Crews complete final phase of earthquake-retrofitting work
SEATTLE – Should the “big one” hit, the Aurora Avenue Bridge is in better condition to roll with the Richter scale than it was a year ago.
Crews recently outfitted the vital corridor that connects Queen Anne and Fremont with new expansion joints, reinforced columns, extra concrete and additional steel that allow the bridge to bend and flex with seismic movement.
“While no one can predict the magnitude or location of an earthquake, this work reduce the quake damage so crews can get the bridge up and running again in the event of a significant shaker,” said Carl Barker, assistant project engineer with the Washington State Department of Transportation.
The work is part of WSDOT’s seismic retrofit program, which identifies structures vulnerable to earthquakes. The Aurora Avenue Bridge is considered a life-safety route. Current construction work began in June 2011 and was substantially complete in early March.
In Fremont, crews added more concrete to girders supporting the bridge and wrapped the unique cross-shaped columns with a special material to increase seismic safety. In Queen Anne, crews dug deep into the hillside and encircled the bridge-supporting columns with steel. They added more steel and concrete to the bridge’s skeleton to make it sturdier. On the bridge deck, crews replaced two and modified one bridge-wide expansion joints. Under the bridge in Queen Anne, pedestrians are walking on a new, wider sidewalk with handrails and extra lighting for safety.
Built in 1932, the bridge earned city of Seattle landmark status and a spot on the National Register of Historic Places thanks to its beauty and design. “It’s a challenge to bring a structure up to current earthquake standards while maintaining the look and feel of a bygone era,” Barker said.
The seismic-safety work was scheduled for completion by Dec. 2012. During construction, however, crews found corroded support beams that had to be repaired before crews sealed the bridge and poured concrete.
The $5.7 million project was funded through the federal and state gas tax.