HSS Zig Zag Stair Stringer 2

[VTenge]

I have a client that wants to use hss tubes to create a stair stringer in a zig zag pattern spanning diagonally between two wood beams. Essentially, the tubes will follow the path of the risers and treads with hss6x2x1/4 horizontals, and hss4x2x1/4 verticals. They'll be two of these frames, with angles spanning between them for the tread attachments.

I've designed the hss members to have fixed connections at each of vertical/horizontal member intersections, but I'm a little uncertain on what type of weld should be used to achieve this. The steel will be exposed per the architect, so any exterior plated connections are off the table. If anyone has done something similar in the past, what kind of connection did you use? Any suggestions or thoughts are welcomed.

 

[Agent666]

I'd imagine once you shag around with all those mitre joints (expensive and a lot of them), just providing a cut plate like your picture is much easier and miles cheaper. Even if it has to be thick, it's just material and cutting. No weld prep, no internal stiffeners, no welding, no grinding back welds to smooth to satisfy some AESS requirement. Architecturally the sharper corners probably look nicer than all the rounded hollow sections (personal opinion maybe).

 

[Tmoose]

I wonder if the sizes of the HSS could be chosen to use them like the attached image ( stolen from dold, and modified to evade copyright prosecution).