Purlin to Purlin Connection Screwed Though Flanges

[EPCI-Steel]

So I have a situation where a C-purlin in connected interstitially between two other purlins (a beam spanning between two girders), and the method of connecting them together at the joint is shown as a single sheet metal screw top and bottom through the flanges of both members. The purlin in the middle is moment controlled for the design and the shearing loads at the ends are not great, approx 700 lbs.

I am at a bit of loss for how to design this connection. This is the first time I have ever seen a connection like this, light gauge framing is typically not my thing. I am assuming the spanning purlin to be simply supported, therefore only shear at the ends. I am using AISI S100 for the design.

Please give me your thoughts on the forces acting at the screwed connections between the flanges and how you would approach it, or how you would make the connection differently.

I had thought about using an L bracket to make a web to web connection or having the spanning purlin flanges cut back and bending the web 90deg to make a screwed connection to the web of the edge purlin.

An example of the connection is shown on page 4 of the pdf at the link below, second diagram.

http://www.muellerinc.com/downloads/20x20Carport.pdf

Thanks

 

[txeng91]

I would keep the screws through the flanges for torsional restraint of the cap channel and add a framing clip to transfer shear. Clark Dietrich and Simpson make lot of connectors for cold formed steel. See link below.

https://www.clarkdietrich.com/sites.../CD_ClipExpress_S-Series_Literature&Loads.pdf