Project map
This is what the new fiber polymer wrap looks like around the column in Fremont.
See more
pictures of the work.
The SR 99 Aurora Bridge is due for another round of seismic upgrades, this time to the unique support columns.
See project photos.
May 2012
- **DRIVER ALERT** Crews will close the Aurora Avenue Bridge in both directions from 11:59 p.m. Tuesday, May 29 through 5 a.m. Wednesday, May 30.
- Crews will close Queen Anne Drive under the bridge May 21 - 25.
- See photos of the work.
- Find more construction information.
- Crews continue to wrap the north end columns with specialized fiber. They continue to put up bracing on the south end. The rivet busting is noisy so we are mostly doing it during the day.
- Looking for something to print out that sums up the work? (pdf)
- View a report from Washington State University on the seismic testing (pdf 764kb).
The SR 99 Aurora Bridge is vulnerable to earthquake damage and the columns, trusses, crossbeams and girders need to be strengthened. Traditionally, WSDOT has used round steel jackets to strengthen bridge support columns. However, round steel jackets would obscure the Aurora Bridge's special cruciform ("+" shaped) columns. The bridge is on the National Register of Historic Places and is a City of Seattle Landmark.
WSDOT engineers are studying different techniques to strengthen the bridge support columns while also preserving the unique appearance of the landmark.
Why is WSDOT
strengthening the Aurora Bridge columns against earthquakes?
This bridge is a key route for commuters and freight and carries about 80,000 vehicles a day heading to and from Seattle. The bridge opened in 1932, when earthquake design standards were not as rigorous as they are today.
Seismic studies in 1995 and 2001 outlined improvements that would strengthen the bridge to better resist earthquake damage.
Previous projects strengthened other parts of the bridge, including installing new expansion joints, adding bearings that absorb movement and replacing some trusses ($7.3 million), and adding restrainers ($2.1 million) to better withstand earthquakes.
This next phase targets:
- 14 columns
- 16 girders
- 4 concrete crossbeams
- 2 expansion joints
- 8 steel members
- 6 steel trusses
The End Result
When the project is completed, the columns supporting the Aurora Bridge will better withstand earthquakes and resist damage. Trusses, crossbeams and girders also will be better able to resist damage and make for a stronger, safer bridge.
This will keep traffic flowing on this key route into Seattle and protect nearby residences, businesses and traffic from damage if the columns were to crumble or fail during or after an earthquake.
Project Benefits
Earthquake-resistant bridge columns will help prevent the collapse of the Aurora Bridge. The improved columns also will be less likely to crumble, split or crack in ways that would make the bridge vulnerable to collapsing later or showering concrete onto businesses, residences and traffic below. Stronger trusses, crossbeams and girders also help the bridge resist earthquake damage.
These benefits protect drivers and nearby residents and keep traffic flowing on this key route into Seattle.
What is the project timeline?
June 2007 - Winter 2010: Project design and testing
January 2011: Advertise for construction
April 2011: Award contract
June 2011: Construction begins
February 2012: Noisy work one weekend to install a new expansion joint
Fall 2012: Construction complete
Financial Information
$5.7 million, including federal funds and gas taxes
How can I get more information?
Contact:
Jamie Holter
WSDOT communications
206-440-4698
HolterJ@wsdot.wa.gov
John Chi
WSDOT project engineer
425-489-5400
chij@wsdot.wa.gov
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