Local HSS Branch Connection Analysis

[engpes]

I have an HSS (rectangular tubing) cross connection and I am trying to perform a local check on the main member.

This is for a fork pocket analysis on a frame. The main beam (10x6x3/8 tubing) is tied into two branches (6x6x3/8 tubing). Please see attached sketch.

I am trying to perform a local check on the fork pocket (10x6x3/8 tubing) and am applying equation K3-16 for out of plane bending in the AISC 13th edition.

I have 2 questions:

1.) Is this the correct equation to anlalyze the fork pocket HSS local section?

2.) Is the Hb variable (overall height of rectangularr HSS measure in plane of connection) in equation K3-16 the length of the branch connection? Or the height of the cross section?

Thanks in advance.

 

[trainguy]

engpes,

Can you add internal and end plates to remove out-of plane bending effects?

tg

 

[engpes]

I typically add shear plates, but this is a special case where I am trying to avoid this.

 

[connectegr]

Is the connection for shear, axial, and/or moment?

Refer to AISC Design Guide 24 for more information and examples.

http://www.FerrellEngineering.com

 

[a2mfk]

A sketch with the loads on the connection would help as connectegr has implied...

 

[engpes]

Thanks connectegr!

It is an out of plane moment connection.

I found an example in AISC Design guide 24 that applies.

The only difference is that my fork pocket connection is at the end of the HSS (10x6x3/8) member.

I cannot find any discount factor for this situation. Should this be considered?

Thanks again!

 

[connectegr]

I would recommend a cap plate on the end of the HSS 10. The plate can be partial pen welded for a flush fit. One wall of the HSS 6 can weld directly to the cap plate, thus no concentrated force in the HSS 10 wall.

http://www.FerrellEngineering.com

 

[engpes]

The attached sketch is what I have come up with. I have a fork pocket with 2 shear plates to account for the shear stresses during lifting.

I have also run a local FEA check on the fork pocket connection.

My concern is the local failure of the fork pocket tubing walls at the edges.

Questions:

Is there an easier way than performing an FEA each time on the fork pockets?

Is there any specific guideline for fork pocket design / sizing?

The aspect ratio "B" falls outside the limitations of equation K3-16 for this connection.

Thanks in advance.