Fillet weld capacity on thin base material

[evanschr]

I am designing a welded steel truss made of round tubes (chords are RMT 2.875x0.120 and the webs are RMT 2.0x0.083). I would normally start with a weld equal to the thinnest base material, but I need the capacity of a 3/16" fillet weld (all around the ends of the webs) to resist the end moments. I am used to designing with thicker material and therefore have the following questions:

Can I design for (and specify) a 3/16" weld in this scenario?
I know the web section (RMT 2.0x0.083) by itself can resist the end moment, but would such a large weld somehow affect its capacity?

Fatigue is not a concern. I attached a rendering if that helps clarify the situation.

I would greatly appreciate any constructive feedback.

 

[paddingtongreen]

No way,not in a single pass.
I don't understand why you need 3/16" fillet for 1/12" thick material. I would try full strength butt welds using backup rings.



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

 

[vesselfab]

you could use a smaller tube fastened to top & bottom chords and then the middle braces put on.

similar to double/triple butted tubing used in bicycle frames.

single wall as shown, yes, possible, but in at least 2 passes, maybe 3

 

[EdStainless]

You are stuck with multiple passes.
Designed for looks and then asked to carry a load.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube