open buildings

huangyhg

open buildings
asce 7-05 has tables for open buildings for pitched roofs.
all the mwfrs tables for open roofs have values for load case a and load case b. i can not find anywhere in the document where they define what load case a and b are and why the values differ so much. does anyone know what these load cases are?
check out our whitepaper library.
they represent two different possibilities of pressure coefficients that could occur at a given time.  you have to check both.
check the footnotes.  i don't have it in front of me, but going from memory i believe one case is for unobstructed wind flow beneath the roof and the other is for when objects below the roof disrupt the wind flow.
they show both unobstructed and obstructed load conditions in the table and load case a & b for both.