Serviceability vs. Minimum Wind Load

[vmirat]

I have a 20ft tall structure with walls on two sides which are all glass. As such, I was checking serviceability wind drift. I used the AISC 7 commentary with 10yr MRI which gives me a wind pressure qz of 10psf. According to AISC commentary, this pressure (Wa) is non-factored, so the full 10psf would be used.

However, AISC also has a requirement for a minimum wind load of 16psf. My guess is that this would not apply to serviceability, but the commentary doesn't address this.

 

[KootK]

My guess is that this would not apply to serviceability, but the commentary doesn't address this.

I would be inclined to agree.

However, AISC also has a requirement for a minimum wind load of 16psf.

I'm not familiar with this. For my own edification, could you point me to the clause?

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[DETstru]

Sounds like you're using the latest AISC (though I've never seen them mention a wind load) and an old ASCE 7. In ASCE 7-10 isn't the minimum wind load 16 psf?

 

[P1ENG]

ASCE 7-05 (and older): Min 10 psf with Load Combination factor of 1.0 = 10 psf [net].
ASCE 7-10 (and newer): Min 16 psf with Load Combination factor of 0.6 = 9.6 psf [net].

In both cases, make sure you consider the 0.7 factor for components and cladding provided in the notes of deflection limits of the IBC. In the 2012 and newer versions of the IBC, it is a 0.42 factor on the nominal wind pressure, or another way of thinking is still using the 0.7 factor on the factored wind pressure: 0.7*(0.6*W) = 0.42W.

... Sorry if the above was not clear. You can take the 0.7 on the 10 [9.6] psf minimum net pressures when checking serviceability.

Juston Fluckey, SE, PE, AWS CWI
Engineering Consultant