Limit states for bottom flange coped only 1

[Buleeek]

Hello,

Like in the subject - what are the limit states of the connection with only bottom flange of the beam coped? It is a beam-girder connection. I'm trying to find an example but no luck so far.
Thanks,

 

[ProgrammingPE]

For beams with only the bottom flange coped, you use Section F9 and check it like it is a T-shape. (Part 9 only has special procedures for top coped beam and top and bottom coped beams.) You'll need to check shear yielding, flexural yielding, flange local buckling, and flexural rupture if there are bolt holes.

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[Buleeek]

ProgrammingPE,

Thank you for your answer. I would like to make sure I use the correct formulas:
Per AISC 15th Ed.
1. Shear yielding - J4.2
2. Flexural yielding - F9.1a
3. Flange local buckling - F9.3a
4. Flexural rupture - Eq. 9-4, p. 9-6

Anything else to be checked (when it comes to coped beam at bottom only)

 

[ProgrammingPE]

Those beam limit state formulas look correct to me. (This is also assuming that you have adequate bracing to prevent LTB and that the load is only in the downward direction.)

Structural Engineering Software:

http://www.structuralcentral.com

Structural Engineering Videos:

http://www.youtube.com/channel/UCOj2mXXf3ZbZtgxTc6BtkGg

 

[Buleeek]

ProgramingPE,

How would you calculate "Znet" for the coped beam for flexural rupture?

 

[ProgrammingPE]

You determine Znet by first finding the plastic neutral axis location, which is the height where the area above and below it are the same. You then multiply each of the areas by the distance from their centroids to the neutral axis. This gets a little complicated when you have to account for bolt holes and the fillets.

If you don't have any bolt holes, then you can use Table 9-A (Plastic Section Modulus for Coped W-Shapes) which is provided in the Companion to the AISC Steel Construction Manual.

If you have bolt holes, then there's no tables provided so you have to calculate it on your own. If you want to validate your calculations, you can use the Steel Connection tool at Structural Central which determines Znet when you have a bottom coped beam with bolt holes.

Structural Engineering Software:

http://www.structuralcentral.com

Structural Engineering Videos:

http://www.youtube.com/channel/UCOj2mXXf3ZbZtgxTc6BtkGg