A trailer brought down the footbridge at Pangani Girls High School, injuring eight students.
The eight were admitted to Guru Nanak and Radiant hospitals, two of them with fractures.
Nurses-in-charge and school authorities said they were in stable condition.
The driver of the trailer miscalculated its height, hitting it and bringing part of it down.
One of the injured students, Yvonne Moraa, said she was in a group walking across the bridge after attending a Saturday evening service.
“The trailer was a little higher than normal in height, but we were not alarmed because we have always seen trailers pass under the bridge,” she said at her Guru Nanak Hospital bed.
The students were in the middle of the bridge when it came apart on the impact, leaving the students suspended on one side.
Motorists had to use alternative routes as both sides of the road were closed until a breakdown vehicle brought down the suspended part of the bridge.
Starehe police boss Samuel Anampiu said there were no fatalities. Like the students, he said trailer’s height exceeded that of the bridge.