Bertha, the plagued tunnel-boring machine at the Alaskan Way Viaduct replacement project in Seattle, has been dismantled and has revealed more damage than was expected.
Grit made its way into the rubber bearing seals, steel casings around the seals broke apart and pinion gears and the teeth that spin the drill were cracked. Tunneling at the $1.35 billion project was to restart in August, but that looks unlikely now.
Damage to the machine was more extensive in some areas than anticipated and some minor damage occurred during disassembly," Washington Department of Transportation (WSDOT) spokesperson Laura Newborn said in a statement.
"For example, the outer seals and the steel retainers that hold them in place were destroyed. There was also damage to the cutter drive motor pinions and the main bearing bull gear."
The tunnel, which will run about two miles under the city, is designed to replace the State Route 99 Alaskan Way viaduct, damaged in a 2001 earthquake. The $2 billion project is two years behind schedule, and transportation officials still do not have a clear date for when Bertha will resume tunneling or when the project would be complete.
The project's contractor, Seattle Tunnel Partners, said they will likely provide a revised of when Bertha will resume digging by June when they understand the scope of the repairs.
The findings, which were presented to the Seattle City Council on Monday, did not sit well with some council members.
"The frustration level at this table is rising significantly," said Seattle City Councilmember Sally Bagshaw.