Cold form purlin and girts

[BAGW]

Hi,

Which is a good reference book for cold form purlins and girts deign? Does anyone has any examples and presentation on these?

Thanks

 

[JAE]

Try the AISI website (

https://shop.steel.org/)

Their design specifications and guides have examples of designing with cold formed steel shapes.



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[KootK]

This is a useful freebie: Link

The Newman book below is a great practical guide. The Hancock book is a great theoretical one.

There are gobs of books available. If you're able to elaborate upon your specific area of interest, we may be able to target our recommendations a bit better.

 

[hokie66]

It is surprising to me that you do not have load tables available, similar to those for bar joists. Both are commodity materials.

In Australia, we use load tables for purlins and girts. And they are produced by Bluescope Steel, an Australian company which has rolling mills in the US, and I think now owns Butler. Is the long term black box of PEMB operators preventing the widespread distribution of load tables?

 

[Ron247]

Unless things have changed, there are no load tables for purlins or girts because there are no standards for physical dimensions. Each manufacturer could make tables for their components but you would have to buy their components specifically.

Even if they are 8" purlins, they could have any width flange, any length of stiffening lip etc.

 

[hokie66]

Lack of uniformity doesn't stop the bar joist manufacturers from publishing their tables. I think it is more likely to do with the PEMB people protecting their proprietary information.

Cold form purlin and girt load tables we use in Australia are based not only on code provisions, but on full scale testing.

The attached brochure is an example of what we use. Most commercial buildings in Australia use purlins for support of metal roofing, but we don't have a PEMB industry as such.

https://professionals.lysaght.com/sites/default/files/LysaghtZedCeesPart1July2014.pdf

 

[ajh1]

At least part of the issue is that the large majority of purlins and girts are now treated as continuous members. With the combination of continuous members, mixed bay sizes, and patterned loading requirements there are so many variations possible that load tables become impossible to maintain. Add to that that many manufacturers have multiple lap dimensions available along with various purlins bracing schemes the size of any load table gets huge. While there is a components industry of sorts in the US, the PEMB industry is providing a complete structure, not just some secondary members, so the computer systems simply design the appropriate sizes from a small stockpile of standard shapes (for BlueScope US, that is about 7 thicknesses available in 4 depths).

 

[Ron247]

hokie,

I think bar joists do have uniformity but it is not material sizes, it is load capacity. All 12K3s can support the same load.

 

[BAGW]

thanks

 

[hokie66]

ajh1,
I think you have just confirmed my opinion.

 

[Ron247]

ajhi,

That makes sense about why they don't make load tables. Most load table components are simple span or at the most, "consistent" multiple spans.