Checking Baseplate connections

[DaveHolder]

Hi guys,

As you will see in the attached picture, the SHS column is in line with the bolts of the right side of the plate, I am checking this design and I don't think it is right to place the column like that, so to solve this issue I was wondering if it is possible to add 2 additional bolts in the centre line of the plate? .

the axial load is about 12 kN moment is 0.75 kN.m.





Any advice would be appreciated

 

[KootK]

The original base plate looks fine and normal to me. As always, eccentricity and fastener edge distances in the substrate need consideration.

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.

 

[P1ENG]

Can you explain why you think the current design is not a good idea? Do you have a moment at the base of the column? If the plate is thick enough, you can eliminate the prying action of the plate if the column tries to rotate. You can likely get a working solution using the original design.

Juston Fluckey, SE, PE, AWS CWI
Engineering Consultant

 

[P1ENG]

Also, you can download Simpson's or Hilti's anchor software for free. It doesn't check the plate that I am aware of, but it does check the concrete bearing and anchor forces.

Juston Fluckey, SE, PE, AWS CWI
Engineering Consultant

 

[WARose]

If you have to have it there (based on dimensional considerations or whatever) that's what you have to have. The design can be proved with calculations.

 

[DaveHolder]

In my point of view, the column shouldn't be in line with the bolts, as I think these 2 bolts are not doing any resistance, and they should be distanced from the outer edge of the column. I suggested maximum offset of the column shouldn't exceed 40 mm from centre line of the base in this example .

The plate thickness is 10 mm.

Please if you could provide me with hand calcus illustrating your thought

 

[dik]

Your forces are so small, the BPl is vastly overkill... Moment is about 0.6 K-ft... Tension in bolt is approx 400# per bolt...

Dik

 

[WARose]

In my point of view, the column shouldn't be in line with the bolts, as I think these 2 bolts are not doing any resistance,...

If the load is reversible, the bolts could be in tension. (Not considering the vertical load because I don't know whether that is a uplift or down load (or both).)

I'm not sure I follow what your objection is to the column placement. Yes it is eccentric.....but I doubt it was done just for the sake of having a odd looking connection. And there is nothing in code that forbids it (as far as I know). I'd just run the numbers on it and be sure it works as far as strength goes. (Be sure you have enough space on that edge to get your weld in. That caught my eye.)

 

[DaveHolder]

I used Tedds Software to solve it and hasn't allowed me to input the plate details stating that the outer edge of the column mustn't be placed on the line of the bolts,


Please if you got any worked example similar to this case, provide me with it that will be very helpful

 

[WARose]

I used Tedds Software to solve it and hasn't allowed me to input the plate details stating that the outer edge of the column mustn't be placed on the line of the bolts,...

Why not do a hand (or FEA) solution? You could make a fairly conservative assumption as to the width of the plate that resists the applied moment (maybe the width of the column) and superimpose that stress on the stress caused by the axial load.

 

[Celt83]

check out AISC design guide 1 or Design of Welded Structures by Omer W. Blodgett section 3.3

you have P and M = M +/- P*e, e is distance from center of column to center of plate. Critical bending in the plate may be from the long side at the face of the column.