On the attached image, i am providing about on average 140 to 160 psi of pre-compression in the slab. (8" thick slab) However, in 2 of the design sections that are within an area of a thickened slab rib (14" thick), the pre-compression falls below the min 125 psi of ACI 318 due to the increase in area. My question is if i am still ok, or if i need to add more strands. It seems like since this is localized to a thickened region that i woulc be ok, and the design sections should be based on the areas outside of the thickened slab. If not, since the depth has almost doubled from 8 to 14", I would need to almost 40% more tendons just for this small area.
I can say that since i am relatievly new to PT design, i have been looking at other engineer's designs and replicating them in my software (ADAPT) to make sure i understand the principles of design and the software. Everything checks out except this small little design, which make me believe that it is not an issue, but wanted to know other opinions.......