----- Original Message -----
From: "doc" <kd4e@verizon.net>
To: "Tower Talk List" <towertalk@contesting.com>
Sent: Sunday, December 19, 2004 7:14 PM
Subject: Re: [TowerTalk] Rusty tower
> Keith Dutson wrote:
> > IMO restoring a rusty 25G is flirting with disaster. Depending on age
and
> > extent of rusting, you could be risking a lot climbing a tower like
this.
>
> Other than minor surface rust the presence of heavier rust could
> suggest non-visible interior rust that could lead to an unexpected
> collapse.
>
> Other than a costly fiber optic camera inspection how might one
> establish the interior integrity of used and rusty tower sections?
Proof testing...just like NASA does with cranes before lifting expensive and
irreplaceable things.
Bolt base to a rigid support, load the tower to twice the design load. (or
some other appropriate overload factor.. watch out for "overtest")
Horizontal loading might be easiest (i.e. tower section horizontal), but
maybe a scale and a winch or car pulling might do for vertical orientations.
The key is looking for a permanent deformation. You measure what the
deflection is, then load it, and assuming no failure, remove the load, and
see if it springs back to where it was before.
Jim, W6RMK
_______________________________________________
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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