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I-5 Skagit River Bridge Emergency Repair

I-5 Skagit River Bridge Emergency Repair

Collapsed Skagit River Bridge section replaced in under three months
Location
Mount Vernon, Washington
Client
Washington State Department of Transportation
Contract Value
$5.8 Million
Completion Date
2013
Market Sector
Roadways & Bridges
Capabilities
Self Performance

On May 23, 2013, a portion of the Skagit River Bridge collapsed after it was struck by a truck carrying an oversized load. The collapse disrupted 71,000 daily commuters and severed the primary freight corridor between Washington and Canada. WSDOT began planning replacement efforts immediately and selected Atkinson—one of only three WSDOT prequalified emergency contractors—the following morning to perform the emergency bridge replacement work. Within 24 hours, Atkinson had loaded barges with equipment—including a 150-ton mobile crawler crane and two long-reach excavators—and mobilized more than 75 craftsmen to the site.

Working with WSDOT and the National Transportation Safety Board (NTSB), Atkinson began demolishing the collapsed span on May 27—less than 60 hours after the bridge collapse. The following day, the first pieces of the replacement span arrived—specifically a modular structure shipped across the country by Acrow Corporation of America. This structure allowed Atkinson to erect two temporary spans—one northbound and one southbound—to quickly re-open the roadway while a permanent solution was designed and constructed.

The project team retrofit the existing bridge piers—building small pedestals to connect with the new structure. At 240,000 pounds, the modular bridge spans were too heavy to be placed by crane. The team orchestrated two cantilever girder launches to push the bridge segments out across the Skagit River. Existing overhead trusses prevented the team from launching the spans in line; instead, the segments were launched off-center of their final location and rolled into place by hand using come-alongs and Hilman Rollers.

With the temporary bridge spans in place, Atkinson paved and striped the roadway and re-opened I-5 on June 19—less than four weeks after the collapse. The temporary bridge remained in place until September 2013 when a separate contractor rolled a new permanent bridge into place.

We’ve asked a lot from WSDOT, Atkinson, and their subcontractors—and they delivered. I want to thank everyone who worked so hard to make this happen and those who have been patient to see it through.
Jay Inslee, Governor, Washington State