[TowerTalk] split tubing in base leg

[Tom Rauch]

> >In aircraft we "stop drill" by drilling a small hole at
each end of the
> >crack, but welding is not an option there. However we do
the same with
> >plexaglass windows.  When drilling plexiglass though you
have to polish the
> >inside of the hole as even the scratches on the inside of
the hole are
> >enough to start cracks propogating.

> Thanks for the info on stop drilling, sounds rather
clever.
>
> With 3 guy levels I doubt there is much torsional force on
the base, most
> of it is absorbed by the guy-wires before it reaches to
bottom plate.

I doubt the crack will propagate anyway since it is caused
by water freezing and not other stress. This isn't a metal
stress issue, and it isn't a stress crack. Once the water
inside freezes one time it now has a drain slot. It's a 100%
"I didn't know how to install a tower" problem and that is
the worse part.

IMO drilling and welding just makes a bad situation worse.
You now know you have a tower with water collecting on the
inside of legs below holes or splits, almost certainly that
water will cause internal rust damage or splitting below the
concrete surface over the years. The split ruins galvanizing
on the edges of the split, and welding can only make things
worse by burning off more rust protection.

The worse part is since the sole cause of the problem is not
installing the tower base correctly, odds are very good
other things are also wrong. Like guy clamps that are
backwards, bad anchors, incorrect guy layouts, or excessive
wind loading.

This is 100% an installation problem.

73 Tom