WSDOT: Fixing Bertha 'Will Take Months'

Feb 10, 2014

The state contractor hasn’t yet decided how to fix the broken seal near Bertha’s bearing, but “either way, this process will take months,” said the state Department of Transportation late Monday.

WSDOT announced Friday that the world’s largest boring machine isn’t blocked as previously suspected, but broken. In addition to the broken seal, transportation officials said dirt clogging Bertha’s cutterhead was also hindering the machine.

Crews have cleared the clogs, and the contractor, Seattle Tunnel Partners, is working with Hitachi Zosen, Bertha's manufactuer, to decide how to replace the broken seal: “through the back of the machine or by drilling an access shaft from the surface in front of the machine,” WSDOT said, adding STP is expected to make a decision by the end of the week.

Bertha is only one-tenth of the way toward completing a 1.7-mile tunnel to replace Seattle's aging Alaskan Way viaduct. The machine has been mostly idle for two months, and there is still no word on how the delays will affect the project’s overall schedule or cost.