Multnomah County’s Community Task Force has made its recommendations for how a new, earthquake-ready Burnside Bridge could look and function.
The Task Force, a group of about 20 community members, area business leaders and others, is recommending a replacement long span bridge — a liftable bridge in the same location and length as the existing Burnside Bridge with a support structure above the bridge with longer spans, or distances, between the bridge’s columns.
The county is soliciting feedback from the community on the recommended bridge option, as well as how traffic management could look during construction — the Community Task Force is recommending a full bridge closure in order to save money and time during construction, rather than other options such as building a temporary bridge, which would cost an estimated $90 million.
If approved, the project would move forward into design and construction would begin in 2024.
“The problem we’re trying to solve is that none of our downtown bridges are expected to be usable after this big earthquake happens,” Mike Pullen, Multnomah County spokesman, said.
Scientists predict that Oregon is due for a 9.0 or greater magnitude earthquake caused by the Cascadia Subduction Zone sometime in the next 50 years.
County engineers had originally studied more than 100 options to create a seismically sound crossing in place of the current Burnside Bridge — the regionally established emergency route over the Willamette River.
Those options were eventually narrowed to four: Retrofitting the existing bridge, creating a taller fixed bridge that would not need to be lifted for river traffic, the long span bridge the Task Force has recommended and another long span bridge that would include a new portion of bridge extending onto Couch Street.
The recommended long span bridge had multiple benefits that made it the top option, Pullen said.
“By having fewer columns [under the long span bridge], we get a number of benefits — it makes it more resistant to an earthquake, makes the cost lower and it really opens up space where there’s currently a lot of columns under this 94-year-old bridge,” Pullen said.
He said the bridge will offer more space on the west side of the river for Portland Saturday Market. On the east side, this bridge option includes the retention of the Burnside Skatepark, which would need to be demolished if the decision was made to retrofit the existing bridge.
The long span replacement option has the lowest construction cost compared to other options — an estimated $825 million, Pullen said.
Metro, the regionally elected government for Multnomah, Clackamas and Washington counties, recently referred a multi-billion dollar transportation bond measure to the November ballot which includes $150 million dedicated toward a new Burnside Bridge.
The Multnomah County Board of Commissioners late last year also passed an ordinance nearly tripling the county’s vehicle registration fees to help fund the new bridge. The county’s vehicle registration fee, wrapped into the state registration fees Oregonians pay every other year, is currently $19 per year. It will jump to $56 per year starting in January.
Pullen said those two sources will fund about half of the price of the proposed bridge’s construction budget.
The county hopes for the remainder of the construction cost to come from state or federal funding, he said.
“What you hear in the transportation arena these days is that the state and federal governments really like to see the local governments, basically the owner of the project, which is Multnomah County in this case, they want to see us put our own money to get to the starting gate of construction,” Pullen said. “That shows them that we have invested in ourselves and that the project has community support.”
Pullen said the project has indeed received community support, though he said, the only concern the county has received about the proposed long span bridge is that it may change the views in the downtown Portland area — specifically the view of the Portland, Oregon, sign in Old Town — since the long span bridge requires supports over the bridge that the current bridge doesn’t have.
One design option for the new Burnside Bridge is a "tied arch," similar to the Fremont Bridge.
Multnomah County
The actual design of the bridge is yet to be determined. Some design renderings include: A “tied arch,” with a somewhat similar look to the Fremont Bridge; “cable stayed,” similar looking to Tilikum Crossing; and a “through-truss,” mostly resembling the look of the Hawthorne or Broadway bridges.
When the bridge makes it to the design portion of planning, it will either have a lifting or pivoting middle moveable portion, depending on what design is finalized.
The county is asking the community to weigh in on the recommended bridge and construction options through two surveys, the results of which will go back to the Community Task Force.
The Task Force’s recommendations will be included in a draft Environmental Impact Statement to be issued by the Federal Highway Administration in early 2021.