Because I live near a river, I want to make sure I'm safe in the event
of a major flood. I plan to build a tower and want the floor of my
tower 50 feet off the ground. I will not attach it to the house in
case the house is destroyed by the flood. The tower will be free
standing in the back yard. I plan to make the top a small room 12 x
15 feet with a gable roof. Inside will be all the things necessary
for survival. There will be cots, blankets, clothing, canned food, a
small refrigerator, propane cook stove, cooking supplies, a portable
toilet, a generator, first aid supplies, and anything else I can think
we may need. There will also be a tank filled with 500 gallons of
fresh water, plumbed to a sink.
I plan to build the frame this week, but I have run into a snag. For
the four posts, I wanted to buy four 53 foot treated 4x4 posts. (3
feet goes in the ground). I had a feeling they did not sell them that
long, but I thought I could buy two 28 footers (for each post), and
nail some of those truss plates on them to attach them together. But
it turns out that the longest ones they have at the lumber yard are 16
foot. This means that I have to attach three 16 foot and one 5 foot
4x4's together for each post with truss plates.
So, my question is this: After I nail the truss plates on all four
posts, and stick them in the holes I dug in the ground, how do I keep
the posts from tipping when I put my ladder against them to nail on
the 2x6 floor joists? I have a feeling they will lean, and then I
can't nail these joists because the pole will be leaning. I have to
take two 30 foot ladders and tie them together to get to the top, and
that means there will be a lot of weight against the posts with the
weight of the ladders and my 270lbs body weight, plus tools and boards
that I take up with me.
I was thinking of buying a 100 foot clothesline rope and tying it to
the top of the post and tying the other end to the bumper of my car,
but I'd have to go to the top of the post first to tie the rope. That
sort of defeats the whole purpose.
Anyone have any ideas?
This sounds so unworkable that I suspect this is a troll. 4 posts
appears to me insufficient to support what amounts practically to a 180
square foot house 50 feet up. So much stuff on a tower having 4 legs
going only 3 feet into the ground sounds to me like a 25 MPH wind, maybe
even a 20 MPH one, can blow it down. I would also wonder about this thing
continuing to stand if a flooding river reaches these posts.
Does your tower design have crossbeams in some sort of triangular /
angled pattern to keep the tower from bending, twisting or slanting?
(Keep in mind that most radio towers have 3 spines rather than 4.)
Then there are FAA regulations. IIRC, if your tower (including
what it supports, including radio antennas and lightning rods) protrudes
more than 10 feet above prevailing rooftops / treetops, then it is subject
to FAA regulations. It appears to me that you will need to apply for a
permit. And, it is probably your job to determine what lighting is
required (choose among suitable lighting units named by mfr and model #
that have the necessary approval). Along with a similar need for an
uninterruptable power source for the lights.
Along with some advanced lightning protection (passing along AC power
but blocking 10's or 100-plus kilovolts of an incompletely-shorted-to-
ground lightning strike). One keyphrase for something you may need:
"ring rransformer". That is basically an air core transformer made of 2
coils of wire, with sufficient number of turns and wire thickness and
overall size to work at 60 Hz. They are not efficient, but they do the
job that they are intended to do.
Furthermore, you have to comply with your local building code including
a possible carpentry code in itself. You likely need to get a building
permit and to get the whole thing approved by a building inspector who
will probably be hostile to such a thing.
One more thing - your homeowners' insurance will almost certainly need
this tower to be declared, especially if its distance from your home or
publicly accessible walkways or anything else where an impact could
result in a claim is close to or less than its height (including the
height of the 180 square foot house on top). That will almost certainly
require a severe change in terms of your insurance policy, likely
including and also not limited to a large premium increase. Otherwise,
you are at high risk of having your policy cancelled or your insurance
company finding a way to either refuse a claim or successfully sue you to
get it back.
And why 50 feet? All the newsworthy river floods that I ever hear about
involve floods less than 20 feet above "flood stage"! Something like 99%
of the newsworthy river flooding problems I hear about involve flooding
no more than 12 feet "above flood stage"!
- Don Klipstein ( firstname.lastname@example.org)
I think it is a troll, as well- why else mention the 3-foot depth of the
posts in the ground?
Read a few books about engineering and flowing water first. First stiff
wind or wind-driven water surge will lay the thing over. 8 pounds per
gallon, 65 lbs per cubic foot (or thereabouts) packs a lot of kinetic
energy. Foot-deep flowing water can knock over a strong man, if it is
moving fast enough. Add in floating debris, and the problem gets even
worse. Debris either acts as a missile, or it build up against the
structure and increases the sail area, loading the structure even more.
Remember, floods also usually come with high winds, other than maybe
spring snow melts.
Unless they have a reinforced concrete structure on a solid foundation,
with an upper floor well above flood stage, only fools try to ride out
an active flood. Even in the coastal areas with raised houses, they
still get the hell out. The blowout panels and raised utility balconies
are just to reduce the damage if the house doesn't get swept away. And
their dozens of pilings go as deep as they can realistically shove them
into the ground.
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