The Seattle snowpocalypse may have slightly delayed the start of the demolition of the now-closed Alaskan Way Viaduct, but there’s no stopping the fact that the aged elevated roadway will soon disappear from the city’s waterfront.
Now that the new SR 99 tunnel is open to traffic beneath downtown Seattle, the Washington State Department of Transportation has provided an extensive online overview of what to expect from the removal of the old highway above ground — a process that should take about six months.
WSDOT says the project will be broken into three parts: removing the Alaskan Way Viaduct, filling and sealing the Battery Street Tunnel, and building north surface street connections along Aurora Avenue North. Demolition on the Columbia Street on-ramp was supposed to start on Tuesday, but was moved to later this week because of road conditions following a series of snow storms.
The Battery Street Tunnel will be filled in two phases, according to WSDOT, with material brought into the tunnel both from its south entrance and through grates along Battery Street above. Here is a graphic showing the process:
The SR 99 project construction camera page also has three new views (below) of the viaduct for those who want to see some of the action in real time. The views show a portion of the west side of the viaduct along Alaskan Way. Time-lapse videos will be recorded and released later of other sections of the highway coming down.
A “demolition tracker” graphic will be updated weekly to show active demolition sites, upcoming locations and where demolition is complete. This offering is very similar to a graphic representation provided during the construction of the tunnel, as the map showed the boring machine Bertha’s progress beneath Seattle.
For a recap of the project, WSDOT is also pointing to the video below featuring Dan Hemenway, a project manager from Kiewit Infrastructure West, which is overseeing the demolition. Kiewit has been involved in such large projects as the new SR 520 Floating Bridge and the new Tacoma Narrows Bridge.
Hemenway says in the video that the top deck of the viaduct will be removed first, followed by the lower deck and then the columns of the 66-year-old concrete highway.