Testing time for State Route 99 tunneling machine

Posted on Dec 21 2012 7:59 AM

Last week, the world’s largest-diameter tunneling machine received a name. This week, it received U.S. visitors, as State Route 99 Tunnel Project leaders traveled to Japan to witness testing of the five-story-tall behemoth that will begin tunneling beneath downtown Seattle next summer. 

Leaders from the Washington State Department of Transportation and its contractor, Seattle Tunnel Partners, spent Thursday, Dec. 20, at the Sakai Works factory in Osaka, watching major components of the $80 million machine rotate, extend, retract and move. Seattle Tunnel Partners will authorize shipment of the machine after testing is completed next month. 

Crews in Japan will spend the early part of next year disassembling Bertha into 41 separate pieces – the largest weighing up to 900 tons – and loading them onto a single ship. After a month-long trip across the Pacific Ocean, Bertha will land at the Port of Seattle’s Terminal 46, to the west of CenturyLink Field. Crews in Seattle will transport the pieces a few hundred yards east to an 80-foot-deep pit where the machine will be reassembled and launched beneath downtown next summer.

A video of the ceremony is available on YouTube. Photos of the machine and construction in Seattle are posted regularly on Flickr, and we're documenting Bertha’s journey on Twitter. A 10-foot-long interactive model of Bertha is on display at Milepost 31, the project’s information center in Pioneer Square.