The semi was westbound on I-80 when the driver left the road for an unknown reason and hit the Center Street overpass about 12:20 a.m., an Illinois State Police District 5 trooper said.
The male driver, whose age was not immediately available, was taken to Provena Saint Joseph Medical Center in Joliet in serious condition, state police said.
The driver was cited for failure to reduce speed and improper lane usage, state police said. Alcohol was not a factor in the crash.
The Illinois Department of Transportation sent inspectors to examine the bridge for damage, and a more thorough assessment will take place later Thursday, state police said.
Crews remained at the scene of the crash about 4 a.m. to remove the truck's cargo so that it could be towed away. As of 7:30 a.m., it appeared one lane was open and a three-mile backup persisted. All lanes were expected to reopen by 8:30 a.m.
The Sun-Times Media Wire contributed to this report.
