MINNEAPOLIS (AP) Old photos of the Interstate 35W bridge show two steel connecting plates were visibly bent as early as 2003 four years before the span collapsed into the Mississippi River, killing 13 people.
Minnesota Department of Transportation officials declined to say when the state first knew about the bending in the pieces of steel, called gusset plates.
Two photos, part of a report issued earlier this month by the National Transportation Safety Board, reveal slight bends in gusset plates that hold beams together at two separate connecting points. The plates are in areas believed to be among the first points of failure when the span collapsed.
The NTSB's Office of Highway Safety confirmed that the bowing is part of the investigation into why the bridge collapsed Aug. 1, the Star Tribune newspaper reported Sunday.
NTSB Chairman Mark Rosenker didn't comment on the photos, but has said the original design for the bridge specified steel for those and other gusset plates that was too thin.