Concentrated Load on Slab on Grade Article

[RPMG]

[URL unfurl="true"]https://www.structuremag.org/wp-content/uploads/2014/08/C-StructuralDesign-Azzi-Apr081.pdf[/url]

This article says that I can place a 65 kip post on an unreinforced 6" slab with a factor of safety of 3, which is like a 4'-0" square footing. Opinions?

 

[WARose]

Looks like it is saying that for 200 pci soils. That's fairly stiff.

In any case, I'm not sure I've ever used a unreinforced slab on grade to support column loads. Given it's tendency to crack, I've used slab on grades typically for non-critical equipment and wheeled traffic loads only.

 

[RPMG]

But it's magic, right? I don't understand the assumptions. I think the soil is in tension.

 

[Once20036]

There are numerous old threads discussing the limitations of this article.
I recommend starting there.

 

[JLNJ]

Those tables call for some big base plates which, I presume, need to be infinitely stiff for the tables to apply. A small, highly loaded rack post on a relatively thin but large base plate won't do the trick.

I also like how the author throws the "good engineering judgment" disclaimer in there for good measure.