[TowerTalk] Screw Anchors

[Tom Frenaye]

At 10:42 AM 7/1/98 -0500, Raymond Dave-CSUS04 wrote:
>
>The biggest problem I've seen with screw in anchors has nothing to do
>with the "screw" portion pulling out of the soil.  I have witnessed one
>situation where the  welds that hold the screw to the rod failed. . .
>the rod pulled nicely out of screw, leaving the screw portion in place.
>Needless to say, the tower went down.  Fortunately, it was not mine.  

	Something else to consider with screw-in or concrete anchors...  I had one
	(screw-in) pull out during a modest hurricane (about 75 mph) several years
	ago.  Turns out that nice looking soil was fill from when the house was built
	in the 1950s - not quite what I should have used.  Fortunately, the tower
	(100' Rohn 45) leaned against a nearby tree and got tangled in my 80/160
	dipoles (using #12 copperweld).  The lean was only about 15% so it was
	eventually possible to put in a new concrete anchor and use a professional
	tower crew to readjust things.

   What caused the original anchor failure was a 4" branch that fell on a
lower
	guy wire (not the one that pulled out).  The tower leg buckled out about
3" and
	was curved outward for about 12".  The tower base shifted as well (small 
	crack visible about 2' out from the tower most of the way around).  A welding
   crew cut out the damaged section, put in a stronger piece and I primed and
	repainted it.  

    Insurance was very helpful.  No more screw-in anchors at this QTH.

				73 Tom
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e-mail: frenaye@pcnet.com
Tom Frenaye, K1KI, P O Box 386, West Suffield CT 06093 Phone: 860-668-5444

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