Got a nasty situation here that needs some brain power to resolve. Earlier
this year, I poured two base piers for a pair of Pirod self-supporting
towers. The 140 ft. tower base has the problem. Unfortunately, the base
J-bolts on two of the three equilateral triangle points are bent inward,
toward the base center by 1/8". That 1/8" may not seem like much, but it
is. In fact, the template used during the pour cannot be removed. During
the pour, the J-bolts were double-nutted, one on top and the other below the
template. Still, the force of the concrete pour managed to push out the 6
ft. J-bolts. As that was settling, I quickly moved the crew to the other
tower as sunset was minutes away. I did not go back and take a level to the
bolts, thinking the template would keep them perfectly straight.
Each 6 ft. bolt is exactly 1-7/8" in diameter. Each protrudes 12" above the
concrete surface. Moving these huge bolts even 1/8" will take a Herculean
effort. The template holes are the exact same diameter and made that way to
minimize shift of the type that occurred anyway. The tower base section has
mounting holes that are exactly 2.0" in diameter. So, there's just a small
amount of wiggle room. If we can get the template off, then I know that the
tower base will absolutely go on without trouble.
Some options:
1) Use an oxy-acetylene torch and apply heat at the point where the J-bolts
exit the base, then pound with a sledge hammer. Trying it now without heat
is futile; we've tried and the bolts are going nowhere. I have no idea what
heating will do to the strength of the J-bolt.
2) Use a telescoping hydraulic cylinder (a.k.a. hydraulic ram jack) to push
the two J-bolts against each other since they are both leaning in by the
same amount. What I don't know is how much adjusting precision I'll have
when expanding the cylinder. Do these things move in very small increments?
What cannot occur is the cylinder "jerking" the bolts to anything beyond
1/8". These cylinders are capable of pushing 30,000 lbs. and are typically
used on large earth-moving front loaders.
I'm open to any other ideas.
Paul, W9AC
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Rudy
Bakalov via TowerTalk
Sent: Saturday, July 22, 2017 9:10 AM
To: TOWERTALK@contesting.com
Subject: Re: [TowerTalk] 80 M 4 SQUARE MODELING
I am in the exact same situation- 95' tower that I plan on using to suspend
wire elements from the top of the tower.
I assume THERE WILL BE interaction between the 4SQ and the tower. What I
have been wondering is how mechanically reliable this setup is compared to
elements made of aluminum tubing. Any thoughts on this?
In addition, I have been wondering if the wire will stretch over time
thereby changing the resonant frequency of the elements. Perhaps CAT5 might
be a better option for the elements as it is less likely to stretch?
Rudy N2WQ
Sent using a tiny keyboard. Please excuse brevity, typos, or inappropriate
autocorrect.
> On Jul 22, 2017, at 8:43 AM, StellarCAT <rxdesign@ssvecnet.com> wrote:
>
> Now that I have finished my tower for 40-10 meters I need to start my next
project. I'm limited to the one 90 foot tower I have by county code. I am
planning on running 4 ropes from the last guy point (84ft) to install a wire
4 square for 80 meters. Wires would be suspended vertically from the ropes
in a typical 4 square pattern using Comtek switching.
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