"Kern" for Round Footing/ Baseplate

[ToadJones]

I understand that the way the "kern" is found to be e=B/6 for a rectangular footing is by setting equal P/A = M/S and solving for "e" (where e=M/P)

Can the same be done for a round footing or baseplate?

I am asking because I have a round baseplate with a very large OT moment and low axial load. I am trying to determine home much of the plate is in bearing in order to design the thickness of the plate.

I am coming up with e=1/8d for the kern. d= diameter of plate.

 

[WillisV]

thread507-225866

 

[ToadJones]

okay, so d/8 is correct.

I guess what I am really after is determining the bearing area on the compression side so that I can accurately determine the anchor tension loads.

 

[ash060]

Design of Welded Structures - Blodgett

Has a very good method for anchor bolt tension and baseplate design

 

[ToadJones]

Yes, I am aware, but I was hoping for a solution for a round plate.

 

[ishvaaag]

You may get a reasonable approximation from equilibrium between the compressed zone and resultant of stresses at the bolts, to meet solicitations; this you can do with different stress blocks, plastically, in compatibility of deformations, etc. Whichever closed form statement you meet anywhere will fit only particular restrictions if it has to be accurate. Prior than that, by extending the recommendation of using Blodgett to the literature of baseplates you may find your case.

 

[JoshPlumSE]

Toad -

Below is the betst reference that I know of for the design of circular base plates. This was put together as a reference for monopole towers (used in the communcations industry). But, it assembles and summarizes the approach from a number of different sources (AISC, process industry practice for vertical vessel base plates, et cetera).

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

Some of the discussion is for rectangular base plates supporting circular poles or equipment. But, it does get into circular base plates as well.