Program Spotlight

Latest updates on the Alaskan Way Viaduct Replacement Program

  • Bertha begins: digging officially underway in Seattle

    This time, there were no crowds or fanfare. It was just Bertha, the world’s largest tunneling machine, finally getting the chance to do what she was built to do: dig.

    Bertha got her first taste of tunneling on July 30, officially starting the 2-mile journey beneath downtown. Early Tuesday afternoon, Bertha’s 5-story-tall cutterhead broke through the north wall of her 80-foot-deep launch pit. She’s expected to emerge in about 14 months near the intersection of Sixth … more

  • Bon voyage party for Bertha draws 5,000 people to SR 99 tunnel site

    Start with some sun, soil and celebration. Then add Bertha, the massive machine that will dig the SR 99 tunnel beneath downtown Seattle, and 5,000 of her closest friends. The result is a party big enough for the biggest tunnel-builder the world has ever seen.

    Thousands of people descended on the SR 99 tunnel launch pit on Saturday for a chance to see Bertha up-close before she starts tunneling later this month. Guests talked to project staff, learned about the project and walked around … more

  • Join Gov. Inslee for a public celebration at launch site July 20

    The power is on, the cutterhead is hooked up and two miles of Seattle soil await the teeth of Bertha, the world’s largest tunneling machine. Aside from running final tests, there’s only one thing left to do before the massive machine’s launch later this month: say goodbye.

    On July 20, Gov. Jay Inslee and the Washington State Department of Transportation will host a public celebration at Bertha’s launch site, west of CenturyLink Field, from 11:30 a.m. to 3 p.m. … more

  • New overpass set to open by the end of the year

    At the start of the year, it wasn’t much more than a few dozen steel beams and some columns sticking out of the ground. As the calendar turns to July 2013, the new South Atlantic Street overpass is taking shape at the southern edge of the State Route 99 tunnel construction site near the stadiums.

    The overpass will address a bottleneck near the entrance to the Port of Seattle’s Terminal 46, where trains crossing South Atlantic Street frequently block traffic. When it … more

  • Where will all that dirt go? Here’s the scoop

    Crews removed more than 86,000 cubic yards of soil during construction of the recently completed SR 99 tunnel launch pit. That may seem like a lot, but it’s nothing compared with the 850,000 cubic yards of soil that will be removed by Bertha, the SR 99 tunneling machine, as she digs her way beneath Seattle.

    How much is 850,000 cubic yards of soil? Put it this way: If, just for fun, you decided to pile it all on top of the turf at nearby CenturyLink Field, your pile would be … more

  • A big goodbye to Bertha’s big red crane

    By now, drivers on State Route 99 near the stadiums are used to seeing large cranes and machinery near the spot where Bertha will start tunneling this summer. A crane is a crane is a crane, right?

    Except when the crane in question is the Barnhart Modular Lift Tower, better known to most as the giant red crane that lowered many of Bertha’s 41 pieces into the pit where she’s getting ready to dig. Aside from having an impressively technical name, the modular lift tower, like … more

  • Face time with Bertha: last day above ground for massive tunneling cutterhead

    Suspended from a towering crane at the south end of downtown Seattle, the five-story-tall face of Bertha, the world’s largest tunneling machine, spent its last day above ground looking squarely at the old viaduct it was built to replace. Next stop: the 80-foot-deep launch pit where tunneling will start this summer.

    Crews working with the Washington State Department of Transportation lowered Bertha’s 838-ton cutterhead into the launch pit today, ending eight weeks of heavy … more

  • Launch pit complete, ready for Bertha

    Last spring, a field of unturned dirt marked the spot where Bertha will begin digging the two-mile State Route 99 tunnel beneath downtown Seattle. One year and 86,000 cubic yards of soil later, it’s a pit fit for the world’s largest tunneling machine.

    Crews finished building Bertha’s 80-foot-deep launch pit on Sunday after nearly a year spent building its underground walls, removing soil and building the infrastructure needed to support the nearly 7,000-ton machine. Its … more

  • Bertha's trailing gear first into the pit

    Last week, crews used a massive red crane to begin lowering the first large pieces of Bertha, the SR 99 tunneling machine, into the 80-foot-deep pit (pdf 485 kb) where she’ll start tunneling this summer. First up: the trailing gear, which will serve as Bertha's support system during tunneling by providing her with all of the equipment and materials she'll need to tunnel beneath downtown. The trailing gear accounts for much of the 326-foot-long machine's total … more

  • Into the pit: assembly of Bertha set to begin

    This week, crews will use a massive red crane to lower the first piece of Bertha, the SR 99 tunneling machine, into the 80-foot-deep pit (pdf 485 kb) where she’ll start tunneling this summer. Reassembling Bertha’s 41 pieces and testing the completed machine will take two to three months.

    Crews from Hitachi Zosen, Bertha’s manufacturer, will assist throughout the process. Bertha won’t officially become the property of Seattle Tunnel Partners, WSDOT’s … more