Designing to the wind speed is normally required for any structure that
requires a building permit including towers (but not antennas on the
towers). Designing to survive all kinds of flying debris is not practical.
Fortunately, you are talking about guyed towers, that even when a section is
destroyed, tend to collapse about their own base rather than fall flat. If
you destroy enough guys, anything is possible.
I live in a 70 mph wind speed area but have my tower designed for 110 mph.
I had a downburst during a storm in excess of 110 mph that took 45 sheets of
plywood off the house (with the metal roofing attached) and sent them over
3/4 mile away. Where they hit a series of 2 3/8 heavy wall pipe fence
posts, they sheared them off level with the ground. Anyone or anything in
the path would have been badly damaged. One large tree limb came through
the window and was inside the den. Another tree was uprooted and took out
my fence and mailbox over 200 feet away.
-----Original Message-----
From: towertalk-admin@contesting.com
[mailto:towertalk-admin@contesting.com]On Behalf Of Rob Atkinson, K5UJ
Sent: Tuesday, August 27, 2002 11:58 AM
To: towertalk@contesting.com
Subject: [Towertalk] Towers in Hurricanes
Hi everyone:
This is a question for the tower professionals (but of course anyone can
chime in).
The local newspaper's wx section yesterday had a writeup about Hurricane
Andrew since this was the 10th anniv. of its landfall. It stated that it
sustained winds of 165 mph with gusts of over 175 mph., when it hit Fla.
just south of Miami. As a ham I naturally thought first of the Miami area
commercial towers (was pretty sure ham antennas all blew down) and wondered
if they were built down there to make it through something like that? Are
commercial towers for tv and radio etc. built for something like that down
there or does everyone keep their fingers crossed and stay out of the way
downwind of the towers and get the heck out of town? I can't imagine
building a tall tower that could survive an extended blast of cat. 5
hurricane. Just wondering.
73,
Rob Atkinson
K5UJ
k5uj@hotmail.com
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