Excerpts from the ChicagoTribune.com:
… workers on the Lake Shore Drive ramp project turned up what officials say is charred debris from the Chicago Fire.
After drilling holes for new pillars on the east side of Lake Shore Drive this year and last year, they turned up bricks, wooden timbers, and ash from the conflagration that destroyed most of the city in October 1871, said Anthony Quigley, IDOT project implementation engineer. They also found a concrete stairway, of unknown age and origin.
Work was slowed down to change methods and equipment to deal with the debris. No historical preservationists needed to be called in, as fire debris was commonly used as landfill along the lake. It’s how Grant Park was made.
The I-55/Lake Shore Drive ramps were originally built in the mid-1960s and have seen multiple bridge deck failures, particularly during the harsh winters of 2013 and 2014, which caused potholes that shut down lanes.
thanks Dan