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[TowerTalk] Leaning Tower

To: <TowerTalk@contesting.com>
Subject: [TowerTalk] Leaning Tower
From: "Wilson Lamb" <infomet@embarqmail.com>
Reply-to: Wilson Lamb <infomet@embarqmail.com>
Date: Sun, 17 Apr 2011 15:31:28 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
That's a fun one!
I expect the dirt back there is fill, or maybe fill on one side.
Is your wind from a narrow range of direction?

I'd think about a slow correction.
Can you get purchase with a come along in th edirection opposite the tilt? 
If so, go a few feet up the tower, maybe 10, and pull with the come along. 
Not hard, just a few hundred pounds.  That will put a few thousand pounds of 
righting moment into the foundation and may be enough to get it to creep 
back in the right direction.  I'm talking weeks here, but you aren't in a 
hurry.

Once you get the bind on the come along, make a jet pipe with a piece of 
small pipe, maybe 3/8", and poke it down along the concrete on th eside 
where you are pulling.  The idea being to liquify the dirt a bit so it will 
make it easier to pull the concrete back into place.

That's where I run out of ideas.  You should probably strengthen the other 
side, but aside from a hydraulic tamper I don't know how you'd do it.

It would look a little funny, but you " could" put a rigid support from the 
ground to the top of the first section.  I've seen it done with telephone 
poles.

Is the soil around the tower well drained?  If one side of the base is kept 
fairly dry by the house and the other side is soaked by rain or irrigation 
it might cause some differential expansion of the dirt or weakening on the 
wet side.

Please use judgement with the comealong.  I'm not even guessing how much 
force you should or could apply.  I do know that the overturning moment at 
design load is tens of thousands of foot pounds, so it seems reasonable to 
put a fraction of that on with the comealong.  I expect the weak point will 
be the attachment point to the leg, so maybe you should pull against the 
opposite side, maybe even on all three legs, to spread the force among the 
members.

No doubt someone here has tried this and will fill in the blanks.
Wilson
W4BOH 

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