[TowerTalk] Tower "DROP ZONE" or "DROP RADIUS" for Rohn 25G &

[K7LXC at aol.com]

From: "John WA2GO" <xnewyorka at hotmail.com>
Subject: [TowerTalk] Tower "DROP ZONE" or "DROP RADIUS" for Rohn 25G &
   Trylon Titan?
To: towertalk at contesting.com
Message-ID: <BAY23-F20BFB0A611BD06BFF03C3AA58A0 at phx.gbl>
Content-Type: text/plain; format=flowed

> The Building Inspector is requiring my engineering drawings to specify what 
he is calling the "drop zone" or "drop radius" of the tower.  >He wants to 
see what is the radius of the circle it will all land inside when it all 
comes crashing down.  (perish the thought!)

> I couldn't find this figure in the Rohn catalog anywhere. The one engineer I 
talked to didn't seem to know about it either.

For the self-supporters just use their length; i.e. falling like a tree. It's not entirely accurate since most towers fail up the tower and generally not at the base but he just wants to know the fall radius.

For guyed towers they generally fall in circle approximately 1/3 of their height. There is a study cirulating that documents a bunch of guyed commercial tower failures and adds creedence to this. The reason they don't fall in a larger circle is because they're constrained by the remaining guy wires and fall in a big heap. I've got a copy of the study if you're interested. (I can't remember the guy's name that did it.)

Cheers,
Steve    K7LXC
TOWER TECH -
Professional tower services for commercial and amateur