Steel Retrofit - Fully Welded Splice

[cuels]

I have a welder requesting to splice a T Retrofit to the bottom of an existing wide flange beam. They are concerned they won't be able to get the T Retrofit into place without cutting it. They said that another structural engineer provided a detail for some previous retrofit work they had done on another job. The detail shows the T-beam being cut at a 45 degree angle through the depth of the beam. The flange would then be prepped on an angle to get a full-depth weld to attach the entire section. Then on the web of the beam they attached a "fish" plate that is welded on the longitudinal edges, but specifically details that the tranverse edges not be welded. Is this a typical detail for a beam splice? I have not come across anything like this, but in my mind, as long as the pieces are fully-welded, this should transfer the flexure loading through the beam.

Any reference or discussion would be appreciated.

Thanks!

 

[connectegr]

A sketch would help

http://www.FerrellEngineering.com

Providing fabrication and erection efficient structural design of connections. Consulting services for structural welding and bolting.

 

[cuels]

Here is a quick, generic drawing of what they would like to do.

 

[connectegr]

I do not understand your condition well enough to comment. Sorry.

http://www.FerrellEngineering.com

Providing fabrication and erection efficient structural design of connections. Consulting services for structural welding and bolting.

 

[dcarr82775]

It seems to me the 45 degree cut complicates things more than helps it, I don't like it for a few reasons.

I would use a plate instead of a full pen weld on the WT flange. Whenever a contractor asks to do the full pen weld I offer them the choice of doing the full pen weld and getting it UT tested, or doing the flange splice plate with fillet welds. They always seem to go with the later after I bring up UT testing.

If the shear load is low there isn't mush load on the web plate

 

[cuels]

So, with the flange splice plate, you are extending the plate along the bottom flange enough to develop the shear flow strength in the weld required to span across the cut location on the beam? And, the plate that I am sizing will be sized to resist the bending moment at the location of the cut?

 

[msquared48]

I believe that the term is "Flitch Plate", not "Fish Plate", but I could be wrong.

I have not seen such a splice yet either.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[fegenbush]

If you are transferring moment, you will need to butt weld the lower flange. This is usually done with a backing bar. Frequently these joints are subjected to UT. My point is, if you already have a UT capable welder on site and you already have the UT crew coming to do the inspection, why not just straight cut the splice and butt weld with a backing bar and UT the joint?