Open Structure Wind Design

[craigmcg]

I'm looking to design a canopy-type open structure using either arched trusses or a hip framing for the roof. Neither of these scenarios seem to be covered in ASCE 7-05. Does anybody have any suggestions or other references that may help me determine the wind load distribution? Perhaps the Canadian NBC has something?

 

[youngstructural]

I don't see anything in the NBC off hand (Sorry, someone else will be a better help with NBCC 2005; Just got back from overseas), however there is information on this in the AS/NZS 1170 wind code. (That's Australia and New Zealand).

Can you post a sketch so I can be certain that I have a possible solution?

Cheers,

YS

B.Eng (Carleton), P.Eng (Ontario), MIPENZ (Structural-New Zealand)
Working in Canada, and missing my adoptive New Zealand family... at least I brought the little Kiwi with me!

 

[jiamin]

Can pitched free roof close enough to approximate it? Just some thoughts.

 

[craigmcg]

Thanks YS. Our photocopier/scanner is being serviced at the moment so I can't scan anything in. The arched roof data I'm looking for would be similar to Figure 6-8 of ASCE 7-05, except for open structures. The hip roof data would be similar to Figure 6-11C, but again for open structures. I don't know if you have the ASCE 7-05 handy, but this is the only reference I have at the moment.

 

[youngstructural]

AS/NZS 1170.2:2002 is almost certainly able to help you out. Section D3 "Free Roofs and Canopies" has pitched free roofs, troughed free roofs and hyperbolic paraboloid roofs...

Aerodynamic shape factors are also provided for frictional drag on exposed members for free roofs, AND attached canopies, awnings and carport roofs are addressed in section D4.

If you want some real-world assistance I'd be happy to help if I'm able. Post your e-mail in the tradition Whatever < AT > Something (DOT) something format and we'll see if we can't get in touch directly.

Cheers,

YS

B.Eng (Carleton), P.Eng (Ontario), MIPENZ (Structural-New Zealand)
Working in Canada, and missing my adoptive New Zealand family... at least I brought the little Kiwi with me!

 

[Ron]

See Fig. 6-18B and 6-19B in ASCE 7-05. For the hip condition, look at using the lateral pressure on the hip as if it had no opposite side (single monoslope).

Look at earlier versions of ASCE 7 for arched roof coefficients over open structures.