Pete,
I made a lot of simulations for various wind conditions and found out that my
tower, unguyed, was going to safe sustain wind up to 85 mph with a surface area
of 20 sqft. As the wind, frequently, reaches that value where I live, on a
hilltop in Southern Vermont, I simulated the possibility of adding guy wires.
That increased the safe sustained value to 135 mph. So, against all advice, I
have a guyed tower that can be unguyed. I don't know where this misnomer comes
from that a self-supported should be weaker if you added guy wires. Maybe
somebody can tell me. I understand if the guy wires have a very steep angle the
load on the tower will increase but that is not the case with mine.
Hans - N2JFS
-----Original Message-----
From: N4ZR <n4zr@comcast.net>
To: TowerTalk <TowerTalk@contesting.com>
Sent: Tue, Apr 9, 2019 11:21 am
Subject: Re: [TowerTalk] Fwd: Tower foundation and bedrock
Was your tower guyed or unguyed? Makes a lot of difference in the
loading on the base. I gather Chuck's would be unguyed, and that
suggests to me that he needs to be very sure of the quality of the
rock. Limestone can be strong or weak (decomposed). A weird example -
50-some years ago, I lived in Hong Kong, right after they built a new
cruise ship terminal. It had two levels, independently supported on
separate columns, and within months of its opening they discovered that
the second level was driving its columns down into the stone at about 8
inches a year. In about 25 years there would have been 6 inches of
headroom on the first floor.
73, Pete N4ZR
Check out the Reverse Beacon Network
at <http://reversebeacon.net>, now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.
On 4/9/2019 8:53 AM, Hans Hammarquist via TowerTalk wrote:
> Hi Chuck,
> Bedrock is, I believe, the best to anchor a tower in. Just make 100% sure it
> is bedrock you have where you are erecting the tower. When I was planning for
> my tower a (big mouth) "friend" of mine told me where to find bedrock. He
> pointed out a spot that was 100% bedrock. He even "tested" it by kicking on
> it with his boot. Well, the "bedrock" turned out to be a relatively large
> rock, ~100 lb but there was no "bed-" with it. I'm just happy I checked
> before I spent the time to attach anything to the rock. I, instead, dug down
> 5 feet, placed a 6'x6' granite block (that just happened to lay around on my
> property), and attach my tower to that. As I also had a ton of scrap metal
> laying around, I placed that on top of the granite to add some extra weight.
> I used 6 galvanized angle irons attached to the granite block with 12
> bolts-and-nuts. The bolts all go through the block. The angle irons are
> encased in concrete. I felt I didn't have to add any yards of concrete for
> this installation. It has been a few years now and nothing has moved.
> 73 de,
> Hans - N2JFS
>
>
> -----Original Message-----
> From: Charles Lind <cxl24@case.edu>
> To: TowerTalk <TowerTalk@contesting.com>
> Sent: Sun, Apr 7, 2019 7:41 pm
> Subject: [TowerTalk] Tower foundation and bedrock
>
> I have the opportunity to put up a TX-455 tower on the property of my
> brother-in-law: 200+ acres and no zoning issues. He says, however, that
> there is limestone bedrock about only three feet down. Before I start
> Digging pilot holes, is there any advice a how to proceed with providing a
> solid foundation if this is the case.
>
> Tnx, Chuck, N8CL
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|