Space for fillet weld

[ajk1]

Is there sufficient space to make a fillet weld on site, to weld the vertical leg of a steel angle clip to the underside of the top flange of a W8x18 steel beam? Please see attached sketch.

 

[KootK]

I'd be concerned. That's what kept me from pitching this in the other thread. Maybe clips on both sides and no welds?

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[ajk1]

Hi Kootk - thanks for your thoughts. My other thought (thugh not posted here) had been exactly what you said, namely clips on both sides and no welds, but I was hesitant because it may be hard to get the clip to fit tight against the flange after they get thru fiddling around with the installation of the Hilti anchor bolt into the concrete. They could install all the anchor bolts first, and then measure the distance from each bolt to the beam flange edge before drilling the holes in the angles, but our experience on another repair project is that is hard to get a contractor to do and there is still the inevitable tolerances and the fact that the anchor bolt does not fit tight to the hole in the steel angle.

My feeling is that the weld is the more positive way to go, if it can be done properly. But I will also consider the fit tight method you suggest if I can think of a way to be sure it fits tight.

I am still interested in hearing whether the illustrated weld can be done or not.

Thanks for your suggestion, much appreciated as always.

 

[KootK]

What if you welded a plate on top of the flange and then welded the angle to that? It's two doable welds versus a singe questionable one.

One thing that you've got going for you is that the quality of the weld here isn't super important.

Another option would be to bolt a plate to the concrete and then weld the angle to that to ensure a snug fit.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[KootK]

Or use a Z-plate and weld to the web.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[gtaw]

The welder should have a direct line of sight to the weld. That isn't possible in this case.

The angle of the electrode should bisect the angle between the members being welded. That isn't possible in this case because of the limited clearance.

It is improbable the welds in this case will be acceptable.

Best regards - Al

 

[ajk1]

To Kootk - I really like the idea in your last sentence of bolting a plate to the concrete; your idea of a Z plate is also good. Thanks.

 

[ajk1]

To gtaw; Perfect. That is precisely the answer I was looking for to put the issue to bed. Thanks for explaining why it should not be done. That is very helpful and very much appreciated.

 

[gtaw]

Consider a Tee consisting of vertical plate welded to the beam web and underside of the flange and seated against the underside of the concrete slab.

Best regards - Al

 

[gtaw]

Here's an alternate detail that may work. It all depends on the nature of the loads.

Best regards - Al

 

[ajk1]

to gtaw: thanks for taking the trouble to make the drawing. The top of the beam is 2.5" below the slab soffit, so the plate would have to be shaped to account for that. It seems to involve a lot of field welding, but perhaps that is what will have to be done. I thought this was going to be something really simple, but it has got me tied up in naughts.

to Kootk - My understanding is that the calculate the force that the brace will take, the entire top flange of the beam and half the web depth must be assumed to be in yield and at a force of Φfy items that area, when designing by limit states design. That means that the resultant force act several inches below the top flange. That seems to mean that a plate or angle on both sides, fitted tight but no welds to the top flange, as suggested earlier, would not be sufficient.

 

[ajk1]

Scrap what I just said about the resultant force. I guess it is no different than when steel joists are sitting on top of the beam and are considered as lateral support.

 

[gtaw]

Here's another option that might work and provides access for welding in the field.

Best regards - Al

 

[KootK]

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.