Hank,
There were three versions of the AB105 tower, the most
recent production was AB105C.
Diagonals for AB105C were constructed from 1 1/2" by
3/32" steel strip, stamped into a 90 degree angle, except
at the ends where the diagonals attach to the tower.
AB105C diagonals were marked G8A and G9A.
My micrometer measures 0.10 inches diagonal thickness,
because of additional galvanizing thickness.
Because the diagonals are critically important to AB105
strength, all military contracts for AB105C required
compressive load testing of the diagonals (on a random
sampling basis) to 1700 pounds compressive load.
The much older G8 and G9 diagonals used on 1950s
era AB105 (not AB105C) were fabricated of thinner steel
plate were not subject to contract requirements for
compressive load testing. I always destroy any G8 and
G9 diagonals I might encounter.
Here are the performance specifications for AB105C tower,
from the current manufacturer, Penntech International:
Max practical height with no additional loads: 280 ft
Max allowable bending momant at tower top: 20,000 ftlb
Max vertical guy span under max loading conditions: 35 ft
Width of tower face between CG of legs: 22.59 inches
Projected area of one face per lineal foot of tower: 0.5513 sq ft
Wind pressure per lineal foot of tower: 27.99 lbs (RS222A no ice)
Radius of gyration (least) of tower: 9.04 inches
Cross sectional area of one leg: 0.603 sq inches
Moment of inertia (least) of tower: 147.76 inches**4
Distance from center of tower to CG of leg: 13.04 inches
Section modulus (least) of tower: 11.33 inches**3
Section modulus of one leg: 0.171 inches**3 (least)
Radius of gyration of one leg: 0.560 inches (least)
Let me know if I can be of further assistance.
73!
Frank
W3LPL
donovanf@erols.com
 Original Message 
From: <kr7x@comcast.net>
To: <towertalk@contesting.com>
Sent: Thursday, August 05, 2004 5:41 PM
Subject: [TowerTalk] AB105 Diagonal
> Hello TowerTalkians:
>
> I need a favor from the list:
>
> I'm in the process of determing the capacity of and AB105 tower for a
building permit. I have a copy of the old TM for the AB105 but the
crosssectional shape and dimensions of the diagonal members is called out
2 different ways with different dimensions.
>
> I can determine that it is 13 ga. but the crosssectional shape and
dimensions are in conflict. Could a owner of such a tower please measure the
diagonals for me. I need verification of the thickness and the dimensions.
Is the shape stamped into a V , or an L or a U or what? A sketch would be
appreciated.
>
> Thanks for the help.
>
> Regards
>
> Lonberg Design Group, Ltd.
>
> Hank Lonberg, P.E., S.E.
> President
>
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 18003339041 with any
questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 18003339041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
