Pile-driving adjacent to an Interstate 65 bridge near Lafayette, Ind., appears to have started a subterranean chain reaction that left one of the structure's riverbank piers skewed out of alignment, forcing a 37-mile closure of the northbound lanes that could extend into mid-September.

Built in 1969 and reconstructed in 1988, the 394-ft, five-span continuous steel multibeam-girder bridge across Wildcat Creek was being widened as part of a two-year, $82.8-million project begun in April to expand a seven-mile stretch of I-65 from four to six lanes.