What factors to consider for perimeter bars in bonded PT slabs?

[Trippelsewe]

For context I am Australian based, I have not seen any definitive literature on this and many consultants use varying reinforcement for similar designs. I consider the following:

1. Minimum strength requirements.
2. ULS strength requirements if present.
3. Slab restraint and minimum reinforcement requirements for crack control for said restraint.
4. Match the P/A present in the rest of slab with reinforcement using fsy = 500MPa (though point 3 normally governs unless the slab is unrestrained).
5. If I'm using Ø15.2 in a thinnish slab I will check bursting moments.
6. Take reinforcement a full development length past the dead end or pan.

Anything I have gotten wrong or missed?

 

[thejonster]

A coworker designed a bonded PT system and ended up with very little mild reinforcing, no shear steel required, it freaked the client out and they had it peer reviewed, he stood by his design because he wanted to make it efficient and insisted that the code said he can. I don't have experience in bonded design myself but in PT.

I would imagine all the requirements for bonded design would be from ACI. This is copied from a guide I created for PT design in RAM Concept focusing on the mild reinf req'ts, all references taken from ACI 318-14, forgive the formatting. I'm hoping the types of requirements for non-bonded PT would help you find the requirements for bonded in there somewhere.

__(8.3.4: max conc stress limit 6*sqrt(f'c) for 2-way slabs)__
__(8.7.5.5.1b: max span = 3x top bar length)__
__(8.3.2: deflection limits)__

Min steel
__(8.6.2.3 & 8.7.5.3b: Min. As & bar count)__
__(8.7.5.5.1b: Min. length = span/3)__
__(8.7.5.3a&c: max group width = 1.5*h*2+c)__
__(8.7.2.1: min spacing)__

Length
__(8.7.5.2: bar cutoffs at length req'd + d)__

I've seen edge bars on drawings "just because", but I can't remember if that's a code requirement