Contents tagged with home

  • Jan. 30 project update: Access pit excavation complete

    Seattle Tunnel Partners has completed excavation of the 120-foot-deep pit that will be used to access and repair Bertha, the SR 99 tunneling machine. Crews removed the final scoop of soil from the pit on Friday, Jan. 30. Approximately 20,000 cubic yards of material was removed from the ground over the course of excavation, which began in mid-October. 
     
    With excavation complete, crews can begin construction of the concrete cradle at the bottom of the pit. The cradle will support the machine after it moves through the pit’s southern wall, which is about 20 feet thick. 
     
    STP plans to tunnel through the concrete wall. The length of time it takes Bertha to reach the pit will depend largely on her ability to mine through and digest the concrete. If she’s unable to mine through the wall, STP will create an opening from within the pit to give her an unobstructed path forward. Once inside the pit, crews will use the massive red gantry crane pictured below to hoist the front end of the machine to the surface for repairs. This narrated video (links to YouTube) explains the repair process in detail. You can also watch raw video of pit excavation on YouTube.  
     
     
    The dewatering system that controls groundwater in the pit will continue to operate at its current level as STP proceeds with its repair work. Settlement levels near the pit remain stable.
     
    Crews building the highway inside the tunnel are also preparing for a big milestone: the first concrete pour on what will become the southbound lanes of the tunnel. Here’s what the southbound roadway currently looks like:
     
     

     

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  • Jan. 27 project update

    Last week, we shared with the public that the dispute review board for the SR 99 tunnel contract had heard and made recommendations on a request by Seattle Tunnel Partners for a differing site condition at the tunnel launch pit. A differing site condition can occur when: 1) actual subsurface or latent physical conditions encountered at the site differ substantially or materially from those indicated in the contract, or 2) unknown conditions at the site are unusual in nature and differ materially from those ordinarily encountered in the type of work.
     
    To clarify, this dispute is related to a differing site condition experienced while building the launch pit; it is not related to the stoppage of the tunneling machine or recent settlement near the access pit. And, there are funds set aside within the existing project budget to deal with differing site conditions.
     
    There has been interest from the public in being able to review the board’s recommendations, which are attached to this WSDOT memorandum (pdf 880 kb). Because these recommendations are technical in nature, there may be questions about what they mean.
     
    As we review the board’s recommendations on the differing site condition in the launch pit and determine our next steps, we will use the terms in the contract to reach the best possible outcome for taxpayers as we continue to build this critical safety project. We will not be offering our opinions of the board’s recommendations or speculating on next steps until our analysis is complete.
     
    It is also important to remember that the board’s recommendations are just that, recommendations. They are not binding. While STP requested $20 million in compensation for this differing site condition, the board’s recommendations did not address the cost and schedule impacts. Thus it is too early to speculate as to the cost and schedule impacts of this recommendation, should it be accepted by WSDOT.
     

     

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  • Take a virtual tour of SR 99 tunnel construction

    Keeping the public informed about our work to replace the Alaskan Way Viaduct is an important part of what we do every day. Our goal is to give you as much access as possible to this amazing project, which is why we regularly post updates, photos and videos of our progress. We even offer walking tours from our information center, Milepost 31, to a viewing platform that overlooks the pit where tunneling began in summer 2013.

    Unfortunately, there’s one frequently received request … more

  • New narrated video explains Bertha repair work

    As reported elsewhere on our website, work to access and repair the SR 99 tunneling machine is coming along. We’ve heard from some people that Seattle Tunnel Partners’ repair plan is hard to picture. Enter STP’s Chris Dixon, who was nice enough to narrate a video that explains what crews are doing to resume tunneling by March 2015. Watch it on YouTube or download a WMV file.

    Other resources 

    Seattle Tunnel Partners repair work plan (pdf 4.8 Mb) … more

  • What we’re doing to keep traffic moving during the four-day SR 99 closure

    We’ve been asking you to do your part to reduce congestion when SR 99 closes for four days starting Friday night, Aug. 22. That includes things like changing your commute habits and choosing an alternate way to get around.

    But what are we, the agencies tasked with keeping traffic moving during this closure, doing to help? Quite a bit, actually. Here’s a roundup of some of the steps we’re taking to help you and your fellow commuters through the closure.

    Washington … more

  • Traffic shift underway on State Route 99 near the stadiums

    Less than three years ago, crews demolished the southern mile of the Alaskan Way Viaduct. When they did, they shifted traffic onto a new section of State Route 99 south of downtown Seattle.

    Much of that new section of SR 99 is permanent, but the piece west of the stadiums is temporary. This curving stretch of road takes drivers around the SR 99 tunnel construction site and connects to the remaining section of the viaduct near South King Street. It’s nothing fancy, but it’s … more

  • Celebrate Bike Month on our new path

    Just in time for Bike Month, we opened a new permanent connection between the on-street bike lanes south of South Atlantic Street and the shared-use path from South King Street. Here’s a map that shows the improvements, which include:

    A dedicated, 14-foot-wide shared-use path with improved paving.

    Improved lighting.

    A separate northbound and southbound path for more efficient navigation.

    Signs warning of vehicles crossing the intersection of … more

  • The SR 99 tunnel contract you’ve never heard of

    You may have noticed more construction along State Route 99, just north of the Battery Street Tunnel. That work is part of the SR 99 Tunnel Project, but it has its own name – the North Access Project. It’s also being built under a completely different contract than the one we have with Seattle Tunnel Partners, the contracting team responsible for most of the tunnel work. A map of major contracts within the program can be found here (pdf 1.1 Mb).

    Our contractor for the North … more

  • SR 99 tunnel’s north portal taking shape near the Space Needle

    A few blocks northeast of the Space Needle, crews are building the north portal of the SR 99 tunnel. It’s a huge piece of the overall tunnel project, but it’s largely invisible to the thousands of people that pass by it every day.

    About the only place you can see the north portal taking shape is from the viewing deck of the Space Needle because most of the construction is underground, inside a pit that’s every bit as impressive as the launch pit where Bertha, the SR 99 … more

  • Lots to see inside the tunnel launch pit

    You can’t see much from the surface, but there’s a lot of work happening in the launch pit where tunneling started last summer. Last week, Seattle Tunnel Partners removed the giant steel frame that Bertha, the SR 99 tunneling machine, pushed against to start her drive into the tunnel. The frame is now on its way to be recycled.

    Work is also well underway to dismantle the temporary concrete tunnel rings Bertha installed to give her additional leverage at the start of her … more