So Long, Viaduct. Hello, Ultimate Boring Machine!
A Wrecking Brawl
For nearly 60 years, Seattle’s polarizing north-south thoroughfare, the Alaskan Way Viaduct, crouched in concrete splendor along Elliott Bay, carrying 100,000 cars a day the length of the city, from SoDo to Belltown and beyond. Irreparably damaged in the 2001 Nisqually earthquake, the thing has since been at the heart of a heated citywide debate: rebuild, repair or remove? Tunnel or “surface option”?
At the height of the squabble last fall, it seemed that the structure that divided downtown from the waterfront would also cause a permanent rift among Seattleites. But now, as the biggest demo project in our city’s history enters its seventh month and traffic revisions slow commutes to a crawl, we look forward to the day—four years from now and counting!—when traffic once again moves along this critical route, through the biggest-diameter deep-bore tunnel the world has ever seen.
Highlights (and lowlights!) of the Alaskan Way Viaduct
1953: Viaduct is built
2001: Nisqually earthquake damages the Viaduct
2004: State and city officials identify cut-and-cover tunnel as preferred alternative
2007: Seattle voters reject cut-and-cover tunnel and elevated alternatives
2009: State, city and port officials recommend bored tunnel
2010: Construction begins to replace Viaduct’s south end
2011: The Viaduct’s south end is demolished, and the new S.R. 99 bridge and construction bypass are opened. Construction begins on second S.R. 99 bridge in the footprint of the demolished Viaduct.
2012*: Begin construction of new overcrossing at S Atlantic Street
2013*: Tunnel boring to begin mid-year. Complete new S.R. 99 roadway south of downtown and new bridge at S Atlantic Street
2014*: Finish tunnel boring
2015*: Open new S.R. 99 tunnel
2016*: Demolish Viaduct’s downtown waterfront section
*estimated completion date
I WANT MY MTViaduct!
A Viaduct music video? Why not! Seattle mag’s arts and culture editor, Brangien Davis, and her husband, Daniel Spils, former keyboardist for Maktub, created a musical ode to the structure. Watch it here:
WHAT A BORE!
Seattle prepares to take delivery of the biggest tunnel-boring machine in history
One year from now, a behemoth bore—disassembled—will arrive by barge and be delivered to a 100-foot-deep pit near the stadiums. Built by Japanese company Hitachi Zosen, the $80 million, 5,500-ton machine will be assembled by crews in early 2013. Finished size: roughly as big as one of our largest ferries.
At 57.5 feet in diameter and 326 feet long, it’s the largest-diameter tunnel-boring machine in history. At its peak, the machine will bore through 36 feet of glacial till, tide flats and fill per day, laying in concrete tunnel sections as it goes. Total drilling time: 16 months. When the drilling ends, the bore will head back to Hitachi Zosen in Japan, thanks to a “bore buy-back” provision in the purchase agreement.
A cross-section rendering of the completed tunnel