Slip Critical connection - ?

[stillfan]

I have a connection where a 3" long cantilevered plate is loaded 2.5" out causing a moment force on the connection point. The connection point is a round tube that sits between two other round tubes. There is one bolt that makes the connection. So the connection appears to be a pinned connection but we all know that would be unstable. So I was wondering if the engineer thought that he could make it a slip critical connection. So the moment you would be resisted by the torque requirement of the bolt to achieve the proper friction value.

The load is almost a joke at .5K giving you a moment of 1.25K*in = 1.25" couple force given a 1" inside diameter. The slip resistance on a 1" diameter bolt = 33.9K. Am I missing something, Does anyone see a problem with this approach?

 

[paddingtongreen]

Your description of the problem is not clear. Does the pipe get squeezed across its diameter?

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[stillfan]

Follow the link for a sketch. Thank you

 

[connectegr]

This would not be a "slip-critical" connection. There is insufficient contact between the faying surfaces. This is simply a hinge. Pretension of the "pin" will obviously resist rotation. But, 500# is a lot with a better moment resisting design.

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Providing fabrication and erection efficient structural design of connections. Consulting services for structural welding and bolting.

 

[TLHS]

What's the purpose of the detail? Is it so the plate can be fit up in the field to match some necessary angle and then clamped into place?

 

[stillfan]

It is a bearing connection. The load that enduces a moment, in detail 2 is from a vertical column. This then is fit up to the pipe section in detail 1. The inside diameter is 1.06, a 1" bolt is then inserted through the pipes and torqued to requirements. So yes it is so that a fixed connection can be fit up to the column above.

Connectegr - could you tell me where I would find the requirements for the faying surface?

Thank you

 

[dhengr]

In your detail #2, the 3" plate, its connection to the column above, and the column itself must take the induced moment caused by the eccentric axial column load from above. Then the pinned (hinged) connection at detail #1 is just a shear connection and the pin and knuckles must be designed for this. There is no meaningful faying surface in your sketch. And, tightening the bolt will not support the eccentric load from above. You better rethink this entire detail.