Wind load on grills and grates-request for references 2

[IJR]

Pals

Sometimes architects specify louvre kind of cladding. This is less porous than a plane truss, and the idea of solidity ratio comes into mind but I can not be sure, because grates and grills are more flexible and less porous

Any idea will be highly appreciated

respects

IJR

 

[JAE]

I usually ignore the porous,or grated, materials and treat them as solids. I do this because in the future, the material may change to solid. Or, a large piece of plastic might blow up against it and create a solid sail.

Or, someone might want to put a banner or sign over it and thus make it solid.

I once had an aerospace engineer friend of mine point out that the guy-wires on a biplane have more drag in the wind than the wings themselves. With that thought in mind, an "open" grating doesn't sound like it would have all that much less drag on it than a solid surface.

 

[sdz]

If it is cladding then you should consider worst case of treating it as porous or solid.
For freestanding panels you can take porosity into account by factor Kp=1-(1-d)^2 where d is solidity ratio. e.g. for 25% solid face Kp=0.438. [AS 1170.2 D1.4]