit), Levelton (concrete testing), ME2 Transportation Data (traffic analysis), Protech Surveys (field surveying), Arbortech /ACL (arborist)
Supplier: Nilex (rock-vegetated MSE walls and geogrid)