ASCE7-10 wind load on canopy at ground floor of a 40 feet tall building?

[dougseason]

Hi All,

I did a quick search on this but can't seem to find an answer.

I need to determine the design wind load (uplift pressure) for a canopy attached at 7 feet above ground floor to a 40 feet tall building. I am designing the canopy per chapter 30 of ASCE7-10 for roof overhang. Which height would you take the pressure from in Table 30.7-2, the building height or the canopy height? My interpretation is use height of canopy at 7 feet. My logic is that, being exaggerating a bit, if I have a building that is 160 feet (max. in the tables), it just doesn't make sense to design the canopy at the 1st floor for pressure at that height.

Please give me your interpretation.

Thanks

DS

 

[Antnyt23]

Use the canopy height for the canopy design

 

[Archie264]

Hmm...respectfully, I'm not sure I agree. Section 30.7 (i.e. "Part 4") is a simplified version of the wind loads for components & cladding for h less than or equal to 160' and I see no provision within it to differentiate between h (the mean roof height) and z (the height above ground level). As the simplified version of that I think it simply applies the same pressure to all heights of wall zones of the building. See the pictures of the zones for the pressures, the first page of "Table 30.7-2, pg. 264 in my version, the Third Printing.) The wall zones show no differentiation along their height.

To get differential wind pressure at various heights of the building I think you would need to use the unsimplified version, that is, Section 30.6 (i.e., "Part 3").

That's my take on it, at least.