ASCE 7-10, length of wind end zone on wall parallel to roof ridge

[ajk1]

This question os for anyone who uses ASCE 7-10 Fig. 28.4, external wind pressure coefficients. My question relates to end zone length "2a". A similar figure and end zone definition appears in the National Building Code of Canada (NBC) Commentaries, but the the NBC figure has a requirement that the length "2a" (in the NBC the nomenclature is "2z") be not less than 6 m (i.e. 20 feet). Does anyone know if that requirement of a minimum 20 foot length for the end zone of the wall parallel to the roof ridge is in ASCE?

 

[OldPaperMaker]

ajk1,
See "Notes", item #9 of Figure 28.4-1
this defines "a" as 10 percent of the least horizontal dimension or 0.4h, whichever is smaller, but not less than either 4% of least horiz. dimension or 3 feet (0.9 m)

 

[ajk1]

To ldPaperMaker - Yes I know that, thanks. My question was whether anywhere else they define a 20 foot minimum dimension. I think that you are telling me that they do not have a 20 foot minimum dimension. So that would make the Canadian Code different than ASCE.

 

[jayrod12]

Are you asking about primary structural action wind load. Or components and cladding wind load.

 

[ajk1]

I am talking about the Primary Structural Actions wind load. Good point. Sorry, I should have been clear about that.