By Midge Pierce
Portland will have a new, Long Span, seismically safe Burnside Bridge within the decade; more than a century after the original span was built, if all goes according to expectations.
A county volunteer taskforce voted to recommend that the iconic landmark, at risk of collapse in the event of the long-expected earthquake, be replaced with a bridge that follows the alignment of the current bridge that has been standing since 1926.
The alternative identified as the least costly and time-consuming to build and most likely to be seismically sound was selected by the group of engineers, architects and community leaders. The cost of the Long Span is estimated at $825 million while the Short Span, cited as a potential way to revitalize neighborhoods near the Willamette River, was estimated to cost about $950 million.
A key advantage of the Long Span is that it would avoid geologically hazardous zones along the river. Eastside soils between I-5 and the railroad tracks are at risk of liquefaction during an earthquake. The Long Span would also reduce the number of columns needed in slurry-prone soils. Fewer columns leave room for a skatepark and other waterfront amenities.
The bridge is considered the city’s lifeline, connecting a major East-West emergency route. 45,000 cars cross the Burnside Bridge daily, with an additional 7,000 traveling the bridge by bus, 2,000 by foot and 4,000 by bike.
To better accommodate pedestrians and bikes, the Long Span would provide 15 feet more width than the current lanes that narrow over the bridge. Between sidewalks and bike lanes, a crash-worthy traffic barrier is planned.
Once the recommendation is approved and funded, construction is targeted for completion in 2028. Despite fiscal complexities resulting from COVID-19, county spokesman Mike Pullen says the project already has funding for the planning, design and right-of-way costs that come from county vehicle registration fees, which will cover about one third of construction costs.
The November 2020 ballot is expected to include a Metro regional funding measure for transportation. If that passes, Pullen expects $150 million toward bridge construction, with the rest coming from state and federal funds.
Taskforce members rejected a temporary bridge option that would add $90 million to project costs and require two additional years of construction. The taskforce was told that diverting traffic to adjacent bridges, roughly one third of a mile apart, would add only minutes to commutes.
A suggestion for a bike/pedestrian ferry was shelved over the possibility of debris hazards in the river following an earthquake.
During years of feasibility studies, more than 100 options including tunnels, a movable bridge and doing nothing were studied and rejected. The taskforce likewise nixed a seismic retrofit alternative.
Despite near unanimous support for the Long Span option, several taskforce members raised the issue of view corridor impacts. To support the horizontal span, the new bridge would require a superstructure above the deck that might block views of downtown including the incandescent Portland sign.
Taskforce member Cameron Hunt asked if there is a way to save the iconic towers on the bridge since it is a registered historic landmark.
Taskforce member Susan Lindsay of the Buckman neighborhood expressed disappointment that the Long Span failed to improve neighborhood-to-neighborhood connections. Asking that Buckman have a role in future decisions, she said, “The Eastside has been the stepchild of Portland for a long time.”
The structure’s relationship to neighborhoods and its scale and design will be addressed during coming bridge type and design processes. The public will be able to weigh in on the task force recommendations later this summer.
Federal Environmental Impact drafts and another comment period are required before approval by the Federal Highway Administration.
For more information visit burnsidebridge.org.
Long Span bridge rendering from Multnomah County.