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C + C wind on open bldgs

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Rick:
 
I have always wondered about open buildings in general in ASCE. Since the only roof they cover is monoslope, what about all of the other types of roofs? What about C + C loads? I think it is a matter of time and funding for more wind tunnel tests. They just haven't got around to testing all the different types of structures yet. And if you think about the types of structures that are open, a monoslope roof is a good place to start- park structures, canopies at schools, gas station canopies, etc. are usually mostly flat or monoslope. Also, since these aren't exactly cricitical structures, then they probably aren't at the top of the "TO DO" list.
 
I have always used Table 6-9 for all design of open roofs, whether MWFRS or C + C. I believe that is all you can do. On top of the lack of testing, perhaps since it is a completely open monoslope roof with no walls, hips, valleys, ridges, overhangs, internall pressure, etc. there isn't as much turbulence causing localized pressure effects. Just a guess.
 
However, if you are completely unhappy with ASCE coefficients and wind pressures, they do allow you to use other sources, I believe there is a list in the book somewhere. One of these is "Wind Effects on Structures" by Simiu and Scanlan, which contains in the back many  charts of all types of structures. However, it doesn't look like they differentiate between C + C and MWFRS, and these tests were done using "uniform flow".
 
Lastly, we do lots of schools and those aluminium canopies are always pre-engineered by the manufacturer. So if you are just designing the foundations as EOR you only need MWFRS wind loads....
 

Andrew kester, PE

 Longwood, FL  32750