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I am building some steel tube structures and it is clear that one of the joints needs a gusset. This will lap over the tube effectively increasing the wall thickness in an area, rather creating any sort of extra triangulation. When thinking about the additional strength that the gusset will add to that location, is this basically an additive process where a gusset of X cross section and Y yield strength with increase the yield strength of the new joint by X*Y?
Basically, I am considering using material for the gusset which has a lower yield strength than the main structure's material, and am wondering if this is actually more of a complicated interaction than it seems.

Thanks in advance for the advice and insight!

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