Workers are busy around the clock to repair a closed stretch of Interstate 35 in Duluth. The repairs began following Monday’s shutdown of southbound traffic between Lake Avenue and 21st Avenue West.
The Duluth News Tribune reports that extra precautions have to be taken for workers on the project. They are working on a bridge deck that is supported by piers. The piers are buttressed with steel pilings that were driven into the bedrock; the pilings were found to be severely corroded. They are difficult to see because they mostly are buried, which is why the defect wasn't discovered during the recently completed I-35 repair project in the area.
"We’re concerned they don’t have enough load-carrying capacity to transfer the loads from the bridge down to the bedrock,” Duane Hill, MnDot's district Engineer in Duluth. He said the plan is to add strength to the pilings with concrete collars. Hill told MPR it's a good thing workers spotted the damage, which is similar to a problem that caused a bridge in Green Bay, Wis., to sag by a couple feet in October.
The Northland's NewsCenter reported that the lanes will remain closed for three to four weeks because repairs required are more substantial than the Minnesota Department of Transportation had originally outlined. The first estimate for repairs on the two-mile stretch of freeway was that it would take about a week. MPR reported that about 5,100 motorists drive the section of freeway every day.
MnDot 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. The initial cost estimate of the project is $250,000. The newspaper reported that a single lane may reopen to traffic before the full repair is completed.