[TowerTalk] cheap hams
k4kyv at hotmail.com
Fri Aug 18 21:54:41 EDT 2006
>I have friends -- fellow hams -- who say, "You're going to put 6 1/2 yds.
>of concrete in a base for a tower!? Whoever designed that foundation must
>be crazy. Engineers are a bunch of idiots. Forget the drawings and just dig
>a hole and put 3 yds. in. It'll be fine."
I went the opposite direction when I built my tower. I followed the
instructions in the Rohn tower book, but went one step above the recommended
size concrete piers for the base of the tower and guy anchors. If I recall
correctly, they recommend building it for 85 mph maximum winds at this
locality, but I built mine for something like 110 mph. I don't think the
additional cost was more than a few percent of the total. Of course, if a
tornado hits it, it might not survive no matter how much overkill is used.
I have never experienced winds in excess of 60 mph here.
I dug the holes (by hand, back in 1980), assembled the rebar per
instructions, and called the concrete company to deliver extra strength
industrial grade concrete (which cost only a few dollars more than a load of
standard quality stuff).
After they had poured all the foundations, they had a couple of yards left
over. The driver asked me where I wanted him to dump it. I asked him if
they didn't take back the unused concrete and flush it out with water. He
said no, they would have to dump it somewhere on my property. I ordered a
certain quantity, a little more than calculated need (better to have a
little too much than too little) and thus had contracted to take full
I thought for a moment. No matter where he dumped it, it would harden, and
I would end up with a hugh boulder that would be difficult and expensive to
remove. So I had him go around and top off my guy anchor foundations with
extra concrete until it was all gone. The original plans called for each
block of concrete to be buried about three feet beneath the surface, but
after topping them off, one of mine is only about a foot below the sod. One
was not topped off at all because the sides of the hole had collapsed during
a rainstorm and I had to build a wooden concrete form for that one.
I figured the extra concrete in the other two couldn't harm anything, and
would do more good added to the tower foundation than sitting in my way
somewhere out in the field. Thus I increased what was already overkill, and
solved the disposal problem maybe resulting in a more sucure tower
I just feel sorry for the poor sucker, long after I am dead and gone, who
tries to remove those concrete foundations from the ground.
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