[TowerTalk] new member with tower question

Patrick J. Jankowiak recycler at swbell.net
Thu May 29 21:33:12 EDT 2008


Thanks Jim,

I don't know the answers to the questions you have asked, but I will add 
this to the information I'll present to the engineer. The plan is to 
drill (many holes) into the caliche and put in rods, although until now 
it has been a discussion about rebar as the rods. At least we seem to 
have the drilling part right.

best regards,
Patrick
KD5OEI

jim Jarvis wrote:
>
> 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
> www.themorsegroup.biz
> coach at themorsegroup.biz <mailto:coach at themorsegroup.biz>
>
>
>

-- 
kind regards,

Patrick Jankowiak
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