Workers were adjusting tension rods when FIU bridge collapsed, NTSB says

Federal agency has sent pieces of bridge to Virginia for testing

MIAMI-DADE COUNTY, Fla. – The National Transportation Safety Board investigators confirmed Wednesday that workers were adjusting tensioning rods when the pedestrian bridge at Florida International University collapsed last week, killing six people.

The NTSB said in a statement that workers were adjusting the final set of rods on the north side of the bridge spanning Southwest Eighth Street when it collapsed Thursday, crushing several cars underneath. Workers had previously adjusted the rods on the south side, the NTSB said.

Southwest Eighth Street was open to traffic during the testing. Lawyers for the victims' families have criticized the decision not to shut down traffic on the road during testing.

The federal agency has also been collecting evidence at the scene to determine the cause of the collapse. Investigators are focused on the parts of the bridge near the north side, where the collapse began. The investigators have sent  core samples, rebar and tensioning rods to the Turner Fairbank Highway Research Center, in Virginia, for testing and evaluation, the NTSB said.

The agency said it does not plan to reconstruct the 950-ton bridge to learn more about the collapse, explaining it would be impractical.

The bridge, which was to connect the FIU campus with the city of Sweetwater, was set to open next year. Using modular construction methods, the main span was assembled off-site and moved into place last weekend like a piece of a puzzle to avoid closing traffic on Eighth Street.

FIU touted it as the largest pedestrian bridge in the nation to ever use the innovative method. When the bridge collapsed, the tall tower that was designed to hold the cables attached to the platform had not been installed.

The Associated Press reported Tuesday that last minute design changes to the bridge caused the project to go behind schedule and millions over budget.