Portland’s Burnside Bridge to close for 5 years during seismic rebuild, starting in 2027

When Portland’s Burnside Bridge closes for a seismic rebuild, probably in 2027, it’s likely to remain closed for five years.

Due to the instability of the soil on which it stands and the infrastructure on either side of the Willamette River, Multnomah County engineers will essentially be building three bridges. Each one will have to connect to the other in a way that ensures they remain standing and functional after a major earthquake.

“We expect that it will be fully closed for five years,” said Multnomah County construction manager Emily Miletich.

There are several reasons for the long closure. Among them is the Endangered Species Act, which means work in the river is constrained to times when endangered salmon are not running.

“That really drives the length of the schedule for construction,” Miletich said.

Additionally, the bridge has a complex downtown location and a complicated design.

The bridge’s environmental review has just been completed, so most of the big structural decisions have been made. But the soil on the east side of the river could potentially liquefy during a large earthquake, so the county is still deciding what type of bridge to use.

“We’ve just selected a contractor to help us make a decision between a cable stay bridge and a tied arch bridge on the east side of the river,” said Miletich.

That area of the bridge is extra delicate because it goes over some key transportation corridors like Interstate 5, Interstate 84 and a key north-south railroad line.