A new eight-lane bridge is on the table as an option for the George Massey Tunnel replacement project, two and a half years after the previous new $3.5-billion, 10-lane bridge plan was cancelled.
Two scenarios are now being seriously considered by the provincial government, based on the latest public consultation for the future of the crossing. The other scenario is an eight-lane immersed-tube tunnel, which is the option recommended by a task force of Metro Vancouver mayors last fall.
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The provincial government has indicated it will take into consideration the recommendation made by municipal officials, after criticizing the lack of consultation behind the decision over the now-cancelled, 10-lane bridge project. However, an immersed-tube tunnel is far from certain.
There is no cost estimate for the scenarios, but they are deemed to be similar at this time.
According to the latest preliminary details, the new bridge scenario does not place the structural piers in the Fraser River, but piers will be required in Deas Slough.
This concept of a long-span bridge is a longer crossing, compared to an immersed-tube tunnel, but it will have a similar grade.
Fly-through animation video of new bridge concept:
Fly-through animation video of new immersed-tube tunnel concept:
The immersed-tube tunnel scenario has lower property impact and offers improved connections within Deas Island Regional Park, but there are in-river impacts during construction.
The immersed-tube tunnel scenario is also more technically challenging, whereas there is proven local construction expertise with bridges. For an immersed-tube tunnel, 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.
Excavation is required at either side of the river for the tunnel portals, and ground densification for seismic resiliency would be needed for the full length of the tunnel. Deas Island would also be temporarily separated for excavation.
Both scenarios have a HOV/bus-only lane in each direction, and pedestrian and cycling pathways.
It is estimated each scenario will take about five years to construct, although construction for an immersed-tube tunnel may be limited to a six-month window each year.
The environmental review timeline for a bridge proposal is expected to be considerably shorter as this scenario will have a far smaller impact to the area.
The scope of the improvements to the rest of Highway 99 corridor are unclear, but some interim improvements are set for phase one, while a yet-to-be-determined “long-term solution” will be implemented in phase two.
The previous cancelled project called for a widening of a 24-km-long stretch of Highway 99 between the southern end of the Oak Street Bridge and the border of Surrey with HOV/bus-only lanes, as well as three new interchanges, rapid bus infrastructure, and a direct bus connection reaching Bridgeport Station.
Feedback submitted by the public will be used to help determine the chosen scenario for the creation of a new project business case by Fall 2020, which will potentially lead to the start of the environmental review process next year. But a new replacement crossing might not reach completion until the end of the decade.
On an average day, the 1959-built, four-lane George Massey Tunnel, which is also an immersed-tube tunnel, sees about 80,000 vehicles. A replacement is deemed required for seismic safety and capacity concerns.