Alaskan Way Viaduct closes for two weeks of tunnelling
3 May 2016USA - The Washington State Department of Transportation (WSDOT) closed the SR 99 Alaskan Way Viaduct on April 29 for two weeks, the period of time when the TBM mining the replacement road tunnel passes under the structure.
Crews closed the a state highway between South Spokane Street and the south end of the Battery Street Tunnel just after midnight Friday. WSDOT said, more than 90,000 vehicles use the viaduct each day and will be "forced to find other routes to their destination, resulting in congestion that will affect nearby surface streets and other commuting routes throughout the Seattle area and beyond."
In preparation for the viaduct's closure contractor Seattle Tunnel Partners (STP) said its overnight crew will spend the early hours of Friday restarting and testing the TBM before beginning the drive that day. The TBM had been in a planned maintenance stop and would require mining 3m in concrete before reaching any soil.
On Monday, May 1 WSDOT reported the TBM had made a "a slow and deliberate departure" from the planned maintenance stop on Sunday afternoon and had mined 39ft (12m) of the approximately 385ft (117m) of tunnel that must be completed before the viaduct reopens to traffic.
