Shear Connection - Short Slotted Holes in the Connector or the Beam?

[Norby_acn]

I was recently asked by an engineer that I work with if our typical shear connection details allow for the short-slotted horizontal holes to be placed in the shear plate (or angle or WT), or if they could also be put in the beam web. My response was that I've always see it done in the supporting connector, not in the beam web. The other engineer asked "Why not put it in the beam web?" And I don't know that I have a really good answer.

My first thought was that if you mess up the connection during fabrication, you only have to throw away the connector piece and not an entire beam, but beyond that, I am not sure. Slots on either the beam or the connect allow for erection tolerances, allows for thermal expansion, etc. Every fabricator I have ever worked with has detailed the slots into the connector. But why not the beam web? What is the reason I am not thinking of?

 

[JStephen]

It may depend on what equipment you have available to make those holes. Long ago, at a former employer, they had an ironworker (a machine) that could punch oval holes, but it wasn't set up to punch them in beams, so you'd always put the oval hole in a little clip and then drill any holes in the beam. I've seen ads for the big beam-processor machines, and with those, it may not matter.

 

[TomLee777]

If the slotted holes are cut on the beam web, the shear and bearing capacity of the beam is compromised. If cut on the connector, the thickness of the connector can be increased as required to meet shear and bearing demand.