Morrison Bridge deck work will reduce traffic lanes until October

Construction to replace the deck on the Morrison Bridge that starts Monday morning will decrease traffic on the Portland structure from six lanes to two until October, Multnomah County officials said.

Two lanes, one in each direction, will remain open on the south side of the bridge and the multi-use path will stay open, the county said. The other four lanes are scheduled to close by 7 a.m. Monday, but the process may stretch into Tuesday depending on weather.

Construction crews will replace the deck on the bridge’s lift span. The new deck is slated to have steel grating with concrete in the top layer and is expected to be strong enough to allow trucks and buses to travel on the bridge again.

The project will cost $10.4 million, the county said. Motorists should expect traffic patterns on the bridge to change several times over the next six months as different areas are worked on. Bridge closures that may last several days are planned in June and September to pour concrete.

The bridge deck was replaced in 2012, but the fiber-reinforced polymer used then began to break apart after just a few months. The bridge has speed and weight restrictions to keep it from failing before the repairs.

During the latest construction, east access from southbound Southwest Naito Parkway will be closed. Drivers can get on the bridge from Southwest Morrison Street and 2nd Avenue, the county said.

Ramps from the bridge to Southwest Naito Parkway and Southeast Water Avenue will stay open. Highway ramps to and from the bridge will also remain open.

However, westbound traffic from Southeast Grand Avenue and Southeast Martin Luther King Jr. Boulevard won’t be able to get to downtown Portland across the bridge, according to the county. Drivers heading west from the central eastside will have to use the Hawthorne or Burnside bridges, or another route to cross the Willamette River. They will be able to use the westbound ramp to get onto Interstate 5 north.