I have been asked to look at an existing framed ceiling supported on partition walls. The walls are 3 5/8", 25 ga. drywall studs. Is there any documented load carrying capacity of these studs?
You need to use the formulas in the AISI Specification. But I wouldn't worry about it, unless the ceiling is a storage mezzanine. If the ceiling is truly just a ceiling, then 25 GA studs will be adequate.
1) They designate anything less than 20 gauge as non structural.
2) They don't provide axial capacities for anything less than 20 gauge.
4) They do provide allowable interior wall heights for 25 gauge under various internal air pressures. Sometimes they're considering sections composite with the drywall. Presumably, a 25 gauge stud wall can at least support its own weight as axial load.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
I plugged it into my spreadsheets quickly and got about 950# allowable axial load if braced at 48" OC. This is assuming Fy = 33ksi and 1.25in flange width with lips.
Might be worth doing a thorough analysis if this is in the ballpark of what you need.