[TowerTalk] Fwd: Earth Anchors

[Hans Hammarquist via TowerTalk]

Be aware that the allowed load is a lot less when you load at an angle. I don't remember how much but side loading a screw anchor is putting strength in places not really designed for the maximum load.


I don't remember what type of screw anchors I am using but the pull-out-strength was quoted to be around #14,000 in dry, packet sand. The allowed side load was just around #1,000. Check the drawing as this is important.


Even if the resting load in a guy wire is only around #400 the load increased to several #1,000-s with the wind load. I believe the problem was the possibility of actually breaking the anchor.


It is very hard to get the right angle putting in an anchor but hand.


Good luck with your tower and best 73 d,


Hans - N2JFS



-----Original Message-----
From: N3AE <n3ae at comcast.net>
To: TowerTalk <towertalk at contesting.com>
Sent: Tue, Mar 17, 2015 5:06 pm
Subject: Re: [TowerTalk] Earth Anchors


Patrick's comments on a vector sum of forces is spot on. The real world is never
as simple as some of the drawings in catalogs. My terrain is uneven. Plus for a
variety of reasons I was not able to locate my anchors to keep all the guy
angles the same (for the set of guys at the same height on the tower). But if
you lay out your installation for each guy to-scale on some graph paper
(side-looking view) along with your terrain, you can figure out the angle with
respect to the horizontal that you need to place each anchor. The average of the
guy angles going to the same anchor (again, with respect to the horizontal) will
get you close to the angle you need to install the anchor at.