[TowerTalk] Using extra anchors

[Eric Schurman]

Enough people have told me now that the pivoting base idea won't work for a 
tower of this size that I have officially given up on the idea. Thanks! This 
is just the sort of knowledge I contacted this community for.

-eric


>From: Pete Smith <n4zr@contesting.com>
>To: "Eric Schurman" <eric_schurman@hotmail.com>
>Subject: Re: [TowerTalk] Using extra anchors
>Date: Sat, 05 May 2001 14:28:47 -0400
>
>At 05:42 PM 5/5/01 -0000, you wrote:
> >>The multi-point anchoring sounds like a very sensible scheme to me.  The
> >>potential for a single point of failure with one guy anchor per azimuth 
>has
> >>always concerned me, and your approach will certainly spread the load.
> >
> >Good!
> >
> >>Any possibility of getting power equipment in there to drive anchors?  
>If
> >>so, you could even use bigger ones.
> >
> >Perhaps-what type of equipment were you thinking of?
>
>Take a look at www.qsl.net/k4ja.  There is a picture in there of a guy with
>a bobcat-type minitractor with a special rig on it for planting guy
>anchors.  Your local utility company or its contractors must have such 
>things.
> >
> >>I would be more concerned about a mishap during the erection process.  
>All
> >>the manpower in the world won't do you much good at the start of the
> >>tilt-up process, because the angles are all wrong.  If they all get 
>under
> >>the tower, say 10 feet from the base, and push up, then there will be a
> >>terrific upward force on the tower base.  You would need to hold it down
> >>with several times the weight of the tower.  Even then, what happens 
>once
> >>they are all standing as tall as they can, with the tower over their 
>heads?
> >
> >Well, I was thinking of having people every ten feet or so along the 
>tower,
> >lifting, and then people pulling on the guys from the other side.
> >
> >>The only way I'd feel comfortable with this would be using a crane, but 
>I
> >>suspect that's probably not in the cards.
> >
> >Unfortunately not.
>
>Eric, what you describe will not work.  Visualize the situation -- the
>highest the top of the tower can get is maybe 15 feet, and at that point
>either the tower itself buckles or the base pulls up out of the ground.
>The people on the guys are pulling almost back along the axis of the tower,
>so almost none of whatever force they exert goes into rotating the tower
>upright.  90+ percent goes into tearing the base out.
>
>If a crane is no-go, then I think the only option is to do what N4KG says
>and build it from the ground up vertically.  I have 100 feet of Rohn 25
>that I personally built that way.  As long as you have a couple of climbers
>(to take turns) it should be doable in a day or two.
>
>
>73, Pete N4ZR
>Contesting is!
>
>The World Contest Station Database
>is waiting for your input at
>http://www.qsl.net/n4zr
>
>

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