Advisories/Updates

  • Aug. 27 project update: Tunneling machine’s front end bolted in place

    Seattle Tunnel Partners has reconnected the SR 99 tunneling machine’s 2,000-ton front end to the section that remained in the access pit during repairs. With the two sections of the machine now bolted together, crews from Mammoet have unhooked the front-end piece from the massive red crane that performed this week’s lift.
     
    Photos of the lift are available on Flickr, and the time-lapse video below shows the whole thing in 62 seconds.
     
     

    What's next?

    Significant work remains for crews tasked with reassembling the machine. Three large pieces of the machine’s outer shield will be lowered into place for reassembly in the coming days, according to STP’s most recent schedule. Crews also must weld the pieces back together, in addition to the lengthy task of reconnecting the hundreds of wires and hoses that are integral to the tunneling operation. STP and manufacturer Hitachi Zosen will conduct a series of tests following reassembly to ensure the machine is ready to resume mining.
     
    You can track the action on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates. We’ll also continue to post photos and videos as STP’s work progresses. 
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  • Aug. 25 project update: Seattle Tunnel Partners successfully lowers tunneling machine's front end into the access pit

    3:20 p.m. update: Seattle Tunnel Partners and crane crews from Mammoet have successfully lowered the 2,000-ton front end of the SR 99 tunneling machine to a platform at the bottom of the access pit.
     
    Crews will now use the crane to fine-tune the position of the piece. When that process is complete, they will begin reconnecting the piece to the portion of the machine that remains in the ground.
     
    The effort to return the tunneling machine's front end to the 120-foot-deep access pit began early Monday morning. Crews started by vertically lifting the piece, which includes the machine’s cutterhead, motors and the new main bearing assembly. The crane then moved horizontally on its rails to the north. When the piece was above the pit, crews rotated it to a semi-vertical position and lowered it partway into the pit before breaking for the evening. Work resumed early Tuesday morning, with the piece reaching the bottom of the pit Tuesday afternoon.
     
    Three pieces of the machine’s shield that remain at the surface will be lowered and reinstalled in the coming days, according to STP’s latest schedule. After the machine has been reassembled, STP and manufacturer Hitachi Zosen will conduct a series of tests will follow reassembly to ensure the machine is ready to resume mining.
     
    Lowering into pit
    The tunneling machine's front end as it nears the bottom of the pit on Tuesday afternoon.
     
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    Original post: On Tuesday morning, Seattle Tunnel Partners and crane crews from Mammoet resumed lowering the front end of the tunneling machine into the access pit. 
     
    The effort to return Bertha to the 120-foot-deep access pit began early Monday morning. Crews started by vertically lifting the piece, which includes the machine’s cutterhead, motors and the new main bearing assembly. The crane then moved horizontally on its rails to the north. When the piece was above the pit, crews rotated it to a semi-vertical position and then lowered it partway into the pit before breaking for the evening.
     
    We’ll continue to provide updates here and on Twitter as the work progresses. 
     
    View from the crane
    The view from the top of the crane responsible for lowering machine parts back into the access pit.
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Program Spotlight

  • SR 99 traffic shift highlights continued transformation at tunnel’s future north portal

    This weekend, crews will shift State Route 99/Aurora Avenue traffic onto new lanes through the construction zone at the SR 99 tunnel's future north portal. For drivers, a traffic shift is a change in the route one takes to get to work, events or a game. For road builders, a traffic shift is a way to mark the next step toward project completion.

    In this latest traffic shift, the progress is significant – 750 feet of new roadway that will be part of the permanent … more