From: Dominic-Luc Webb 
To: Anthony Stillman 
cc: atm{at}shore.net, Steve Shegiden 
Reply-To: Dominic-Luc Webb 



On Mon, 16 Jun 2003, Anthony Stillman wrote:

>
> Some time ago (I think about a year)  I secured permission to erect a pier
> in the back yard.  After the requisite delay I'm again considering the
> details.  My thoughts surround foundation, enclosure, and to some degree
> location.


From whom do you need permission in your own home, one could ask?


> There are no good locations where I live, nor within twenty miles.  What I
> have to choose from is wholly hemmed in by vegetation.   On the plus side,
> least along the ecliptic.   And on the minus side, trees obscure Polaris.


I have a suggestion I hope will work. Mount a camera, and align as close as
possible to Polaris, camera aligned with axis. Take long exposure and
develop. Next, measure on the film how far the deviation must have been for
the center of the film to Polaris. A little math, which you are good at,
should come in handy. The stars should form enough of an arc to interpolate
an entire circle and determine where the polar axis is. I presume you can
use a 20-25 mm lens on a 35 mm camera, unless the obstruction is really,
really severe.



> I heard on NPR that until man came along, grasses were loosing the battle
> for world dominance to trees.  I guess I'm not doing my part, yet.


Yup, something like that. Here in Scandinavia, immediately after the ice
age there was only one plant (dryas octopetala), that was pretty much the
exclusive vegetation here for about 20 thousand years. In modern times, we
need to choose strategic location to search for it, although it can be
found. Grass likely has some similar story.


> I must remove Irises, lightly mortared bricks, and dirt to pour a
> foundation.  How much dirt is one of my questions.  As are, ground
> preparation, reinforcement, casting forms...

Over here, I do not pour into dirt. I find or place a very large rock at
the chosen site and pour concrete onto this. I make the mount in segments
rather than a single poor. The uppermost piece is a concrete cube that a
flat chair bearing bolts to. Interestingly, I place that screws into the
concrete when I pour, and they unscrew easily once the concrete is hardened
and the concrete ends up with very nice threadings to bolt the bearing
down. Next, I pour a larger concrete cylinder (onto the rock). Once poured,
I push the upper concrete cube into the poured cylinder and tilt it such
that the bearing points as closely as possible to polaris. The rest is a
common fork mount and small imperfections dealt with by computer
programming and motors, if necessary. At least for my 35 mm camera, no
adjustment has actually been needed, so I only turn the polar axis. I'll
try to get some pics posted.


I know very little about
> concrete construction and I'd rather not haul away a heavy mistake.  Think
> "Casting Pier Foundations for Dummies."

I often just dig in and do a small prototype and get a hint where my
problems might reside. With concrete, I found the real trick is in mixing
before pouring and sealing before pouring so that you don't end up with
half of the concrete pouring all over the ground.

Also, my best
friend just visited (architectural engineer in Eugene, Oregon). He pointed
out something quite interesting. He was starkly impressed with the
"quality" of the concrete we have here in Sweden. I used the
cheapest stuff I could find, to see if this would work, and had great
success. He pointed out that my success would have been much worse in the
States due to the poor quality of most concrete relative to what I was
using. I am still not sure what "quality means", but can get you
in contact with this friend (his name is Steve Shegiden). I believe his
comments were directed at the small and very uniform nature of the material
I used. I have no direct translation to English of the exact type of
concrete, but it is the finest particle size we have available in common
hardware stores. I could mention that there is a construction technique
becoming increasingly popular in the States, as I am told, that mixes paper
with the concrete. Apparently this has some unique properties. I made some
of this and it pours and sets very nicely. I don't know details about the
properties of this material, but will ask Steve (in fact, I have cc'd this
to Steve)... Steve, ideas?


Dominic-Luc Webb
near Uppsala, Sweden

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