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RE: Ice Expansion Force

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Ice expands to fill the space available. It builds pressure if contained in
a pipe to the point of bursting the pipe. Pressure does not build if the ice
is not contained, such as in clean grovels, where the ice flows to fill

Ice pressure is difficult to resist if the ice-water is contained. Ice
forming under a foundation will expand and lift the foundation unless
extreme methods are used to hold the structure down. Selfweight of the
structure is seldom sufficient to resist ice pressure. Piling and over
excavation/backfill with non-frost susceptible gravel are used in Alaska.

Ice under a base plate should expand and flow from under the plate unless
the ice-water is contained. 

-----Original Message-----
From: Christopher Wright [mailto:chrisw(--nospam--at)]
Sent: Wednesday, March 01, 2000 10:08 AM
To: ?
Subject: Re: Ice Expansion Force

>Water collects in 1" space between underside of base plate and concrete 
>foundation and freezes.
You can pretty much assume that the ice will expand as much as it wants. 
Frozen pipes can develop several thousand psi, about what it takes to 
rupture fittings, when the freezing is confined. It just expands enough 
to make up the difference in density between liquid and ice. Handle it 
pretty much the same as a thermal expansion problem. The only real 
difference is that with ice, the difference in density comes from a phase 
change, not a temperature change.

Christopher Wright P.E.    |"They couldn't hit an elephant from
chrisw(--nospam--at)        | this distance"   (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)