Moment capacity of circular base plate 1

[pir8engineer]

Hey guys.
I'm trying to figure out how to size a circular baseplate. I have a circular bolt group, and I've solved for tension/compression and shear in the bolts, but my brain is absolutely stuck on how to convert that into plate bending. I feel like it has to be something fairly straightforward.
Thanks!

 

[HDStructural]

I would take your worst case tension in a bolt, and pretend that every bolt has that much tension it (only for the base plate thickness design). Then it is a simple circular base plate with a tension load.

You could also look at AISC DG 24, HSS connections. It should have HSS round splice to connections that are configured similarly.

 

[JoshPlumSE]

There is a program called TNX Tower that specializes in monopole cell phone towers. I mentions this because the founder of the program (who has since passed away), wrote a great design guide for the base plates for such towers. It might be a little dated today, not sure. But, a few years ago it was the best resource I could find for such things.

You might find it useful. Here is a link:

https://www.towernx.com/downloads/Technical_Manual_MP_BasePL.pdf

 

[pir8engineer]

There is a program called TNX Tower that specializes in monopole cell phone towers. I mentions this because the founder of the program (who has since passed away), wrote a great design guide for the base plates for such towers. It might be a little dated today, not sure. But, a few years ago it was the best resource I could find for such things.

You might find it useful. Here is a link:

https://www.towernx.com/downloads/Technical_Manual_MP_BasePL.pdf

Thank you!! I'll go look that up!

 

[pir8engineer]

I would take your worst case tension in a bolt, and pretend that every bolt has that much tension it (only for the base plate thickness design). Then it is a simple circular base plate with a tension load.

You could also look at AISC DG 24, HSS connections. It should have HSS round splice to connections that are configured similarly.

Wouldn't that yield an overly conservative plate thickness?

 

[HDStructural]

It shouldn't. You need to design the plate for the worst case stress which would occur at the highest loaded bolt. This method essentially makes the entire plate have that same stress.

 

[jhnblgr]

Research fatigue on these structures and you will understand why conservative is needed