RENEE MONTAGNE, host:
This is MORNING EDITION from NPR News. I'm Renee Montagne.
STEVE INSKEEP, host:
And I'm Steve Inskeep.
The Minneapolis bridge that collapsed yesterday spanned one of the world's great rivers. Any investigation of what went wrong may begin with how the bridge was designed to cross the Mississippi.
Jim Foti covers transportation for the Minneapolis Start Tribune.
JIM FOTI: Steel girder construction, and it didn't have any piers in the middle of the water. There was a 450-foot span with no support underneath it. And it had no support above, either.
INSKEEP: Oh, an engineer was telling us earlier this morning they didn't want to have to a pier in the water because that would just be affected by the current. And you're telling me it's not a suspension bridge, it didn't have cables up above. So it was just a very, very long span is what you're saying?
Mr. FOTI: Correct. Yeah. There's a lot of barge traffic going through there and so they tried to minimize the obstruction in the river.
INSKEEP: The roadway rested on steel trusses. Those are enormous diagonal braces. We do not know why the bridge failed, but you get a sense of the force of this collapse from the images of those steal beams twisted like plastic and resting in the river.