Design in light gauge Steel - PURLINS 2

[saad73joss]

Hello everybody
I have not a real experence in designing Z or C purlins.
Anybody can show me a real good book with good examples of calculation.
I m designing a warehouse and to optimise sections I would like to use 4 mm C cold formed purling
Many thanks

 

[smb4050]

If in North America, the AISI (

http://www.steel.org)

specification(s) and commentary(s) should have the information you're looking for. ASCE has seminar on cold-formed steel design which would help, and Cold Formed Steel Engineers Institute (cfsei.org) has information online and webinars. Normally Z-sections are used for roof purlins. Not that a C shape can't be used.

 

[saad73joss]

Thank you I will have a look on sites and look for a webinar course.
As for C, we did a very big project using C purling 4 mm thickness.
Why we can't ! I m curious
Thanks again smb4050

 

[ajh1]

If you are wanting to use continuous purlins, the Z-purlins nest together better than the C-purlins. They also stack better for efficient shipping bundles. US practice is almost 100% Z purlins when working with cold-formed sections.

 

[MiketheEngineer]

There is an association for PEMBs - Google it

 

[ajh1]

Metal Building Manufacturers Association

http://www.mbma.com

 

[BAretired]

smb4050 did not say that C sections could not be used. He said:
Not that a C shape can't be used.

That is a double negative meaning they can be used, but they are not favored over Z sections because of nesting.

If C sections overlap at supports, they must be placed back to back. That way, the flanges are not aligned, making it more difficult to attach the deck.

BA

 

[saad73joss]

Thanks BAretired and sorry smb4050
It prouves I m not good in english
sorry guys and thanks you

 

[hokie66]

Cold formed purlins are normally much lighter than 4 mm thick, in the range 1.5 to 3 mm. In Australia, we use steel purlins for most commercial and industrial structures. In our case, load tables are provided by the manufacturers, and are based on extensive testing. We use them as a commodity, not something you design individually, sort of like steel joists in North America. One manufacturer's literature attached:

 

[BAretired]

Interesting brochure, hokie. The flange widths 'E' and 'F' vary by 4 to 8 mm so they can nest properly. Section properties are based on the mean width of the top and bottom flanges.

There may be some manufacturers in North America who do the same thing, but I believe the more common method is to use the same flange width top and bottom and slope the return at the outer end of the flange at 45 degrees instead of 90.

BA

 

[saad73joss]

Thanks Hokie66
I have this doc. I asked the manufatur to send me their freeware but i have to be australian.
Actually tables are useful and normally the manuf. Who give the calculation note. My case is that i m working in morocco and u have to do everything by yourself because of luck of good manuf.
I had a freeware from an english manuf i do not remember the name but not that easy to use , i mean u should learn it gentely the time to masterise it before using it correctely....
Sorry for mistakes

 

[BAretired]

There are several manufacturers who provide load tables. Why do you need freeware?

BA