Wind Load on Horizontal Roof & All Sides Open
Wind Load on Horizontal Roof & All Sides Open
(OP)
I am a ME by trade but am trying to learn how to apply ASCE 7 to this particular problem:
* Corrugated sheet steel horizontal roof (angle ~ 1 degree)
* Roof supported by four posts and otherwise open.
* Spec provided for wind pressure and velocity.
I am trying to select the thickness, pitch, and height of the corrugated sheet steel roof and want to consider potential wind loading.
Since this is open, and the roof is horizontal, is there a wind load in principle? It seems like applying the wind velocity spec over the entire area (length X width) will result in an oversized plate thickness since wind flows horizontally only?
Suggestions would be appreciated.
* Corrugated sheet steel horizontal roof (angle ~ 1 degree)
* Roof supported by four posts and otherwise open.
* Spec provided for wind pressure and velocity.
I am trying to select the thickness, pitch, and height of the corrugated sheet steel roof and want to consider potential wind loading.
Since this is open, and the roof is horizontal, is there a wind load in principle? It seems like applying the wind velocity spec over the entire area (length X width) will result in an oversized plate thickness since wind flows horizontally only?
Suggestions would be appreciated.





RE: Wind Load on Horizontal Roof & All Sides Open
RE: Wind Load on Horizontal Roof & All Sides Open
And don't think that because the roof is flat, the vertical forces are trivial. They're huge. Think of an airplane wing. As I remember, depending on the Effective Wind Area (EWA, the uplift forces start at .8 times the basic wind pressure and go up from there.
You'll not only have to worry about the roof spanning between supports, but anchoring it to the supports and then anchoring the posts (or whatever) to the ground.
RE: Wind Load on Horizontal Roof & All Sides Open
Mike McCann
MMC Engineering
RE: Wind Load on Horizontal Roof & All Sides Open
RE: Wind Load on Horizontal Roof & All Sides Open
RE: Wind Load on Horizontal Roof & All Sides Open
But posts will need to be checked for uplift and some side forces....
RE: Wind Load on Horizontal Roof & All Sides Open
I ran the numbers this morning and got 9.9 psf - close to your range. The code said to use a miniumum of 10 psf.
I did a "beam stess" calc using tabulated moment of inertia values for glavanized corrugated steel sheet. It looks like p = 2.67" X 1/2" in 0.04 thickness passes. Is this a reasonable selection?
RE: Wind Load on Horizontal Roof & All Sides Open
What is the Sxx or Ixx??
Fb = M/S - keep Fb around 20,000 psi or less - usually!!!
RE: Wind Load on Horizontal Roof & All Sides Open
Don't know where you are, 10 PSF is not much. If you have snow, that will likely control for the roofing selection.