Single bolt through HSS 1

[WARose]

I am bolting a HSS 4x4x0.25" beam to a column (of the same size) via a single threaded rod. (Basically the beam to the side of a column.) I am doing this because I want it easy to detach.

The shear being transferred here won't even be 200 lbs. Is there any specific check for something like this as far as the wall strength of the HSS goes? This is so light....I'm thinking of just noting it "by inspection [ok]".

 

[phamENG]

If you want to run a calc, I'd do a pin bearing check using J7-1 (R.n=1.8F.y*A.pb). Not perfect since you'll have threads, but you'll probably find that it doesn't care at all.

 

[XR250]

I would not bother checking anything for 200 lbs

 

[WinelandV]

My only concerns would be on the install side. If I'm understanding your situation right, you've got a 9-ish inch bolt running through both tube members. You definitely want the slop taken out of the joint, but you also don't want to overtighten and reduce your 8" out-to-out dimension to (hypothetically) 7.5" out-to-out.

And if you have to do a check, phamENG has pointed you in the right direction.

 

[KootK]

First off, I like the cantilevered pin model too. All good there.

That said, I slightly favor the model shown below. My gut feel is that it's a bit more truthy in terms of the mechanism that will develop. AND, it's got no bolt bending which is kind of sweet. You know, if you believe it.

If this is all about simplicity of erection and tear down rather than material cost, I would favor a 3/8" x 3" x 3" washer plate on both ends of the bolt just to stiffen things up on the draw in.

And yes, 200 lbs probably warrants no checking. But, then, you specifically asked about checking so here were are.

 

[KootK]

This is also pretty sensitive to where on the beam you expect the load to get delivered to. If it would be on the right side of the beam in my sketch, I'd be temped to just treat the HSS beam as a faux channel with much less connection eccentricity.

 

[WARose]

Thanks Kootk. Your FBD is kind of what I had envisioned.

 

[Tomfh]

By inspection ok at 1kN. It takes far more than that to crush a tube.

Critical mode will be bolt tension crushing the tubes. As the load increases I’d check the wall for the applied bolt tension: A point load on a steel plate.

 

[BridgeSmith]

The only thing I would be concerned about is keeping the nuts from loosening up, if you can't crank them down tight without risking crushing the tubes. For something where the nuts may need to be removed periodically, perhaps the use of nylock nuts would be appropriate.

Rod Smith, P.E., The artist formerly known as HotRod10