[TowerTalk] Tower Concerns continued

[Lonberg, Hank]

 Wes:

Remember though the exterior walls are designed to take the load spread out
over their full area, that is how the wind load is actually applies. The
problem with bracket loads is that they are applied in a relatively small
area and typically exterior walls are not designed for this.

Hank Lonberg P.E. / KR7X


-----Original Message-----
From: Wes and Linda
To: Mike Murphy; towertalk@contesting.com
Sent: 1/15/01 8:33 PM
Subject: Re: [TowerTalk] Tower Concerns continued

At 02:45 PM 1/15/01 -0500, Mike Murphy wrote:
>I have been watching this post for some time.  I can't help but wonder
if we
>are forgetting that an exterior wall of a house was never meant to take
a
>lateral load, especially from 30 or 40 feet of tower hanging over it.
An
>exterior wall is meant to support the roof, not a tower pushing and
pulling
>on it.

You better damn betcha that the exterior wall of a house is designed to
take lateral loads.  If you're worried about that (XXX) MPH wind blowing
against the tower and antennas what do you think is going on with the
flat
wall of the house.  The wall typically has a lot more square footage
that
any tower/antenna and is a "flat plate" with a higher drag coefficient
that
the round stuff in the antenna.

Furthermore, in a good windstorm, the walls are probably holding the
roof
down, not up.

I'm not advocating bracketing to a house. I would never do it to mine
and I
built it and it's way over engineered, but it happens to be stuccoed and
I
have enough cracking problems.

Nevertheless, don't forget the story of the three little pigs.

Wes  N7WS




>
>I have put up, taken down and serviced a number of towers.  And it
simply
>amazes me what hams "get away" with.  It may work for a while, maybe
>forever.  But if you need 110 MPH wind survival, put up a free standing
>tower that is designed for it.  Otherwise you are playing with fire,
not to
>mention taking a chance on pulling down part of your house.
>
>Michael Murphy - KD8OK
>
>
>>The bracket is over designed as much as I could.  Where it attaches to
the
>>house it is 5' long and it has three bolts that go through vertical
2x4.  I
>>have this backed up with a horizontal 2x4.  All of this including the
bolts
>>are stainless steel.  Several locals have agreed that this is done
properly
>>and I believe it to be a better bracket then the one Rohn uses in
their
>>bracketed towers.
>
>
>
>--
>FAQ on WWW:               http://www.contesting.com/FAQ/towertalk
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>
>
>


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