I-5: Willamette River Bridges (Whilamut Passage)

After cracks developed in the concrete of the original Willamette River Bridge, which carried an average daily traffic count of more than 70,000, Oregon Department of Transportation designed and constructed an emergency detour bridge that would carry busy Interstate 5 (I-5) traffic while the team designed and constructed a permanent replacement.

Getting there was a complex task. For starters, the massive project had to stay within the existing right-of-way which resulted in the reconstruction of the I-5 freeway and connector ramps within their current footprints. This required complex construction sequencing that resulted in nine traffic control stages. To keep traffic moving safely, DOWL roadway engineers modeled in 3D to resolve all potential construction conflicts before they could lead to delays in the field.

Because of the high-profile nature of the project and the desire of area residents to be involved in the process, DOWL facilitated design workshops to develop aesthetic enhancements all around the project area. This ultimately led to public art installments that are visible from the traffic lanes and significant path improvements beneath the bridges.

The result was a set of parallel landmark concrete arch bridges, officially named the Whilamut Passage (in honor of the area’s native population), that serves as a graceful addition to the essential I-5 corridor.