Rick (W-A-one-R-K-T) wrote:
On Mon, 01 Oct 2007 13:38:14 +0000, John Passaneau wrote:


I've seen profesonal towers put up that way, sorta. They had a single pin
that a hole in the flat tower base set over.


Hmmm... Now that you mention it, I recall that the base plate had what
looked like a capped tube rising from its center. Maybe that tube goes
down over a pin of some kind that was embedded in the concrete.

I'll have to ask him about that.


that would be what's known as a "pier pin" base, and, as noted, it
greatly reduces the torsional load on the tower. Whether the force
causing the tower to fail is torsional, I'm not sure. Guyed towers fail
by buckling from the compressional force exerted by the guys.
Obviously, putting another force on the tower in addition to the
compressive force is going to increase the load on at least some member
of the tower, and if failure of that member causes enough asymmetry to
get the buckle going, then it is an issue.