Columbia River Bridge Design

A new river crossing will replace the existing Interstate Bridge structures to carry I-5 traffic, light rail, pedestrians and bicyclists. Once the new structures are built, the existing bridges will be removed. Additional engineering and architectural work is currently underway.

Community input will be important as bridge aesthetics and architecture are developed.

Cross-cut illustration of two side by side deck truss style bridges with auto traffic on top and transit, pedestiran and bicycle traffic below

Deck truss bridge type recommended by governors

Based on analyses by a Bridge Review Panel and the Oregon and Washington departments of transportation, Oregon Governor John Kitzhaber and Washington Governor Chris Gregoire made a final recommendation for a deck truss bridge as the replacement structure for the aging Interstate 5 bridge. Factors influencing the decision included: affordability, reducing risk to schedule and budget, and ability to secure funding.

Navigation and aviation clearances affect bridge design

In consultation with the U.S. Coast Guard and Federal Aviation Administration standard safety guidelines, the project established clearances for both river and air traffic. Current plans call for about 95 feet above the Columbia River datum, which provides between 75 and 95 feet of navigational clearance depending on water level. This proposed navigational clearance was identified in 2006 by CRC based on a previous survey of river users and airport navigation limits. Some river users have stated they require greater clearances. The planned river clearance eliminates the need for a lift span. The air traffic clearance limits of Pearson Airfield and Portland International Airport could influence the height of features above the deck of the new bridge. Additional coordination with the Coast Guard and FAA on the bridge design is ongoing.

Urban Design Advisory Group helps guide bridge design

The CRC's Urban Design Advisory Group drafted design guidelines that are being used in continuing design efforts. The goal of the draft guidelines is to create structures that are of exceptional design and are sensitive to the natural and built environments. The guidelines establish that the bridge should “celebrate passage over a mighty river between two states,” and be an “apt and iconic” presence in the landscape.

Next steps for bridge design

The project will add an architect to the project team and establish architectural specifications for a design-build contractor to follow. The design community and public will be engaged in this next stage of the bridge design process.

Bridge history

The Interstate Bridge has a rich history in the Portland-Vancouver region. Find out more about the construction and operation of the bridge over its decades of service.