Looks like there may be strain gauges on the beams -- but not on the failing (in 2003) gusset plates...
Looks like there may be strain gauges on the beams -- but not on the failing (in 2003) gusset plates...
Where did the third image come from, the post collapse image?
The beam in the foreground of that image shows fresh paint, visible in the image, covering the discoloration visible before and immediately after the collapse.
I find the fresh paint there...very interesting.
The foreground beam matches the upper end of the L9-U10 compression diagonal at the U10 east gusset that I believe triggered the bridge’s collapse
I don’t know what the thing in the other two images is.
It doesn’t look familiar, it doesn’t look like it belongs there, it doesn’t appear to be serving any structural purpose.
Best guess is that it’s an add on, or something that was altered after construction. The H beam above it shows a stiffener/gusset in an unusual location. It is possible that cracks developed there, and the “bent” appendage was a temporary fix, while the unusual stiffeners were part of a permanent fix.
That third image, however, is at the core of this bridge’s failure, at least parts of it are. That sloppy job of fresh spray paint is highly disturbing.