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Lightly loaded brace to column connection

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skeletron

Structural
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Jan 30, 2019
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The attached connection is for a lightly loaded brace framing into a column (circular tube). There is a 4" bent plate that is tied to the face of the column with U-bolts. The red line indicates where I see the workpoint for the brace. The intercept of the workpoint & column CL is about 11" below top of plate (you can deduce the relative geometry from that).

I see a couple things that bother me about the connection:
1. U-bolts
2. A double bent plate
3. A single bolt for the brace end connection
4. A large eccentricity from the workpoint to the bent plate center

Is this a "bad" connection? Or am I just so accustomed to seeing robust connections on industrial structures that something like this isn't as sensitive to the four points above?

The braces are mainly for stability for the top beams in the long direction and lateral stability in the short direction. I'm kind of withholding some info to focus on the above questions.
 
 https://files.engineering.com/getfile.aspx?folder=8974a79e-15b9-41ac-87e9-82acf3bac853&file=lightly-loaded-brace-to-tube-connection.png
skeletron said:
Is this a "bad" connection?

Bad? Bloody horrible mechanically. That said, it surely does have some capacity and may well be the right solution for whatever your application is: light load, nominal stability, perhaps a functional need for being easily added or removed from an existing post without welding...

In my opinion, the capacity of this connection could not be accurately ascertained without physical testing. One might be able to come up with a reasonable lower bound capacity via calculation however.
 
Ha! Okay, thanks for putting my gut feel at ease. I think the design is a response of chasing the problem's own tail, so I'm on the hunt for a different solution.
 
There is no actual work-point that intercepts the column is there? Any particular reason you do not let the braces get closer to the column before you connect to them? If the picture is to scale, it looks like the braces will almost pass right behind the column.

As far as analysis, I agree with KootK, you would have to test it. Since both braces can act simultaneous or separate while also having one in compression and the other in tension, it gets even more complex. What would "mirroring" the brace do for you?
 
Ron, you're correct. The work-point doesn't intercept the column...eccentricities gone wild. Not sure of why this detail was designed this way; I'm looking after the approval drawings and noticed this while flipping through. It's not my cup of tea and I think the designer might have been in the mindset of "keep the steel weight low to keep the cost down". I'm looking at a redesign where proper beam sections are used to reduce the need for the braces (they are knee braces).
 
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