When I say old, Blake, I mean like thousands of years ago, judging by the
geology. This is Karst country, and it is very uncommon to find that much soil
depth in one place; much of our front yard is 4-12 inches of soil over
limestone. Local hams often wind up running Hilti fasteners into solid rock
for guy anchors.
The sponginess in the spring is rainfall derived, and it is 75 feet away, not
at the tower base. I think it would be hard to describe this as much of a
departure from whatever Rohn thinks is normal soil. In any case, it's done.
73, Pete N4ZR
At 09:58 AM 1/16/2006, Blake Bowers wrote:
>You poured to Rohn Specs? Rohn does not spec that kind of
>soil, which is far from what Rohn does spec - "Normal Soil".
>I can't even imagine building a tower in an old river bed, with
>5 feet of spongy soil, without having a local engineer involved.
>----- Original Message ----- From: "Pete Smith" <firstname.lastname@example.org>
>Sent: Monday, January 16, 2006 7:43 AM
>Subject: [TowerTalk] Speaking of structure issues
>>I was out working at the base of my tower yesterday (97 feet of Rohn 25), and
>>was surprised to discover that the base concrete block - poured to Rohn specs
>>- is visibly tilted. Because I have a pier pin base, this isn't a big
>>concern - the hole in the base for the pier pin is more than large enough to
>>handle the misalignment - but I was wondering what would have happened if I
>>had used a rigid embedded base section. Maybe the concrete block wouldn't
>>The tower is in an old river bed, with about 5 feet of spongy topsoil, and it
>>gets pretty squishy nearby in the spring. Fortunately, a guyed tower base
>>isn't called on to take much but vertical loads.
>>73, Pete N4ZR
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