What kind of post-post horizontal tolerancing can you hold with those
things, and how is it adjusted or compensated for while driving
in? Usually at least one of the two horizontal surface coordinates
has a reasonably tight alignment tolerance in my experience.
They look like a great idea, although one advantage of concrete is
you have lots of time to tweak the post alignments if necessary while
the concrete sets. I would think a helical screw would be prone to
walking just a little, unless the drive apparatus is extremely well-anchored.
John Raynes
RE Solar
Torrey, UT
At 08:45 AM 1/26/2009, you wrote:
We have also used the local franchisee of TechnoMetal Posts for many
jobs that are ground mounts.
Around $250 per post is what we paid also.
They were in and out on our last job in 2 days, but their machine
did break down for a while. They placed 32 posts in 2 arrays for a
12.6 kWp array (60 modules).
We marked the 4 corners of each array & told them how far apart to
place the posts & off they went. Marked, drove, cut off those too
high & welded on extensions to those too short, then ground the
welds & painted.
We also topped them with Unirac U-LA racking and it lined up well.
-Glenn
From: [email protected]
[mailto:[email protected]] On Behalf Of Larry Brown
Sent: Monday, January 26, 2009 7:24 AM
To: [email protected]; RE-wrenches
Subject: Re: [RE-wrenches] helical screw piers
Wrenches,
We used a company called techno Metal Post (
<http://www.technometalpost.com>www.technometalpost.com ) I believe
it is a franchise arrangement with the main company in Canada. Here
is a business opportunity if a franchise does not exist in your community.
They are screwed into the ground while hydraulic pressure is
applied. We received a stamped engineering report after completion
that identified how many posts were set, to what depth and how much
hydraulic pressure had been applied for load bearing capacity
It requires a special unit designed for this purpose
We set 8 posts in 2 rows of 4 and then attached a UniRac U-LA Ground
Mount racking system for 28 Sanyo 200's
The posts in this case were 2" schedule 40 galvanized steel pipe
ready for the UniRac mounting system
They also shot the elevation and cut each pipe to the proper height
so that the relationship between the front row of pipes and the back
row of pipes was set to receive the racking system and then the
mounting rails would be at latitude for this site. We supplied the
heights that were required.
Many other uses for these screw piers. Pictures on their website
Larry
_______________________________________________
List sponsored by Home Power magazine
List Address: [email protected]
Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
Check out participant bios:
www.members.re-wrenches.org
