channel thickness check uplift

I'm looking at base plate thickness ASD guide where

t = sqrt(6*M/0.75Fy b)

but not sure what moment and b to use.

Follow the loads. The load from the column is resisted by bending of the channel web as it spans between flanges. Each flange then acts like a column to transfer the load to your foundation.

delagina said:

I'm not sure what formula to use to check the thickness of the channel against anchor bolt uplift.

Click to expand...

I'd think that you'd want to undertake a local, yield line check at the bolt to make sure that the channel web can do it's job.

delagina said:

but not sure what moment and b to use.

Click to expand...

I don't think that there would be a moment. The way you've got it set up, it seems to me that you'll have more or less pure tension at one connection and pur compression at the other.

I would add base plates under the channel toes at your bolt groups. Firstly, you may need that for concrete bearing stresses. Secondly, creating a gap between the channel and concrete will help this setup to behave more predictably. Avoid weird moments and prying action etc.

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.

They have bunch of this all over the plant with just channel, no base plate and it works fine. So I'm hesitant change it for a new equipment shed. The loads are not heavy.

Is this what you mean by yield line

delagina said:

Is this what you mean by yield line

Click to expand...

Mirror the yield line pattern about the bolt and that'll be about it.

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.

Check the channel web strength. treat s strip (strip width is suggested to be 8 times of web thickness) of channel web as a beam supported by channel two flanges, and the tension load of the bolt is applied to the middle of the beam.

"They have bunch of these all over the plant with just channel, no base platen and it works fine."

How long has the oldest shed been in service?

How windy is it ?

I'm guessing the channels are oriented parallel to the shed walls, so folks and machines won't trip on them when walking inside or outside.





What are the dimensions of the post/columns welded to the channel? 6 inch square ?
1 - All over the plant.
2 - Your new shed

Are there diagonals and what not in the walls of the shed so the posts/columns are not asked to provide moment resistance

It would be pretty easy to hide a couple of web stiffeners under each column and within a few Øs of each anchor