ASCE 7-98, Section 6.2 1

[jike]

When calculating whether a building is enclosed or partially enclosed, do you take each "side" of the building (by strict definition), even if one side is 5 feet long and another is 200 feet long? Should small offsets be included as part of a longer side or as an individual wall?

How about a building that has stepped roof, should the upper wall be included?

How about a building that is connected to another building? To consider as two separate buildings, do the openings have to be air tight (so the pressure is not equalized)?

Isn't there a simpler way to do this?

 

[Ron]

jike...if it has a separate roof section, I would consider it to be a separate building section without regard to its dimensions. ASCE 7 does not clearly state such, but it seems to be implicit that your example would be dealt with as a separate, attached building section. The definition of partially enclosed would then be checked for each of the exterior walls receiving wind pressure (the "hidden" common wall would not apply, but the remaining three walls would). If it doesn't meet the requirement for partially enclosed, it is then by default, enclosed (as stated in the ASCE 7 Commentary).

For a building with a stepped roof, I would include the upper level of wall in the assessment for that section only, not the lower abutment/offset.

For a building connected to another building, the common wall would not be included in both sections, only one. It is perhaps arguable that if a common wall is shielded by another building section, and the protection for openings in that shielding section fail, then the common wall becomes an exterior wall subject to direct wind loading. I would not generally approach the analysis in this manner but would apply the internal wall requirement for the shielded wall (10 psf).