Tee-beam stanchion (onto a T-beam chord)

Long time lurker, first-time poster. (For construction).

Needing to intersect two (2) structural tees (in any case—but for this one in particular, a load-bearing stanchion onto its supporting bottom chord)... C may be optimal, but multiple have merit—what do you think they are?

Diagonals (and supporting brackets) omitted for clarity.

 

The joint design and structural orientation is based upon the loads and moments needed to be carried. In your drawings A is similar to B but totally different from C. Additionally, you really need to decide if you need a 3-corner intersection, as they are not preferred (see Design of Weldments by Lincoln Electric). If it is truly a stanchion, un-balanced sections are also not preferred (see Design pf Ship Structure by SNAME).

 

I don't suppose mentioning a "desert-isle" scenario would impress anyone coming after; but somewhere in between that and textbook ideality must lie any number of less than-preferable solutions to real world design problems... and would an angle-doubler appease just such a discerning eye?

 

What material? How thick? What process? Can you edge prep? And just for complete clarity on terms, is this a bulwark stanchion (cantilever "to structure") or a deck stanchion (compression "in structure")?
I could just send you to the handbooks which fully detail weld design requirements, structural efficiency requirements, etc... but I will highlight some points....
1) Welds "in" structure should be 100% efficient. This means full penetration welds only
2) Partial penetration fillet welds are never 100% efficient because they are crack starters.
3) Never weld stresses into a corner, always use a mousehole leaving the bending stress weld continuous. Use light sealing plates for watertightness.
4) Built-up sections should not have a flaying surface.

Edit, just noticed and changed "toy" to "you"...I hate having old slow fat fingers.

 

In addition to JEH's summary above you should also:
5) Establish the load paths and ensure there are adequate load paths for transferring the load to surrounding structure.
6) Establish what the design allowable stress will be - which takes into account the duty, environment and any possible fatigue aspects of the joint - and design to that, with the procedures noted.