- A revised schedule from contractor Seattle Tunnel Partners (STP) could see Washington's $2.2 billion State Route 99 tunnel opened to traffic this fall, according to The Seattle Times. The eventual replacement for the Alaskan Way Viaduct is still three years behind its original schedule, but months ahead of what officials had most recently projected would be 2019.
- The new schedule shows fast-tracking of completion and testing from Oct. 25 to Aug. 14. Crews must then take an additional three to five weeks to perform necessary ramp work, but state transportation officials said it is unclear how soon they would start that work after the tunnel's completion.
- STP has filed claims of up to $600 million alleging that the project's initial delay was caused when its tunnel boring machine (TBM), Bertha, hit a steel pipe, the location of which STP asserts was not disclosed. Washington's Transportation Department contests the claim, and the matter is working its way through the courts. The state legislature has provided $60 million to cover the costs of project delays, but that amount is far less than the projected $149 million officials feared might be necessary.
The entire Alaskan Way Viaduct replacement program is budgeted at approximately $3.2 billion and, although there is a significant amount of other road and infrastructure work associated with the project, the tunnel portion is, by far, the most expensive piece. But Seattle isn't alone, as tunneling operations anywhere and under any circumstances tend to be expensive.
New York City's Metropolitan Transportation Authority is connecting the Long Island Railroad to Grand Central Station, and the projected costs for the 3.5-mile East Side Access tunnel are $12 billion. That figure is up from a 2015 estimate given by Michael Horodniceanu, the MTA's chief engineer and head of capital projects.
Back then, Horodniceanu said the project would cost about $1 million per mile, which was still more than twice the original estimate. Horodniceanu told The Wall Street Journal in April 2016 that, in comparison to manually digging a tunnel, using a TBM had cost the city $19,000 a foot on a separate 3-mile tunnel project.