All lanes of northbound Lake Shore Drive have reopened following the discovery of two cracked steel beams on a section of the main artery.
"All lanes are now re-opened," Chicago Department of Transportation spokesman Mike Claffey said.
Northbound lanes of Lake Shore Drive were closed Monday between Randolph Street and Grand Avenue for a "structural emergency" on the bridge after Chicago Department of Transportation workers noticed cracks in two structural steel girders that support the road over the ramp from Randolph.
Shoring towers were placed under Lake Shore Drive at Randolph overnight, Claffey said, and crews began jacking up the support beams Tuesday morning.
Shoring towers are part of a temporary fix for the roadway. Once the supports are in place and Lake Shore Drive reopens, construction will begin on a permanent fix to fully repair the girders.
Eastbound Randolph will remain closed between Columbus Drive and Lake Shore Drive as crews continue work.
Claffey said the agency believes the cracks were caused by a combination of corrosion and "extreme temperature swings."
The bridge was built in 1986 and was last inspected in June of 2017, when it was found to be in "fair condition," Claffey said. The next inspection was scheduled for June.