Latest program news

  • Crunch time: Demolition of the Alaskan Way Viaduct is underway

    Contractor Kiewit Infrastructure West Co., began demolishing the Alaskan Way Viaduct today, Feb. 15. Over the course of approximately six months, they will use large machinery to crunch, munch and cut the structure into pieces to be hauled away by truck. When the viaduct is gone, the City of Seattle will begin work on a new surface street and public open space along the waterfront.

    Demolition started today in two locations: at the Columbia Street on-ramp, and a section of the viaduct near Pike Street. Soon a third crew will begin work at the viaduct’s very north end near the intersection of Western Avenue and Bell Street. Demolition will occur in sections, with crews generally spending no more than 30 days working in each area. This video explains the demolition plan in more detail. A new interactive web tracker will provide weekly work zone progress updates.

    The demolition contract requires Kiewit to protect buildings, streets and utilities as they complete their work. They also must keep businesses open and people moving. Alaskan Way will remain open throughout demolition, though it will be reduced to one lane in each direction in areas directly adjacent to the work zone. Closures of streets that intersect with Alaskan Way will be minimized as well, to keep east-west access between the waterfront and downtown open.

    The waterfront, Pike Place Market and Pioneer Square will all be open for business throughout demolition, and will provide good vantage points for watching this historic transformation unfold. Visitors can take advantage of the free Waterfront Shuttle that runs between the downtown waterfront and three nearby neighborhoods (Seattle Center, Pioneer Square and the Central Business District). The shuttle program, extended through summer 2019, is paid for with WSDOT funding set aside to help neighborhoods most affected by the project. Information about nearby parking is available at

    In addition to viaduct demolition, Kiewit’s contract includes work to decommission and seal the Battery Street Tunnel. They will also reconnect John and Thomas streets across Aurora Avenue North, just north of the Battery Street Tunnel. Those streets have been closed to east-west crossings for more than 60 years. This work will involve lane reductions and closures near the new SR 99 tunnel’s north portal.

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    Order: 4.1

  • Update on opening the northbound off-ramp to downtown and Alaskan Way

    The remarkable snow Seattle received last week and weekend slowed construction of the one remaining SR 99 tunnel ramp not yet open. At the tunnel’s south end, the northbound off-ramp to downtown and Alaskan Way remains under construction.

    This ramp is a critical link to downtown for drivers and transit coming from the south and west. Without it, there are no exits on northbound SR 99 between Spokane Street and the north end of the tunnel. This ramp was always going to open later than the rest of the tunnel, but the snow delayed some construction activities.

    With a break in the weather, crews are working to get back on track. Barring more bad weather, they hope to complete forming and pouring the barriers on the ramp in the next few days. Sand that was placed on the ramp during the storms will be cleaned up over the weekend in preparation for lane marking. Signing, lane striping, wiring and lighting also must be done before the ramp can open. The photos below show barrier work in progress.

    A section of rebar formed in the shape of a highway barrier

    Above: The rebar and conduit are in place for this section of ramp barrier, but the concrete has not yet been poured.


    Crew working on newly poured concrete for a highway barrier

    Above: Crew work on a section of barrier for the new off-ramp to downtown and Alaskan Way.


    Wide angle shot of south portal of tunnel with seattle skyline in background

    Above: The blankets at right are covering concrete sitting to cure.

    If the weather cooperates and work goes well, the ramp could open next week – perhaps in time for the Sounders match on Feb. 20 at CenturyLink Field. We’ll continue to provide updates as work progresses. You can watch crews work on the ramp on our construction cameras.

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    Order: 4.2

  • Work on viaduct, Battery Street Tunnel and Aurora Avenue North begins later this week

    Update 2/15/19 9:00 a.m.: The closure of Aurora Avenue North between Harrison St and Denny Way will occur tonight.

    Update 2/13/19 11:50 a.m.: The closure of Aurora Avenue North between Harrison St and Denny Way planned for tonight will be rescheduled for a later date.

    With the SR 99 tunnel open, work can begin on removing SR 99’s old route through downtown Seattle. This big project is broken up into three work areas: removing the Alaskan Way Viaduct, filling and sealing the Battery Street Tunnel, and building North Surface Street connections along Aurora Avenue North.

    The recent snow has made the start of work unpredictable, as icy roads are making it difficult to get equipment to the job site. Below is what to expect from construction this week, although further weather developments, especially icy roads, could change these plans further.

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    Viaduct removal: What to expect the rest of this week

    • Overview:
      • The main challenge with starting viaduct demolition is having safe roads for trucks that need to carry machinery to the job site and haul away demolition debris. The new dates below could change if road conditions improve or deteriorate from what current forecasts predict.
    • Columbia Street on-ramp
      • Demolition was previously scheduled to begin today, Feb. 12. Now, due to current weather conditions, crews plan to begin later this week.
      • Crews will continue preparing the site this week in preparation for demolition.
      • Crews will work on the ramp east to west. Fencing will extend west along the structure as demolition progresses.
      • Columbia ramp removal will follow the process outlined on our website.
    • Viaduct between Blanchard and Battery streets
      • Demolition was previously scheduled to begin today, Feb. 12. Now, due to current weather conditions, crews plan to begin demolition later this week.
      • Crews will continue preparing the site this week in preparation for demolition.
      • Crews will remove the viaduct starting at Battery Street and working south. Fencing will extend south along the structure as demolition progresses.
      • Viaduct removal will follow the process outlined on our website.
    • Viaduct between Pike and Virginia streets
      • Demolition was previously scheduled to begin today, Feb. 12. Now, due to current weather conditions, crews plan to begin demolition later this week.
      • Crews will continue preparing the site this week in preparation for demolition..
      • Viaduct removal will follow the process outlined on our website.


