The project studied over 100 options during the Feasibility Study Phase from 2016-2018 including tunnels, ferries, double-decker bridges, and other bridge options. Four bridge alternatives were recommended for further evaluation in the Environmental Review Phase, including the Replacement Long Span Alternative.

In fall 2020, after a robust evaluation process and gathering input from the public, the Replacement Long Span Alternative was recommended as the Preferred Alternative because it is the lowest cost and would have the fewest impacts to natural resources.

In early 2021, Multnomah County published a Draft Environmental Impact Statement along with an estimated range of costs for the project. Upon reviewing the range of costs, County leaders asked the project team to analyze ways to reduce the cost so that the project is more likely to be fully funded and built.

The County is now considering refinements to the Long Span Alternative that reflect: (1) cost-saving measures, (2) feedback from government agencies on environmental impacts, (3) input from project stakeholders. If the County moves forward with refinements, these changes will be reflected in a Supplemental Draft Environmental Impact Statement for publication and public comment in spring 2022.

If approved, the project will move into final design in mid-2022 and construction in 2025, depending on funding.

Oregon is in the Cascadia Subduction Zone (CSZ), making it subject to some of the world’s most powerful, recurring earthquakes. Studies show that there is a significant risk that the next major earthquake will occur within the lifetimes of most Oregon residents.

The Earthquake Ready Burnside Bridge project is designing a bridge that would withstand and be immediately useable after a 9.0 magnitude CSZ earthquake. This exceeds the standards of every other downtown bridge and requires advanced engineering and construction design.

An expensive part of the project is addressing the unstable soils around the Burnside Bridge near the Willamette River. In the event of a CSZ earthquake, soils on the east and west sides of the river will liquify and destabilize the bridge’s support columns. This problem is not unique to the Burnside Bridge site and is a major threat to all aging downtown bridges that cross or are adjacent to the Willamette River. To avoid this problem, the project will need to extensively reinforce the soil around the columns to keep them secure. The project team must also plan for construction activities over the Union Pacific Railroad tracks and I-5 on the east side of the river.

In addition, the cost of labor and materials grows considerably with this complex bridge consisting of long members and a movable span requiring lots of specialty construction work. While the project team initially considered widening the bridge, it now recommends the bridge stay at about the same width as it is today, but carry only four lanes of traffic.

Project cost estimates reflect the current high demand for construction materials. However, we don’t know what the cost of labor and materials will be 4-5 years from now when construction starts.

The estimated cost range for the revised Preferred Alternative if the recommended cost-saving refinements are adopted is $825 to $915 million. This estimate will be refined and updated during Final Design.

Project leaders considered these cost-saving measures but decided not to pursue them: 

• Reduce seismic resiliency standards
• Eliminate potential for future Streetcar on the bridge
• Provide less than four vehicle lanes
• Eliminate capacity for oversized and specialized heavy haul vehicles
• Reduce bike/ped width to less than 14 feet on each side
• Remove the crash-worthy barrier between vehicular lanes and bike/pedestrian facilities

This option would have:

• Two lanes toward east Portland: one bus-only and one general purpose lane.
• Two general purpose lanes toward downtown.

Traffic and transit summary:

• Would work well for transit.
• Would work well for vehicle traffic into downtown during the morning commute.
• Would cause significant general traffic congestion and queuing toward east Portland during the evening commute.

This option would have:

• Three lanes toward east Portland: one bus-only and two general purpose lanes.
• One general purpose lane toward downtown.

Historical data tells us that more people use the Burnside Bridge when leaving downtown Portland in the evening than use it to commute downtown in the morning.

Traffic and transit summary:

• Would cause moderate congestion for general vehicle traffic, and travel delays for transit traveling toward downtown during the morning commute.
• Would work well for transit and other vehicle traffic to east Portland during the evening commute.
• Presents challenges for a potential future westbound bus-only lane.

This option would have:

• Two lanes toward east Portland: one bus-only and one general purpose lane.
• One reversible lane: toward downtown during the morning commute and reversing toward east Portland at all other times of the day.
• One westbound general purpose lane toward downtown.

