For the environmental review, the project team analyzed three bridge replacement alternatives and one retrofit alternative along with the no-build option. The team also analyzed four options for managing cross-river traffic during construction.

Because the Project is intended to serve two reasonably foreseeable future conditions (both before and after the next CSZ earthquake), the EIS analysis considers how each alternative would perform in both of those scenarios.

More information on the Preferred Alternative is available on the project website.

The Build Alternatives include the Enhanced Seismic Retrofit Alternative that would partially retrofit the existing bridge as well as three different replacement alternatives that would remove the existing bridge structure and build a new bridge at the same location.

• Enhanced Seismic Retrofit - Some parts of the bridge would be retrofitted and some parts would be replaced.
• Replacement Alternative with Short-Span Approach - The Short-span Alternative would completely replace the existing structure but would be very similar in alignment. As with the existing bridge, the structural members of the approach spans would be below the bridge deck and the span length between the columns would be typically less than 100 feet. The bridge would have the same connection to West Burnside Street and only slightly modified connections to North East Couch Street and East Burnside Street on the east end.
• Replacement Alternative with Long-Span Approach - Bridge alignment and connections would be very similar to the Short-span Alternative. The primary differences would be that the Long-span Alternative approaches would be supported by above-deck superstructure to allow longer spans between the piers and columns.
• Replacement Alternative with Couch Extension - The Couch Extension Alternative has the same west approach and movable-span sections as the Short-span Alternative but the east approach span would extend the Burnside/Couch couplet approximately 1,100 feet farther west resulting in a bridge that splits just east of the movable span.

A temporary bridge could be constructed to allow some level of vehicular, pedestrian, and bicycle traffic to cross the Willamette River at Burnside while the main bridge is closed during construction. A temporary detour bridge would help reduce the impacts on cross-river travel but it would not accommodate all of the bridge’s current vehicle travel demands.

• Temporary Bridge Options
  The EIS studied three different options for a temporary bridge:
  1. Two general traffic lanes (one in each direction) allowing all motor vehicles, as well as bike lanes, and sidewalks
  2. Two bus only lanes, bike lanes, and sidewalks
  3. Bicycles and pedestrians only
• No Temporary Bridge (Full Closure during Construction) - Because of the high cost and impacts associated with a temporary bridge, the Project is considering detouring all trips to other existing bridges during construction. With this option, the Burnside crossing would be fully closed to all modes for about 2 years with the Retrofit Alternative and 4 years with the replacement alternatives.

In June 2020, following almost two years of coordination, analysis and input, the Project’s Community Task Force (CTF) recommended that the Long-span Approach Alternative and the No Temporary Bridge option be the Preferred Alternative (PA).

While this combination has received broad agency and public support, the decision won’t be final until the Record of Decision is signed by the Federal Highway Administration at the end of the NEPA process.

A Long Span bridge could be composed of the following bridge types