    Battery Street Tunnel: What to expect the rest of the week

    • Initial work will take place inside the tunnel, as well as staging equipment and trailers at the south end of the tunnel.
    • While crews are working in the tunnel, the ventilation fans will run intermittently from 7 a.m. to 5 p.m. weekdays. Keeping the fans on provides fresh air for crews working in the tunnel. This safety measure will be maintained until fall 2019.
    • Crews will place plastic sheeting at the Battery Street Tunnel’s north end. This sheeting helps contain debris generated from the early work occurring inside the tunnel.


    North surface streets: What to expect the rest of the week

    • An overnight closure of Aurora Avenue North between Harrison Street and Denny Way had been planned for Feb. 11. This been rescheduled.
    • The closure could occur as early as tomorrow night, or at a later date depending on weather, transit and construction considerations. During the closure, the southbound lane will be closed 8 p.m. – 5 a.m. The northbound lane will close an hour later, at 9 p.m., and will also reopen by 5 a.m.
    • This closure will allow crews to install protective barrier around the center median work zone where the first phase of this project will occur.
    • Visit King County Metro's website for the latest on bus routes during inclement weather.
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    Order: 4.3

  • Know before you go: the SR 99 tunnel’s new ramp intersections

    The Feb. 4 opening of the SR 99 tunnel brings big changes to several important intersections at the tunnel’s north and south ends. New intersections can be confusing, so use the renderings below to help familiarize yourself with what you will encounter on the road. You can also preview the intersections via narrated videos.

    North end of the tunnel: Harrison Street and Aurora Ave North

    What’s changing:

    • New northbound SR 99 on-ramp
    • New southbound SR 99 off-ramp
    • Harrison Street open east-west across Aurora Avenue North

    The new tunnel dives underground at Harrison Street, several blocks north of where the now-closed Battery Street Tunnel begins. The new intersection of Harrison Street and Aurora Avenue North is where the northbound on-ramp begins, and the southbound off-ramp ends. Harrison Street  is now also open east-west across Aurora Avenue North.

    Rendering of Harrison and Aurora intersection

    Note: Construction begins this month on the inside lanes of Aurora Avenue North between Denny Way and Harrison Street (yellow zone at bottom). Learn more about how the North Surface Streets project is rebuilding Aurora Avenue North.

    North end of the tunnel: Republican Street and Dexter Avenue North

    What’s changing

    • New northbound SR 99 off-ramp

    The intersection of Republican Street and Dexter Avenue North is where the northbound SR 99 off-ramp ends. New signals will control traffic coming off the highway. From the off-ramp drivers will be able to turn left toward Mercer Street, head straight toward South Lake Union, or turn right to head toward Denny Way. Stay alert for people using the Dexter Avenue bike lanes on both sides of the street.

    Dexter and Republican intersection rendering

    South end of the tunnel: Alaskan Way, South Dearborn Street, and First Avenue South

    What’s changing:

    • New southbound SR 99 on-ramp
    • New northbound SR 99 off-ramp [NOT YET OPEN]
    • New east-west street, South Dearborn Street
    • New primary path between First Avenue South and Alaskan Way
    • Alaskan Way extended farther south

    One of the biggest changes to surface streets is at the tunnel’s south end, just west of CenturyLink field. Alaskan Way no longer ends with a jog under the viaduct onto Railroad Way South. Instead, it continues straight to a new intersection with a new road, South Dearborn Street.

    South Dearborn Street is the new east-west connection between Alaskan Way and First Avenue South. This intersection connects SR 99, Alaskan Way and First Avenue. Alaskan Way continues south from this intersection toward East Marginal Way South. Railroad Way South is currently closed from First Avenue South, and when it reopens it will be a local-access-only road.

    IMPORTANT NOTE: The northbound SR 99 off-ramp bridge is still under construction and will open one to two weeks after the tunnel opens.

    Dearborn and Alaskan intersection rendering

    Note: The rendering above does not show the now-closed Alaskan Way Viaduct, which sits in the yellow-highlighted work zone and will be removed section by section over the next six months.

    South end of the tunnel: South Royal Brougham Way and First Avenue South

    What’s changing:

    • New northbound SR 99 on-ramp
    • New southbound SR 99 off-ramp
    • Colorado Avenue South with two-way traffic to South Atlantic Street

    Drivers who previously joined SR 99 northbound from Royal Brougham Way will find striking changes to that intersection. Where once there was a ramp to the viaduct, now there are two ramps to the tunnel. This is where southbound drivers in the tunnel will exit to reach SODO, the stadiums, and I-90 and I-5. This is also where drivers coming from I-90 or the stadiums will enter the tunnel for northbound SR 99.

