Bent gusset plates on the Interstate 35 W bridge are seen ( center) in this 2003 photo released by the National Transportation Safety Board.old photos of the Interstate 35W bridge show two gusset plates were visibly bent as early as 2003 — four years before the span collapsed into the Mississippi River, killing 13 people.
Photos released this month by the National Transportation Safety Board show the plates that hold beams together at two separate connecting points are slightly bent.
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If that was 2003 and there were slightly bent then....then how the hell did they inpsectors miss them later?
In theory they should of been bent more by then...and much more then what is shown here if that was indeed the cause
That amount of bend did NOT “cause” the failure (speaking as a registered professional structural engineer). It was not even a very good warning.
They say that the original design was flawed (gussetts half the thickness of what they should have been). If so, why did the MNDot approve to add additional lanes a few years ago. Did they not check the calculations when they approved that?
If the original design was flawed, why did MNDot allow it to continue in service when half of the thickness of some of the gussetts were rust (presumably they were then only 1/4 the thickness they needed to be at that time). Didn’t they check the calculations?
If the original design was flawed, why did MNDot decide to redeck the bridge, which implies that they expected the bridge to last another 15 years before replaceement. Didn’t they check the calculations?
The people who made the later decisions were more responsible for the collapse than the people who did the original designs. The later people approved heavier loads and a longer life than they should have. It if VERY obvious that the later people DID NOT CHECK THE CALCULATIONS before they made their desisions.
It looks like the gussets in the photo are on the topside of the truss. The ones that failed were on the bottom side of the truss. This had nothing to do with the failure.
These had to be in compression to have a slight bend like that. Fatigue breaks don’t happen in compression. They happen in tension. Of course, gussets in tension would not bend like that.
This means absolutely nothing.