Contents tagged with home

  • Oct. 12 project update: After a brief checkup, Bertha is back on the move

    Seattle Tunnel Partners resumed mining on Tuesday following a week of planned maintenance on Bertha, the SR 99 tunneling machine. During the stop, crews performed routine maintenance, including the inspection of cutterhead tools.
    Crews initially expected to spend several weeks changing tools in hyperbaric conditions. However, after a full day of hyperbaric work and tool inspection on Monday, STP determined the cutterhead tools were in satisfactory condition and decided to continue mining.  
    With the machine functioning well and the cutterhead tools in good condition, STP will continue mining north beneath First Avenue. They plan to make at least one more stop to perform hyperbaric work, but the timing and location of future stops will be determined by STP based on soil conditions and maintenance needs. 
    The top of the tunneling machine is located nearly 200 feet below First Avenue, approaching Pine Street. As of this morning, crews had tunneled 4,750 feet of the 9,270-foot-long tunnel drive. Progress updates are posted on Mondays and Thursdays at our Follow Bertha page. You can also follow Bertha on Twitter @BerthaDigsSR99.
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  • Oct. 6 project update: Bertha reaches planned maintenance stop

    Seattle Tunnel Partners has paused mining to begin planned maintenance on Bertha, the SR 99 tunneling machine. Crews stopped tunneling approximately 190 feet beneath First Avenue, just north of Pike Street, on Tuesday, Oct. 4. STP chose the location of the stop in advance because dense soils in the area are suitable for hyperbaric work – a process this post explains in detail.
    Crews will spend several days preparing the hyperbaric work environment. They will then begin the difficult task of inspecting and changing cutterhead tools. There are more than 700 tools on Bertha’s rotating cutterhead, some of which can be accessed and changed from within the cutterhead spokes during the course of STP’s regular weekend maintenance. The cutting tools that crews will focus on during the upcoming maintenance period can only be accessed in hyperbaric conditions. 
    Replacing cutting tools and performing other maintenance is crucial to maintaining the tunneling machine and ensuring it performs well for the remainder of the tunnel drive. This is STP’s third planned maintenance stop in 2016. The machine was stopped from March 12 to April 29 as crews prepared to tunnel beneath the Alaskan Way Viaduct. A second maintenance stop occurred beneath Spring Street from June 23 to July 18. STP expects the current maintenance period to last approximately one month, but the length of the stop will depend on the extent of the needed work.
    Crews have mined a total of 4,721 feet and installed 717 concrete rings since tunneling began. They are now more than halfway through the tunnel drive. We’ll continue to provide updates on hyperbaric work and other progress around the viaduct program as STP’s machine maintenance continues.


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  • Oct. 3 project update: Bertha pushes past halfway point in SR 99 tunnel dig

    The SR 99 tunneling machine Bertha has passed a significant milestone in its journey underneath Seattle. When the machine tunneled past Pike Place Market on Friday, Sept. 30, it pushed beyond the halfway mark of a 9,270-foot-tunnel that will lead to the removal of the Alaskan Way Viaduct.

    Seattle Tunnel Partners has now excavated more than 4,635 feet of the SR 99 tunnel. Much of that progress occurred during the past five months, with STP tunneling more than 3,000 feet since leaving a planned maintenance stop on April 29 to begin the push beneath the viaduct.

    Bertha is now about 190 feet beneath First Avenue between Pike and Pine streets. According to STP, crews will continue mining for a short time and then stop to perform approximately one month of planned maintenance.

    The finish line – a 90-foot-deep receiving pit near Thomas Street, at the north end of downtown – is largely complete, along with many other aspects of the tunnel portals. Although future contractors will make final connections to the highway, several of the ramps and roadways into and out of the tunnel are already in place, along with tunnel operations buildings at each of the portals. New drone footage of Bertha’s finish line is now available.

    Other important work is ongoing, including construction of the double-deck highway within the tunnel.

    While STP’s crews are making progress, they are also taking time for routine maintenance to help ensure the machine successfully completes the tunnel drive. Like previous maintenance stops, crews will use the upcoming stop to inspect machine components and replace cutterhead tools in hyperbaric conditions. STP expects this round of maintenance to last approximately one month, but it could take more or less time depending on the extent of work needed.

    STP’s most recent schedule shows that tunneling will wrap up in summer 2017. Work to complete the tunnel’s interior structures, along with installing and testing systems should be finished by late 2018. Based on STP’s schedule, WSDOT estimates the tunnel would open to traffic in early 2019 when crews finish connecting the tunnel to the existing SR 99 roadways.

    Recent tunneling updates 
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  • #99closure feature: Drone footage inside the SR 99 tunnel

    Just a few days before the SR 99 tunneling machine started tunneling under the Alaskan Way Viaduct, the Washington State Department of Transportation flew a video-equipped drone through the SR 99 tunnel to show Seattle Tunnel Partners’ construction progress. There has been continued interest in seeing what has been built below ground and this video gives a glimpse of the tunnel as well as the nooks and crannies of the complex tunneling machine.

    On an average day, the tunnel is … more

  • The choreography of a concrete pour

    This week, at the south entrance to the bored tunnel, Seattle Tunnel Partners is pouring concrete for a section of the future southbound highway. On one hand, the pouring of concrete (also known as a "concrete placement”) is nothing extraordinary – it’s a common occurrence on a project that will use enough concrete to build nine football stadiums. But their frequency belies the complex choreography that goes into executing each pour successfully. Since concrete plays … more

  • 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