AASHTO Journal, 13 May 2016
The Washington State Department of Transportation said its “Bertha” tunnel boring machine finished tunneling early underneath the downtown Alaskan Way Viaduct (SR 99), allowing that heavily traveled route to reopen to traffic May 8 after a 10-day closure.
The agency had closed the viaduct, which normally carries about 90,000 vehicles a day and 30,000 transit riders, on April 29 for what it expected to be about two weeks of tunneling directly underneath. That is part of a long-term project to create a new underground route that will replace the earthquake-damaged highway overhead.
Re-opening the viaduct early after 10 days of round-the-clock work was a signal achievement for Bertha, which earlier in this major tunnel project suffered damage that required extensive repairs to the TBM and put the whole project on a delayed timetable.
Acting Transportation Secretary Roger Millar said in reopening the downtown freeway segment that “removing traffic from the viaduct was critical to the success of this work, but we don’t want the closure to last a moment longer than it needs to.”
Gov. Jay Inslee lauded WSDOT and contractor Seattle Tunnel Partners for “a job well done. To finish this piece of the project almost a week early is commendable. The planning and flexibility of commuters, along with strong coordination between WSDOT and partner agencies, ensured commuters had access to real-time information that helped them plan ahead.”
Although state officials thanked the community and its commuters for showing patience during the viaduct closure, the Seattle Times reported that the closure caused significant problems for area drivers.
“Traffic that typically used the highway squeezed onto surface streets and Interstate 5, causing major delays that frustrated many commuters,” the Seattle Times said. “The heavier-than-usual traffic also led to an increase in car crashes.”