On 3/28/2011 11:47 PM, Mike Ryan wrote:
> How do the legs of the tower drain while in dirt? Depending on whether you
> are in state that gets 'frosty' or not can also be a clue to the short life
> of a tower due to the dirt it's planted in. No way I would even consider
> that kinda' project. Unless...I could convince my mother-in-law to climb it
> that is. - Mike
This is what I do, I am not advocating others do it unless they decide
that is what they want to do. That is their decision.
I'm in Michigan where the ground is frozen solid for about 4 months out
of the year and two more months where there are lots of freeze and thaw
cycles. Freezing tower legs due to poor drainage has never been a problem.
First, this is a "Guyed tower" we are talking about, not one that needs
a lot of concrete to stay upright. Remember all the concrete does is
serve as a large enough plug to keep the tower from sinking or the base
moving sideways.
For dirt bases I now make my own. they consist of 1" or 1 1/4" solid rod
for the legs with 1/8" steel plate for the side plates.
Drainage. Depending on the base (I use bases with solid legs)The tower
legs have about a 1" clearance between the bottom tower leg and the top
of the base legs. The only towers I've seen with freezing problems were
from cobwebs in the legs serving as dams to stop moisture. That froze
and then more water collected on top of it. The other freezings were
from improper drainage of the base legs. I'd also seen legs rust off
right at the top of the concrete due to poor drainage or no crown on the
concrete.
There is no real secret to long tower life in dirt unless you count
keeping air away from the moisture and dirt interface.
BTW the sol around here is quite acetic.
Nor do you need soil tests or an engineering degree to know whether the
soil is adequate or not. Normally after the soil has settled you can
not move the base, or even pull it out of the ground using an 4 ton
engine hoist. IF you can move the base at all after two or three weeks
the soil is not adequate. I install the base plus one or two tower
sections, plumb it and let it set for a couple weeks, then check it.
For hollow base legs, (remember we used to set the tower base in
concrete rather than using pier pin base)
The legs must reach into a gravel or crushed rock base. by several
inches with dirt "on top" of that. ROHN even used to make a dirt base
for the 20 and 25G. If hollow those base legs *must* drain into crushed
rock just as if it were a concrete base.
In over 50 years of using dirt bases on "small" towers I've never had
one fail, nor have I ever had tower legs freeze, or rust. I have seen
poorly installed bases go to pieces because the ham though the light
soil or sand would provide enough drainage.
Climbing? I do not advocate any one climbing any tower where they are
uncomfortable climbing. I have taking towers with improperly installed
bases where the legs had rusted. I cut them off, set them on the ground
and set them in by several inches. With adequate guys the tower was a
solid as one set in concrete. I've climbed 90 footers set in dirt that
felt every bit as solid as those set in concrete. I've also tested a
few set in concrete and refused to climb them with the suggestion that
they just cut the legs and guys and dump it over. I climbed one that
was set in concrete, bracketed to a house, and guyed that almost got me.
One of the base legs was rusted through, but was not apparent in the
inspection. No problem, it's guyed and in concrete AND guyed anyway?
Well... while I was up thee at the top of the *3 story* house, I turned
around and felt the tower move. I grabbed behind me and by luck caught
the bracket with my left hand. It seems that the bracket at the top of
the house had broken as well. After getting two hams to hold the tower
in place against the house I climbed down and we just tipped it over
into the snow.
I am far more concerned about water trapped in tower legs due to spiders
or other critters. I once took a tower apart and dumped about a quart
of corn kernels out of each leg. There were several splits from
freezing in that one and one of them was within 2' of the top.
My 45G sets in several yards of concrete and each guy anchor weights
over 17,000#.
I would put neither that much weight or that much wind load on a 25G
even with a concrete base.
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of Cqtestk4xs@aol.com
> Sent: Monday, March 28, 2011 10:55 PM
> To: TOWERTALK@contesting.com
> Subject: [TowerTalk] towers in dirt
>
>
> In a message dated 3/29/2011 2:25:10 AM Greenwich Standard Time,
> k8ri-on-towertalk@tm.net writes:
>
> For up to a 50 or 60' 25 G I just use dirt and a dirt base. It's a
> guyed tower and all the base does it keep it from sinking or sliding
> sideways.
>
> NOTE: not all soil is suitable for a "ground base"
>
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> That is a scary thought. Who determines what is "suitable" and how is it
> determined by the layman. Compaction tests? Engineers? How acidic is the
> soil? etc., etc, etc.? It sounds a lot easier and safer to dump ready mix
> down the hole and do it right. 5 yds of ready mix (3000 lb) runs $80/yd
> down here.
>
> I've seen guys put a tower in dirt and a few years later it looks like
> something I wouldn't climb. Leave a tower section laying on dirt a couple
> of
> years in an average moisture location and you'll see what I mean. That's
> why guys raise them off the ground when storing them.
>
> Bill K4XS/KH7XS
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
> __________ Information from ESET NOD32 Antivirus, version of virus signature
> database 5995 (20110329) __________
>
> The message was checked by ESET NOD32 Antivirus.
>
> http://www.eset.com
>
>
>
>
> __________ Information from ESET NOD32 Antivirus, version of virus signature
> database 5995 (20110329) __________
>
> The message was checked by ESET NOD32 Antivirus.
>
> http://www.eset.com
>
>
>
> __________ Information from ESET NOD32 Antivirus, version of virus signature
> database 5995 (20110329) __________
>
> The message was checked by ESET NOD32 Antivirus.
>
> http://www.eset.com
>
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|