PORTLAND -- A mechanical malfunction closed the southbound span of the Interstate 5 bridge over the Columbia River for more than four hours overnight.
The bridge was undergoing a routine maintenance lift late Thursday when it failed to completely close, said Oregon Department of Transportation spokesman Don Hamilton.
Southbound traffic was detoured to Interstate 205 and over the Glen Jackson Bridge.
Crews worked through the night to remove a span roller that failed. The southbound lanes reopened at 4:20 a.m. Friday.
The northbound span of the bridge was open and unaffected by the malfunction.
Hamilton said Friday morning that sudden, cold weather could have been a factor in the roller malfunction. He added that ODOT will not lift the bridge again until after engineers get a chance to assess the damage.
Bridge lifts will be at half-speed when they are resumed, meaning delays will likely last at least 20 minutes per lift. Replacing the faulty roller could take several weeks.