Advisories/Updates

  • Jan. 17 project update: Tunneling crews resume mining

    Seattle Tunnel Partners resumed mining late Monday following 10 days of hyperbaric maintenance on Bertha, the SR 99 tunneling machine.
     
    Crews replaced approximately 300 of the nearly 500 scrapers on Bertha’s cutterhead during the hyperbaric maintenance period. As this post explains in more detail, the scrapers line the sides of the cutterhead spokes. STP also conducted other important inspections and maintenance during this time.
     
    Completing routine maintenance is an important part of ensuring that the machine continues to operate properly. STP will continue to perform inspections and maintenance as needed over the remainder of the tunnel drive.
     
    Crews are less than 2,500 feet from the receiving pit near Seattle Center where Bertha will emerge at the end of tunneling. The top of the cutterhead is located approximately 160 feet below Third Avenue in Belltown. 
     
    Progress updates are posted on Mondays and Thursdays at our Follow Bertha page. You can also follow Bertha on Twitter @BerthaDigsSR99.
     
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  • Jan. 13 project update: Hyperbaric work continues

    Seattle Tunnel Partners is making good progress as they continue performing hyperbaric maintenance on Bertha, the SR 99 tunneling machine. Since the maintenance period began on Jan. 5, crews have replaced 250 cutterhead tools (see example below) over the course of 184 hours of hyperbaric shifts. This maintenance is critical as STP prepares for the final 25 percent of the tunnel drive.  
     
    Some of the cutterhead tools replaced during this maintenance stop
     
    The work is taking place in the chamber behind Bertha’s cutterhead, as shown in this image (PDF). As the video below explains, working in this environment is similar to performing an underwater dive.  
     
     
    STP will resume tunneling when the maintenance period is complete. The top of Bertha’s cutterhead is located approximately 160 feet below Third Avenue, about halfway between Blanchard and Bell streets. Crews are less than 2,500 feet from the receiving pit near Seattle Center where Bertha will emerge.
     
    Progress updates are posted on Mondays and Thursdays at our Follow Bertha page. You can also follow Bertha on Twitter @BerthaDigsSR99.
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  • Jan. 5 project update: Bertha reaches next planned maintenance stop

    During the holiday break, Seattle Tunnel Partners performed routine maintenance and inspections on Bertha, the SR 99 tunneling machine. This included inspection of some of the machine’s cutterhead tools under normal atmospheric pressure. STP decided to begin a hyperbaric maintenance stop this week to inspect the other cutterhead tools on the machine under hyperbaric conditions (this post explains the different types of tools in more detail).  
     
    Crews plan to spend between one and two weeks inspecting the tools, and replacing them as necessary. However, the duration of the stop could be longer or shorter depending on the number of tools that need to be replaced. STP’s most recent hyperbaric maintenance stop in late October lasted one week. 
     
    The top of the cutterhead is located approximately 160 feet below Third Avenue, about halfway between Blanchard and Bell streets. Crews are less than 2,500 feet from the receiving pit near Seattle Center where Bertha will emerge at the end of her tunnel drive.
     
    Progress updates are posted on Mondays and Thursdays at our Follow Bertha page. You can also follow Bertha on Twitter @BerthaDigsSR99.
     
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Program Spotlight

  • A new place to stroll above the SR 99 tunnel

    Frequent observers of the project’s construction cameras may have noticed some white blocks being placed next to the north operations building at the corner of Sixth Avenue North and Harrison Street.

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    Crews are building a public plaza that will be a centerpiece of the landscaping at the project's future north portal. The reconnection of Harrison, Thomas and John streets will make walking between each side … more