estimation of winkler foundation modulus

[eponalank]

thread256-151955

Hello.

There was this thread that gave a very simple formula for estimation of winkler foundation modulus as "K = E*(1/B+1/L+1/h)".
K : Winkler modulus [kN/m3]
E : average Young modulus of the soil [kN/m2]
B : width of the strip [m]
L : length of the strip [m]
h : limit depth of the soil [m]

I am not an expert on this, but I was just curious where this formula comes from, as in a paper/textbook reference, as I can only seem to find this approach on the aforementioned thread.
Also, how does one "know" the limit depth of the soil?

All advice is welcome =)

eponalank

 

[rowingengineer]

Before we get too far into this, are you by any chance trying to use this equation to estimate K for the design of other elements other than a slab on ground?

An expert is a man who has made all the mistakes which can be made in a very narrow field

 

[JoshPlumSE]

I'm not an expert on this. But, I recall seeing an ACI report that talked a good bit about Winkler Foundations and how to model them in FEM.

336.2R-88, “Suggested Analysis and Design Procedures for Combined Footing and Mats".

It's a bit dated, for sure. But, it might help out a little.

 

[Bluefoot]

Modulus of subgrade reaction was rooted from a structural approach, as indicated in the Soil Mechanics in Geotechnical Engineering by Terzaghi et al. The referenced paper shows a review on this approach.

http://www.iasmirt.org/iasmirt-2/SMiRT18/K06_3.pdf

The equation you referred is likely, very simplified for a reservoir sitting in a homogeneous soil (I may be wrong). For building structures, it may be not applicable.

 

[eponalank]

Thanks for the information and the links.

Indeed the element in consideration was a rod rather than a slab, so probably the equation above is not applicable.

Thank you,

eponalank