[TowerTalk] Tower failures

[Jim Lux]

At 09:46 AM 9/28/2005, Cqtestk4xs at aol.com wrote:
>In a message dated 9/28/05 4:00:52 PM Greenwich Standard Time,
>martin.ewing at gmail.com writes:
>Makes a difference if a Cat 4 hurricane is blowing! The demolition (in still
>air) seemed to blow the guy wires and possibly the base. I didn't see any
>explosions up the tower, though there may have been some. I think you could
>cause a controlled collapse by blowing the top guys on one side, the second
>set on another side, etc.
>Although it can vary, most of the pictures I've seen, as well as viewing in
>person support the concept of the tower not falling over like a 
>tree.  Unless a
>tree came across the lines, or the tower had guywire failure, or the base was
>undersized for a self-supporting tower, most of the towers kinda crumpled.
>Of course the trees, guywire failures and undersized bases add a prejudice as
>to having the tower lean over in one direction like a tree.

And even trees tend to break into pieces or have the base kick out in the 
opposite direction as they fall.

It's that moment of inertia thing.  All parts of the object are subject to 
the same force of gravity, but the angular acceleration of the top is 
higher, so there's a bending moment created.

Some 20yrs back or so, there was a Scientific American article all about 
why long skinny things fall like they do.

Jim