----- Original Message -----
From: "Doug Rehman" <rehman@surveil.com>
To: <towertalk@contesting.com>
Sent: Monday, October 17, 2005 8:33 PM
Subject: Re: [TowerTalk] Concrete Fiber
> Thanks to everyone for their comments and experiences.
>
> I decided to not use the fiber because of lightning concerns. My tower
> base
I sure wouldn't worry about it affectin lightening damage.
http://www.rogerhalstead.com/ham_files/tower.htm
My tower went up late 2000 to early 2001 with the antennas and mast being
installed late in the Summer of 2001.
So, counting the summers of 2002,3,4, and 5 it has been up 4 years and has
taken an average of 3 confirmed hits every summer. Most have been observed
by the neighbors in one direction or another. The only thing I've had to do
has been to replace some electrical tape "up there". I don't know what the
top of the mast looks like but I'd guess it's getting a bit "worn" by now.
All of the paint is gone from near the top.
However the tower base runs completely through the concrete and there is a
ground rod about 6 inches outside the concrete adjacent to each tower leg.
The ground rods are bonded together with a network of 30 some 8' ground rods
through over 600 feet of #2 bare copper cadwelded(TM) to the ground rods
around the back yard.
BTW, we poured my shop floor when it was cold. So cold the contractor came
back to finish power trowling at 1:00 AM using the headlights from his truck
to see what he was doing. There was frost on the grass that night.
Unfortunately I let the contractor talk me into saving a little money and
put in a rat wall instead of a seperate foundation. This means the floor of
a heated building is also part of the outside wall which is subjected to
temperatures well below zero. BTW that floor is also insulated from the
ground with one inch of Styrofoam (TM) which is on top of about 2 1/2 feet
of fill sand. This did result in some very find stress cracks that run
diagonally across the inside of the corners. They have been there since the
first winter and have not gotten any worse. There are no other cracks in
the floor. The shop is heated with a 75,000 BTU tube, or hangar heater. This
is basically a gas fired IR heater. The floor and even my tools are at room
temperature. so the temperature is 70 to 72 degrees F to within a couple
inches of the wall where it drops to below zero in about a foot. That puts
one whale of a lot of stress in the corners. OTOH you could run around in
there barefoot and never get cold feet, IF you didn't have to worry about
metal splinters.<:-))
Were I going to do it again I'd put in the foundation and use 1/2 beadboard
as a buffer between the foundation and floor. I'd still use the high
strength stuff. I'd also use it in the garage and shop aprons which were
poured on a very hot day, aparently had too much water in the mix and were
over floated. I haven't been able to get a cent back.
Even with the two big garage doors and staying at 72 degrees 24 X 7 it costs
less than half as much to heat as does our home which has the same floor
area, an high efficency furnace and a programmable thermostat.
5 years ago the cost of concrete was a lot less and the high fiber was less
than $10 a yard more than standard. It was recommended by both the building
inspector and the contractor. I have no way of knowing if I had not used it
whether the cracks would have been worse or not.
Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
www.rogerhalstead.com
> is a welded rebar cage (Tri-Ex LM-354HDSP), so the base will act as a Ufer
> ground bonded to the main grounding system.
>
> I couldn't find any literature about what happens to the fibers if the
> tower
> takes a hit and the concrete conducts some serious current. While nothing
> may happen, I decided not to gamble on a complete unknown. It would make
> an
> interesting research project though.
>
> Doug
> K4DDR
>
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
> any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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