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Wind Pressure on Closed Pitched Free Roof

Wind Pressure on Closed Pitched Free Roof

Wind Pressure on Closed Pitched Free Roof

(OP)
How would you apply wind pressures on the attached roof shape using ASCE-7 ? Or even if the shape was turned upside down.
It is a canopy structure so it is open below the bottom of the roof.

Basically it is a structure very similar to the shapes given for Pitched Free Roofs, however the bottom is closed not open. Would you apply pressures using the Open - Pitched Free Roof, then apply a pressure to the flat top surface as well (also internal pressure)?

Thanks for any comments.

https://dl.dropboxusercontent.com/u/65240332/Eng-T...

EIT
www.HowToEngineer.com

RE: Wind Pressure on Closed Pitched Free Roof

RFreund,

for me its an open canopy - I mean no cover on sides. that is ,you will two cases: net upward case and net downward case.

RE: Wind Pressure on Closed Pitched Free Roof

(OP)
That makes sense because the pressures given in the Standard (ASCE 7) are net pressures, meaning acting on the top and bottom. Maybe I am over thinking this a bit. For some reason I was thinking that the fact that the canopy was closed is changing the applied load. And maybe it does to some degree.

EIT
www.HowToEngineer.com

RE: Wind Pressure on Closed Pitched Free Roof

depending on the horizontal flexibilty of the structure you may experience entirely different lift and drag coeff when the structure rotates....the more the structure deflects/rotates the more severe these coeff become...so I would draw the deflected shape and then evaluate the appropriate coeff...you may have more than one wind load case...

RE: Wind Pressure on Closed Pitched Free Roof

As I interpret From SAIL3,
the canopy may be on one column, if so, you have two things to check:

1-frequency is more than 1hZ
2-you have to take an eccentric load this is according, somehow, to the EC

I once designed a canopy on one column, the column was torsionally weak , the canopy kept moving in a twisting form almost in no wind situation

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