CEDAR RAPIDS — A bridge inspector thought he’d found a potentially hazardous sinkhole near an Interstate 380 access ramp late last month, but a preliminary investigation suggests it’s 150-year old beer caves, a remnant of a long closed brewery, officials said. During a routine bridge inspection on July 31, an Iowa Department of Transportation staff member noticed an 18-inch void in a grassy shoulder off the Seventh/Eighth Street access ramps to I-380 southbound.The ramp was closed to evaluate possible safety concerns, but they found more than they bargained for.