We retrofitted 19 bridges on or near I-5 from central King County to south Snohomish County. Six of these bridges are located in Tukwila, and 13 are located in Mountlake Terrace and Lynnwood. Retrofitting the bridges brings them up to current seismic standards.
Earthquakes pose substantial risks to transportation infrastructure in Washington State. Completing seismic improvements to select bridges along I-5 in Tukwila and Lynnwood will reduce the risk of serious damage or failure during an earthquake.
This project is part of WSDOT’s Seismic Retrofit Program, which attempts to minimize and avoid catastrophic bridge failures throughout Washington by strengthening bridges and structures to resist future earthquakes. Nearly 900 bridges are scheduled for improvement under the program.
Retrofitting the bridges will help keep drivers safe during future earthquakes.
Crews used three different methods to strengthen the bridges, depending on the individual needs of each bridge. They added concrete blocks between bridge girders to prevent lateral movement, widened existing concrete caps on top of bridge columns to enhance their stability, and reinforced bridge columns by wrapping them in steel jackets.
Partnerships & Cooperation
We awarded the project to Granite Construction in September 2008 and began construction in October 2008. Crews completed the improvements on March 5, 2010, nearly six months ahead of schedule.
This project was funded through the following sources:
- 2005 Gas Tax (Partnership Funding) - $12.5 million
- Pre-existing funds: $300,000
- Total funding from all sources: $12.8 million
Project Engineer Amir Ahmadi
9029 El Capitan Way
Everett, WA 98208
WSDOT Communications Meghan Pembroke
15700 Dayton Ave N
Seattle, WA 98133
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