City of Vancouver turning to Seattle for advice on viaducts demolition

Officials with the City of Vancouver are keeping a keen eye on what has been happening south of the border with Seattle’s very own viaduct demolition project.

The Alaskan Way Viaduct through downtown Seattle was permanently closed last week to commence a three-week-long construction process of linking a new 3.5-km-long, four-lane tunnel burrowed under the downtown waterfront.

Demolition of portions of the viaduct is well underway, and the new tunnel will open once the new links at both ends of the highway route are established.

There have been many lessons learnt from the Washington State Department of Transportation and the City of Seattle for the planned Georgia and Dunsmuir viaducts demolition, according to Kevin McNaney, the Director of the City of Vancouver’s Northeast False Creek Project Office.

“Because they are a few years ahead of us, it is an amazing opportunity to get a sense of the types of things we need to be thinking about right now,” McNaney told Daily Hive, who said city staff visited Seattle last year to meet with their counterparts. “It was incredible how much we have in common.”

Before

After

He explained that there are very similar contexts with the viaduct demolition projects in both cities. Both viaducts were built during a similar era, they are located within a tight urban area along the waterfront, and large stadiums are situated on one end and downtown on the other.

Spaces currently occupied by the viaducts will be turned into new public space uses for the most part.

But there are also stark differences too; as a part of State Route 99, Seattlelites have historically depended on their viaduct for their transportation needs, with traffic volumes of about 100,000 vehicles per day and 30,000 bus passengers — about twice as many as the 45,000 vehicles per day on the Vancouver viaducts.

The Alaskan Way Viaduct is also 3.5 km long, whereas the pair of viaducts leading into downtown Vancouver are only about one km.

McNaney says they discovered both cities have similar challenges with viaduct deconstruction and precinct reconstruction.

“Some of the buildings are are literally a foot or two away from the Alaskan Way viaducts. We talked a lot about how we do construction and deconstruction and it really informs some of our thinking,” he said.

For the Vancouver viaducts, traditional deconstruction and construction methods can be used in the easternmost areas of the viaducts and along Pacific Boulevard.

However, he says a surgical demolition approach will be required for the western end of the viaducts around BC Place Stadium and Rogers Arena, as well as the residential towers in the surrounding area. This may involve cutting a section of viaduct and using a crane to lift the piece out of the area to avoid contact with the buildings.

McNaney notes the municipal government has been working closely with adjacent businesses and the stadiums, as events held inside both venues have to continue during the deconstruction and construction process.

However, McNaney said the city’s biggest takeaway from the Seattle project was how project planners there engaged with the public on the planned traffic disruptions and how to mitigate it.

Phasing of viaducts demolition and new road network construction

As for an updated timeline on when deconstruction work on the Vancouver viaducts could begin, he said the earliest was 2020, with early geotechnical soil testing work possibly conducted this year.

The first change that can be expected is the widening of Pacific Boulevard into a two-way, six-lane street between the Cambie Street Bridge and Quebec Street.

This will be followed by the construction of a majority of the two-way, four-lane West Georgia Street extension ramp in the area between BC Place and Rogers Arena — above where Griffiths Way is currently located. Then the section of the Georgia Viaduct will be demolished, and work will be performed as quickly as possible to finish the remaining portion of the ramp between Beatty Street and Pacific Boulevard.

Only after the opening of the ramp will demolition begin on the remaining portions of the viaducts. Overall, this will take about three years.

“We have really looked at phasing very carefully to ensure the project is self-funding and also to minimize traffic disruption,” said McNaney. “We have really done a lot of careful modelling to ensure the disruption is minimized.”

Overall, the entire viaducts demolition and Northeast False Creek Plan is anticipated to cost $438 million, with the vast majority coming from the future private developments in the precinct.

A total of $1.7 billion will also be largely raised from these developments to help build the area’s new public amenities and spaces.

There will be new homes for 12,000 residents (including 1,800 social housing units for over 3,000 low-income residents), over 30 acres of new and renewed public spaces, and the creation of a commercial waterfront to create a new events and entertainment district.

Rezoning applications for Canadian Metropolitan Properties’ Plaza of Nations redevelopment and Pavco’s BC Place tower, with the latter approved with conditions. City council has yet to deliberate on the larger redevelopment by Concord Pacific.

“Like Seattle we really need to keep reminding people of that long-term vision, what a special place this will be,” he said.

So far in the first week of the viaduct closure, it has not been all doom-and-gloom, but the Seattle Times’ daily live updates have been reporting of vehicle trips taking a few minutes longer than average during the peak hours.

There have not been any significant delays from arterial traffic spilling out into local streets, however, the usual peak hour congestion experienced on the routes now begins earlier and ends later.

With commuters warned for months to consider alternate transportation options, there has also been an uptick in public transit ridership. For instance, one major ferry route into downtown Seattle saw walk-on passenger volumes increase by 23% and the number of vehicles fall by 25% in the first day of the viaduct closure.

See also

• The stark differences between Seattle and Vancouver's viaduct demolition plans
• City Council approves viaducts demolition and Northeast False Creek Plan
• Concord Pacific unveils massive plans for its portion of Northeast False Creek
• Vancouver releases plans for new 11-acre Northeast False Creek park
• Massive Plaza of Nations redevelopment and new Canucks practice rink approved