[TowerTalk] TowerTalk Digest, Vol 47, Issue 7

[Dudley Chapman]

Message: 2
Date: Thu, 02 Nov 2006 20:49:13 -0600
From: "John Barrett" <ke5crp at verizon.net>
Subject: [TowerTalk] Homebrew Tower for 500lbs load help needed
To: <towertalk at contesting.com>
Message-ID: <03ef01c6fef2$a792bbf0$0a00a8c0 at zombie>
Content-Type: text/plain;	charset="iso-8859-1"

I'm looking to design a freestanding tower that can support up to 500lbs of
load at 50 feet with a wind loading of approx 40 sqft and 100 mph
survivability. Guy wires are not an option for the location we must use. I
have a few problems to solve and am not finding much in the way of
references online to work out all the details. 

1> what kind of pipe/tubing to use (diameter/thickness) -- assuming that the
"mast" will be a single run of pipe (welded and reinforced with smaller tube
inside at the joints if needed).. This has to be able to support the 500lbs
dead weight load in the tilt-down position if a tiltover is recommended.
Stepping the pipe size down as we get higher is ok (unless a carraige setup
is recommended)

2> footing recomendations -- how wide a hole and how deep ? 

3> should I look at a tilt and crank-up design to reduce the stresses when
raising/lowering the tower ?? or perhaps a "carraige" design where the load
is pulled up the tower after it is erect ??

This is obviousy overkill for an antenna tower :) and while there will be
antennas on it., it will mostly be used to support a wind turbine. (that is
until I build the 2nd one to support a stacked beam :)

now I just need the references or some advice to work out the rest :)

------------------------------


John,
    There was an excellent article in Ham Radio magazine back in the 80s on
just this subject.  It contained construction advice and a simple method for
determining the length of each section, given the weight and wind loading
considerations.  I included a derating table for used steel tubing.  I am
sorry I don't have the reference at hand.  I am hoping someone on the list
will have that article handy.  

Regards,
Dudley - WA1X