http://www.miaminewtimes.com/news/fiu-bridge-collapse-mystery-explained-by-foul-mouthed-canadian-youtuber-10186504
he cites a nut tightened against a metal plate: but the construction mess photos show nuts were against CONCRETE, not metal
he found a "dangling hydraulic tensioner" that he said was supposedly "in the concrete". i see no evidence concrete was poured around it (that it was ever imbedded inside the bridge - i'd have to see it up close and check these were on all columns - meaning that it was not being used to TIGHTEN the column from the outside)
he says the only way it could still be straight is if it was the cause (the cause, over-tightening). however: had the concrete failed while tightening, (ie, had like i said - no metal plate was in the wreckage for the bolt to tighten against: which is a design flaw))
however: the thing is a L shape and had it pulled straight out - that L would have significant pulling damage (it's actually a tube much wider than the rods with a large box 3/4 down the length sticking out the side: something that is NOT going to just "pull out" unless "moving the speed of a slow bullet" (which would cause wear on it - especially the undamage still square side box). that's my guess. things that "shoot through concrete" can do so but are damaged doing so)
HAD THE CONCRETE AROUND IT BROKEN in failure (leaving it dangling somewhat straight) - it the stub of the L could remain undamaged from "pulling out rapidly"
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i think the auto cites he found the cause - but only found a symptom - furthermore the video footage seen does not support his conclusion
on the other hand, far above i sighted "rebar pulling out and being straight" all over the footage not just in one spot
the evidence and diagrams I SEE do not show the hydraulic puller is integrated inside the bridge, and i guess it was a tool being used for tensioning. if that is so: then we ALREADY KNEW a problem occured at that point. the question IS NOT HOW IT BROKE, but if the structure was strong enough to be doing the job it was sold to do