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Re: stack foundation

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If you get anything other than zero when including soil pressure in your 
moment calculations, then, yes, you are doing it wrong.  From elementary 
statics, Sum(M) about *any* point must equal zero.  If it does not equal 
zero, then your reaction calculations are wrong.

Basic statics requirements must always be met:

   Sum(Fhoriz) = 0
   Sum(Fvert) = 0
   Sum(M) = 0

A. Roger Turk, P.E.(Structural)
Tucson, Arizona

Michael Bryson wrote:

>>Maybe I've been doing it wrong all these years, but I thought the lever
arm is a function of the allowable soil pressure and weight. If you are
taking moments about the toe then you should include the soil pressure
acting at this distance. Summing the moments will then tell you whether
you have a overturning or not.

Incidentally, I assume a rectangular stress block for the soil pressure
distribution since overturning can't happen without this occurring.<<

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