Advisories/Updates

  • Summer is the season for Milepost 31

    Hoping to catch a glimpse of SR 99 tunnel construction? Summer is an ideal time to visit Milepost 31, our project information center, located at 211 First Ave. S. in Seattle’s Pioneer Square neighborhood. Our free public tours give visitors a great view of the work site from a section of the Alaskan Way Viaduct that has been permanently closed to traffic. 

    Tours depart from Milepost 31 Tuesday through Saturday. Advance registration is required. Each tour is a half-mile round trip, and visitors must be able to walk over uneven ground and climb up and down 50 stairs.

    After the tour, stick around to look at the exhibits about the people and projects that shaped Pioneer Square. Learn how natural forces and people transformed Seattle’s landscape over time, and get an inside look at the SR 99 Tunnel Project.

    No speaker series in July

    Normally we host a monthly speaker series in conjunction with Pioneer Square’s First Thursday Art Walk, but due to the holiday we won’t be hosting the event in July. Milepost 31 will remain open until 8 p.m. on July 2 for the Art Walk. The center will be closed on July 3 and 4. Speaker Series will resume on Aug. 6.

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  • June 5 project update: Installation of new seal system underway

    Seattle Tunnel Partners has begun installing the SR 99 tunneling machine’s newly redesigned seal system. Crews lowered the new outer seal ring into place Wednesday, marking the first new piece to be installed in the machine as part of STP’s effort to resume tunneling.
     
    The new outer seal system arrived in October and was stored on-site prior to Wednesday’s installation. The new inner seal system arrived last week and is currently being installed. Made in Japan by manufacturer Hitachi Zosen, the new seal system will be easier to access should the need arise.
     
     
    Crews look on as the tunneling machine’s new outer seal ring is moved and placed on the cutterhead.
     
    We will continue to provide updates as we receive them.
     
    Digging into STP’s repair plan
    You can continue to track STP’s work on our time-lapse cameras and follow @BerthaDigsSR99 on Twitter for updates. Don't forget to check out the other resources we've created to give you a fuller understanding of Bertha's story:

     

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  • May 29 project update: New parts for Bertha arrive at Terminal 46

    The SR 99 tunneling machine’s new inner seals arrived from Japan as scheduled this week. The pieces, which are integral to Seattle Tunnel Partners’ effort to repair the machine, were offloaded at Terminal 46 and trucked a short distance north to the repair area. The piece shown below is the new inner seal ring, which houses the rubber seals that will protect the new main bearing. Additional photos of crews transporting the piece are available on Flickr.

    The SR 99 tunneling machine's inner seal ring

    STP and manufacturer Hitachi Zosen chose to redesign the machine’s seal system as part of their repair plan. Manufactured by Hitachi in Japan, the new seal system will be easier to access should the need arise. It will be installed in the coming weeks, along with other essential components designed to equip the machine for the remainder of its journey beneath Seattle. Other important elements of the repair plan include:
    • A new main bearing
    • Enhanced monitoring systems
    • Added steel to strengthen the machine and accommodate the new seal system 
    • Widened openings at the center of the cutterhead
    • Extended arms to mix excavated soil in the chamber behind the cutterhead
     
    Simulation showing additional steel to be installed in the SR 99 tunneling machine.      Crews installing additional steel in the SR 99 tunneling machine
    These images show the steel crews are adding to strengthen the tunneling machine.
     
    As owner of the tunneling machine, STP and Hitachi are responsible for all aspects of the repair effort, including the schedule. STP provides an updated schedule  to WSDOT each month, but the state cannot verify the schedule until work to resume tunneling is further along. We will continue to provide updates as we receive them.
     
    Digging into STP’s repair plan
    You can continue to track STP’s work on our time-lapse cameras and follow @BerthaDigsSR99 on Twitter for updates. Don't forget to check out the other resources we've created to give you a fuller understanding of Bertha's story:

     

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Program Spotlight

  • Making progress on the south end

    If you regularly drive SR 99 near the stadiums, you’ve probably noticed a lot of changes to the roadway during the past 16 months. For example, crews divided the northbound and southbound lanes into two separate roadways near South Atlantic Street to make room for more construction. And you’ve no doubt witnessed huge changes taking place in the work zone on either side of the road. Did you know that crews have been hard at work completing the southern portion of the SR 99 tunnel … more