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

[netjaws]

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.

 

[jehardiman]

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).

 

[netjaws]

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?

 

[jehardiman]

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.

 

[Ad Hoc]

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.