post tensioned flat slab

[aldorankin]

I have an issue here. I'm calculating a post tensioned residential flat slab. The thing is that the columns that support the roof fall directly onto the slab. I was wondering what type of this methods should I use :

1- apply the column loads directly onto the slab as point loads. this could take a lot of time

2- apply a superimposed load equal to the forces that the roof will generate added to the loads that the slab will have such as partitions, floors etc. The problem that I see with it is that the floors may have an uplift by the additional tendons if there are areas where there are no roof columns over the slab.

what do you think !!!

 

[austim]

My own experience is fairly thin on residential buildings, but..

Assuming that your column loads are not "trivial", then I would treat them as point loads. (And, of course, check for possible uplift loads due to wind).

 

[dik]

I haven't done any PT work for a couple of years, but I would treat the column load as a point load and if possible, and depending on the magnitude of the load, would run a strand or two in the vicinity of the column.

In addition, would add a couple of non-tensioned portions of strand or rebar at the point of application.

In the analysis, would also pay particular attention to moment and shear for punching shear.

 

[aldorankin]

thanks for the recomendations, I will work with the point loads. I think is more real than the distributed load