Wind Loads on T-Shaped Canopy

[ToadJones]

I apologize in advance for being vague as I am just stating this...

I'm calculating wind loads (ASCE 7) for a T-shaped canopy and would like some thoughts of others. Canopy has a series of T-shaped frames.

The main issue I am having trouble with is that in all directions, the canopy has very little horizontal projection which sees wind.

The roof structure sees uplift pressures but with the structure being symmetrical there is really no overturning caused by the roof pressures.

Are there some other combination or provisions I should be following that would be similar to unbalanced snow for wind?

 

[Whoofbang]

Look at ASCE 7-10 pp 267- 270. This has design notes for Free roofs. I would try using monoslope free roof with 0 (zero) roof angle.

The Corps of Engineers have some design guides for open structures, but I can't locate it right now.

 

[waytsh]

MBMA 2010 also describes a method for calculating wind loads on a "bare frame" structure with only a roof. It looks like it is a free download at

http://www.mbmamanual.com/

 

[Ron]

TJ....have done lots of "Tee" bents like this. If you consider the wind along the "ridge", you have a balanced condition. Wind perpendicular to the ridge will result in an unbalanced condition.

I realize there is no "ridge", but same concept.

Whoofbang is correct. This is the correct procedure to use. Also, when the column deflects, the wind load will increase because of the exposure change.

 

[ToadJones]

Ron-
Is the unbalanced condition from the pressure varying as you go back away from the eve? I am trying to recall from memory (on road, no books)