POst/column load on a slab near a free edge.

[beam4u]

I've looked at point loads and walls at/near a free edge, but now I have a client who wants to build a small Ramada on an existing slab. The max load is small (<4000#'s)and I've checked punch and uplift/pull out, but with Ringo and Anderson's procedure I'm getting irregular results. The column placement is right at 1 X the relative stiffness - 1.5 is preferred, but I should get some result to quantify my results.

FYI, we have no frost, so depth is not an issue, I'm taking k as 100-pci and f'c at 2500. my gut tells me I'm OK, but I'd like some backup.

TIA,
fadams

 

[dik]

Can you up the concrete strength a tad and 'throw a couple of top bars in?

Dik

 

[beam4u]

thanks Dik, but slab is already in. Trying to avoid saw-cutting a perfectly good slab for a 4K load.

f

 

[WARose]

Do you have the budget/time for a FEA model? With 100 pci subgrade and only 4k load, I would think just about any slab would be ok. (If the load is properly distributed.)

How thick is the slab?

 

[beam4u]

WARose, slab is 5" and I don't have software for FEA unless there's a way to trick RISA.

f

 

[WARose]

WARose, slab is 5" and I don't have software for FEA unless there's a way to trick RISA.

If you've got RISA......you've got FEA. RISA (at least the last time I used it, which has been years) allowed you to model plates sitting on springs.

What is your contact area (on the surface of the slab) for the 4k load? I can run it myself in a spread sheet I have.

 

[beam4u]

WARose - much appreciate the help. I should get familiar with the spring constants on RISA...............

here is a really quick sketch...........sizing is big for the "look" the owner wants


[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1494445193/tips/Scanned39_o0szxw.pdf[/url]

 

[WARose]

I ran it myself (based on the sketch) with a few software packages I have and I came up with the slab being light as well. (I was visualizing a thicker slab before.) You may have to cut out the slab at those locations and put in footings.

 

[beam4u]

OK - will proceed accordingly. Thanks again WARrose

 

[beam4u]

WARose - you still have RISA to look at a model??

 

[WARose]

WARose - you still have RISA to look at a model??

No. I have STAAD Pro. You could probably still post a pic if you want.