Contents tagged with home

  • Fly the SR 99 tunnel – from the Space Needle to the stadiums

    Today we are excited to share a drone's-eye view of two miles of tunnel in two minutes. This video captures the ongoing construction of the interior roadways, safety systems and other elements that will carry and safeguard drivers passing beneath downtown Seattle in the new SR 99 tunnel.

    The drone enters at the tunnel’s north end, near Seattle Center. Crews are building the tunnel’s interior structures starting from the south, so as the drone advances the tunnel becomes more complete. The drone flies along the tunnel's upper deck, which is 85% built. At the tunnel’s south end, the drone passes from the bored section of the tunnel (9,270 feet long and dug by Bertha, the tunneling machine) and into the cut-and-cover section, built in the launch pit where Bertha began her tunnel drive.

    One big tunnel element not seen in this video is the tunnel’s lower deck. In early November, the tunnel contractor Seattle Tunnel Partners plans to begin delivering large, prefabricated roadway panels to build that deck (the future northbound roadway). You can track progress on that and other tunnel elements on our tunnel progress tracker.

    There’s much work still to come in building the tunnel’s interior roadway and completing systems like ventilation, sprinklers and traffic cameras. We’ll continue to share and document crews’ progress building the tunnel on in our Flickr albums and on Twitter

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  • Progress update: Transforming Bertha's launch pit

    If you’re a fan of our construction cams, this summer has been all about the pits.

    Up at the SR 99 tunnel’s north portal, our disassembly pit camera gave viewers a front-row seat for the SR 99 tunneling machine’s remarkable disappearing act. Down at the south portal, cam fans have seen something equally remarkable – the transformation of Bertha’s launch pit into a section of the SR 99 tunnel.

    The timing of these twin transformations is no coincidence. During tunnel mining, the launch pit served as the access point for delivering tunnel ring segments and supplies to the machine. The pit also housed a major piece of the conveyor belt that delivered muck from the machine to barges docked at Terminal 46 on Seattle’s waterfront.

    After tunnel mining concluded in April 2017, contractor Seattle Tunnel Partners began the transformation of Bertha’s launch pit into a section of the SR 99 tunnel. In June, after removing the conveyor belt, crews started constructing this section of the tunnel. Three months later, the transformation from pit to tunnel is nearly complete. This slideshow shows how they did it.

    Putting a lid on it

    The last phase of the launch pit transformation is underway now. Crews are building the top of the tunnel, a 4 1/2-foot-thick slab of reinforced concrete known as the lid. Building the lid makes it possible to build streets on top of the tunnel. In 2018, crews will rebuild part of Alaskan Way South directly atop what once was Bertha’s launch pit. When the tunnel opens, three levels of roadway will move people north and south across what was once the launch pit.

    This graphic shows a cutaway view of the future tunnel just west of the south portal operations building.

    Diagram showing two decks of traffic in the tunnel, with five lanes of traffic above it on the surface.

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  • Sept. 14 project update: Photos of progress inside the tunnel

    Many different elements of work must be completed before the SR 99 tunnel is ready for traffic. A previous program spotlight went into these areas of activity in detail. The linear distances of completed work are tracked on the progress tracker, which we are updating monthly (look for an update to the numbers soon). 

    But numbers only tell part of the story. This photo slideshow takes you inside the tunnel to see the recent progress being made beneath downtown Seattle.

    Drivers on the viaduct may have caught a glimpse of the recent transformation of the launch pit where Bertha began her journey (see the final photo in the slideshow). This summer, crews working for Seattle Tunnel Partners have been busy transforming the pit into the section of tunnel that will connect the bored tunnel to the SR 99 roadway near the stadiums. We will go more in-depth on this pivotal section of the tunnel in a future program spotlight.

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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