• April 21 project update: Bertha reaches her final resting spot

    With one last push from her thrust jacks, Bertha came to rest today in her final position within the disassembly pit near Seattle Center. Seattle Tunnel Partners began slowly moving the tunneling machine forward on April 13. You can watch the machine’s progress into the pit by scrolling back through the disassembly pit time-lapse camera.
    A crew member holding balloons in front of the TBM sitting in the disassembly pit

    Nowhere to go but up (and out)

    With Bertha’s movement complete, crews will begin disassembling and cutting the machine into pieces for removal. Some pieces will be lifted from the disassembly pit by crane, while others will be taken out south through the tunnel. A new fact sheet in our Program Library gives a brief overview of what this work entails.
    As Bertha moved into the disassembly pit, crews also began removing infrastructure within the tunnel that supported tunneling. More than 20 miles of pipe has to be removed, as well as the yellow ventilation duct and the conveyor belt.

    Video: Bertha's final push 

    While the time-lapse camera linked above captures the view from above the disassembly pit, this video provides an on-the-ground perspective. Watch a condensed time-lapse of Bertha's two-week move into the disassembly pit (with a pause for a group photo of the workers who built the tunnel).  
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  • April 13 project update: Bertha's next move

    Seattle Tunnel Partners began moving Bertha, the SR 99 tunneling machine, into the disassembly pit this morning. Crews began pushing the machine forward at approximately 9 a.m. this morning and have completed building ring 1,419.
    In the coming weeks, the machine will move forward approximately 80 feet before coming to rest in its final position. Along the way it will build the final rings of the tunnel, as well as a short section of temporary partial rings that the machine will use to push itself forward in the pit.
    Once the machine is in place, crews will begin cutting the machine into pieces and removing them from the pit. Some parts may be salvaged for use on other projects, while other parts will be recycled.
    Brace removal
    Crews spent the past several days cleaning the pit and removing the braces from the wall Bertha bored through on April 4. The time-lapse video below shows crews removing the braces.
    We’ll continue to provide progress updates on our breakthrough page and on Twitter.


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  • Recapping Bertha's breakthrough

    Bertha's 9,270-foot journey beneath Seattle ended in dramatic fashion on Tuesday as the machine broke through into her disassembly pit near Seattle Center:


    On Tuesday morning all that stood between Bertha and daylight was the five-foot-thick concrete wall at the south end of the disassembly pit. Crews from Seattle Tunnel Partners began mining around 8 a.m. on Tuesday and broke through shortly before noon.
    WSDOT shared updates from the scene on Twitter, Facebook and Periscope, and hosted a livestream. (Roughly a half million people tuned into WSDOT's web channels to watch breakthrough, and another one million watched the livestream via local news outlets.)


    What comes next?

    In the coming weeks, STP will remove the braces in the disassembly pit and move Bertha into her final position in the pit. You can watch that work on the Bertha's Breakthrough page. The machine will be taken apart and removed from the tunnel.

    There is much work left to be done before the tunnel opens to traffic, currently scheduled for early 2019. Our recent program spotlight explains the interior structures and tunnel systems work that cres have already begun. 

    We will be transitioning the Bertha's Breakthrough page in the coming weeks to a page that tracks this progress. As always, follow the program Twitter feed and this website for updates on the work to replace the Alaskan Way Viaduct.
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Program Spotlight

  • Life after Bertha: Focus shifts from mining to other tunnel work

    Bertha, the SR 99 tunneling machine, has completed her 9,270-foot journey beneath Seattle. Although tunnel boring has come to end, crews have significant work to do before the tunnel can open to traffic in 2019.


    Construction of the SR 99 tunnel can be broken down into five activities: 


    Mining (completed in April 2017)

    Disassembly and removal of the tunneling machine

    Interior roadway construction

    Installation of mechanical, electrical … more