Advisories/Updates

  • Seattle Tunnel Partners schedule update: Construction of the access pit’s underground walls will continue through August

    Today, Seattle Tunnel Partners notified us that building the underground walls of the circular pit (pdf 2.5 Mb) crews will use to access and repair the SR 99 tunneling machine will continue through August. While this date is later than anticipated, STP reports that tunneling is still expected to resume as scheduled in March 2015.

    Building a self-supporting, concrete ring that is 120 feet deep and 80 feet wide is no easy task, especially given the difficult ground conditions near South Jackson Street. STP crews have completed more than half of the underground piles and are working around-the-clock, seven days a week to complete the approximately 31 remaining piles.

    There are several reasons the work is taking longer than anticipated. One factor is the addition of 11 piles to the pit’s design, bringing the total number of piles to approximately 84. Crews are also working with exceptionally large interlocking piles, which are necessary to make the pit self-supporting without tiebacks or other reinforcements. A self-supporting pit is what will allow the tunneling machine to mine through its walls, but the large piles take longer to install than standard piles.

    While pile work continues, crews are making progress on other areas of the repair plan on schedule, including:

    • Shipping repair pieces: The new main bearing has arrived in Seattle and will be assembled closer to the time it’s needed, likely this fall.
    • Manufacturing repair pieces: Other repair pieces, such as the new outer seal ring, the thrust seal ring and bearing block are nearing completion. After these pieces are fabricated and inspected, Hitachi Zosen will ship them to Seattle.
    • Assembling a 300-ton crawler crane: This crane will be used to help assemble the 600-ton crawler crane. Pieces of that crane will arrive in September and assembly will begin shortly thereafter.
    • Assembling a 600-ton crawler crane: This crane will be used to assemble the modular lift tower (massive red crane) that will lift the largest pieces of the machine from the access pit. Parts of that crane will also arrive in September and assembly will begin in late September.
    • Assembling the 2,000-ton modular lift tower: Starting in late July and continuing through fall, crews will begin to stage the modular lift tower. Parts of the modular lift tower will arrive over the next several months beginning in late July.

     

    We will continue to update you on STP’s efforts to resume tunneling by March 2015. You can watch the access pit take shape on our time-lapse camera, and view photos of recent construction on Flickr

    Previous updates 

    June 16, 2014 update – Contractor announces details of repair work plan for the SR 99 tunneling machine

    May 13, 2014 update – Construction of access pit’s underground walls now underway

    May 8, 2014 update - With environmental review complete, access pit construction begins in earnest

    April 29, 2014 update - A summary of change orders on the SR 99 Tunnel Project

    April 21, 2014 update - SR 99 tunneling machine to resume digging in March 2015

    Click here to see a full archive of progress updates

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  • Early warning: Four-day closure of SR 99 coming in late August

    In August, crews working on the North Access contract near the SR 99 tunnel’s north portal will demolish the bridge on SR 99 over Broad Street. Not sure what bridge we’re talking about? Don’t worry. Even the most seasoned SR 99 commuter may not realize they are crossing a bridge at Broad Street.

    That bridge, and Broad Street itself, must be completely transformed to make room for the future connection to the tunnel’s north portal and on- and off-ramps at Harrison and Republican streets.

    Crews have already begun to fill in Broad Street with recycled concrete from the former roadway. Once we close this section of SR 99 to traffic, crews will bring in heavy equipment and demolish the old bridge in about 12 hours. They’ll then spend the next two days adding more fill material to make the new roadway level with the existing lanes of SR 99. After paving the new SR 99 roadway, crews will stripe the lanes and reinstall barriers. Once all of this is completed, SR 99 will reopen.

    Closure information
    Demolishing a bridge and building a new road in its place isn’t easy work. It is especially challenging on a major highway through Seattle. To minimize disruptions to drivers, crews will replace this portion of SR 99 in a mere four days. Drivers should plan ahead for SR 99 closures from Friday night, Aug. 22 to Wednesday morning, Aug. 27.  View a map of the closure. 

    • From 10 p.m. Friday, Aug. 22 to 5 a.m. Monday, Aug. 25 SR 99 will be closed in both directions from the West Seattle Bridge to Valley Street.
      • Northbound SR 99 will be open from South Royal Brougham Way until midnight on Friday, Aug. 22 for exiting Seahawks traffic.
    • From 5 a.m. Monday, Aug. 25 to 5 a.m. Wednesday, Aug. 27 SR 99 will be closed in both directions from the south end of the Battery Street tunnel to Valley Street.

    There’s a lot of other work that will happen on SR 99 during this closure as well, including utility work at Harrison Street, concrete panel replacement in SODO, expansion joint repairs on the viaduct near the Seneca Street off-ramp and removal of ivy and other maintenance on the viaduct.

    We will continue to share information to help drivers plan ahead and get around during the closure.

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Program Spotlight

  • Remodeling Bertha’s launch pit

    Seattle Tunnel Partners, our contractor for the SR 99 Tunnel Project, is remodeling the giant concrete box where they assembled, tested and launched Bertha, the world’s largest tunneling machine.  

    Fittingly, Bertha’s launch pit is massive – 400 feet long and 80 feet wide. It was 80 feet deep, but it’s a little shallower now due to the remodel, which is turning the pit into part of the future State Route 99.

    Remodeling the launch pit isn’t too much … more