A dump truck hauling gravel fell through the roof of a second-story garage in Quincy, Mass., last month when the driver, following his GPS, attempted to turn around on the upper level of the garage.

“When the driver’s GPS told him to make the next left ... he made a huge mistake by pulling into the garage,” where the floor did not have the load capacity to support his truck, says Jim Anderson, inspector at Quincy Inspectional Services Dept.

Quincy police did not release the name of the driver since no charges were filed and there were no injuries in the partial roof collapse that occurred at 11:34 a.m. on Aug. 21, says Sergeant Karyn Barkas. About 50 cars were trapped in the garage from fallen debris.

The truck was removed from the garage at 234 Copeland St. at 4 a.m. the following day, says Quincy Deputy Fire Chief Paul Griffith. “The parking garage is unsafe.”

Following the incident, police evacuated two medical office buildings, one three-stories, the other four-stories, which share a two-level garage, Barkas says. The buildings were reopened at noontime the following day, but the garage remains closed. Both Quincy and the Massachusetts state police are investigating the incident.

The driver was following his GPS when he exited a no-truck route onto the upper level of the garage, Barkas says. “The entrance looks like a parking area at the second story level…When he got off the rotary onto Furnace Brook Parkway and it said ‘no trucks’ he got diverted into a parking lot.”

As the driver attempted to turn around, a seam of the roof collapsed under the weight of the truck with the rear of the vehicle falling toward the first floor while the front remained on the top level, Barkas says.

The Quincy Inspectional Services Dept. reportedly moved vehicles away from the collapse using dollies. Two vehicles were damaged.

Ken Burke, the department’s code enforcement officer, says his agency was investigating the structure. It will evaluate the extent of the damage and determine what repairs are necessary before the garage can be reopened.

ESI Waterproofing and Masonry Restoration, the lead contractor working the night of the incident, was planning to remove loose concrete, Griffith says. ESI was not willing to comment on work underway.

A source at PEDA Inc., the structural engineer, also declined comment on the incident since its investigation is still underway.