Bertha, the tunnel-boring machine for 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, reports Western Washington's King TV.
"Damage to the machine was more extensive in some areas than anticipated and some minor damage occurred during disassembly, Washington Department of Transportation 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.