Column Embedment into Base Plate
Column Embedment into Base Plate
(OP)
A legacy practice of my engineering group has been to cut a hole in our base plate and embed an 8x8x1/4 HSS column 5/8" into the plate. The new manager wants detailed calculations on each structure, including base plate design. It is my understanding that the individual that detailed our base plates went with this design due to the moment on the structure. Unfortunately, this is a unique design and I cannot find any similar calculations to analyze this plate. The TIA, AISC, and ASCE 113 don't answer this question. To continue with my analysis of the base plate, how do I determine if this plate is adequate? The plate is A36 and column is A500 grade B, design loads are as follows:
Bearing Case: Shear = 4kips Axial = 9 kips Moment = 55kip*ft
Uplift Case: Shear = 5kips Uplift = 6kips Moment = 49kip*ft
Any direction would be appreciated.
Bearing Case: Shear = 4kips Axial = 9 kips Moment = 55kip*ft
Uplift Case: Shear = 5kips Uplift = 6kips Moment = 49kip*ft
Any direction would be appreciated.






RE: Column Embedment into Base Plate
That said, the weld transfers your forces from the column to the baseplate, and should be analyzed for all combined actions. I think the baseplate should be assumed as 5/8" thinner than its specified thickness for a bending check per AISC.
RE: Column Embedment into Base Plate
This seems like someones "clever" idea that was adopted years ago without any real benefit and results only in added cost.
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RE: Column Embedment into Base Plate
- Utilities running up the inside, right?
- I've evaluated similar poles assuming that prying action in the base plate ties the column walls down. Similar to monopole splice connections. Kinda depends on your base condition. Grout bed? Double nuts elevated?
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RE: Column Embedment into Base Plate
In some cases we do have utilities running up the inside but not for this structure. This structure is for supporting rigid aluminum pipe (conductor,I'm in the substation group for the utility). It is a 2 column structure with a beam across the top supporting all 3 phases.
RE: Column Embedment into Base Plate
With levelling nuts and the detailing as shown, I'd expect this to have a very limited, and difficult to determine, moment capacity.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Column Embedment into Base Plate
RE: Column Embedment into Base Plate
BUGGAR, I think ours is like how you describe yours, in my opinion the details aren't shown correctly. There is a hole completely through the plate with the column "suspended" 5/8" deep into the plate.
Thanks for the input
RE: Column Embedment into Base Plate
RE: Column Embedment into Base Plate
RE: Column Embedment into Base Plate
1) moment conn btw plate and sidewall. Not much there with 1/4" walls.
2) model plate as discrete strip beams.
3) FEM
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Column Embedment into Base Plate
RE: Column Embedment into Base Plate
RE: Column Embedment into Base Plate
I'd say this detail needs being revised, based on my non-expert opinion.
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RE: Column Embedment into Base Plate
RE: Column Embedment into Base Plate
RE: Column Embedment into Base Plate
Once I do get a grasp on how strong this is, I'd like to get it re-detailed to show the hole going completely through the plate and the column suspended halfway through the plate (5/8"). This has led to confusion in the past but our internal fabrication shop has done so many of these that they know what we are looking for.
RE: Column Embedment into Base Plate