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RE: PT Construction

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"Obviously there's no way I could possibly determine if this is the case,
but contractors doing this type of work aren't typically "stupid"."

They are usually a sharp bunch that do PT work, but I have seen reshoring messed up a few times, so I wouldn't rule it out.  The most common mistake I have seen is to try to use the full, unreduced LL capacity of the decks below to carry the weight of the forms and wet concrete above, ignoring the fact that the reduced LL is probably noticably less, and you can't "reduce" the weight of the wet slab above based on area - it's all there.  

In the case shown, I would hope that the beams below have been stressed, and they just haven't had the tendons tails cut and so they appear unstressed to the casual observer.  I like to see them cut the tendons off and cap them shortly after stressing approvals are received, but not everyone is diligent about that.  It is also possible that there is enough rebar in the beams to carry the construction load, but that wouldn't be the most obvious answer since usually the beam rebar is only barely enough to keep the beams themselves up, with a modest LL, without their PT being functional.  Normally you want to stress the beams before stripping their own forms, just to help them support themselves, let alone before expecting them to take any additional load.  Only the designer knows for sure, though, and there is no way to tell from a photo or casual observation alone.  If this job belongs to a "friend", you might suggest that your "friend" make a few calls and look into the matter, to see if the load and the resistance are safely balanced, particularly if you have reason to believe that the beams aren't stressed.  As I mentioned, in my experience misunderstanding about reshoring are not unheard of, although I wouldn't call them common, either.  



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