    Royal Brougham Way and First Ave intersection rendering

    Note: A shared-use path along Colorado Avenue South will be built in a future phase of the project.

    South end of the tunnel: South Atlantic Street and Colorado Avenue South

    What’s changing:

    • New surface-street connection to Alaskan Way South
    • Colorado Avenue South with two-way traffic to Royal Brougham Way South

    The changes around South Atlantic Street are less drastic but still worth knowing. The Atlantic Street overpass over SR 99 is now a complete connection to Alaskan Way (to the north) and East Marginal Way South (to the south). You can now reach both via South Atlantic Street by taking the ramp labeled below.

    Colorado Avenue South (previously called East Frontage Road) is now a two-way street, providing a north and south route between South Atlantic Street and SR 99 on- and off-ramps. A common path from SR 99 southbound to reach I-90 will be to take Colorado Avenue south, then take a left turn onto South Atlantic Street.

    South Atlantic Street and Colorado Ave intersection rendering

    Note: At tunnel opening South Atlantic Street does not pass beneath the SR 99 overpass to Alaskan Way South. That connection will open later in winter/spring 2019.


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    Order: 4.5

  • Road to tunnel’s south portal begins to take shape this weekend

    The new SR 99 tunnel’s south portal sits just west of Pioneer Square and the stadiums, on the southwest corner of downtown. One big piece of work to be accomplished during the #Realign99 closure is building a new street connecting the south portal’s on- and off-ramps to First Avenue South.

    That one-block street will be called South Dearborn Street, as labeled in the rendering below:

    Rendering of south tunnel portal with South Dearborn Street labeled

    Building South Dearborn Street requires removing part of the ramp structure (see it on Google Maps) that today carries northbound SR 99 from the construction detour up onto the viaduct. Crews will demolish the ramp this Saturday and Sunday, crunching the concrete in daytime hours while working on the future intersection’s traffic lights at night. The work will close Railroad Way South for the weekend; our Construction Notices and Detours page has more information.

    Yesterday Rhine Demolition, the subcontractor doing the demolition, moved equipment into the work site:

    Heavy machinery sitting adjacent the viaduct ramp, with stadium in background

    While this is technically demolition work, removing this section of ramp is not the start of true viaduct demolition. This short span of ramp is the only part of the structure that will be taken down before the new tunnel opens. The full-fledged viaduct demolition is scheduled to begin in early-mid February.

    With the ramp down, crews can pave the new South Dearborn Street beneath the (closed) southbound SR 99 ramp structure and build the new intersection with First Avenue South. Our new videos offer more detail on how South Dearborn Street works for northbound drivers getting off SR 99 right before the tunnel, or southbound drivers getting onto southbound SR 99 right after the tunnel.

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    Order: 5.9

  • Rolling with it: How the SR 99 tunnel is designed to withstand earthquakes

    You’ve heard it before but it bears repeating: the primary purpose of the Alaskan Way Viaduct Replacement Program is safety. The viaduct is an aging and seismically vulnerable structure, and retiring it from our highway network will make us all safer.

    It’s not just addition by subtraction. We are replacing the viaduct with a modern tunnel, built with sophisticated systems that work together to keep vehicles moving and drivers safe. Learn more about how the tunnel’s systems work on our new Tunnel Safety page.

    The viaduct’s vulnerability to earthquakes was the biggest motivation for its replacement, and here is another way the new tunnel shines. As it happens, tunnels are a rather safe place to be in an earthquake. If you find this counterintuitive, we’ve produced a video in conjunction with seismic and structural experts to help us explain:

    Engineers in our earthquake-prone region designed the tunnel to withstand a strong earthquake – roughly one that happens every 2,500 years. This would include a magnitude 9 earthquake off the coast of Washington, where the Juan de Fuca plate of the earth’s crust forms the Cascadia Subduction Zone. The tunnel design also takes into account earthquakes that might occur along the Seattle Fault.

    There are many design elements that work together to create a safe tunnel:

    • Structure: The SR 99 tunnel is built with more than 1,400 strong concrete and steel rings, each 6.5 feet wide. These rings are bolted together to form the tunnel, and while very sturdy, they have some flexibility to account for ground movement. This means they can move and return to their round shape. The roads inside are also designed to be flexible, allowing them to move with earthquake waves and remain functional.
    • Shape: The round tunnel can withstand lots of pressure from the outside – much like a submarine underwater keeps its round shape and withstands oceanic pressure.
    • Location: Tunnels that are deep underground experience less movement from the energy waves of earthquakes. Those energy waves increase in size as they approach the surface, so a tunnel will not experience the same degree of movement as an above-ground structure like a viaduct.

    The inherent advantages of a tunnel, combined with state-of-the-art seismic engineering, means the new SR 99 tunnel is designed to stand up to future earthquakes.

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    Order: 6.0

Media requests

If you'd like to schedule an interview with a member of our team, please contact:

Laura Newborn
Media relations, Alaskan Way Viaduct Replacement Program