Project map
Crews dug deep into the hillside to wrap the columns in steel jackets.
See more
pictures of the work.
February 2013
- The work on the travel lanes is nearly done. We will be on the bridge this week to lay the final piece of rubber seal, bolting plates into place with more than 195 bolts.
- We hope to remove the asphalt bump by Feb. 15 and then move under the bridge to re-establish plats.
- Daily construction information can be found here.
- See photos of the work.
The SR 99 Aurora Bridge is vulnerable to earthquake damage and the columns, trusses, crossbeams, and girders are not up to current earthquake standards.
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. To bring this bridge up to standard, crews are adding steel and concrete to the skeletal portion of the bridge on both the Fremont and Queen Anne ends of the bridge.
We are also modifying two expansion joints and replacing one expansion joint. This work is done primarily on the bridge deck.
Why working on this bridge is difficult
Working on this bridge is difficult because crews must balance the needs of nighttime sleepers, daytime at-home workers, and daily commuters.
Working with steel and concrete is inherently noisy and there are many residences on both sides of the bridge. Sound carries very well across the water and under the bridge.
The bridge is on the National Register of Historic Places and is a City of Seattle 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
- 3 expansion joints
- 8 steel members
- 6 steel trusses
What are WSDOT and the contractor doing to reduce noise?
Crews are:
- using noise shields whenever possible to shield noise from generators, jackhammers and any concrete and steel work.
- working during the day under the bridge to reduce the impact on nighttime sleepers.
- looking for opportunities to work long weekends to expedite the schedule.
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. The expansion joints will be up to current earthquake standards.
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
Fall 2012: Construction complete
Financial Information
Project signage will reflect the cost of construction engineering, project bid award and sales tax.
$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
425.225.8741
chij@wsdot.wa.gov
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