Advisories/Updates

  • Four-day closure of SR 99 begins tonight at 10 p.m.

    Crews building the future north portal of the SR 99 tunnel will close SR 99/Aurora Avenue North near South Lake Union for four days beginning Friday night, Aug. 22. During this closure, crews will demolish and replace the section of SR 99 that crosses above Broad Street. 

    Closure information

    Drivers should plan ahead for SR 99 closures from Friday night, Aug. 22 to Wednesday morning, Aug. 27.

    • 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 and southbound SR 99 will be open from Columbia Street 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.

    Other construction during the closure

    To minimize the need for additional closures, separate crews will complete the following work elsewhere along the SR 99 corridor during this time:

    • Utility work at Harrison Street
    • Concrete panel replacement in SODO
    • Expansion joint repairs on the Alaskan Way Viaduct near the Seneca Street off-ramp
    • Ivy removal from the viaduct

    Driver tips 

    The upcoming closure is expected to cause backups on city streets and increase delays on I-5. Travelers should consider the following:

     

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  • 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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Program Spotlight

  • Four-day SR 99 closure shines spotlight on tunnel’s north portal

    You may have heard that SR 99 will close for four straight days starting Friday night, Aug. 22. It’s the longest full closure of SR 99 in Seattle since crews demolished the southern mile of the Alaskan Way Viaduct in 2011. While this is probably not welcome news for travelers, it is a sign of progress at the tunnel’s north portal. 

    The 2011 demolition of the viaduct cleared the way for construction of the tunnel launch pit and the commencement of tunneling. During this … more