drywall soffit calculations

huangyhg

drywall soffit calculations
i have a client who wants some calculations for a drywall soffit. the soffit will hang from a metal deck roof and span approximately 30ft over some shelving. my first thought is just put it up. it seems as if the drywall will act like a deep beam against the studs and make the span, but i'm unsure of how to calculate this. any ideas on drywall properties?
thanks, ryan
does it hang vertically or horizontally?  i would not rely on the drywall strength for anything, and i have not done so in the several ceilings and soffits for which i have done engineering.  use light gauge framing and hang it from the roof members.  i never attach any hanger wires to metal deck, always to joists, beams or slabs or the like.