Re[2]: [TowerTalk] New Tower Construction - Questions

[R. Otto]

Hello Bob,

Interesting point you make.....  I'm using a Heights Tower, and my
last tower was a heights Tower as well (great towers BTW).  One was
80' and the new one will be 112' and both required rebar "cages" even
though their "hinge bases" are made of heavy gage steel.  My comments
(which were personal opinion, not necessarily fact) about putting
rebar in ANY base, was due to:

A)  Every single structural project I've ever done, house or building,
has required some form of rebar cage for cement.  Even cement pools
have a complete rebar cage.  Driveways, walks, all when properly built
have a rebar or wire screen imbedded.

B)  All the Polyphaser data says that tieing the rebar cage to the
ground system enhances/improves the ground system.  Period.  Not maybe
-- it does!  <G>

C)  The specifications for both my Heights Towers, and even my old HBX
tower, required rebar in the concrete base.

Last but not least, it seems prudent to NOT place the tower in
the cement because once you do that, you can never replace a base
section. You would have to start over and pour another base.
Additionally, there are two observations I've made about Rohn towers
I've seen that were imbedded in cement.  One - when I've looked at a
tower that's been placed in the cement (and it's been there a while)
there seems to be degradation of the metal leg right at the place it
enters the cement.  I'm not sure if it's corrosion, or the affects of
freezing and thawing. Whatever the cause, it concerned me that the
tower may be weaker right at the bottom. Two, I agree with previous
comments from Steve, K7LXC, that if you do put the tower in the
cement, it has to go through the cement - and assume as he did that
this is to allow water to pass through the tower leg.

I guess there is one more thought to consider.  The discussion started
regarding a Rohn tower that isn't very tall -- and I 'spose I've
applied what I think is correct based on erecting a FREE STANDING
tower of significant height.  Perhaps if you are erecting a guyed 45'
tower, there is little need for a large cement base and rebar, etc.
For taller towers, or freestanding towers where the loads are directly
and completely in the base, rebar is essential.........  What do Y'all
think?

73's from.......

R. Otto
N8NGA@one.net
Cincinnati, Ohio

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Thursday, August 31, 2000, 2:39:45 PM, you wrote:


FB> I think KC4ZXX explanation has cleared up some confusion that I have had in
FB> my mind for many years.  I put up a Universal free standing aluminum tower
FB> at two locations, per the spec's, which did not call for any re-bar in a 4
FB> ft x 4ft x 4 ft hole.  I always wondered about the lack of re-bar, but
FB> apparently their base legs (solid steel with L shaped lips) evidently took
FB> care of it.  (my tower never came down except when I took it down.  Yet
FB> Heights with essentially similar  tower design does specify re-bar in their
FB> base layout.  comments?
FB> 73 de W9GE .-.-. -.-
FB> -

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