Help with telescope pier on a patio......

I'm planning to mount a telescope pier (Astro Pier) on a to be poured
concrete slab. The slab would be on a slope (although the slab obviously
would be level) and would vary between 1 and 5 feet in depth, being at least
4 feet deep under the telescope pier. The overall size of slab would be
approximately 8 x 13 feet.

Would NOT isolating the telescope pier from the rest of the slab be a
problem? If my children or dogs walk on the slab am I going to get all
sorts of vibration in the mount or is the mass of the slab such that
vibration shouldn't be a problem?

Thanks in advance!!!

Scott

On Sun, 2 Nov 2003 18:35:45 -0500, "Scott M. Petty"
wrote:

I'm planning to mount a telescope pier (Astro Pier) on a to be poured
concrete slab. The slab would be on a slope (although the slab obviously
would be level) and would vary between 1 and 5 feet in depth, being at least
4 feet deep under the telescope pier. The overall size of slab would be
approximately 8 x 13 feet.

Would NOT isolating the telescope pier from the rest of the slab be a
problem? If my children or dogs walk on the slab am I going to get all
sorts of vibration in the mount or is the mass of the slab such that
vibration shouldn't be a problem?

I'd suggest putting the pier into its own footing and pouring the slab around
that, with a sand gap for isolation. You'd be surprised how much vibration gets
transmitted by solid concrete. It probably wouldn't be an issue for visual work,
but if you image, or ever plan on imaging, the vibration will likely be enough
to cause you no end of headaches.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

"Scott M. Petty" wrote in message ...
I'm planning to mount a telescope pier (Astro Pier) on a to be poured
concrete slab. The slab would be on a slope (although the slab obviously
would be level) and would vary between 1 and 5 feet in depth, being at least
4 feet deep under the telescope pier. The overall size of slab would be
approximately 8 x 13 feet.

Would NOT isolating the telescope pier from the rest of the slab be a
problem? If my children or dogs walk on the slab am I going to get all
sorts of vibration in the mount or is the mass of the slab such that
vibration shouldn't be a problem?

Thanks in advance!!!

Scott



The best way to mount a pier is to isolate the pier from the rest of the pad.
I would suggest that the central pier section be cast separately, and then
fill in at least a foot between the walking slab and the pier with large
loosely fitting rocks so that the resulting waling slab is completely
isolated from the pier itself. As agregate is less expensive than concrete
thsi may also save money.

Good luck

Is your concrete slab really going to vary from one foot to five feet THICK?
I must have read your post wrong. 8 x 13 x (1 to 5 feet) is around 10 cubic
yards of concrete -- that's a lot of concrete. What sort of forms are you
using?

Just curious.
--

----
Joe S.

"Scott M. Petty" wrote in message
...
I'm planning to mount a telescope pier (Astro Pier) on a to be poured
concrete slab. The slab would be on a slope (although the slab obviously
would be level) and would vary between 1 and 5 feet in depth, being at
least
4 feet deep under the telescope pier. The overall size of slab would be
approximately 8 x 13 feet.

Would NOT isolating the telescope pier from the rest of the slab be a
problem? If my children or dogs walk on the slab am I going to get all
sorts of vibration in the mount or is the mass of the slab such that
vibration shouldn't be a problem?

Thanks in advance!!!

Scott

Is your concrete slab really going to vary from one foot to five feet THICK?
I must have read your post wrong. 8 x 13 x (1 to 5 feet) is around 10 cubic
yards of concrete -- that's a lot of concrete.

He said it was on a hillside....


Richard Navarrete

Astrophotography Web Page - http://members.aol.com/richardn22

I think the rationale behind his question about the forms used is that that
amount of concrete will tend to move down the hill.

(Spoken from experience by one who has had a form pop loose.)

Bill in Cave Creek.

"Scott M. Petty" wrote in message ...
I'm planning to mount a telescope pier (Astro Pier) on a to be poured
concrete slab. The slab would be on a slope (although the slab obviously
would be level) and would vary between 1 and 5 feet in depth, being at least
4 feet deep under the telescope pier. The overall size of slab would be
approximately 8 x 13 feet.

I think you're implying that the slope of the hill is 1/2; that is a
verticle drop of 4' over 8' of ground; quite steep. Such a slope is
plastic and will tend to flow, especially when wet and supporting the
weight of a concrete slab.

Since you want to level the ground, hire a landscaping/patio
contractor and build a proper retaining wall and fill the hole with
rock and dirt as he suggests. Then pour a proper slab ( depending on
your temperature zone and subsoil - you'll probably only need 6" -
streets are built with 9" concrete and highways with 12") over
aggregate & sand, isolated from the pier as others have described.
Expect to pay $100 per cubic yard for the concrete,

Thanks so much for the responses..

I'm going to pour the pier first, surround it with a sand buffer, and then
let a concrete contractor do the rest. As many of you stated, the
contractor said that a solid slab was NOT the way to go. Instead he'll pour
a retaining wall, backfill with dirt (and drains), and pour a slab over the
dirt.

Thanks again, I sure do love the newsgroups...

Scott

"Barry Gloger" wrote in message
om...
"Scott M. Petty" wrote in message
...
I'm planning to mount a telescope pier (Astro Pier) on a to be poured
concrete slab. The slab would be on a slope (although the slab
obviously
would be level) and would vary between 1 and 5 feet in depth, being at
least
4 feet deep under the telescope pier. The overall size of slab would be
approximately 8 x 13 feet.

I think you're implying that the slope of the hill is 1/2; that is a
verticle drop of 4' over 8' of ground; quite steep. Such a slope is
plastic and will tend to flow, especially when wet and supporting the
weight of a concrete slab.

Since you want to level the ground, hire a landscaping/patio
contractor and build a proper retaining wall and fill the hole with
rock and dirt as he suggests. Then pour a proper slab ( depending on
your temperature zone and subsoil - you'll probably only need 6" -
streets are built with 9" concrete and highways with 12") over
aggregate & sand, isolated from the pier as others have described.
Expect to pay $100 per cubic yard for the concrete,