ASCE7 Chapter 29 - Wind Force

[CURVEB]

We are calculating the wind force on a structure using Chapter 29 of ASCE7-10. The equations give the force as "F", which is essentially the pressure times the area of the structure. I would have taken F as equal to W for purposes of using the load combinations in Chapter 2, where we would factor F by 0.6 for most of the ASD combinations. However, F is explicitly defined as a fluid load, not wind in this chapter.

Does anyone know if it is explicitly stated somewhere that F = W when F is the calculated wind force from chapter 29?

 

[azcats]

Is the definition of 'F' in chapter 26 (F = design wind force for other structures) enough?

 

[WinelandV]

CURVEB,

You'll find in chapter 27 that the wind load calculated is "p", not W. Whether you're calculating the pressure on the building, or the force on "non-building structures", you're still calculating the wind load W. So yes, if you calculate F per chapter 29, you are calculating the wind load W, and needs to be factored per the wind load factors in Chapter 2.

 

[CURVEB]

F is defined as design wind force in Chapter 26, but it is note equated to W anywhere in the code it would seem. Unfortunately, W is also defined as the building Width in chap 26.

As I look into it more, I'm starting to think of this similar to the way that seismic loads are defined. E is the load, but it is based on Q, the effect of the seismic force, or .2SdsD, or Eh + Ev, etc. Although it doesn't seem to be explicitly defined this way, in the wind provisions it seems that W represents the load resulting from "p" (pressure), or "F" (force), depending on which chapter you are in.

In any event, the important thing is knowing whether or not it needs to be factored, which it sounds like at least 1 other person agrees that it does.

 

[MR_E30]

I calculate wind loads out of Ch. 29 almost exclusively, and I always factor F (as W) for ASD LC's.

So now you have two.