if you would have done your same technique with a buried section and 2 more
sections on it, you would have gotten the same results.
ken/ken's antenna services
n8gan
----------
> From: Bill Long <wlong@wmdc.edu>
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] pier point vs section in concrete
To: <towertalk@contesting.com>
> Date: Tuesday, March 24, 1998 10:29 AM
>
> >>What are the pros and cons of using a pier point bottom instead of
> >>burying a 5'
> >>tower section in concrete? Thanks, Pete
> >
>
> Sure, Pete.
>
> I have 100 feet of Rohn 45 that stands on a pier pin.
>
> I chose that option because:
>
> 1. it was a recommended installation in the Rohn catalogue, which I trust
> thoroughly.
>
> 2. I thought (probably correctly in my case) that inaccuracies in my
> positioning of guy anchors and in the installation of the buried section
> (both vertical and rotational directions) would cause unbalanced forces
on
> the installed tower.
>
> 3. The ability of the tower to rotate under tension of the guys would
> automatically balance initially unbalanced forces. You could actually
see
> this happening when we erected the tower. The whole thing shifted into
> alignment when we tightened the first guys. I had a surveying engineer
> check the alignment of the tower after it was up, with a transit. It was
> out of line by only 3/4" at the top when we finished, less than the
> diameter of a tower leg.
>
> 4. Any accident that occurred during the pouring of the concrete around a
> buried base section (like the base section shifting unexpectedly) would
be
> permanent and potentially disastrous. I know that this can be guarded
> against with proper technique, but I am not a professional at this, and I
> was worried about my own abilities). (Remember, once you whip up a batch
> of concrete, you only have a half hour to figure out what to do with it.)
>
> 5. I saw the problem from #4 actually happen in a tower installation just
a
> few months before I installed mine. It resulted in a twisted, unbalanced
> tower that scared me to climb. It was fresh in my mind when I planned my
> own installation.
>
> 5. Raising the tower with temporary guys was not really a big deal. We
> bolted three sections together on the ground, added the base and hauled
it
> to the vertical (like we sometimes do at field day). Then six of us
lifted
> it and set it on the pier pin. Slick as a whistle. My bottom set of
> permanent guys is at 28 feet, so we could attach them in advance. The
> first time I or anyone set foot on my tower, it was 30 feet tall guyed
with
> 1/4" galvanized cable attached to permanent anchors (themselves set in
> concrete). In that sense, there were never any temporary guys at all.
>
> I don't mean here to criticize those (the majority, I think) who bury
their
> base sections. That's undoubtedly a fine way to go. I just wanted to
> describe my choice. The tower has been up now since 1990, and I am happy
> as a clam with it.
>
> Gl es 73, Bill
>
> Bill Long NY3M
> wlong@wmdc.edu
>
>
>
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