Officials say it happened around 3:15 p.m. near Cates Avenue at an addition to the Talley Student Center.
ABC11 was told the incident involved a crane and a steel beam which was about 8 feet off the ground.
University officials told ABC11 that two of the injuries were minor. Another was considered serious. All three victims were taken to WakeMed.
The construction site was fenced off. No students were involved.