SEATTLE — The Washington State Department of Transportation said the Alaskan Way Viaduct has settled two to three inches in some spots since the Nisqually earthquake in 2001.
Seattle Tunnel Partners joined the state Monday for an update on the troubled project and its problematic boring machine, Bertha.
Bridge experts say they have surveyed new settlement on the west side of the viaduct. Previously, they surveyed settlement on the east side. Overall, they found the viaduct had settled two to three inches in some spots.
Cracks near Seneca Street that were filled with epoxy have reopened.
A WSDOT engineer told the city council the viaduct scores a little over 9 on the 0-100 scale that rates bridge sufficiency, with 100 being the best, but said the viaduct was safe.
In December 2013, excavation was stopped about 1,000 feet into the dig after measuring increased temperatures in the tunneling machine.
While investigating the cause of the high temperatures, STP discovered damage to the machine’s seal system and contamination within the main bearing.
The machine has been under repair ever since.
STP said it might be able to resume tunneling before Christmas, but the exact date could be determined next week.
"We're very close to the final stages" of testing Bertha after repairs, said Chris Dixon with Seattle Tunnel Partners.
Dixon said the next step is to backfill the shaft with sand until four feet above the drill then fill rest of shaft with native soil.
Aurora Avenue North closures
SR 99/Aurora Avenue North will be closed between the south end of the Battery Street Tunnel and Valley Street, Dec. 18-19, from 9 p.m. Friday to 5 p.m. Saturday.
WSDOT is planning to start work requiring more lane closures on Aurora Avenue North on January 18. The work will close a southbound lane for seven weeks and a northbound lane for five weeks.
KIRO
