Design End-Plate Beam Splice in DG16

[helfreco]

Hello,
I am trying to design an end-plate beam splice with the same detail as DG16 Figure 1-3(a). However, the splice also needs to carry a moment in the weak direction of the beam, so I have biaxial bending.

I am OK using Part 7 of the SCM manual to calculate bolt loads, so I am not concerned about figuring the bolt loads.

My issue is the end plate.

The equation for determining the end plate thickness in DG16 (either 2-7 or 2-9) is based on the no pry moment and the yield line mechanism. It does not seem that these equations would lend themselves to accounting for biaxial bending.

Does anyone know of a reference to determine the end plate thickness for a splice in biaxial bending?

Thanks

 

[JoshPlumSE]

I don't know of anything that directly addresses.

Off hand, I would suggest a simplification similar to what is done for axial load. So, when you have axial tension, you just treat it as an equivalent moment that would cause that same tension on the tension side of the bolts. Right? I'm not looking at the design guide right now, but I believe that's the basic gist.

If you do the same thing with the weak axis moment (i.e. calculate the tension it would cause in the bolts) then you can convert that into an equivalent strong axis moment. This should be conservative. Maybe too conservative.

 

[FloydLloyd]

I haven't used DG16 but I'm guessing that the yield line theory used in base plate design is the same as that for end plate design.
The yield line mechanism used in AISC DG01 for base plate and anchor design is based on a paper written in 1992 by W.A. Thornton, Design of Small Base Plates for Wide Flange Column, which resulted in the well known m and n cantilever bending distances used for calculating base plate thicknesses.
The great thing about yield line theory is it only considers the failure mode, of which there are limited possibilities, and it doesn't matter if you have biaxial or triaxial bending. Your required strength is a summation of the work done in bending along the yield lines. Have a look at the Thornton paper, it might be helpful.

 

[Agent666]

Going with what FloydLloyd is hinting at, start looking at it from first principles, this was posted recently which I thought was quite an innovative use of sketchup to work out the rotations and make easy work of the yield line analysis.

 

[helfreco]

Both are good suggestions. Thank you for the help. I have already pulled the Thorton article and I am reading it now.