FIU's pedestrian bridge collapsed during construction — a design error killed 6

The FIU-Sweetwater UniversityCity Pedestrian Bridge was a 320-foot long, $14.2 million bridge designed to connect Florida International University's campus to the city of Sweetwater, crossing a 7-lane highway (SW 8th Street). It was built using accelerated bridge construction — the main span was assembled adjacent to the highway and lifted into place in a single weekend event in March 2018.

On March 10, 2018, just five days before the collapse, cracks were observed in the northernmost diagonal truss member (member 11) and near the area where the bridge contacted its supporting pier. FIGG Bridge Engineers, the designer, and Munilla Construction Management, the builder, discussed the cracks. The engineer on site concluded they were not a safety concern. The bridge remained open to pedestrian traffic and the highway remained open beneath it.

On March 15, 2018, at 1:47 p.m. EDT, the 175-foot main span collapsed onto the highway below, killing six people and injuring ten. The victims included five motorists and one construction worker who was on the bridge at the time of the collapse. Dashcam and surveillance video captured the truss failing suddenly with no visible warning signs.

The NTSB investigation found that the probable cause was a load and capacity calculation error made by FIGG Bridge Engineers. The design miscalculated the resistance to sliding of the connection between the walkway surface and the truss. The connection was insufficient to prevent sliding, which caused the cracks and ultimately led to the collapse. The NTSB also noted that the peer review by Louis Berger Group failed to catch the error.