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RE: [TowerTalk] Concrete Base?

To: <WW5L@gte.net>, <k2qmf@juno.com>
Subject: RE: [TowerTalk] Concrete Base?
From: "Hank Lonberg" <kr7x@comcast.net>
Date: Sun, 14 Nov 2004 11:11:24 -0800
List-post: <mailto:towertalk@contesting.com>
That was a good thing to do.

My standard specifications for concrete work requires that:

Flat work - slabs and  foundations can be stripped after 7
days of curing and loaded with component dead load only.
Full loading to be allowed after 28 days.

Vertical and elevated work - columns, beams and elevated
slabs stripped after 14 days with component dead load only.
Full design loading after 28 days. Stripping and dead load
can be applied earlier if concrete cylinder tests indicate
that the concrete has cured to 67% of its design mix
compressive strength (typically after 10 to 14 days.)

Note: I also specify that test cylinders be take for 7, 14
and 28 day breaks based on ACI-318 rrequirements.

Now you can do what you will if no inspection requirements
are is force, but if it were me, I would wait at least 7
days.

Regards

Lonberg Design Group, Ltd.

Hank Lonberg, P.E.,S.E. / KR7X
President


-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Tom
Anderson
Sent: Sunday, November 14, 2004 9:44 AM
To: k2qmf@juno.com
Cc: towertalk@contesting.com
Subject: Re: [TowerTalk] Concrete Base?

Ted:

When I put in the 4x4x6 base  for my freestanding WT51 TriEX
crankup 12 
years ago I let the base cure a month and periodically
sprinkled it with 
water to keep it from drying out too fast (since I put it up
in the 
middle of a hot Texas summer) and developing cracks.
Previously when I 
put up 40 ft of Rohn 25 at another QTH I let the base
(3x3x3) dry a 
couple weeks since the 40 ft. tower would be bracketed to my
house. 
Either way I sprinkled the concrete a couple times a day
just to keep it 
from drying out too fast.  With the Rohn I also attached the
first 10 
ft. section the the 3 foot base and roped it off to the
fence and patio 
so it would remain plumb throughout the drying process.
Also with the 
Rohn I put in a layer of river rock gravel at the bottom of
the hole so 
the tower could drain any condensation into the ground and
not collect 
inside the tower legs and cause corrosion.

Tom, WW5L



k2qmf@juno.com wrote:
> Hello All,
> 
> I have a question regarding tower base concrete.
> 
> How long should concrete cure after pouring to
> be safe to install a crank-up, tilt over tower???
> The mix is 3500 psi.
> 
> Many Thanks in advance.  73,  Ted  K2QMF
>   
> 
>
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_______________________________________________

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.

_______________________________________________
TowerTalk mailing list
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_______________________________________________

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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