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Bertha fully emerges into the disassembly pit

The tunnel-boring machine has thrusted its last thrust

By Sarah Anne Lloyd
WSDOT’s time-lapse camera shows Bertha fully emerged into the disassembly pit.
WSDOT

Bertha, the boring machine that drilled the Alaskan Way Viaduct replacement tunnel, has pushed its last push. As of Friday, the machine has fully emerged from the tunnel into the disassembly pit.

The five-story drill is too large to cart through the city, so over the next several months, the machine will be dismantled into chunks of a maximum of 20 tons each. The machine itself weighs 8,000 tons—meaning several trips for Seattle Tunnel Partners (STP), the contractor managing the machine.

A series of images show Bertha’s progress into the disassembly pit
A series of diagrams show Bertha’s progress into the disassembly pit. The machine has completed this process.
WSDOT

Because STP owns the machine, they’ll be the ones to dismantle the machine, and are entitled to any salvage value.

Bertha officially finished the length of the two-mile tunnel on April 4, but wall braces still separated the machine from the pit. Crews finished removing the braces April 12, and the machine began moving forward into its current position shortly after.

On Friday, Bertha took one last push into the pit “with one last push from her thrust jacks,” said the Washington State Department of Transportation (WSDOT) in their update.

A time-lapse video posted late last week shows the machine pushing into its final position.

This is the end of the line for Bertha, marking the end of a nearly four-year journey. While the entire tunnel project was initially slated to be open for traffic in December 2015, a series of delays—including a two-year halt between 2013 and 2015—have pushed the project end date considerably.

WSDOT estimates the tunnel should be open for traffic in 2019.

Even before the tumultuous journey of the machine, the tunnel project was a point of political contention, with many alternative transportation activists—including current mayoral candidates Cary Moon and Mike McGinn—pushing for a surface-street option with transit accommodations.

Many critics worried not only about the tunnel-boring machine getting stuck underground, but about cost overruns for the project, which now total more than $200 million.