[Antennas] RE:Concrete To Use For Your Tower

Mon, 9 Sep 2002 07:41:54 -0400

I have put up several towers over the years with at least a yard of
concrete at the base and have never used rebar.  Ignorance I guess.

I'm gonna be putting up another one in the next year or so and this one
will need to last a long time!!!  

Let's say I have a 3' x 3' x 3' hole.  How should I orient the rebar.
Fill me in on the whole process guys.....

Thanks and 73,

Dave, N1PC

-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Wendell Wyly W5FL
Sent: Sunday, September 08, 2002 9:21 PM
To: Chris BONDE; Karl Kanalz
Cc: [email protected]
Subject: RE: [Antennas] RE:Concrete To Use For Your Tower

For non structural applications, fiberglass should do fine.  4 inch
slabs, small retaining walls, lightly loaded concrete tanks, etc.  Where
there will be thousands of pounds of tension, good old 5/8 and larger
rebar will remain king.  Concrete has very good compressive strength -
hence the 3000 - 5000 psi rating.  In tension it breaks very easily.
High strength concrete is never made from a pea gravel (sack-crete) mix,
rather using 1 to 1 1/2 inch rock in the mix to add tensile strength,
when combined with rebar in the areas of the concrete that will be put
under tension, it is a very strong structural member.  The rebar has
ridges that prevent it pulling out and does not depend on a good bond
with the concrete mix, although if you have ever taken a sledge and
broken it off, it bonds better than you think.

Don't wait to put up your tower for a replacement to re-bar.

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of Chris BONDE
Sent: Sunday, September 08, 2002 7:03 PM
To: Karl Kanalz
Cc: [email protected]
Subject: RE: [Antennas] RE:Concrete To Use For Your Tower

At 01:12 PM 2002-09-08 -0500, you wrote:
>Yes there are, Dave!  Again, the user must refer to the manufacturer's 
>recommendations for the size of re-bar to be used and the recommended 
>"pattern" of how the re-bar(s) are connected together (usually in a 
>sort of "cage" shape).
>
>Karl K -  W8TIF
>McKinney, Texas
Has anyone studied the use of concrete with fibre glass ans reinforcing?
There are a few reports out that the concrete is stronger!  The rebar is
usually oxidized before the concrete is pured hence a poor bond sithe
the concrete.  The fibre glass (I think that is the strings that is
mixed with the concrete) adheres and the mass is much stronger as it
becomes a solid mass rather than a mass interupted with poor iron.

Has anyone anything thereon?

Chris opr Ve7HCB

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