A reversible lane allows for traffic to move in either direction depending on the time of day. It would carry traffic westbound, into downtown Portland during the morning commute, and then reverse for all other times of the day including the afternoon commute. This could be done through a combination of traffic design techniques such as signage, overhead signals, gates, striping and vertical delineators. Although they are not currently used in Portland, reversible lanes on bridges and other roadway segments have been used successfully for decades in other regions. Examples include the Golden Gate Bridge in San Francisco and Lions Gate Bridge in Vancouver, British Columbia. The County would work together with the City of Portland to develop a design that is safe and easy for drivers to understand and use.

Traffic and transit summary:

• Would work well for general traffic during both morning and evening commute times.
• Would match the number of lanes currently available toward downtown.
• Presents challenges for a potential future westbound bus-only lane.

This option would have:

• Two general purpose lanes toward east Portland.
• Two general purpose lanes toward downtown.

In this scenario, all the lanes are general purpose except for near the intersections at each end where the bridge widens allowing buses to have their own priority lane and signal to pass other vehicle traffic.

Traffic and transit summary:

• Would work well for general traffic during both the morning and evening commute times.
• Would work well for transit during the morning commute into downtown but would result in transit delays during the evening commute toward east Portland.
• Would delay the Fire Department during congested times compared to any option with a dedicated bus lane.
• Removes existing bus-only lane toward east Portland.
• Substantially higher cost than other options due to need to widen bridge at each end to accommodate bus queue lane.

The bike and pedestrian facilities on today’s Burnside Bridge are 12.8 feet wide in both directions, not including the buffer that contains the tubular candlesticks. The proposed cost-saving measure of 14 to 17-foot shared spaces will add two to five feet of space on each side compared to today’s bridge, allowing users to have a safer and more comfortable experience on the bridge.

Final decisions about painting and striping to clearly designate walking and biking spaces will be determined during the Final Design Phase.

The revised recommendations still include plans for constructing a crash-worthy barrier between motor vehicles and the bike and pedestrian space. The County will not consider options that remove the physical barrier.

The design of the barrier will be decided during the Final Design Phase.

A 14 to 17-foot shared space for pedestrians and cyclists on both sides of the bridge would be wider than any other downtown bridge. For comparison, the bike and pedestrian space on both sides of the Tilikum Crossing is 13.5 feet wide. The Hawthorne Bridge, which carries roughly twice the number of people walking and cycling compared to the Burnside Bridge currently, has a bike and pedestrian space of 10 feet 8 inches in width on each side.

While transportation-related greenhouse gas emissions would not change significantly, the wider bike and pedestrian facilities, along with reduced vehicle lanes compared to the existing bridge support the bicycle commute mode split goal first identified by Multnomah County and City of Portland in the jointly produced 2009 Climate Action Plan. That desired outcome has since been codified in the City of Portland Comprehensive Plan to a desired outcome of 30 percent bicycle commute mode split by 2035.

The refined girder option can save $20-$40 million because it uses less material and has a lower construction cost than the other westside bridge type designs considered, such as a Tied Arch or Cable Supported.

Recent environmental technical analysis and agency input reveal that the other above-deck bridge types considered would have an adverse effect on the historic districts, posing significant permitting challenges.

A girder structure on the west side benefits the historic Old Town and Chinatown neighborhoods and Skidmore District by keeping conditions similar to today. By not having a structure above the surface of the bridge, we can maintain the open views of and from the west side, an important aspect of maintaining the experience of the nearby downtown historic districts.

A girder structure also means that the west side of the bridge could look similar to today’s bridge, allowing it to maintain more of its current character.

A girder structure on the west side would have two fewer rows of columns in Waterfront Park and greater horizontal and vertical clearance compared to the existing bridge.

A girder structure on the west side helps preserve views from the bridge that were valued by many community members who completed the online survey about bridge type. Because this option does not have a structure above the surface of the bridge, it allows for more direct sightlines of the historic Old Town and Chinatown neighborhoods, the Skidmore District and the historic “Portland Oregon” sign from the bridge. 

• Avoids potential adverse impacts to views to and from downtown historic districts
• Opens views of the historic “Portland Oregon” sign
• Is supported by community survey findings and key stakeholders
• Provides unlimited vertical clearance when spans are raised
• Costs $25-$35 million less than the vertical lift option

• Poses a negative impact on views to and from downtown historic districts
• Would obstruct views of the historic “Portland Oregon” sign from some angles
• Has low support from community survey respondents and key stakeholders
• Limits the height of ships that can pass through when the span is raised