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Slotted Holes in Beam Flange - Possible?

Slotted Holes in Beam Flange - Possible?

Slotted Holes in Beam Flange - Possible?

I am contemplating a beam connection where one W section beam bears on top of another W section beam.

My question is:

Can a fabricator cut a short slot or long slot hole in a beam flange? The slot could be parallel or perpendicular to the longitudinal axis of the beam.

Maybe I could make the lower beam a H-pile section, which would give a flatter flange?

I've tried googling this, but no luck.


RE: Slotted Holes in Beam Flange - Possible?

Why would an HP section have a flatter flange than a WF? Both are covered by ASTM A6 tolerances.

One other consideration from the ASTM A6 tolerances, the beams may be up to a 1/4" deeper than advertised. Might not be an issue if your top flange is a bit too high, but it's worth considering. If you have multiple floors this issue can be accumulative.

Short slots are usually punched into plate and angle material, which is not possible on WF sections. Many fabricators can machine a short slot into flanges, but special machinery is needed. Otherwise they might be drilling 2 holes and grinding the rest of the material away manually. Make sure your specs do not allow for manual flame/torch cutting of holes, as that will make a mess of the flanges.

RE: Slotted Holes in Beam Flange - Possible?

Sbisteel - Thank you for the response. I could have said it better. The inside portions of W-Section flanges get much thicker as they approach the fillet and web (the bolts always require beveled washers).

The HPile flanges have a consistent thickness.

I was thinking it might be easier to punch a slotted hole on the HP flat surface versus the varying thickness of a W section flange.

RE: Slotted Holes in Beam Flange - Possible?

For S beams I agree, but both WF and HP sections have a constant flange thickness up until the start of the fillet (k1 in the AISC manual). Just make sure you pick a section with a flange wide enough for the slot & bolt to stay clear of the fillet.

RE: Slotted Holes in Beam Flange - Possible?

Slots are possible for the right fabricator with the right equipment. Multi axis plasma cutting machines have been cutting copes, holes, slots, openings in webs, etc for a while now.


If it's just a one-off, they might just punch them with a portable punch or drill & ream as indicated above. I wouldn't be afraid of specifying a slot if you can make the geometry work.

RE: Slotted Holes in Beam Flange - Possible?

we very commonly slot beams - overhead crane runways where beams need to be aligned properly
We drill two holes & torch cut the bridge. Slots either way depending on requirements & edge distance
I disagree with SBIsteel. Thermal cutting is accepted practice. but it need to be done in a professional manner.... and it is tricky

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