Cold Form Zee Purlin Properties

[SteveMort]

Where can I find minimum section properties and allowable bending moment capacities for 8" Zee purlins with 2-1/2" flange and thickness of 9/64".

 

[ToadJones]

Usually from a manufacturer of such purlins.

 

[MiketheEngineer]

Or figure it out manually

 

[j19]

You can download free software at rsgsoftware.com that will help you. Make sure you have all of the shape information and not just the depth, thickness and flange width. You will need to know the bend radii, lip length, lip angle, material properties, etc.

As Toad alluded to, if you know who made the purlin contact them.

 

[msquared48]

Z purlins are metal building manufacturer specific in many cases. If you can find a metal building manufacturer who uses them, such as HCI in Arlington, WA, ask who made the ones they use. They may make them themselves.

You could also contact the MBMA (Metal Building Manufacturers Association) in Cleveland, OH.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[Splitrings]

The 1999 AISI database that is part of RISA 3D doesn't list a ZU shape of that size. The largest is 8x1.25x0.105. They do list a ZS shape that is 8x2.5 but it is only 0.105" thick.

Maybe your shape is specific to one manufacturer.

 

[BAretired]

Try this link:

http://www.loseke.com/lgsifile/zgppa.htm

9/64" = 0.1406" = about 10Ga, not in table but you can work the properties from the sections shown.

Best is to specify the properties you require and let the fabricator supply that or better.

BA

 

[blackmaddog]

The Light Gage Structural Institute has lots of design information with capacity tables for common sections.

http://www.loseke.com/lgsi.html

 

[MikeHalloran]

CUFSM is free, easy to use, and gives credible results:

http://www.ce.jhu.edu/bschafer/cufsm/

Mike Halloran
Pembroke Pines, FL, USA

 

[asixth]

Cold-formed steel design is complicated and a lucrative industry for those involved. There is quite a lot of research that goes into the development of cold-formed sections to make them more efficient. Lately in Australia, the two biggest col-formed purlin manufacturers have released a new section which has additional ribs which increases the strength and stiffness of the sections. Unfortunately they cannot be lapped with the standard Z-shaped purlins as I found out on-site one day.

If you do obtain a manufacturers technical guide I would stay within the recommendations of their span tables. This will save you performing the calculations for cold-formed sections.