[TowerTalk] new member with tower question

[jim Jarvis]

Patrick,

Two areas of comment:

1)  You live on what is essentially a solid rock, albeit somewhat  
porous...  why can't you
drill into it and epoxy rods into the caliche to hold the tower  
base?   Or pressure-grout?
Similar techniques are used in New England with bedrock.

      It will require some engineering work, and cost you a few  
hundred to get it documented,
but it's surely doable.

2)  The idea of holding up a rohn 25 by partly relying on guys, and  
partly on the base isn't
quite right.   When a tower is guyed, the overturning forces get  
translated into compression
forces, which push the base down.   The main role of the foundation  
is to keep the tower from
sinking.

I think your best solution will be to find an engineer who has worked  
with caliche, in
erecting light poles or similar structures.   He'll know what's  
available to machine drill
clean holes for the foundation rods, to tie into the stratum.    You  
may actually have to
pour a small concrete cap, just to make up the distance from the  
caliche to grade level.
But it would be the underlying stratum itself which provides the  
resistance to the overturning
moment of the loaded tower.

N2EA

Jim Jarvis, President
Corporate Coach
The Morse Group, LLC

People-Process-Strategy
Achieving Results in a Changing World
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