Sorry Mike - just scrolled down further and noticed your follow-up post, and
that you need 90 mph figures not 70 mph figures.
Can't help you there....
Maybe plant some pine trees around the tower?
Another useful thing to consider is this: A freestanding tower is more likely
to "fall like a tree" (as opposed to a guyed tower, which collapses in a pile.)
So if you assume the tower will fall like a tree in the most undesirable
direction (which, after all, is exactly where it would probably fall anyway,
due to corollary 1 of Murphy's law), what damage will it do?
If it will cause no harm to life or property that is not your own, then whoever
is asking for the 90 mph drawings is just making you jump through a useless
hoop that doesn't protect the town or any of its other residents.
I wonder... if you were to assure them in writing in your application that if
the permit is approved you would hold them harmless and release them from any
and all liability if the tower falls for any reason, and that you are accepting
the risks associated with installing a tower whose rating at 90 mph is not
known, maybe they will accept that? I dunno - it's a stretch, but maybe you
want to ask the zoning officer if that would be acceptable, in lieu of making
the investment in getting the proper calculations done.
Then again, if you want to be able to sleep at night when it's howling like
gangbusters out there, then just bite the bullet and get the calculations done,
unless you are lucky enough to find someone else who has.
To: email@example.com; firstname.lastname@example.org
Subject: RE: TowerTalk Digest, Vol 108, Issue 25
Date: Tue, 6 Dec 2011 12:30:34 -0800
The HDBX-48 is rated for 18 sq. ft of Area, and 360 lbs. of Thrust.
The components are: BX3A, BX4, BX5, BX6, BX7, BX8, ACWS.
The base is 5'9" square x 4' deep, which requires 4.9 cu yds of concrete.
Source: 1979 Rohn Ham Tower Catalog.
TowerTalk mailing list