Spats,
I stand corrected, equation 6-20 is the more relevant equation in this case. I should have gone to the code instead of citing references contained in my spreadsheet.
By the way, CAB30 refers to his/her's structure as an "other open structure", not an "open...
First of all, I am venturing to guess that you are not a structural engineer. If your not an engieer, I suggest you consult w/ one because you are dealing with a subject many structural engineers have trouble with. Secondly, if you are a structural engineer, you must only have a portion of...