Interstate Bridge Replacement

With one of its two spans exceeding 105 years old, the Interstate Bridge on I-5 is at risk of collapse in a major earthquake. The I-5 corridor serves as a vital trade route between the U.S., Canada, and Mexico and is a critical connection between Oregon and Washington families. Bridge failure here would lead to rapid and severe economic impacts. The Interstate Bridge Replacement (IBR) program is a multi-state effort to replace the aging I-5 bridge with a modern, seismically resilient, multimodal structure that improves mobility for people, goods, and services. The project seeks to identify a solution that meets community needs and priorities and looks at design options such as high-capacity transit options, interchange improvements, urban design, travel lanes, bridge height and type, and multi-use path facilities and connections.

Parametrix, in partnership with WSP, is leading a large consultant team that has collaborated closely with local, state, federal, and tribal partners and the community through online surveys, listening sessions, working groups, public meetings, and steering and advisory groups to define the foundational elements for the project. The entire program is committed to centering equity in all aspects of work, facilitating inclusive outreach programs, and identifying climate-smart solutions and building resilient infrastructure.

A modified locally preferred alternative for the replacement bridge has been approved and is being further studied through a supplemental environmental impact statement. During the environmental process, benefits and impacts of the preferred alternative will be further analyzed. Elements such as additional transit improvements, active transportation, and river crossing structure type and alignment are anticipated to be determined in the next phase of the program. During this phase, the team will also advance the project through 30 percent design.

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