ASD vs. LRFD minimum C&C wind pressure 1

[AnimusVox]

Hey all,

I'm working on a project where I'm designing the exterior walls, and I used a 16 psf mininimum wind pressure per ASCE 7-10 30.2.2, which states:

Minimum Design Wind Pressures

The design wind pressure for components and cladding of buildings shall not be less than a net pressure of 16 psf, acting in either direction normal to the surface.

I was using a reduced wind pressure of 14 psf previously, but I was told by my PE supervisor that 14 is acceptable due to the change of ASCE 7-10 treating wind as a strength load than a service load (and we use ASD in design).

Is that true? Can that 16 psf load mentioned in ASCE 7-10 30.2.2 be reduced in ASD design?

 

[JAE]

My understanding is that the 16 psf is an minimum required ultimate, or factored, wind load.
This replaced the previous ASCE 7-05 minimum of 10 psf.

So to convert the 16 psf to a service-level wind you'd use 0.6W or 0.6 x 16 = 9.6 psf...essentially the same as the former 10 psf.



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[TehMightyEngineer]

Seconded JAE, for ASD the minimum C&C wind pressure works out to be equivalent to the 10 PSF from previous editions of ASCE 7.

Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries

https://www.facebook.com/AmericanConcrete/

 

[AnimusVox]

Thanks for the quick responses, the language seems really explicit, I wish it referred to the minimum as an unfactored or nominal load rather than a net load

 

[TehMightyEngineer]

That would actually be more confusing in the context of ASCE 7-10 which is very explicit that all wind loads are given as factored (strength design) loads, similar to seismic loads. "Net load" only means that the minimum pressure should be compared to the net effects of internal and external pressure.

Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries

https://www.facebook.com/AmericanConcrete/