Yeah, I think it’s possible there was damage in transit, but …
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SUPPORT NEAR FAILURE POINT?
But you’ll note that when they moved the bridge, the lifting rig was already supporting it where the failure occurred.
So it was positioned near the point of stress failure already, and I don’t know how that would cause damage unless the deck beam was canted when lifting it. -
SHEAR FORCE LIKELY?
It appears likely to me that shear force along the length of trusses punched through the deck, kind of like creasing the outside of a soda can. -
FLEXING?
As even grade-school kids can show you with models and simple software, without symmetrical truss-spacing, a bridge will not flex evenly in the middle of its span.
There would have to be countervailing force inside each diagonal member tensioned differently. -
VARYING TENSIONING?
This would likely require either thicker trusses toward one end of the bridge (to provide more mass for both more tensioning rods and static support).
Or it would require additional support trusses. Unless the PT rods were rated at different strengths and gauges, like bicycle spokes. -
TEMPERATURE!
However, one thing I haven’t seen mentioned is temperature control:
I know for a fact, when they install welded steel rails in long (quarter-mile?) lengths, they put them in during warm temperatures, so that the rail is expanded along its length.
Then during winter time, the rails contract by pulling against each other at the expansion joints.
Problems arise when there are big swings in temperature from nighttime to daytime: if the rail expands sufficiently under high heat in summer months, it will literally butt against itself.
This will bow the rail out-of-alignment, forming a heat kink that will derail a train.
If “heat-kinks” formed in the PT rods while the bridge was being cast, the variable-tensioning would be completely “out of alignment” as the concrete set.
This could create tortion that would twist the rods inside the concrete, leading to failure.
