"Rick (W-A-one-R-K-T)" wrote in message
news

I went to visit a ham acquaintance of mine today. He is putting up a
100-foot tower with a large HF beam on top, guyed in three places.

He is not fastening the base plate of the tower to the concrete base in
any way... the tower just rests on the top of the concrete base, and the
three sets of guys hold it in place.


Somewhere on the internet was a very detailed computer simulation of this.
The base is just made so it can not kick out. You have a bending force and
a shearing force on the base of a tower. If the base can wiggle some, it
will take more stress than if the base is bolted down or placed in cement.
It also gets on the climbers nerves when the tower does its shifting.

You can think of this as placing something in the sand or dirt like a yard
stick. Place it a couple inches in sand and it will bend way over , place a
couple of inches in a crack between some bricks that can not move and start
bending it at the top, It will soon snap .