SHS to CHS connection check using doubler plate

[e104909]

Hi,

I have a beam square hollow section (SHS150x8) connected to a column circular hollow section (500Dia15).

Attached is an excerpt from CIDECT design guide 1 referring to another design guide by choo.

Unfortunately, I cannot find anything relevant for me to check this connection subjected to axial, shear & moment.

Can you recommend a solution in this? Any references you can refer me to?

I am looking for a conventional/manual design. I have done a finite element analysis for this but I prefer to show my calculation using proven hand calculations.

Thanks in advance

Regards,
E104909

 

[SAIL3]

There may be some test results or theory out there to address this conn but have not done a search....AISC Design Guide 24 is on HSS conn but may not have your particular case. My first shot at it would be as per attached sketch. The concept gives me alot of latitude in handling different magnitudes of load and member sizes. It also requires only basic engineering principles or easily available data to analyze. The only area that I might have to do a further research on would be the panel zone "A" on each side of the col wall for shear zone buckling, but if I keep the shear in the wall of the pipe col low enough by increasing the distance between the rings I may not have to worry about. I assumed for shear in the pipe that only 1/3D on each side is fully effective. I am sure there are many engineers out there with better concepts, but I believe this concept would work without doing alot of research.

 

[e104909]

Thanks SAIL3. Appreciate your response

The detail that you have shown is quite far from my detail. If I will do an FEM analysis of what you have drawn, the stresses will spread in the perimeter and there is a certain amount of circumferential stress in the column. Whereas the connection which I have shown has a stress concentration on the plate specially in tension. This will not only fail the end plate but also the SHS beam.



Regards,
E104909

 

[dhengr]

E104909:
I don’t have a nice clean formula to solve your problem. But, I would think that the collar or doubler pl. are intended to spread the punching or tensile forces/stresses over a greater area of the unsupported face/wall of the hollow structural section (HSS). AISC has a design guide which covers these details, and it would be well worth reviewing. The shearing forces/stresses should be no problem. The more difficult issue will be the bending forces/stresses, tension or compression, through the doubler pl. and finally out into the wall of the HSS. Good sound use of our regular engineering mechanics principals should be applied. Take a look at some good advanced Strength of Materials or Theory of Elasticity texts.

 

[dhengr]

E104909:
In addition to the above, pay some attention to the fact that at some point on the weld btwn. the doubler pl. and the HSS, tensile bending forces will tend to cause a tensile prying action/stress across the root of the weld, due to the bending of the doubler pl. This might be the critical part of the design, that is, that you get good clean penetration, etc. at the root of this weld.