[TowerTalk] 10 inch tube 100ft wind load? NN7J

[Jim Lux]

At 10:29 AM 8/31/2006, Robert Chudek - KØRC wrote:
>Dan,
>
>You can put your numbers through the WD9P mast calculator and see what you 
>get, Here's the URL:  http://www.math.niu.edu/KARC/mast/
>
>Free standing rotating tower systems like this have been engineered by 
>HyGain (I think) and were called "Big Berthas". I knew of 3 installations 
>in Minnesota, but nothing more. I'm sure other TT members can jump in with 
>facts, figures, and stories about these types of installations.

This kind of structure is actually fairly common for things like 
advertising signs and highway illumination, so I would imagine there are 
(expensive) cookbook products out there.  Going to a 1/2" wall thickness 
would make the mast alone weigh several tons.  A typical "high mast 
lighting" pole of 100ft (which is far from the highest.. apparently, 200 ft 
is typical in Texas) from Millerbernd is about 5400 lbs, 7.5" diameter at 
the top, and 24.4" at the bottom.  From the dimensions, you could probably 
figure out the wall thickness.

A tapered mast with 20 foot sections welded up would also probably be a 
decent idea.  Greatly reduces the weight, while probably being stronger 
overall.

You can even get them in "spun concrete", whatever that is: 
http://www.stresscrete.com/