Pittsburg Seam

[jheidt2543]

I'm looking at a 1.5" x 3.5" x 20 ga. cold formed box section used as a girt. The section is roll formed and instead of welding it closed or using screws to stitch it closed, a "Pittsburg Seam" is used. The seam is in one of the wide sides. The loading is applied as a uniform load (wind load) to the narrow side.

I'm assuming that this friction fit seam should be discounted some amount to account for the seam used. Does anyone have any suggestions on how much? Does anyone know of any test data on this type of seam for a beam like member?

Thanks in advance for any help!

 

[HgTX]

http://www.ras-systems.com/press/22_19.pdf

makes some mention of various requirements that the joint meets, but I don't know if it's meaningful. You might ask the box fabricator or the manufacturer of the seaming equipment to provide you with some data.

Hg

 

[jheidt2543]

HgTX:

Thanks for the ideas! I've tried to find information at AISI and a sheetmetal association, but no luck so far. I've also talked to a standing seam roof manufacturer and struck out there too -- they actually test the SS roof as a system and don't look at just the seaming strength. I'm still looking.