Where does the 1.4 Sds come from exactly? I understand that the 4psf minimum is a gravity design load for the main runners and minimum total dead load for the lateral system; isn't the actual horizontal seismic design force less?
I believe the 2.6k capacity indicated in the program output for the stud to track connection is for an out-of-plane end reaction of the stud to track (web crippling type load) not an axial bearing capacity.
It doesn't seem like it should be allowed for metal studs either. Whether it is wood or metal studs it is still light frame construction and the gyp panels are still gyp panels. But, I do not see anything in the IBC or AISI lateral design standard that specifically does not allow it for metal...
Make sure you are using the correct/converted wind speeds between the two methods... then I believe they should be fairly close for the resultant pressures (not 50% difference).
UBC uses 'fastest mile' wind speed
ASCE uses '3 second gust' wind speed
90mph(3 second gust) converts to...
You might try calling this company:
http://www.thecableconnection.com/
I dealt with them a few years ago on some cable/railing connections and they were extremely helpful - they even provided example calculations.
The 2003 IBC Table 2306.4.1 provides shear values for plywood shearwall sheathing placed over the top of gypsum sheathing (most codes have a similar table). This is not your situation - and it appears that the gypsum sheathing can actually give you higher shear values when you combine the...