A southbound stretch of Interstate 35 through Duluth will be closed three to four weeks to repair a bridge.
The nearly two-mile stretch of freeway was first closed late Monday after inspectors discovered corrosion in the piling supporting one of the bridge's 38 piers.
At the time, the Minnesota Department of Transportation estimated repairs would take about a week. But in a statement, District Engineer Duane Hill said "more substantial repairs are required than originally thought."
MnDot has awarded an emergency contract for the repair work that will be done on an accelerated schedule, including multiple shifts per day, seven days per week.
Earlier this week, Hill said there were no signs of failure in the bridge, but as a precautionary measure the department detoured traffic around the bridge until repairs could be completed.
About 5,100 motorists drive the section of freeway every day.