Multnomah County commissioners unanimously approved a design for a new earthquake-resilient Burnside Bridge on Thursday.
The board selected an “inverted Y” design, including a cable-stay tower extending into a single column at the bridge’s east side.
Earlier this summer, the county conducted a survey looking for people’s input on the bridge’s new look. The county received over 19,000 responses, with a majority choosing a tied arch design.
The cable-stay, “inverted Y” design was also popular based on survey responses, but commissioners relied on other factors as well, including recommendations of county staff and an advisory group. Ultimately, the board accepted the Community Design Advisory Group’s recommendation to go with the “inverted Y” cable-stay design.
A rendering of the cable stay type design, chosen by the Multnomah County Board of Commissioners as the preferred structure for a new Burnside Bridge. It's part of an $895 million replacement project to earthquake-proof a critical corridor connecting the east and west sides of Portland.
Courtesy of Multnomah County
Freelance architecture and design journalist Brian Libby says he has mixed feelings about the design.
“I think the inverted Y tower is the most unique option,” Libby said. “It would also be the most compatible with some of the tall buildings that are nearby.”
Libby says despite this design being the best among the options presented, he sees its asymmetrical design as a big flaw.
This comes after years of planning to seismically upgrade the nearly 100-year-old bridge. According to the county’s website, studies show many of Portland’s aging bridges are not likely to withstand a major earthquake.
The Burnside Bridge, like many others in the region, would not be operational should a magnitude 8+ earthquake hit the area. Officials say it could take weeks before any downtown bridge is usable after a major earthquake.
Jon Henrichsen, Multnomah County’s transportation division director and engineer, said the project started with about 120 different options to bring the bridge to current seismic standards.
He says it’s hard to feel all the emotions this phase of the project brings as it’s been eight years in the making.
“There’s not much time to take a breath and feel the excitement in this moment,” Henrichsen said. “It is a tremendous milestone for the project to finally know all the components that we’re going to build.”
Henrichsen said the county oversees six bridges within the city’s limits, most of which cross the Willamette River and serve as gateways into downtown Portland.
Like the Burnside Bridge, the Hawthorne, Morrison and Broadway bridges were originally built without seismic fittings.
While the costs are too high to upgrade all the county’s bridges, officials have marked the Burnside Bridge as a “lifeline route,” because it would aid transportation for first responders in the event of a major disaster.
In 2022, the county estimated the overall cost to upgrade the Burnside Bridge would be around $895 million. Henrichsen said he does not have an updated estimate but said the county is working to release that information next spring.
In the meantime, he said the department will continue to develop costs at different milestones of the design project. The first one comes in October when the design is set to be 30% completed, he said.
“Schedule is everything on this project,” Henrichsen said. “To keep the cost down, we need to make sure that we stay on a schedule where we finish it as soon as possible.”
Construction is expected to begin in 2027 and take about 5 years. The county has not yet secured all the necessary funding.
Several grants, federal aid as well as funding from a county vehicle registration fee have helped support the project so far. Henrichsen said they plan to ask for additional funding at the next legislative session.