Work is starting on the northbound I-5 lanes over the Boone Bridge south of Wilsonville.
The expansion joints on the bridge need to be replaced and the work will take four months to complete.
Starting Thursday, there will be intermittent nighttime lane closures from 8 p.m. to 5 a.m. while crews get ready for the work.
Starting late next month, three of the four lanes will be closed from 8 p.m. to 5 a.m.
In late August and September, there will be up to four full closures of the northbound lanes with traffic diverted to I-205 in Oregon City.