Why use angles? Why not just a welded cleat?

I get that in some jurisdictions angles are popular, but I don't see the benefit here over a simple welded cleat plate.

Check out AISC commentary CJ2.2b & CJ2.2b(2) on page 16.1-424 (15th Ed). The consensus since experimental testing in the 1940s is that the 2t returns are recommended for improving plastic deformation capacity, even though they do not increase the connection strength. AISC recommends 2t <= return <= 4t to achieve a flexible welded connection to the support. This leaves a substantial portion of the tension-edge of the outstanding angle/plate leg unwelded.

Practical notes:
1) I've almost never used angles welded to the support. It's impractical for erection because you'll need to do a lot of field welding or you can't swing your beams in.
2) You don't have a case where there is a true "prying action". That check comes with member axial loads. There is technically a small "prying" force from gravity loads and connection flexibility, but that is small and should be disregarded, unless you really want to dig into bending forces on your welds from a small horizontal offset.
3) Your skewed connection to the column web is impractical. At large skew angles, you are better served by another connection type, likely an extended shear plate or an end plate welded directly to the beam web (if the bolts can actually be installed).

Thanks for the info.

Quote (human909)

Why use angles? Why not just a welded cleat?

When the supporting girder and supported beam are not connecting at 90°, we are going with folded plates for double shear connection instead of angles.

In that case, is it fine to use the bolted-bolted clip connection?

As we know, the folded plate strength would never match the steel angle stiffness. So, I am afraid of the prying effect that will be much more than the steel angle.

And is it also fine to use 2t weld same as the angle for folded plates?

Thanks in advance!!

In theory, there is no prying on your connection. The way I look at it is, there is a shear force at the bend in the clip. This shear force causes a vertical shear and a moment on the leg attached to the supporting web, and a vertical shear and a moment on the leg attached to the supported web. At the bend in the clip, there is shear but zero moment.

DaveAtkins

thanks for the info. so, there will be no major effect on bent plates due to prying action, right?

It can easily transfer shear force. But, if the beam has an axial force, no issues to use this, right?

Thanks in advance!!

If you have an axial force, there WILL be prying.

DaveAtkins