Aug. 16 (UPI) -- Florida International University in Miami released a new time-lapse video that shows the bridge collapse that killed six people in March, as well as footage from the days leading to the disaster.
The bridge collapsed March 15, only days after it was installed over Southwest Eighth Street in Miami to allow pedestrians, including those in nearby student housing neighborhoods, to cross over the busy street to get to FIU.
The video the school released Wednesday shows at least four workers using a jack to re-tighten steel rods that ran through a concrete support at the bridge's north end, the Miami Herald reported.
Some wonder if the workers' actions may have caused the bridge, which had already developed cracks by that time, to buckle.
The Herald reported it's still unclear who ordered the construction crew to the bridge and why. The newspaper is seeking documents that may include that information.
The six time-lapse videos were made from still photos at various angles from March 1 to March 19.
In an investigative update last week, the National Transportation Safety Board said a structural failure caused the 174-foot-long bridge to fall about 19 feet, killing five vehicle occupants and a bridge worker.
Eight others were injured in the collapse.
The NTSB is still investigating what caused the structural failure, with the intent of issuing safety recommendations to prevent similar incidents. The board has interviewed employees from eight firms and organizations involved in the design, inspection and construction of the bridge. Bolton, Perez and Associates Consulting Engineers was recently added as a party to the investigation.