A newly-erected 174-foot-long section of a pedestrian bridge recently collapsed onto a six-lane highway in a suburb of Miami, FL, leaving six dead and at least nine injured. Investigations into the cause of the Florida bridge collapse are ongoing, though a crack in the bridge’s structure had reportedly been discovered just two days earlier.
FIU-Sweetwater UniversityCity Bridge Project
The FIU-Sweetwater UniversityCity Bridge is located west of Miami over the intersection of the Tamiami Trail (US Route 41) and Southwest 109th Ave. It was designed to connect the campus of Florida International University (FIU) in University Park to student housing neighborhoods in Sweetwater, with the goal of improving pedestrian safety. The project was funded with grants from the United States Department of Transportation and local agencies, though it was overseen by the university itself.
Construction of the bridge began in March 2016, with a proposed project completion date of December 2018. The construction was largely conducted by Miami-based Munilla Construction Management and Tallahassee-based Figg Bridge Engineers.
The prefabricated main stretch of the bridge was assembled adjacent to the Tamiami Trail utilizing “Accelerated Bridge Construction” (ABC), a technological method promoted by FIU that promises to streamline the building process to complete bridges more quickly and cost-effectively. According to a statement by the university, the bridge was designed to last more than 100 years and withstand a Category 5 hurricane.
Munilla Construction Management rolled the main span of the bridge into place and erected it during a weekend closure of the Tamiami Trail on March 10, 2018, five days before the Florida bridge collapse. The cable-stay tower, access ramps, and a second canal span had not been built at that time, and the bridge was to have been closed off from pedestrian use until the project was complete.
Crack Discovered Two Days Earlier
On the early morning of March 15, Mr. Pate delivered a technical presentation about the crack, with the project construction manager and representatives from FDOT and FIU in attendance. According to a statement released by the university, Figg Bridge Engineers “concluded there were no safety concerns and the crack did not compromise the structural integrity of the bridge,” a judgment that Mr. Pate relayed both at the meeting and in his earlier voicemail for the FDOT employee.
Florida Bridge Collapse Kills Six
Just hours after the technical presentation, at approximately 1:47 p.m., construction crews were reportedly tightening cables inside a diagonal beam at the north end of the installed bridge span, where the crack had been found. At that time, the span began to sag deeply before fracturing, folding, and dropping onto the roadway, which was open to traffic and where multiple vehicles were stopped at a light directly below. The collapsed span, which weighed 950 short tons, crushed eight vehicles.
In all, the Florida bridge collapse killed six people, including five motorists and an on-site worker for Structural Technologies VSL, a company that was also employed on the project. Nine other people were injured in the construction accident.
NTSB Conducting Investigation
The cause of the Florida bridge collapse has yet to be determined. The National Transportation Safety Board (NTSB) is conducting an investigation into the incident that is expected to continue for several months.
NTSB spokesperson Robert Accetta pointed out that a crack in a bridge “does not necessarily mean that it is unsafe,” though the NTSB has so far not placed any blame for the Florida bridge collapse on the cables or the cable-tightening work being conducted at the time of the incident.