Amain002:
I think that Bill Thornton’s dislike of the double angle shear connection, which also see significant axial tension down the length of the beam is as follows.... When the axial load is applied and resisted, and the angles flex due to this load, there is considerable prying or a tensile stress field applied right across the weld root (perpendicular to the weld length axis) on the angle legs, and also at the terminations on any weld returns on the legs. This is a serious tensile stress across unprotected, and inferior, weld roots. Draw a FBD, a horiz. section through the connection and the beam web, and show how the angles flex and rip at the weld roots. We just don’t want to do that. That rationale for allowing this on a simple vert. shear connection is that the beam end rotation and movement is small enough, so that with weld returns, we fairly well protect the weld roots.
I have no trouble imagining Dozer’s screen shot of the stresses at that connection, and those are only due to the horiz. lateral force of 15k. You really should take a look at some combined stress conditions if the 100k vert. shear, the 25k axial tension along the beam axis, and the 15k horiz. lateral load can happen at the same time. I would take a look at a single shear plate on one side of the beam web, bolted to the beam web. This should be able to take the vert. shear and the axial load. Someone designed you into this pickle, and it leads to a pretty complicated connection, thank them for that. And, this all assumes that the embedded pl. can actually take these loads and reactions. This will likely be a thicker plate than you would see just for normal shear. I would bevel the two vert. edges on this shear pl. so I could get a good weld throat, both sides, without too large a fillet weld out onto the embedded pl., a PJP with a fillet weld reinforcement, both sides. I would stop these welds short of the t&b edges of the shear pl. and not weld around the t&b. This weld around is much too likely to leave a nick on the shear pl. outstanding edge (corners?), another stress raiser, we don’t want. This welding of the shear pl. provides a superior root, and a protected root, as the vert. shear and axial loads (stresses) move through the connection. Now, for the lateral horiz. load, still finally taken by the single shear pl., I would apply a single fitted, web stiffener pl., flg. to flg., clipped at the web/flg. radii, on the side of the beam away from the single shear pl. I would apply this stiff. pl. as near to the end of the beam as my welding would allow, so as to minimize the eccentricity “e”of this stiff. pl. line from the embedded pl. This web stiff. pl. will more likely apply a 15k line load to the vert. shear pl., as a moment on the shear pl. and its welds [(15k) / (vert. shear pl. height, less 1" or so in height)][ e inches to the embedded pl.]. This moment, over the vert. shear pl. height is resolved as a tension and compression stress, separated by the distance btwn. the center axis of these two vert. welds. Now, what do my combined weld and shear pl. stress look like, and I would be conservative.
