canadian wind coefficients for parapets

[alindenver]

Hey guys,

I was wondering if anyone has designed a parapet using the 2010 National Building Code of Canada. I have looked at the structural commentaries, but cannot figure out what are the appropriate CpCg factors are and how to apply them. My first thought would be to calculate the wind pressure using the parapet height to get CpCg from the tables in the commentaries, and add that with the suction using the same logic. is this too conservative? Is there another way?

Thanks!

 

[jayrod12]

At our office for smaller designs such as that we typically just use CpCg=2.0 (Figure I-8 I think) as that is the worst possible case. Is it too conservative? Maybe but it lets us sleep at night.

And honestly unless your parapet wall is ridiculously tall the difference between the actual CpCg and using 2.0 will make little to no change in your wall design.

Hope that helps,

 

[amecENG]

Instead of using figure I-8 you may want to use Figure I-23 (free standing plates, walls and billboards). In this case there is no Cp coefficient and Cg = 2.5 (Clause 4.1.7.1 6b)