[Abigail Adams]

Photos from the NTSB here:

http://www.ntsb.gov/dockets/Highway/HWY07MH024/387406.pdf

The first two photos above show a slight bend in the gusset plates on both sides of the joint. A similar bridge in St. Cloud was shut down a few days ago because the same kind of bending was found in the gusset plates.

[jeffers]

Thank you.

[TXnMA]

Thanks, AA! WOW! What a collection of sharp, clear, close-up photos!

Jeffers, those photos should keep you busy for a while!

I am struck by the absurd thinness of some of those gusset plates. They appear to be ~20% as thick as the width of the rivet heads. In places they look like torn paper...

Jeffers, look at the overhead, pre-collapse view of the bridge. Could live-load lateral thrust from traffic on that curve leading to the south end of the span have caused the lateral deflection/bending/failure that we see?

Too bad that NTSB report is a PDF. That prevents us from live-linking to specific photos for discussion. Even worse, they didn't even number the figures; that makes it extremely difficult for us to "stay on the same page"... :-(

[XR7]

Thanks for the photos and the ping.
Do you suppose the fresh paint, may be from grafitti eradication efforts?