When the tower is vertical the wind will exert a force, in which the
critical factors are wind speed and area of steelwork presented to the wind.
When the tower "lays over" gravity exerts a force on the mass of the tower
(plus aerials, rotators etc).
Given the variables of wind speed, tower size, aerial array etc, the
original question can't be answered without much more info.
However, I have a Versatower here which "lays over" at about the 6ft height,
and it is held down by four epoxy anchors. It's been in position for around
15 years.
I chose the epoxy anchors when I learned that the same fixings were used by
the highway authority to fix safety fence (crash barrier) to bridges.
It's tough work drilling the holes (you should worry if it is not), and
crucial to make sure the hole is free of dust and moisture.
John G4ZTR
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
K7LXC@aol.com
Sent: 21 June 2013 18:26
To: towertalk@contesting.com; wk1w@ivanshapiro.com
Subject: Re: [TowerTalk] Tower Replacement - what would you do?
>> K7LXC wrote:
>> Installing just about any kind of base in an existing base is easy.
Just
rent a rotary hammer and coring bit and drill new holes for your new anchor
bolts. Use industrial epoxy to glue them in and you're good to go.
> I wanted to ask Steve the following about this post:
> Steve: I imagine you would not recommend the above for a tower that
lays
down, like a US TOWER HDX series. The vector forces would be quite
different from a strictly vertical that doesn't lay down. Am I correct?
No. Not being an engineer I can't comment authoritatively. But I
suspect the forces on a tower that's being lowered from vertical to
horizontal
is significantly less than the same tower vertical in a big wind. The
anchor
rod epoxy is stronger than the concrete so I don't see any reason why you
couldn't do it.
I've used the above technique many times and I think that all of the
towers of interest for this were crank-ups.
Cheers,
Steve K7LXC
TOWER TECH -
Professional tower services for amateurs
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