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# stress on 4 foot square pavers under concentrated load

## stress on 4 foot square pavers under concentrated load

(OP)
How can I calculate the flexural stress in 3 foot square precast concrete pavers, due to 15 kip concentrated post load? Pavers are 3" thick and bear on 2" thick HL 60 polystyrene insulation, and 2" pea gravel material below that, then suspended reinforced concrete slab below (the suspended reinforced slab can be considered to be rigid relative to the paver).

A few years ago I wrote a spreadsheet of the Westergaard equations, to evaluate this type of situation, but I would like to have a check of that. There used to be a neat thing on the internet where you input he parameters and it showed the stresses, with load placed at mid-panel, at edge of panel and at corner. But I can no longer find that. Would anyone know where something like that might be on the internet?

Also is there any simple way of doing a finite element type of analysis to determine the stresses in the paver? If so, is there something explaining the method, so I could proceed to carry it out?

### RE: stress on 4 foot square pavers under concentrated load

(OP)
Sorry - I say 4 foot square in the title and 3 foot square in the paragraph. Should be same in both places.

### RE: stress on 4 foot square pavers under concentrated load

(OP)
I just found that I posted a similar question in May of 2013.
Ron suggested EverSTRESS. If Ron is still around, or anyone else has comment on this, is that still the recommendation?

### RE: stress on 4 foot square pavers under concentrated load

ajk1...it should be the same in both places, but which is it? 3 or 4?

You can check your Westergaard solution using Everstress or any elastic layer analysis program. Since you have only the pavers and it is not a multi-layer system, you can also use FEA (RISA, Bentley, or similar), considering the paver as a plate element with concrete properties.

### RE: stress on 4 foot square pavers under concentrated load

Maybe I'm nuts, but for a significant project I'd have a similar make up, possibly smaller dimensions to make it fit and run a few tests at a structural lab. Of course run the calculations, but there is nothing like proving that you are correct.

Edit: I doubt that any equation can come up with a factor for those gravel layers, possibly something like marbles with questionable friction angle or compressibility.

### RE: stress on 4 foot square pavers under concentrated load

How large an area is the concentrated load? I would not put a 15K load on a 3" paver.

Dik

### RE: stress on 4 foot square pavers under concentrated load

#### Quote (dik)

I would not put a 15K load on a 3" paver.

....on styrofoam nonetheless! Sounds like a really bad idea even if you CAN get the numbers to work out.

### RE: stress on 4 foot square pavers under concentrated load

xr250... and nothing can go wrong go wrong go wrong go wrong go wrong go wrong go wrong...

### RE: stress on 4 foot square pavers under concentrated load

If you explain more,we might help. Right now it seems like other alternatives might be better.

### RE: stress on 4 foot square pavers under concentrated load

Can someone show the link to download everstress software. I was only able to find the link to its user guide pdf. This is a free software, right?

### RE: stress on 4 foot square pavers under concentrated load

(OP)
I don't have all the details, as I was going by memory, as to load and thickness, so forget what I posted. I was just assisting another engineer. He now says that he has all that he needs after he researched it out himself.

As a matter of interest, I started to download Everstress, but it wants to check/update my printer driver, which I am reluctant to give it permission to do for fear that something will be screwed up on my computer and then my computer will not work.

### RE: stress on 4 foot square pavers under concentrated load

ajk1 One way for us to forget this post is for you to flag it and request that it be deleted.

### RE: stress on 4 foot square pavers under concentrated load

Why delete it? It was briefly interesting.

Dik

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