Some screw anchors are pretty heavy duty and could easily hold an 80' ft
Rohn 45G tower. I imagine that you need some machinery to properly screw
them in and the pullout resistance should be tested. I would not use the
farm store screw in anchors.
John KK9A
To:"'TowerTalk'" <towertalk@contesting.com>
Subject:Re: [TowerTalk] Tower Guy Anchors
From:"Edward Sawyer" <SawyerEd@Earthlink.net>
Date:Fri, 8 Nov 2013 14:06:34 -0500
List-post:<towertalk@contesting.com">mailto:towertalk@contesting.com>
70 - 80 feet of 45G using screw anchors in ANY soil would give me the
willies.
If its "screw anchor" worthy of a load, then why not use 25G? If it needs
45G then, in my opinion, there is no business considering screw anchors.
Save your engineering money if its truly a 45G worthy load.
Ultimately, the proper anchor needs to withstand the pulling expectation of
the tower guy, This, in its simplest form, can be a heavy enough piece of
reinforced concrete that just sitting on the surface provides enough weight
to accomplish the job. Usually, the block buried in the ground is much
smaller and uses soil resistance and soil weight on the top of it to provide
some of the strength.
With that said, if I was seeing water filling in my anchor holes at the 18
inch level, I would assume that there was NO ground strength and either look
to find rock down deeper to drill into and cement in anchor bolts or use a
cement block big enough to provide enough strength through weight alone.
73
Ed N1UR
Built a lot of towers and an EE but certainly not a Civil/Mechanical PE.
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