Alaskan Way Viaduct2018-02-21T16:53:00-08:00

The Alaskan Way Viaduct

This $3.2 billion Seattle project is actually a collection of 32 individual projects that launched in 2010 to replace an outdated section of State Route 99. The most famous part is the 2-mile-long tunnel dug by the “Bertha” drill, which started burrowing into the Seattle soil in summer 2013. After a two-year delay to diagnose and repair technical troubles with the drill, Bertha finished tunneling on April 4, 2017. State and local government officials estimate the entire project will be completed in 2023.

Bertha Launch Pits Become Tunnels

ENR Northwest » The launch and exit pits created for tunnel-boring machine Bertha in Seattle are in the last phase of being transformed into parts of the multilevel roadway that replaces the Alaskan Way Viaduct. Here’s how the process works.

October 2, 2017|

Video: Bertha’s journey under the streets of Seattle

The Seattle Times » A 360-degree video shot inside the tunnel being built beneath Seattle gives viewers a unique new perspective of what it’s like to bore a 2-mile tube and construct a highway 200 feet underground.

March 10, 2017|

Bertha veers a few inches off course, stops digging

The Seattle Times » The massive drill has veered a few inches off course.

March 1, 2017|

Video: How a double-deck highway is built inside the Seattle tunnel – with enough concrete to fill 9 football stadiums

GeekWire » The Washington State Department of Transportation (WSDOT) takes viewers on a behind the scenes construction tour of the new double-deck State Route 99 tunnel. WSDOT’s Deputy Administrator explains how the tunnel boring machine, known as Bertha, works to dig through the ground and place concrete rings to form the tunnel wall as she goes. Watch as the tunnel takes shape and construction crews build the framework and pour concrete for the roadway. It is estimated the new tunnel will use enough concrete to fill nine football stadiums. Click here for the video.

July 14, 2016|
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