[TowerTalk] Adjustments to Tower Base Pier J-Bolts

Jim Thomson jim.thom at telus.net
Mon Jul 24 10:20:44 EDT 2017

Date: Sun, 23 Jul 2017 19:41:20 -0500
From: "h.duck" <h.duck at ameritech.net>
To: "Dick Green" <dick at mailgreen.us>, "Paul Christensen"
<w9ac at arrl.net>, "'Grant Saviers'" <grants2 at pacbell.net>,
<TOWERTALK at contesting.com>
Subject: Re: [TowerTalk] Adjustments to Tower Base Pier J-Bolts


What you just said, I was going to suggest next.  If possible test the fit 
with the bottom section by itself.


<Regardless of what you decide to do, I'd sure want to check the fit of the 
base before and after any adjustments and before bringing in a crane. Can 
the base section be disconnected from the rest of the tower for a test? f 
it's too tall/heavy for you and a helper or two to lift (e.g., a 20-footer), 
you might be able to lift it into place with a bucket loader.

73, Dick WC1M

##  You folks realize this is a 140 ft tall  free standing Pirod ? 
Bottom legs will be a minimum of 2.5 inchs..and solid.   Typ
2.5  to 3.0 inches. Pirod is known for its solid legs. Im guessing 
base is 6-8 ft across, each face..maybe more.   Dunno if its in 10 or 
20 ft sections.  Either  way, the very bottom section is gonna weigh
one helluva lot more than you think.   1000-2500 lbs. 

## Those J bolts he is using, are massive... at  1.875 inchs across, with
12 inches  sticking above the concrete.  Paul  did not say how many are used on
each corner, probably at least 4.    They are not gonna budge, whether a sledge hammer, or
hydruaulic jack used...or trying to crank up on the lower nuts, trying to raise the template...
and then trying to bend the J bolts, not gonna happen.
He did not say what the template is made of,  nor how thick it is. Paul did note the base section,where 
the J bolts pass through are 3 inches thick.   How the heck  you are going to elongate the oem 2 inch 
diam hole in the base section is beyond me.   Even if its possible, you will want to spray it asap with some
cold galvanizing compound...since you just ripped the oem zinc off.  

##  those J bolts typ come in either  36 ksi yield strength, or 53 ksi, or 103 ksi.  Color coded
at the very top is how portland bolt does it.   Blue-Green- Red  for the 36-53-103 ksi material.   
I used the 103 ksi, Red, for my  12 x 1.125 diam  anchor rods for the HDX-689.  Rods are 6 ft
long, and  a 6 inch thread on each end.    9 inch square steel plates on the bottom of each group
of  4 x rods.   That 103 ksi material is rock hard stuff to work with. 

##  Paul calculated  3 inchs of exposed thread  above the top nuts.  A 1.875 threaded J bolt will require
at least a 3 inch wide socket....and super deep..and also a 3 inch open end wrench to hold the nuts below the 
tower base.   Each of the nuts are 2 inches thick, so any socket will have to be at least  3+2 = 5 inches deep.  
Those sockets  will only come in .750  or  1.00  drive variety. 

##  Thats a monster tower project he has taken on....and  two of em.   It would almost require a small crane to 
assemble the tower in the horizontal position..then a monster crane to lift it upright to the vertical position, then
lift, swing..and lower onto the myriad of 1.875 inch base bolts.   This is where you want multiple deep sockets, 
open + box end wrenches, tq wrenches, loads of help, etc.   Both my 1.625 and also  1.8125 sockets, both deep types,
are the .750 drive variety. I used a .500  to .750  drop in adaptor, so I could use my .500  tq wrench and also my
.500  corded electric and also .500  air impact wrenches.  You can also buy cordless tq wrenches with up to 600-700
ft lbs of tq.   Great when the commercial AC power goes out.... or you are up the tower...and  dont want to drag an
extension cord ....or air hose with you. 

##  IMO,  I would test fit the very bottom section by itself, onto the 1.875 bolts.  You may well be able to cut as much as 
3.5 inches off the tops of the offending  threaded rods.   Nuts below the tower base assy, need only be .5 inch above the
concrete.   At that point, the rods will be  8.5 inches above the concrete.   8.5  / 12 =  .71        .71 x .125 =  .089  
So if you do have to elongate the offending anchor base holes, it will not be very much,  .089 inch. 

Jim   VE7RF 

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