[TowerTalk] Climbing and working on Rohn 25g/45g towers -

Mon Nov 24 15:52:20 EST 2008

 Al

 Well I am not an " Engineer" either but have spent many an hour elevated  above the terraferma hanging from welded and or bolted together Tower /structures. 

IMHO Richard made some clear precise points that should be observed while venturing aloft.

Frank W3LPL also shared some basic mild carbon steel  weld sheer facts.

Every aspect of climbers position in relations/angle to the stress and also the type OD steel and filler rod used. let alone the penetration of the weld it's self, These variables could be examined and debated for hours.

 Any  tower safety BASIC info shared  IMHO are words to live  by or ignore and DIE or be injured by
 What have I gleaned from this thread,      NEVER use the welded Z-bar on welded lattice  or bolted cross brace AB105) tower as a anchor point for your fall arrest lanyard.
 The Fall arrest lanyard attachment hook to be positioned not at some easy place like your waist/chest level, but the your positioning lanyard be extended above you as far as possible to minimize drop if it's to be uses to save your life and limit the shock from sudden stop.

 The fall arest safty hook encompassed the vertial support tube of angle slides down to stop at not one but two whelded or two  bolted cross braces. the shear failure forces are no  about doubled.

 Wayne W3EA   
> Date: Mon, 24 Nov 2008 15:11:01 -0500> From: ke1fo at arrl.net> To: baycock at hughes.net> CC: relizondo at ionoscom.com; towertalk at contesting.com> Subject: Re: [TowerTalk] Climbing and working on Rohn 25g/45g towers -> > What is difficult in this entire conversation for me is that I'm not an> engineer - I'm trained as a manager and I'm an amateur radio operator by> choice. You can talk about specs and theory all you want. What I need to> know is where do I connect my fall arrest lanyard. It seems to me that no> matter where you connect to on xxG tower you're connecting to a cross> brace. If I connect directly on the cross brace, obviously I'm on the cross> brace. If I connect on the tubular vertical member and I fall, the force> still rests on the z bracing where it is welded to the vertical tube.> > So, how does one safely connect their fall arrest lanyard on xxG tower?> Must it be connected to multiple legs to be safe?> > A pictoral tutorial of this information would be helpful. My knot book with> diagrams, pictures and drawings is invaluable to me - is there such a thing> for tower rigging and climbing?> > 73 de Al, KE1FO> > -----> Visit my amateur radio contesting blog at ke1fo.wordpress.com.> > > On Mon, Nov 24, 2008 at 2:55 PM, Bill Aycock <baycock at hughes.net> wrote:> > > Richard-> > 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> > fact.> >> > 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?> >> > Bill-W4BSG> >> > ----- Original Message -----> > From: "Richard Elizondo" <relizondo at ionoscom.com>> > To: "Bill Aycock" <baycock at hughes.net>; <towertalk at contesting.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> > > to> > > 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> > > sections.> > >> > > What I have stated are just the facts. Like it or not, take it to heart,> > > or> > > with a grain of salt.> > >> > > Ever wondered why Rohn used to make comments about climbers being less> > > than> > > 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.> > >> > > Richard> > >> > > ----- Original Message -----> > > From: "Bill Aycock" <baycock at hughes.net>> > > To: "Richard Elizondo" <relizondo at ionoscom.com>;> > > <towertalk at contesting.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> > >> irrelevant.> > >> The statement about the strength of 25g is worthless, because the shear> > >> strength is not define with respect to direction and method of loading,> > >> and> > >> is not related to the type of load applied by a falling body.> > >> If the loading is cleared up, the rest might be germane.> > >> Bill-W4BSG> > >>> > >> .contesting.com/mailman/listinfo/towertalk> >> > _______________________________________________> >> >> >> > _______________________________________________> > TowerTalk mailing list> > TowerTalk at contesting.com> > http://lists.contesting.com/mailman/listinfo/towertalk> >> _______________________________________________> > > > _______________________________________________> TowerTalk mailing list> TowerTalk at contesting.com> http://lists.contesting.com/mailman/listinfo/towertalk
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