Investigators: Construction Material Was On Weakest Part Of Collapsed Bridge

MINNEAPOLIS (AP) — The National Transportation Safety Board has found that more than 191 tons of construction material had been piled over the weakest areas of an interstate bridge that collapsed last August in Minneapolis.

In a followup to a preliminary report released in January, the federal investigators report that the piles of rock and sand were placed over steel plates that were thinner than they should have been.

Calculations by the agency have determined that the bridge was carrying a 630-ton load at the time it fell into the Mississippi River. About half of that load was sitting on the center span.

The collapse killed 13 people and injured 145.

The NTSB says it should have its final report on the cause of the collapse by the end of the year.