SEATTLE – A new highway tunnel through downtown Seattle won’t be open until August 2017, about 20 months behind schedule, state transportation officials said Monday.
The contractor, Seattle Tunnel Partners, said it expects to resume tunneling in April.
The massive tunnel-boring machine stopped work on the 2-mile tunnel in December 2013 after going about 1,000 feet, and the massive machine that’s stuck underground needs repairs before drilling can resume.
The contractor and state officials say they can’t nail down an exact completion date until tunneling resumes.
“Schedule is very important to us,” Matt Preedy with the Department of Transportation said in a call with reporters. “At the end of the day, this is a safety job.”
He added, “The state fully intends to stay the course and complete this job.”
“We still have plans to mitigate that delay,” Chris Dixon, project manager at Seattle Tunnel Partners, said Monday of the delayed completion date. But that largely depends on when digging happens, when it is complete, and what work remains with the overall project at that time, Dixon said.
The August 2017 date is outlined in a monthly schedule the contractor provides to the transportation agency, and it could change again, Preedy said.
That date is also nearly a year later than what the contractor had targeted when the tunnel-boring machine got stuck.
The project hit another obstacle last month when work temporarily stopped so engineers could investigate ground settlement around the access pit being dug to reach and replace the damaged head of the boring machine.
Workers have been “de-watering” to reduce pressure from underneath and on the sides of the pit. Crews resumed excavation last week, and transportation officials said Monday that settlement levels near the access pit has remained stable since late last month.
While some ground settlement is to be expected, “the settlement measured is greater and farther reaching than anticipated,” the agency said Monday.
Crews doing building surveys since early December “found some minor cosmetic damage in a handful of buildings, but no structural damage has been discovered,” the agency said.
The $2 billion tunnel is designed to replace the aging Alaskan Way Viaduct that was damaged in a 2001 earthquake.