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@arrl.net> To:
> baycock@hughes.net> CC: relizondo@ionoscom.com; towertalk@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@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@ionoscom.com>>
> > To: "Bill Aycock" <baycock@hughes.net>; <towertalk@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@hughes.net>> > > To: "Richard Elizondo"
> <relizondo@ionoscom.com>;> > > <towertalk@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@contesting.com> >
> http://lists.contesting.com/mailman/listinfo/towertalk> >>
> _______________________________________________> > > >
> _______________________________________________> TowerTalk mailing list>
> TowerTalk@contesting.com>
> http://lists.contesting.com/mailman/listinfo/towertalk
_________________________________________________________________
Proud to be a PC? Show the world. Download the “I’m a PC” Messenger themepack
now.
hthttp://clk.atdmt.com/MRT/go/119642558/direct/01/
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|