The entire AB-105C/FRC Technical Manual
is available online in PDF form at:
https://www.logsa.army.mil/etms/data/A/028953.pdf
73!
Frank
W3LPL
donovanf@erols.com
----- Original Message -----
From: Frank Donovan <donovanf@erols.com>
To: <towertalk@contesting.com>
Cc: <kr7x@comcast.net>
Sent: Thursday, August 05, 2004 7:49 PM
Subject: Re: [TowerTalk] AB-105 Diagonal
> Hank,
>
> There were three versions of the AB-105 tower, the most
> recent production was AB-105C.
>
> Diagonals for AB-105C 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.
> AB-105C diagonals were marked G-8A and G-9A.
> My micrometer measures 0.10 inches diagonal thickness,
> because of additional galvanizing thickness.
>
> Because the diagonals are critically important to AB-105
> strength, all military contracts for AB-105C required
> compressive load testing of the diagonals (on a random
> sampling basis) to 1700 pounds compressive load.
>
> The much older G-8 and G-9 diagonals used on 1950s
> era AB-105 (not AB-105C) were fabricated of thinner steel
> plate were not subject to contract requirements for
> compressive load testing. I always destroy any G-8 and
> G-9 diagonals I might encounter.
>
> Here are the performance specifications for AB-105C 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 ft-lb
> 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 (RS-222A 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] AB-105 Diagonal
>
>
> > Hello TowerTalkians:
> >
> > I need a favor from the list:
> >
> > I'm in the process of determing the capacity of and AB-105 tower for a
> building permit. I have a copy of the old TM for the AB-105 but the
> cross-sectional 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 cross-sectional 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, 1-800-333-9041 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, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
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TowerTalk@contesting.com
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