Wind Pressure on Screen Wall

[strucguy]

I am designing a roof top screen wall for a three story building. The wall consists of a screen that spans between posts that cantilever 14 ft above roof and spaced 10 ft on center. There is a 2 ft gap between roof and bottom of the screen. I am using ASCE 7-05 for dermining my design wind pressures. So my question is which criteria do I need to use to obtain screen wall design wind pressure? I discussed this with my colleagues at work and got three different opinions.

1. parapet (section 6.5.12.5.4) or
2. solid freestanding wall (section 6.5.14) or
3. rooftop structures and equipment for buildings with h<= 60 ft (6.5.15.1)

I have considered screenwalls as being similar to parapets in all my previous projects with both windward and leeward pressures acting on the screen. Now, I am confused as to whether I was doing it right or not. Appreciate your help in this regard. Thanks in advance.

 

[COEngineeer]

Pretty sure it is parapet.

Never, but never question engineer's judgement

 

[sdz]

Parapet.

 

[strucguy]

Thanks for the response guys. Now, would it be component and cladding pressure or MWFRS pressure? I try not to consider screen wall posts as being part of the MWFRS. So, I use component and cladding pressure for designing my posts. Is that a valid argument??

 

[swivel63]

C & C

 

[COEngineeer]

yes, C & C. If it is not working out so well, you can always put a kicker if it is not getting in the way with RTU.

Never, but never question engineer's judgement

 

[msquared48]

CC&7...

Mike McCann
MMC Engineering

 

[UcfSE]

1 or 3, more inclined to use 3, but compare first. C&C

 

[plasgears]

We had a lot of mechanicals on the roof of a chem lab [3 story], and we screened it with slats 6 ft high total. If I were to do it again, a more elegant solution would be flattened tubes similar to small airplane struts set horizontally. A cheaper solution would be lightweight angles set with the apex facing up. It has aero appeal and sheds rain. Our support structure was tied into the roof steel. Cor-Ten would avoid damaging corrosion.

 

[StructuralEngGuy]

I typically use parapet component and cladding. It tends to give a pretty high wind pressure. Just out of curiosity, is your screen perforated? It seems to be awfully high for a 14' cantilever post.

 

[strucguy]

Don't have that information yet. But, would it help reduce the pressures?? Does code let you do that??