Update: Transportation officials on Thursday night announced that planned work on the Interstate 5 Bridge between Oregon and Washington has been postponed, citing a need to keep the bridge as clear as possible while wildfires threaten to displace people.
“This closure would have created additional congestion and right now we need to keep the highways moving for evacuees and emergency responders,” said Rian Windsheimer of the the Oregon Department of Transportation.
The announcement said a new schedule is being discussed. OPB’s original story follows below.
Original story: Maintenance on the Interstate Bridge connecting Interstate 5 between Vancouver, Washington, and Portland is slated to close half of it over a nine-day period starting this weekend.
Beginning Saturday, the northbound lanes will close so crews can replace mechanics that lift the bridge for passing boats. All traffic will share the southbound lane. The work is expected to end Sept. 20.
The work means roughly 135,000 vehicles that cross the bridge daily will share three lanes instead of six. Transportation officials have encouraged drivers to minimize trips or consider using the Glen Jackson Bridge and Interstate 205.
Traffic across the span has dropped about 10% already this year due to the novel coronavirus, according to Washington State Department of Transpiration spokesperson Tamara Greenwell.
“We’ll need even more folks than that to consider using a different mode of transportation, maybe teleworking if that’s something folks can do, to help reduce congestion and delays during the closure,” Greenwell said.
The work, specifically, is the replacement of a trunnion, sheaves and some steel cables. The bridge segment raises and lifts with the aid of 760-ton counterweights, connected by steel cables. The cables pass through sheaves – large wheels – and the sheaves are joined by a shaft called the trunnion.
The trunnions bear much of the weight in a lift. In 1999, crews discovered cracks in one of the trunnions on the northbound side, Greenwell said, and have monitored the cracks since. Plans to replace the trunnions started two years ago.
During the nine-day project, crews will use a zipper barrier to adjust which direction of the southbound lanes have two lanes during rush hour traffic, Greenwell said.
“So during the morning commute, there will be two lanes southbound from Vancouver into Portland,” she said. “And for the PM commute, there’ll be two lanes northbound from Portland into Vancouver. And the zipper barrier will move the barrier in the middle of the bridge to allow for that transition to occur.”
The replacement will cost an estimated $13 million. The costs will be split between both Oregon and Washington’s transportation agencies.
Work starts at 12:01 a.m. Sept. 12, Greenwell said. If all goes according to plan, the northbound section will reopen Sept. 21.