In a Wednesday letter to lawmakers, Secretary of Transportation Lynn Peterson said the state "had concerns about the machine's operations and critical systems since its launch on July 30, 2013."
The enormous machine ground to a halt on Dec. 6 after running into an 8-inch diameter pipe that had been left in the ground in 2002 after the department checked groundwater in the area.
In her letter to lawmakers, Peterson said transportation officials have discussed Bertha's issues with the project's contractor, Seattle Tunnel Partners, numerous times since the machine began digging.
"We have discussed these concerns with STP frequently over the past five months and this week sent a formal letter stating our concerns and asking STP how they will address them prior to tunneling under the viaduct and downtown," the letter reads.
Among a host of other issues, Peterson wants STP to address what's causing the wear on cutting tools, details about changes to soil conditioners, how STP plans on getting back on schedule and what experts the contractor have spoken to since Bertha stopped digging.
Peterson said STP should have answers to those questions by Wednesday evening.
Bertha is stopped about 60 feet underground and one-tenth of the way toward completing a 1.7-mile tunnel. It will carry Highway 99 traffic and allow the removal of the Alaskan Way Viaduct.
Bertha is another woe added to a growing list for WSDOT. The ferry system faces budget cuts and staffing shortages, which have led to cancelled trips. The 520 bridge is another issue as new construction has dealt with huge overages, design flaws and delays.