[TowerTalk] Tower Base rotated 5 to 10 degrees off correct bearings

[Grant Saviers]

I would avoid any fix that puts a torque on the tower.  TIA-222-F sec 
6.1.1.2 re tower twist - "No more than 0.5 deg in a 10' elevation change 
and no more than 5 deg entire tower".  So your guy locations may violate 
that rule.  IIRC, +/- one degree, maybe two is the standard for guy 
anchor position accuracy.  IMO (not a PE) a stiff adapter frame mounted 
at each level with guy attachments at the anchor 120 deg positions would 
work as well as the guys directly to the legs.  After all, a rotating 
tower has guys pulling at every possible angle with respect to the legs 
rather than directly bisecting the leg angles.  By "stiff" I mean 
something fabricated like 3x3x3/8 angle and hot dip galvanized since it 
is PJ4.  This is where I'd get a PE design/analysis for a tower this 
tall with a 24" face.  I'm not familiar with how the guy attachments 
work on AB-105, but attaching at a cross bar is the standard for R65.  
The fab, any welding, and HDG could happen in the USA.

Grant KZ1W

On 8/8/2017 22:10 PM, Richard Smith wrote:
> Asking for some assistance with a tower issue...
> I'm involved with some folks in building a station in PJ4. One of the first tower bases was accidently set in concrete in a position that it is rotated 5 to 10 degrees from its correct position in relation to the guy anchors. I'm hoping that there might be a good suggestion or two as to what might be a good fix or work-around.
> The tower is AB-105, and the base is a section of AB-105 set in concrete. The plan is to have the tower built up to 140 feet, with guys at 40, 80, and 120 feet.
> Some alternatives:
> If we "use as is", will the torque of the guy wires cause problems for the tower?
> Should we consider some kind of adaptor plate for the guy brackets to correct the situation?
> Are we stuck digging and pouring a new base, or new guy anchors, with the correct positioning?
> Any ideas will be much appreciated.
> Thanks, 73,
> Rich, N6KT
>
>
>
>     
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