Mobile Handrail - Three Way 90° Joint Calculation

[Riversidean]

Hello!

I am looking to get some advice regarding a mobile hand railing system possible weak point. I've been asked to look into creating mobile hand rails to act as sign mounts. These mobile hand rails would be moved on occasion to different locations as needed. I created two designs due to a concern about force being applied to a three way elbow. The first attachment marks the joint I am concerned about. The second drawing is my attempt to add stiffness to the joint. Am I being overly concerned with the strength (or weakness) of the three way elbow? Or am I right to be concerned?

I am uncertain as to what would be the best method to calculate the forces on the elbows to ensure failure won't occur; if anyone wants to point me towards literature or equations it would be greatly appreciated. The attachments shows the sign loads. Also attached are aluminum hand railing parts with the three way elbow circled.

-Riversidean

 

[Riversidean]

Elbow in question diagram.

 

[Riversidean]

Frame stand with diagonal to add stiffness.

 

[phamENG]

More than likely, the elbow will be as strong or stronger than the pipe itself. Best thing to do is to call the manufacturer, though. They will either have an engineer on staff or will have submittal documents. If they make these for handrails, you can bet you're not going to be the first engineer to call them.

 

[JStephen]

It may be quicker and easier to test a piece than to prove otherwise that it is adequate.
If the thing locks with a set-screw or something like that, I can see there being a problem from vibration/repeated movement.