In a message dated 7/10/2005 10:39:28 PM Pacific Daylight Time,
towertalk-request@contesting.com writes:
> The ability to dig an "undercut" hole no doubt depends on the soil. I
gave a local concrete contractor the AN Wireless foundation plan, and he
said there was no way to dig such a hole. He said the only way to do a
pad and pier foundation around here would be to dig the hole the size of
the pad, construct a form the size of the pier, then backfill.
A couple of comments about the Trylon base design. First, IMO it's a
stupid design. I'm sure there's a valid engineering reason to have the bottom
belled-out but it's not only dangerous to be in a hole that deep but it's also
illegal per OSHA rules to be that deep in a hole without being shored up. This
was designed by an engineer in an air-conditioned office that never has to
install one of them. In many cases the soil won't allow it anyway.
Second, the design calls for 7 yards of concrete. Make the hole bigger
(usually happens when you use a backhoe anyway), put in a little more concrete,
and you're good to go. The Trylon design is one-size-fits-all so there's some
engineering overhead already built in.
Cheers,
Steve K7LXC
TOWER TECH -
A professional tower erector, not an engineer
Cell: 206-890-4188
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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