Metro Vancouver mayors select new 8-lane immersed tube for Massey Tunnel replacement

Oct 3 2019, 12:03 am

A task force of select mayors and other representatives of Metro Vancouver has selected an eight-lane, immersed-tunnel configuration option for the future project to replace the ageing George Massey Tunnel.

The option was selected during a meeting today from a shortlist of eight options provided by the provincial government, varying between a six- or eight-lane crossing, as a deep-bore tunnel, immersed-tube tunnel, or bridge.

Additionally, they passed a recommendation by New Westminster mayor and TransLink Mayors’ Council chair Jonathan Cote that requests the provincial government to improve the bus speed, reliability, and carrying capacity of the entire transit corridor along Highway 99.

The configuration and method of an immersed-tube tunnel is essentially a modernized version of the construction method used to build the existing tunnel, which would be dismantled under the task force’s recommended option.

One of the two proposed additional tunnel options to the George Massey crossing by the City of Richmond. This option was not chosen. (City of Richmond)

According to a regional district report ahead of the meeting, the cost of an immersed-tube tunnel is roughly the same as the bridge options, and about one-third of the cost of a deep-bored tunnel. No precise cost estimates have been provided at this early stage of planning.

However, the immersed-tube tunnel has the greatest environmental impact of the three option types, necessitating a complex environmental assessment.

The Fraser River bed between Richmond and Delta would be trenched to hold a pre-fabricated tunnel structure, which would be dropped into the river by barges. The tube would then be covered to protect the structure from the river’s turbulence and marine traffic.

Both sides of the river also require excavation, and ground densification for seismic resiliency would be required for the full length of the tunnel.

It is anticipated construction can only occur during a six-month window each year, requiring two or more construction seasons.

Deas Island Regional Park on the Delta side would be temporarily separated for required excavation.

George Massey Tunnel

Portal into the existing George Massey Tunnel. (Government of BC)

While the existing 1959-built, four-lane tunnel has about 50 years of serviceable life remaining, with regular maintenance and rehabilitation, it does not meet current seismic standards.

The options included the possibility of retaining the existing tunnel for public transit uses, but this would necessitate highly costly retrofits to enhance flood protection and ground densification to increase the structure’s seismic resistance. Furthermore, TransLink does not support options that retain the existing tunnel for transit services.

Premier John Horgan, BC Greens leader Andrew Weaver, and some mayors previously suggested a twinned tunnel could be feasible.

While the project now has a more defined vision, subject to final provincial approvals and funding, it could still be a decade away from completion.

Artistic rendering of the cancelled 10-lane bridge to replace the George Massey Tunnel. (Government of BC)

In 2017, the BC NDP provincial government cancelled the original $3.5-billion, 10-lane project over concerns the crossing would provide too much capacity and that the previous BC Liberals-led government did not consult the region’s mayors. Construction was slated to begin that year for a completion and opening in 2021/22.

The provincial government previously indicated a possible 2030-completion timeline for the new Massey Tunnel replacement project, but regional mayors rejected this idea, urging for a more timely replacement no later than 2025 or 2026. They also requested an eight-lane crossing early on in the task force’s deliberation process, dismissing the previous notions of a six-lane crossing.

Claire Trevana, the BC Minister of Transportation and Infrastructure, is scheduled to comment on the task force’s immersed-tube tunnel recommendation Wednesday afternoon.

Video animation explaining how the Fehmarnbelt immersed-tube tunnel in Denmark will be constructed:

Kenneth ChanKenneth Chan

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