Reg Edwards wrote:

"Richard Clark" wrote in message
...
On Tue, 17 Feb 2004 17:47:39 -0000, "Richard"
wrote:

I'm wondering about the spacings, A, B, C, and D.

Hi Richard,

You should be thinking more of the tensile failure of the brick mortar
leveraged by the moment of the load above. Chimneys are very strong
to compressive loads, and as brittle as candy to torsion.

The upshot of this is that on a windy night you may find the chimney
in your bed.

73's
Richard Clark, KB7QHC

========================

Better get in a stock of viagra.

Brickwork is weakest when under a tensile stress. So the chimney brickwork
is most likely to fail under tension due to sideways thrust of the wind.

Placing the chimney under torsion causes only a horizontal shear force on
the brickwork to which it is more able to resist.
----
Reg.

All this presupposes the chimney is brick.

Mine is cast concrete and has had a big TV antenna on it for years and
this is a high wind area.

There is a smoke and soot problem and I only run the fireplace a few times
a year. I wouldn't put an expensive ham antenna (or a rotor) up there.


--
Jim Pennino

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