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

John WA2GO xnewyorka at hotmail.com
Thu Jan 13 07:53:59 EST 2005


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.

In case anybody here knows about these, here are some possibly relevant 
figures for each tower I need this figure for:

1) A 98' Rohn 25G, guyed for 90 mph at 95', 63' and 32' at a guy radius of 
80', with 33' boom on top antenna.)

2) A 108' Rohn 25G guyed for 90 mph at 105', 70', 35' at a guy radius of 
88', with 24' boom on top antenna.)

In both cases, assume 7 sq. ft. of wind load at top of tower plus 4 sq. ft. 
of wind load at 2/3 tower height and 4 sq. ft. of wind load at 1/2 tower 
height.

3) A 96' Trylon Titan freestanding with 4.5 sq. ft. at 97' on a 23' boom, 
4.5 sq. ft. at 67', and 4.5 sq. ft. at 37', plus 3.1 sq. ft. at 77' and 3.1 
sq. ft. at 47'.

If someone can tell me what the values are for the figures I need, or where 
I can look to find these figures, or how to calculate them myself, I would 
be very grateful!

John
WA2GO




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