Feasibility Study

We spent two years evaluating alternatives for the Burnside Bridge to withstand a major earthquake, and determine what improvements are needed to extend the life of the bridge.

We spent 2016-2018 conducting a feasibility study for an Earthquake Ready Burnside Bridge. The bridge has served us well for almost a hundred years, but it needs an upgrade to carry us safely over the river for a hundred years more.

Over 100 river crossing alternatives were studied by our own staff, stakeholder and community groups, three committees and the public. They were studied for a broad range of requirements, as described below.

After all this, four alternatives rose to the top. These alternatives were presented to the public in summer and fall of 2018. Following this last round of public input, the Board of County Commissioners gave final approval to the feasibility study in November 2018. The final alternatives approved by the board will move on to the next phase of the project - environmental review.

Outreach schedule for Earthquake Ready Burnside Bridge project
Outreach schedule for Earthquake Ready Burnside Bridge project

Alternatives

Over 100 alternatives have been through a lengthy screening process to make sure they meet the requirements for a reliable river crossing after a major earthquake. These alternatives can be grouped into five categories:

No Build
Maintain existing bridge as-is.

Seismic Retrofit
Upgrade the existing bridge.

Enhanced Seismic Retrofit
Retrofit most of the existing bridge, but replace the spans over I-5 and the railroad.

Replacement
Build a new crossing such as a high fixed bridge, low movable bridge, twin bridges or a tunnel.

Enhance Another Bridge
Retrofit or replace a different bridge across the Willamette River.

Screening

The first step of the screening process screened each alternative against the core requirements of seismic resiliency, emergency response, and compatibility with major infrastructure. The second step of the screening process studied how well each remaining alternative will function immediately after an earthquake in addition to everyday use.

In the final step, each remaining alternative was further evaluated for its performance in six key categories:

Seismic Resiliency
Does the option support reliable and rapid emergency response after an earthquake?

Non-Motorized Transportation
Does the option support access and safety for bicyclists, pedestrians, and people with disabilities?

Connectivity
Does the option support street system integration and function for all modes?

Equity
Does the option minimize adverse impacts to historically marginalized communities and promote transportation equity?

Built Environment
Does the option minimize adverse impacts to existing land use as well as parks and historic resources?

Financial Stewardship
Does the option ensure public funds are invested wisely?

The results were shared in September 2018 at two public open houses and online. The alternatives that remain after this step will be evaluated in more detail in the environmental review phase.

For more information on our screening process, please view our project factsheet:


Project Phasing

Scheduled phases for the Earthquake Ready Burnside Bridge project.
Last reviewed December 3, 2024