Date:  Monday, November 10, 2008

Contact: Amir Ahmadi, WSDOT Project Engineer, 425-225-8700 (Everett)
Aurora Jones, WSDOT Communications, 206-440-4470 (Seattle)

Improvements will bring 19 bridges up to current seismic standards

MOUNTLAKE TERRACE – Today, WSDOT and contractor Granite Northwest crews will kick off a two-year project to improve 19 bridges on I-5 from Tukwila to Lynnwood. Crews will upgrade the bridges to current seismic standards, reducing the risk of serious damage during an earthquake.

“Earthquakes pose a substantial threat to aging bridges in Puget Sound,” said Project Engineer Amir Ahmadi. “Upgrading these bridges to current standards will help strengthen our bridge infrastructure and keep drivers safe in the event of an earthquake.”

Bridge preservation engineers surveyed 26 bridges along the I-5 corridor in central King and south Snohomish counties, finding 19 bridges in need of improvement. Six of the bridges are located in Tukwila and 13 are located between Mountlake Terrace and Lynnwood. Improvements will vary depending upon the individual needs of each bridge, and may include:

• adding concrete blocks between bridge girders to prevent lateral movement
• widening existing concrete blocks on top of bridge columns to enhance their stability, and
• reinforcing bridge columns by wrapping them in steel jackets.

At each of the 19 bridges, crews will build work platforms below the bridge deck to provide access to bridge columns and girders. Today crews will begin constructing platforms under the I-5 overpass at SR 104 in Mountlake Terrace, the first bridge scheduled for improvement. This work will not require lane closures, but drivers should expect occasional closures at other I-5 bridge locations over the next two years. Crews will coordinate necessary closures with other construction projects along I-5.

To protect against catastrophic bridge failures, WSDOT is strengthening bridges and structures throughout Washington to resist future earthquakes. Over 900 bridges are scheduled for improvement under the Seismic Retrofit Program.

The 2005 Gas Tax provided $12.3 million for this project. Crews expect to complete work in late 2010. To learn more about the project, visit the project Web site: www.wsdot.wa.gov/Projects/I5/KingSnoBridgeRetrofit/.

For more information on the Seismic Retrofit Program, visit: www.wsdot.wa.gov/Bridge/Reporting/SeismicRetrofitProgram.htm.. 


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