AASHTO Journal, 25 April 2014
Bertha, the world’s largest boring machine tasked with tunneling under downtown Seattle for the new State Route 99, will not resume her job until March 2015, Washington State Department of Transportation officials announced this week.
The machine, which is creating the tunnel as part of the Alaskan Way Viaduct Replacement Program, had been placed in the ground last summer with the hope of opening the new tunnel in late 2015. Bertha abruptly halted digging in December and WSDOT reported that the seal system protecting the machine’s main bearing was damaged. Construction will begin in May on the pit that project lead Seattle Tunnel Partners will use to get to the machine in order to complete its repairs to Bertha. From July through September, STP will excavate the pit so that in October it can begin repairing the machine. STP plans on testing the machine post-repair in February and to resume digging in March.
“Resuming tunneling will take longer than any of us would have liked, but making these repairs is a significant engineering challenge that must be done safely,” said STP Project Manager Chris Dixon in a statement. “We are committed to this project, and to taking the necessary steps to recover time and open the tunnel to drivers by WSDOT’s original target date.”
According to WSDOT, the timetable released this week delays tunnel work by up to 16 months, though STP is attempting to “recover as much as four months of schedule” to meet WSDOT’s original tunnel opening in November 2016. STP had previously proposed opening the tunnel in late 2015.
“We are disappointed by this delay, but we believe the new schedule is moving in the right direction,” said WSDOT Alaskan Way Viaduct Program Administrator Todd Trepanier. “We’ll continue to work with STP in their efforts to resume tunneling. We’re also focused on the rest of the program, which includes more than $750 million worth of work at the tunnel portals and elsewhere along the SR 99 corridor. That construction is not affected by the tunneling stoppage and continues full speed ahead.”
Additional information on the entire Alaskan Way Viaduct Replacement Program is available here. Those interested may follow Bertha’s progress through her Twitter account.
