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Re: DeVere (vs. Madden)

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Bogdan:

You are correct!  I looked at the 4th edition of Bowles and found "The
Winkler Foundation".   The early edition of Fang & Winterkorn's FDN.
Eng. Hnbk also covers this very well.  Thanks for the information.

Peter  De Vere
Houston, Texas
devere(--nospam--at)asme.org



Bogdan wrote:
> 
> Dear Mr. DeVere,
> 
> I would appreciate very much if, in answer to my message, you could tell me
> the principles (theory) on which american calculations regarding foundation
> beams are based ; I doubt they are entirely "strange" of "these authors"
> I've mentioned.
>     However...:
>         JEMOCIKIN is the (russian) author of this calculation method based
> on the hypothesis of "elastic semi-infinite space (or plane)", being
> considered only vertical forces on beam (plate); this calculation method
> involves the sharing of beam in a finite number of "panels", every one being
> supported by a spring; problems: does this model (very much like a fem
> model) describes correct the curves of displacement? Is it possible to have
> a correct definition (value) for spring's constant ?
>         FUSS-WINKLER is a method developed considering a continuous link
> between beam and ground, involving the equivalence of ground and beam
> displacement for every point; it is established the formula p=Ks*y, where Ks
> is the rigidity coefficient for the ground and "y" is ground defformation;
> practical calculation is based on the differential (4-th degree) equation of
> an infinite beam deformed axis on ground. In order to transform the infinite
> beam to a finite one (usually having both ends free), the beam is elongated
> at both sides with virtual pi/4 distances, on wich are applied known virtual
> forces choosen in such manner to respect end conditions imposed by real
> problem (usually null end bending moments and shear forces). All
> calculations are very accurate IF Ks is well defined (i.e., for uniform
> granulation sand Ks=5.52...13.8, meaning more than double !!!)
>         UMANSKI-KRILOV method is also known as "initial parameters method"
> being recommended for "finite length" beams (alpha*L<5); it is also based on
> 4-th degree differential equation of an infinite beam, where for every
> constant of integration is given a phisycal meaning; the results are also
> very accurate, but more easy to obtain by manual calculations, who can be
> made for any desired section (the method can be assimilated to "Ritter
> section" method for girder poles).
>     Even if both UK and FW methhods use the same initial equation, the
> results are (sometimes) very different; I have found UK being the most
> satisfying method because its simplicity and range of applicability.
>     But WHY these differences for some ACCEPTED calculation methods? Where
> is the calculation accuracy reflected in solutions? In these condiyions, I
> could simply meka a choice for some no matter what dimensions, looking for
> the appropriate method of calculation AFTER !
>     The same thing can be done in case of using differential or FEmethod
> (due to necessity of defining of Ks).
>     Do you know any method to define it correct?
> 
>     Thanks in advance.
> Bogdan Dumitrascu - no title
> 
> Mr De Vere replied to a personal message of Mr.Madden:
> >
> > I have been able to find only brief citations of these authors in the
> > foot notes of my reference books. Books by the authors seem to have been
> > published in Russia circa 1935.  Would you be willing to share this
> > information with us?   Your efforts will be greatly appreciated.
> >
> >
> > Best Regards,
> >
> > Peter  De Vere
> > devere(--nospam--at)asme.org
> 
>