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Re: Pier design and sand
Hi Don,toggle quoted messageShow quoted text
My engineering background reminds me of these pitfalls as well, and it is
a concern at the back of my mind, but I still wonder how much stiffness in
this application, is really enough. If I were building an "observatory pier",
fully committed to location, I would go for maximum strength of materials, but
this pier is a test system, if I can call it that. If it works sufficiently
well, (and I don't kick it, intentionally out of frustration, or
unintentionally), then I will consider it a viable success. Since this is my
backyard, I don't expect blustery winds (certainly not if I have to be
outside - in which case the seeing will be a deciding factor, not the pier).
There are enough buildings, shrubs, fences, and low trees, etc. to provide
some wind break. Heaving of the ground from year to year, might eventually
require a reset, or redesign with heftier materials, but a 4 foot depth and
packed with yard soil (not necessarily sand). I don't expect much long term
motion, especially since there is no "footing" to push up - it's just a
relatively thin 1/2" cylinder wall rather than a flat bottom. As for short
term stability, I am trusting that the wall thickness will suffice for the
load being carried. But by then I will know if this is the best spot -
certainly can't be worse than using my 6" diameter Losmandy G11 aluminum
tripod supporting my AP900 and Questar-7. If there is any shift caused by
seasonal heaving, I can realign the mount, but hopefully it won't be required,
or at least not often. I like the clean lines of green PVC, no painting
required, no pitting or rusting below ground, and it won't ring like a bell.
As for pulling cables, or unbalance - if cables are pulled, I have some
serious soldering repairs ahead of me. The mount should be perfectly
balanced - after all it's one of the best, and if anything, we like our setups
I'm still investigating the feasibility, but appreciate any heads up and
warnings I can get from you and others. For now, I am considering it a
"temporary pier" - with no early plans to require dismantling it (once
planted). I had hoped someone had already tried this approach, but I might
have to be the first to do so.
What I really would like is to turn it into a Greek Column during the day,
as I described - that WOULD be the topper!
----- Original Message -----
From: "dmwmpd" <westergren@...>
Sent: Wednesday, October 31, 2007 8:51 PM
Subject: [ap-gto] Re: Pier design and sand