• Plan ahead: Semiannual viaduct inspection closure set for Halloween weekend

    October is here, which means the semiannual inspection closure of the Alaskan Way Viaduct is just around the corner.
    Both directions of SR 99 will be closed between South Spokane Street and the north end of the Battery Street Tunnel from 6 a.m. Saturday, Oct. 31 to 6 p.m. Sunday, Nov. 1. Please plan ahead and be prepared for additional congestion as a result of this closure.
    Closing the viaduct will allow crews to perform maintenance and thoroughly inspect the structure, as they do each spring and fall. Read our viaduct safety fact sheet (pdf 2.9 Mb) to learn more about what we do to keep the viaduct safe and open to drivers until the tunnel project is complete.  
    Viaduct inspection
    Survey crews walk the viaduct during a previous inspection.
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  • Sept. 8 project update: Final three pieces of tunneling machine safely in the access pit

    Seattle Tunnel Partners has successfully lowered three large pieces of the SR 99 tunneling machine’s front shield into the access pit for reassembly. On Saturday, Aug. 29 and Monday, Aug. 31, respectively, crane crews from Mammoet lowered two 98-ton side body pieces:

    Side body piece being lowered into the access pit

    On Friday, Sept. 4, the 278-ton middle shield was lowered. Our construction cameras will show you a photo sequence of Friday's lift and lowering. Here's a capture from the camera:

    top shield being lowered

    With all major components of the machine now in the pit, crews are focusing on reassembling the machine and preparing for the testing phase of the repair effort. Crews will spend the coming weeks welding 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 continue to track STP’s repair effort on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates.

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Program Spotlight

  • Another underground connection at the south portal

    Future connections between the SR 99 tunnel and city streets are continuing to take shape at the south portal, even if they're only partially visible from the surface. Drivers passing overhead didn't know it, but Seattle Tunnel Partners recently demolished a temporary wall separating the future mainline section of the tunnel from the on-ramp that will one day allow travelers to access northbound SR 99 from the stadiums.

    The first photo shows the view from inside the cut-and-cover … more