[TheForge] Is anyone on-line ? OT: Washed away?

[Andrew Vida]

On 11/7/2012 4:43 PM, Jerry Frost wrote:
> Screw pile? What's wrong with driven piles?

If you want strength in the sandy conditions of coastal areas, the screw 
pile is a good way to go if the piles are to bear vertical load.  I 
suppose hydraulic cement would be at least as good... perhaps better.  I 
was only mentioning one possible method.  I am sure there are several. 
Piles would have to be hella deep in any event because the wave action 
in a hurricane will strip sand away faster than you can say "oh shit".

So long as you don't get too
> carried away with end bearing the skin friction will keep them from jacking
> from freeze thaw. Virtually any foundation that penetrates the freeze zone
> has to allow the soil to slip in freeze thaw or it'll be jacked out of the
> ground. If by screw pile you're referring to some kind of auger it'd have
> far too solid a grip in the freeze zone and you'd end up with one of those
> carnival tilte houses.

Not sure that last bit is true.  Lots of  light houses are of screw pile 
construction and not all of those have submerged foundations, though 
AFAIK most do.  I would imagine that is you pour a couple thousands of 
tons of  cement foundation upon such piles you will be good to go for a 
long-ish time.  Screw piles are brutally strong and well known for their 
stability.  There are companies that reinforce house foundations with 
them and I have heard more than one story of houses in floods where the 
entire underlying earth had been washed away yet the house remained, 
still entirely stable upon the piles alone.