Aluminum 3mm thick, Perforated Sheets Wind Load Analysis 1

[Robert_spider]

Hi, I am trying to do analysis on the Perforated 3mm thick aluminum sheets which has features like openings as bricks and these will be installed in front of unitized cladding system.
I am unable to find any document which can help me in any reduction factor to apply of there is any for such kind of sheets.

 

[jjl317]

try Iperf.org - the Industrial Perforators Association - I think they have a design guide that can clarify a design approach.

 

[Robert_spider]

thank you for your response,
I have been to their website, by the help of some previous discussion in this forum.
But the website Is of no help.
may be other people who have gone through such scenarios can guide me also.

 

[jjl317]

Their "Designers, Specifiers and Buyers Handbook for Perforated Metals" document includes a section on "Strength of Perforated Metal" and "Elastic Properties of Perforated Metals (Stiffness)"(or at least my older copy does), which is based on an equivalent solid material concept. I have used this approach in the past.

I will be following to see if anyone else has any other (or potentially newer) information.

 

[Robert_spider]

I see, thank you for such guidance.
Please correct me I am thinking wrong,
I am thinking to have some reduction in the calculated wind loads, which I have calculated to act on the façade of the building.
As this sheet has to be analyzed separately the wind load acting on it should be reduced due to the perforations. (If their is any clause from EuroCode)

 

[jjl317]

In the US, my interpretation of section 30.1.5 of ASCE 7-10, is that for air permeable cladding, unless there is specific testing, or you can find "recognized literature" justifying a lower pressure, you essentially use wind pressures as if the material was solid. Years ago, I remember having a discussion with a consultant about this very issue, and one of their points was that something (i.e. plastic sheathing) could end up airborne in a wind event, and "stick" to the face, essentially creating a solid panel. Personally, I feel this approach is likely pretty conservative, but I can also imagine that in many cases, the effective wind load would end up higher than just the wind load over the solid areas, due to the drag around the holes.

And in terms of Eurocode (or any other design criteria worldwide), I have no idea on how this might be addressed.

 

[Aesur]

I agree with jjl317, I don't recall any reductions for perforations in the US code at least.

 

[Tomfh]

Previous threads:

https://www.eng-tips.com/viewthread.cfm?qid=424736

There’s a fairly simple formula in the Australian code, based on the percentage of solid area (solidity ratio).

 

[Robert_spider]

Thank you all for such a nice help,
this Australian Kp Factor can be multiplied with the calculated with load to reduce the pressure I guess. I will dig into euro code as well and will post it here. (It isn't like that, that I have not dig in yet the thing is I am also busy in other projects as well), so will get through it once again and will post it here.

From the bottom of my heart thank you all for contributing to my post.

It is my first time discussing something related with Engineering on any sort of forum.
I would love to make friend across board
Thank you all