One-Way Post Tension Slab Design

[Gabe_StrEng]

Hello All,
I'm designing a PT one way slab supported by PT girders and I'm considering the section analysis.
ACI 318 states in section 24.5.2.1 that all two-way prestressed slab shall be designed as Class U (Uncracked) with ft<6sqrt(f'c). This implies that prestressed slabs that aren't two-way are allowed to be Class T (Transition) or Class C (Cracked) so I'm wondering if in anyone's experience they had an engineering judgement that one-way slabs should be limited to Class T or if Class C was alright.
My judgement is that these should be limited to Class T under service loads to limit cracking typically and if Class C is required, increase the cover to protect the reinforcement (this is for a garage and a pool deck design) but I wanted to put this out to get other's opinions.

Thanks!
Gabe

 

[AUCE98]

ACI will allow you to design beams and one-way slabs beyond 6sqrt(f'c), so your assumption is correct. Typically I would not design a one-way slab beyond 7.5sqrt(f'c). If it is a parking deck or slab that is going to experience significant weather or road salts, etc., I would design it at or below 6.