NTSB: I-35W Gusset Failure Could Have Been 'Catastrophic'
A buckled steel plate may be all it takes to bring down a 40-year-old structure like the Minneapolis I-35W bridge, which collapsed suddenly on Aug. 1 and killed 13 people.
Forensic engineers probing the collapse have not yet found all the bridge's gusset plates but have seen enough damage "in some gusset plate locations that warrants further investigation," the National Transportation Safety Board says in a Sept. 5 bulletin.