Design Pressure of Architectural Perforated Panels
Design Pressure of Architectural Perforated Panels
(OP)
I'm looking for suggestions on the "correct" wind pressure to apply to perforated aluminum panels acting as cladding. In particular, the panels that are installed at corners of a building or even wrap around a building.
Does anyone have technical documents or case studies that prove effects of certain hole patterns on perf panels?
My engineering judgement tells me that you cannot develop negative wind pressure with perforated panels at the corner if the percent open is large enough. However, I am unable to determine what percent open I would need to eliminate the negative pressure.
Thanks for your suggestions or any documents to support your response.
Does anyone have technical documents or case studies that prove effects of certain hole patterns on perf panels?
My engineering judgement tells me that you cannot develop negative wind pressure with perforated panels at the corner if the percent open is large enough. However, I am unable to determine what percent open I would need to eliminate the negative pressure.
Thanks for your suggestions or any documents to support your response.






RE: Design Pressure of Architectural Perforated Panels
RE: Design Pressure of Architectural Perforated Panels
My typical condition is cladding installed over subgirt tube/zee framing on the wall. Its simply aesthetic. Most of these panels are 3-4' tall by 4-6' wide lapped together or have some form of 1/2" joint system. (Reference CENTRIA Ecoscreen for more info)
My inquiry is when the panels exist within the 'a' corner zone dimension of a building. I'm trying to support my theory that the panels would not be able to develop negative pressure. Thanks.
RE: Design Pressure of Architectural Perforated Panels
But why refine the calculation that much? Consider it solid (it's not that conservative) and use that value.
RE: Design Pressure of Architectural Perforated Panels
If you have a thin cable perpendicular to the wind direction you get as much drag as a full airplane wing (per my aerospace engineer friend).
It is not a direct linear function of percent open vs. wind pressure either as the shape of the holes, the hole/opening edge condition, etc. all affect the drag on wind running through the panel.
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RE: Design Pressure of Architectural Perforated Panels
I know there is a "rain screen" system out there where they can place images on the outside of the panel by varying the size and type of perforation (they also do something with the ingot leftover)
http://www.dri-design.com/dri-design/imaging
Maybe you could contact them to see if you could pry some information out of them.
RE: Design Pressure of Architectural Perforated Panels
JAE, I completely agree and this is the main point to the thread. My hope was to get dialogue about other engineers experience. I am hoping there is some actual tests conducted or technical documents that I can reference to justify my design pressures I use.
As you mention JAE, and I agree, the hole pattern and shape makes an impact to the amount of pressure. I'm trying to develop an educated procedure.
One may argue also that the panel will pressure equalize but I am leery of making this argument. Per ASCE 7/10, making this argument is difficult to back up.
Thanks again everyone.
RE: Design Pressure of Architectural Perforated Panels
RE: Design Pressure of Architectural Perforated Panels
RE: Design Pressure of Architectural Perforated Panels
That way you have something to go on. Otherwise, you probably need to use a solid surface in your calculations per ExcelEngineering or at the very most assume 90% of the wind force as a conservative assumption.
Part of this assumption depends on how much of this stuff you have on the building and how sensitive your assumption is to the total design/stability of the structure.
If it doesn't affect the overall wind forces (MWFRS) as much perhaps you can be a bit less conservative. If your assumptions (70%, 80%, 90%) significantly alter the overall, then I'd go safe.
When in doubt, make it stout.
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RE: Design Pressure of Architectural Perforated Panels
RE: Design Pressure of Architectural Perforated Panels
One item you might scrimp on is the factor of safety. Normally, wall panel loads are quite high to keep the panels from tearing and allowing rain to damage the building's innards. If part of a screen wall tears away, the consequencess seem less severe.
RE: Design Pressure of Architectural Perforated Panels
RE: Design Pressure of Architectural Perforated Panels
RE: Design Pressure of Architectural Perforated Panels
RE: Design Pressure of Architectural Perforated Panels
That being said, there has been research done for the Industrial Perforators Association who commissioned O’Donnell & Associates, Inc. to try and come up with some sort of method to effectively calculate some of these properties. Below is a link to an article which summarizes the findings of the study performed by O'Donnell & Associates.
http://www.fergusonperf.com/pdfs/tolerances-option...
Although this article may help if your trying to take reductions as reference in 30.1.5 of ASCE 7-10, it by no means addresses all of the different factors that need to be considered for each particular application. From my experience the design of perforated panels ultimately comes to using the professional engineers own engineering judgement as to what reductions in wind pressure and strength should be taken.
If you do find something that may better address your issue please share as I'm always looking for more information to substantiate my own calculations.
RE: Design Pressure of Architectural Perforated Panels
However, to get back on track to the main goal of this discussion was to ask what other engineers thoughts were on the negative pressure effects of perforated panels. Can you really develop a negative corner zone pressure on moderately open panels (say 50% for argument)?
RE: Design Pressure of Architectural Perforated Panels
I'm working on an art piece involving perforated aluminum. We're considering a load case that involves icing concurrent with a statistically sensible concurrent wind speed. For that case, we've deemed it prudent to assume that the ice makes the aluminum essentially solid.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Design Pressure of Architectural Perforated Panels
I completely agree that if ice is present, treat the perforated panel as closed and used concurrent ice wind withour open area reduction.
RE: Design Pressure of Architectural Perforated Panels
RE: Design Pressure of Architectural Perforated Panels