Parts of northbound SR 99 will close from 6 to 11:30 a.m. this Sunday, April 8 between South Spokane Street and Bridge Way North in Fremont. This closure is part of the Emerald City Ride. Details for the closure:
6 – 11:30 a.m. - Northbound SR 99 closed between South Spokane Street and Western Avenue.
6 – 9:30 a.m. - Northbound SR 99 closed between Western Avenue and Bridge Way North.
In addition, the bike ride will close the I-5 express lanes 6:45 – 10 a.m. Follow WSDOT Traffic on Twitter for updates on highway openings.
One year ago, with a roar of water and concrete tumbling, the tunneling machine Bertha broke through into the disassembly pit, completing her 1.7-mile journey under downtown Seattle. It was and remains a remarkable engineering achievement.
At the time, Seattle Tunnel Partners was working on the double-deck highway inside the tunnel and had completed about half of the upper roadway deck. Since Bertha’s dramatic breakthrough, the machine has been fully disassembled and crews have finished building the roadways and walls inside the tunnel.
What happened to Bertha?
The machine needed to be removed from the tunnel so crews could finish the tunnel’s roadways. STP spent four months disassembling the machine, cutting it up into pieces small enough to be lifted out by crane. Roughly 8,300 tons of machinery were hauled out of the disassembly pit, to be repurposed or recycled. Approximately 6,850 tons of metal were sent to be recycled, but pieces of Bertha’s signature cutterhead were donated to the Port of Seattle and cutting tools and the machine’s control panel were given to Seattle’s Museum of History and Industry.
Bertha is no longer around but you can relive her breakthrough moment with our drone video:
A year in tunnel progress
Since Bertha placed the last tunnel ring, crews have made great progress on the structures and systems inside. The roadways and walls inside the tunnel are done, with the last of the roadway panels that make up the tunnel’s northbound (lower) deck placed last month. Crews are hard at work installing the electrical, ventilation and other systems that will make the tunnel functional and safe.
At the north and south portals, all signs of Bertha’s support equipment and the large pits that bookended the machine’s journey have disappeared. Crews have covered the launch pit and are preparing to build new city streets and intersections. The disassembly pit at the north end has been covered and the final section of the north operations building is taking shape on the surface.
Other highlights of construction progress since Bertha’s breakthrough:
April 4, 2017: Tunneling breakthrough, viewed online by more than one million people
March 15: The last of the 1,152 road panels for the northbound deck goes into place
While the past year has seen impressive progress, there’s still plenty of work left to do. Before the tunnel opens, crews must finish installing the tunnel’s mechanical, electrical and plumbing systems, then test them to ensure they function properly. Stay tuned as we continue to report contractors’ progress building toward the tunnel’s opening, which could happen as early as this fall.
A double-deck highway now runs end to end inside the new SR 99 tunnel. Earlier this month, contractor Seattle Tunnel Partners (STP) installed the last of the 1,152 road panels that together form the lower (northbound) roadway.
Now crews are installing and testing the tunnel’s operational and safety systems. It’s a big job. Inside the tunnel there are:
More than 300 cameras to monitor traffic and security at all times as part of an incident-detection system.
Automatic ventilation systems designed to keep air quality and visibility high.
Automated sprinkler systems designed to put out a fire quickly at its source.
Together, these systems will make the SR 99 tunnel one of the "smartest" tunnels ever built. This video explains how the critical air quality and fire safety systems work together:
Thousands of components that make up the safety and operational systems will be tested at least three times – once to make sure they work, then to make sure they work as a system, then together with other systems to make sure all systems are integrated and functional. After the systems are all certified, STP will hand the tunnel over to the Washington State Department of Transportation so a different contractor can realign SR 99 and build the final ramp connections to and from the tunnel.
It’s been almost a year (April 4) since the tunneling machine Bertha broke through into the disassembly pit near Seattle Center. Today all visible signs of the machine and the large pits that bookended its 1.7-mile journey beneath downtown Seattle are gone.
At the south end, the launch pit is now a smooth plane that will later become the roads and ramps connecting the tunnel to SODO, downtown and the Seattle waterfront:
At the tunnel's north end, the machine’s disassembly pit has been filled up to the surface, and now the final portion of the tunnel's north operations building (the building with the yellow ventilation stacks) is being built above it:
Zooming back and you can clearly see where the closed block of Sixth Avenue North between Harrison Street (in the foreground) and Thomas Street (behind the operations building) will be rebuilt:
Once completed, Sixth Avenue North will provide a north-south connection between Mercer Street and Denny Way, with an on-ramp to SR 99 southbound and the new tunnel. You can follow construction progress on our construction cameras page.
City of Seattle crews will close SR 99 in both directions 6 – 11 a.m. Sunday, March 4 between the south end of the Battery Street Tunnel and North 45th Street. This closure is part of the Hot Chocolate Run. Details for the closure:
6 – 10:25 a.m. - Southbound lanes closed between North 38th Street and the south end of the Battery Street Tunnel.
6 – 11:15 a.m. - Northbound lanes closed between the south end of the Battery Street Tunnel and North 45th Street.
Several city streets are also closing. Check here for a complete list.
We’ve installed a new time-lapse camera to capture work on the SR 99 Connections Project, which will finish building the ramps and roads that connect SR 99 to the new tunnel.
Seattle Tunnel Partners has completed some of this work, and the remaining work will occur in their existing work zones at the tunnel portals (near the stadiums in the south and near Seattle Center in the north). A new contractor, Scarsella Brothers Inc., will complete this work.
The circled structure above is where southbound traffic will exit the tunnel. The rendering below shows that same tunnel exit in relation to the completed south portal.
SR 99 Connections will start work this month along East Frontage Road South and South Royal Brougham Road, just to the west of Safeco Field. Crews will be installing drainage, illumination and signals, as well as building roadway, curbs and sidewalks. Crews are scheduled to complete this work by the end of May.