The National Transportation Safety Board confirmed Wednesday that workers were adjusting tension rods on the newly-installed Florida International University pedestrian bridge when it collapsed last week, killing six people.
The NTSB said workers were adjusting the final set of rods on the north side of the bridge 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 at the time.
The federal agency has 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 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.
The Associated Press reported Tuesday that last minute design changes to the bridge caused the project to go behind schedule and millions over budget.