parapet pressures

[Galambos]

i have calculated parapet pressures using ASCE 7-02 for a recent project. in a 130mph windzone, the resulting pressure is about 110 psf when taking into account windward and leeward pressures for Ae=10sf. that would equate to 210mph on a wall.

am i missing something? what professor decided that parapets are exposed to windward and leeward pressures that are additive? have we had many parapet failures that would cause us to double our wind forces?

 

[JKStruct]

I didn't double-check your math, but there is a running joke in our office that somewhere between '95 and '98 there must have been a massive influx of parapet failures somewhere in the world (probably a university). I believe ASCE 98 was the first to have the increased parapet wind pressures. I don't like it either, but I do what it tells me to. Just use a 12 gage roof deck.

 

[WillisV]

Prior to 7-02 there was no explicit guidance in the code at all.

7-02 factors were essentially a best guess by the committee to try to fill this gap in the code pending further research.

Additional wind tunnel testing was performed (Western Ontario) and in 7-05 the GCP factors were revised based on this research to +1.5 and -1.0 (from +1.8 and -1.1 in '02).