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Transportation :: Bridges and Structures

I-5 Interstate Bridge Trunnion Replacement

Portland, OR and Vancouver, WA

The I-5: Interstate Bridge is a vertical-lift, through-truss steel bridge that serves as a critical connection point between Oregon and Washington States. Transporting an estimated 150,000 travelers per day over the Columbia River, an essential marine route, this historic bridge has the ability to lift and lower to allow large shipping vessels to pass under the bridge. The century-old trunnion shafts, sheaves, bearing assemblies, and counterweight cables in the south tower of the northbound bridge were in need of replacement to maintain the lift span function.

Typical bridge traffic includes interstate automobile commuters, public transportation vehicles, emergency vehicles, freight vehicles, bicycles, and pedestrians as well as marine traffic travelling under the bridge on the river below. Closing the northbound bridge without accommodating northbound traffic was not an option. The Oregon Department of Transportation (ODOT), the bridge’s owner, partnered with the Washington Department of Transportation (WSDOT) and the DEA team to develop a solution to complete the trunnion replacement project while still maintaining traffic operations throughout.

DEA served as prime consultant for this project. We provided preliminary engineering and construction engineering services to safely and efficiently complete this complex project on a tight schedule. There was an extensive list of stakeholders involved, so DEA led the team effort using highly coordinated communication strategies, collaborative problem-solving, and detailed planning leading up to the project and during construction. We maintained efficient and safe operations with minimal surprises, resulting in a successful trunnion replacement appreciated by stakeholders and public alike.


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