Tunnel boring machine schedules, traffic decks and pedestrian detours will all be part of Broadway's future as the new subway tunnel and stations are built over the next four years.
The Transportation Investment Corporation, the crown corporation administering the $2.83 billion project, released a variety of details and schedule updates today as part of a technical briefing, and while all that may sound dull, the megaproject will affect anyone using the Broadway corridor between Arbutus and Main streets, as well as sections of Great Northern Way and the Mount Pleasant neighbourhood.
Construction has already started and is due to wrap up in 2025, but the excavation, which will affect the public the most, is happening first.
To help mitigate vehicle traffic impact, decks are being installed along Broadway in Mount Pleasant and near the intersection with Cambie Street. The decks will be used to allow excavation to occur underground while 4 lanes of traffic pass over top. While they use columns and bridge girders and act as a type of bridge the decks will be the same level as the street.
To build them, though, traffic will be reduced to three lanes (to install the columns): two eastbound and one westbound. Parking will also be removed from along Broadway at that time. Once the decks are in place traffic will once again, but parking won't be back until the road returns to normal. The goal, though, is to keep traffic on Broadway the entire time construction is happening.
Construction will also affect cycling and pedestrian traffic, with detours planned. For cyclists parts of the Central Valley Greenway and Arbutus Greenway will be closed, while sidewalks along Broadway will go through periods of closures. Signage will be in place for the detours.
Preparation for the actual tunneling won't start until the end of the year, and the tunnel boring machines won't arrive until the mid part of 2022. Before they get going they'll have to be assembled.
That's because the boring machines are massive. With a diameter of 6 m they'll fill the tunnel as they grind away, and with a length of 100 m they're about as long as four blue whales. And they weigh over 907,000 kg, about the weight of nine blue whales if one of them was a calf. Totally unrelated, but if you forgot, there's a Vancouver museum with a blue whale skeleton.
The machines will get through about 18 m of ground a day. By the end of 2022 they should be near the Broadway-City Hall station at Cambie Street and should finish the 5 km of tunnel by mid-2023. At that time they'll be pulled from the ground and taken apart at Broadway and Cypress Street.
Once the machines are out the tunnels will be finished up and work on the stations will continue through 2023.
At the same time about 700 m of elevated guideway will be built between the VCC-Clark station and the new Great Northern Way-Emily Carr station, where the trains will drop below ground. The new track will be constructed to match the rest of the SkyTrain system with 21 new pillars.
In 2024 tracks will be installed and the systems will be connected. By 2025 the stations will be getting finished off, the trains will get tested and, if all goes according to plan, the first public trips will start.
A variety of mitigation efforts are in place, depending on what needs to be mitigated. Of note people may feel vibrations at certain times during demolition, construction of the traffic deck or when the boring machines are at work.
Plans are to limit noise and light with most work happening during the day, though some night work may be needed.
For those looking to contact the project management, a community office has been opened up on West Broadway and there's a 24/7 phone line at 1-844-815-6114.