A 43-year-old man was talking and in stable condition after being hit and trapped under a dump truck near the Chinatown gate, according to Ottawa paramedics.
The man is being treated for severe leg injuries, paramedics said.
Fred Jackson saw emergency crews use the "jaws of life" to rescue the man at the intersection of Bronson Avenue and Somerset Street West.
"His leg was all busted open and twisted in the bike," he said. "Both of his legs were twisted in the bike."
Ottawa police collision investigators are trying to determine the cause of the crash.