If these are the Chance style anchors, as I recall there is a chart that
shows pull out force by type of anchor (size and number of helices on it)
and soil type, given that the anchors are screwed in to a given torque
value. I think the spec is force along the axis of the anchor. They can be
very strong if properly installed, but that is normally done by a trained
installer that sells the anchors.
73 John N5CQ
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Gene Fuller
Sent: Saturday, November 14, 2009 3:02 PM
To: donovanf@starpower.net; towertalk@contesting.com
Subject: Re: [TowerTalk] New Tower installation
Hi Rex -
Another two cents worth -
A four foot shank sounds a bit short, even though installed at a 50 degree
angle it still has to pull tthrough 4 feet of earth. Remember that closer
to the surface the soil is not as compact and would offer less resistance
than deeper. If, including some of the tower, the effective surface area
would be at least 10 square feet, at 30 psf wind pressure you would have a
300+ lbs horizontal force, which, translated down to a 50 degree guy angle
would look more like 400-450 + lbs, again, perhaps a challenge for a 4 foot
anchor rod only 3 feet deep - especially since 30 pfs may be on the light
side and higher gusts, and a bit of pumping. I agree with Frank - 6 foot
minimum.
Gene / W2LU
----- Original Message -----
From: <donovanf@starpower.net>
To: <towertalk@contesting.com>
Sent: Saturday, November 14, 2009 2:10 PM
Subject: Re: [TowerTalk] New Tower installation
Rex,
Four feet is unusually short for a guy anchor. When you set that anchor in
at an angle, as you must, it will be buried less than three feet below the
surface. An appropriate anchor should be at least six feet long.
73
Frank
W3LPL
---- Original message ----
>Date: Sat, 14 Nov 2009 13:52:20 -0500
>From: "Rex Lint" <rex@lint.mv.com>
>Subject: Re: [TowerTalk] New Tower installation
>To: <towertalk@contesting.com>
>Cc: "'Michael Ryan'" <mryan001@tampabay.rr.com>
>
>
>DAVE,
>
>..."or do I need to angle them at 50 deg. as stated in the Rohn
>spec's."
>That should be taken as the answer... if it didn't make any difference,
>they
>wouldn't specify it. Don't forget LXC's maxim - do what the manufacturer
>says.
>
>I once climbed a tower where the guy rods were put in sticking STRAIGHT UP.
>I won't do THAT again - it wobbled like a noodle.
>
> -Rex-
>
> K1HI
> Rex Lint
> Merrimack, NH
>
>
>-----Original Message-----
>From: towertalk-bounces@contesting.com
>[mailto:towertalk-bounces@contesting.com] On Behalf Of Michael Ryan
>Sent: Saturday, November 14, 2009 1:11 PM
>To: 'Dave'; towertalk@contesting.com
>Subject: Re: [TowerTalk] New Tower installation
>
>I would install at an angle, if not sooner or later they are going to want
>to lean in the direction of the tower at the angle they were supposed to be
>installed at in the first place. You will constantly be re-tightening your
>guy wires. - Mike
>
>-----Original Message-----
>From: towertalk-bounces@contesting.com
>[mailto:towertalk-bounces@contesting.com] On Behalf Of Dave
>Sent: Saturday, November 14, 2009 1:01 PM
>To: towertalk@contesting.com
>Subject: [TowerTalk] New Tower installation
>
>I have just put up a Rohn 25G. My question is, and I haven't researched
>the
>archives due to the interest of time before the snow blows. Can I use the
>3/4" x 4' screw anchors with 6" blade to secure the tower with out using
>cement. If I just screw them in all the way straight down, no angle, will
>they hold, or do I need to angle them at 50 deg. as stated in the Rohn
>spec's.
>I would like some feedback on this way of doing it. These things are
>suppose to hold trailers down. Are they reliable enough for the tower.
>Wind load on the only beam is 6.9 sq. ft. with a 10' 2" mast.
>
>Thanks, Dave
>_______________________________________________
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