I still consider that your post contains statements that are essentially
meaningless, because they relate to loads in terms that do not directly
relate without more explanation and definition.
My career was as a Rocket motor designer, and , of necessity, included a
working knowledge of material properties and how they relate to applied
loads. My problem with your statements is that there is no meaning to the
phrase "shear strength" without knowing how the loads are applied. The
primary loads on a guyed tower are compressive and tensile; on an unguyed
tower, bending becomes more important. In a tower, the applied loads are
compression and tension, with shear being induced, not directly applied. The
resistance to shear in a complex structure is different for different parts
of the structure, and can not be determined if the point of force is not
given, with respect to the geometry.
When a climber hangs on a tower, the total load is his weight, but the
stresses are distributed differently if he is in line with a 'point' or a
'face'; to determine factor of safety, one must know where he is. This is a
At one point in your answer you claim that you have just stated the facts.
To be a useful fact, the statements you made need more clarification. Where
did the shear strength statement come from, and did it originally
come with a definition?
----- Original Message -----
From: "Richard Elizondo" <email@example.com>
To: "Bill Aycock" <firstname.lastname@example.org>; <email@example.com>
Sent: Monday, November 24, 2008 11:24 AM
Subject: Re: [TowerTalk] Climbing and working on Rohn 25g/45g towers -
> The strength of the section is made up of its parts. If the section fails
> provide a 5000lbs anchor point, in no way will any of the welds, legs or
> lattice, provide it either.
> I am not stating the 25g tower is worthless. I actually quite fond of this
> tower and own several gin poles that are made of 25g, 45g and 55g
> What I have stated are just the facts. Like it or not, take it to heart,
> with a grain of salt.
> Ever wondered why Rohn used to make comments about climbers being less
> 250lbs in their field erection manuals ? (Hmmmm ...250lbs ...10-1 safety
> factor for positioning.... I must not know what I am talking about.)
> Seriously though however, I am open to discussion on what you see as
> erroneous in my post, since it is the same lecture given in all comtrain,
> belltech, and Radian fall protection classes.
> ----- Original Message -----
> From: "Bill Aycock" <firstname.lastname@example.org>
> To: "Richard Elizondo" <email@example.com>;
> Sent: Monday, November 24, 2008 8:31 AM
> Subject: Re: [TowerTalk] Climbing and working on Rohn 25g/45g towers -
>> This Whole post contains a major flaw that makes the real part
>> The statement about the strength of 25g is worthless, because the shear
>> strength is not define with respect to direction and method of loading,
>> is not related to the type of load applied by a falling body.
>> If the loading is cleared up, the rest might be germane.
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