Thoughts on "Triaxial loading of a belay loop, waist belt, leg loops"?

I will care what petzl says about carabiners when they can manage to make a screwlock that doesn't chronically bind with normal tightening.    Just saying!   

Greg D wrote:

Nicely done. 

One tries to keep it simple.

Going to be interesting when Viper Scale starts drawing coloured lines on this one, it´s a 16 actuator BIAXIAL test rig from Auckland University. Just imagine what a triaxial one is going to look like!

Jim Titt wrote:

One tries to keep it simple.

Going to be interesting when Viper Scale starts drawing coloured lines on this one, it´s a 16 actuator BIAXIAL test rig from Auckland University. Just imagine what a triaxial one is going to look like!

Not sure this is a strange looking biner... and if it isn't a biner we aren't talking about the same thing.

Also btw biaxial loading of a biner (real biaxial or biner biaxial) is impossible unless something was to catch on the gate because the biner should always spin so that the 2 points pulling on it are aligned in the same line. Well I mean I guess you could always force it by pitching part of the biner or something but if you are doing test compared to real world it won't happen.

Not that this applies to climbing that much and I don't have the exact picture to share..., but at a past job we had a beefy industrial steel carabiner failure when lifting a 500 lb load (roll of membrane) with a triaxial?/biaxial?/multi-directional? setup using industrial slings. The biner gate ended up on the outside (like this pic minus the break): 

Doubtful if this has occurred in a climbing related hauling scenario, but here is a chart showing how the angle influences strength reduction in such a system: https://www.lift-all.com/assets/pdf/Angle-of-Lift.pdf 

Steve Skarvinko wrote:

\Doubtful if this has occurred in a climbing related hauling scenario, but here is a chart showing how the angle influences strength reduction in such a system: https://www.lift-all.com/assets/pdf/Angle-of-Lift.pdf 

Climbers, though perhaps not at a deep level, know about this as the V angle in anchor building.

ViperScale . wrote:

Not sure this is a strange looking biner... and if it isn't a biner we aren't talking about the same thing.

Well lets put it this way;- there are some ill-informed climbers using the term triaxial loading in a completely different way to the rest of the world of science, engineering, mechanics. It´s not our problem, it´s theirs because it means they can´t intelligently communicate with the people they depend on to design and test the equipment that keeps them alive. It´s easier if we all speak the same language and use the same definitions.

The tester shown is a perfect illiustration that biaxial loading can have an infinite number of forces acting on the object at any angles as long as they are acting on the XY axes (normally four actuators are enough but this one is a bit special). For triaxial load testing there´s normally a rotator slung in there somewhere to get the third axis.

Jim Titt wrote:

Well lets put it this way;- there are some ill-informed climbers using the term triaxial loading in a completely different way to the rest of the world of science, engineering, mechanics. It´s not our problem, it´s theirs because it means they can´t intelligently communicate with the people they depend on to design and test the equipment that keeps them alive. It´s easier if we all speak the same language and use the same definitions.

The tester shown is a perfect illiustration that biaxial loading can have an infinite number of forces acting on the object at any angles as long as they are acting on the XY axes (normally four actuators are enough but this one is a bit special). For triaxial load testing there´s normally a rotator slung in there somewhere to get the third axis.

Very true we never do true triaxial loading on a biner. We normally do single axial loading or biaxial loading. However if you say triaxial loading to most climbers they think of 3 point pull on a biner and if you say biaxial they think of standard single axial loading... so if you want to go try to change how everyone uses the terms when talking about biners go for it because most climbers out there always increase the number by 1.

It's been on my mind for over a year to start a thread about "triaxial" loading, but maybe I'll just rant here instead :)

This triaxial thing seems to have started cropping up a lot, with what reminds me of the whole microfractures fiasco (though admittedly a much better base in reality). 

Numerous practices considered fine in the past, will now get drive by comments of "triaxial" loading!.

- Wrap a sling around a tree and clip both ends, "triaxial"!

- Put 2 clove hitches on a big biner on your harness while building an anchor, "triaxial"!

If this is such a risk that it bears mentioning all the time, where is the pile of bodies from the last 50 years of guys who had "triaxial" loading in their anchors.

Yeah, you can break a biner with in certain loading configurations, we've always known that. Personally I'm going to keep triaxially loading whatever I feel like, because what really counts is the geometry and forces involved.

(Yeah I know, maybe its easier to teach everyone "Never do X" than it is to teach them when its safe to do X.)

r m wrote:

(Yeah I know, maybe its easier to teach everyone "Never do X" than it is to teach them when its safe to do X.)

'Cause all the new climbers/millenials want a set of rules to follow since learning concepts is too hard.

How about we get rid of axial loading and just go back to what is the real problem... cross loading / partial cross loading the biner. If you have are pulling on the biner anywhere in the direction toward or partially toward or away from the gate you are doing it wrong!

r m wrote:

It's been on my mind for over a year to start a thread about "triaxial" loading, but maybe I'll just rant here instead :)

This triaxial thing seems to have started cropping up a lot, with what reminds me of the whole microfractures fiasco (though admittedly a much better base in reality). 

Numerous practices considered fine in the past, will now get drive by comments of "triaxial" loading!.

- Wrap a sling around a tree and clip both ends, "triaxial"!

- Put 2 clove hitches on a big biner on your harness while building an anchor, "triaxial"!

If this is such a risk that it bears mentioning all the time, where is the pile of bodies from the last 50 years of guys who had "triaxial" loading in their anchors.

Yeah, you can break a biner with in certain loading configurations, we've always known that. Personally I'm going to keep triaxially loading whatever I feel like, because what really counts is the geometry and forces involved.

(Yeah I know, maybe its easier to teach everyone "Never do X" than it is to teach them when its safe to do X.)

My guess is these are practices employed with less frequency.  Certainly, they are practices I avoid.  All for the physical reasons discussed in the last 2 pages.  I'll girth hitch the tree and if needed, I'll cut and/or tie the soft good around the tree if too short for girth hitching (which, I would add probably means it is too short for "triaxial" loading.)  Are they dangerous?  for knowing, unlikely.  We all take risks in life, hopefully everyone gets to calculate and weigh the options before taking them.

I've chased my fair share of crane hooks, and the rigging is clearly marked with the angle limitations of the equipment for "triaxial" loading.  Of course, with crane rigging you get the luxury of watching it load and almost no chance of the rigging shifting once loaded.  Something not always afforded to climbers and the equipment they use.       

Todd Skinner's harness had immensely deteriorated.  No one know whether or not it would also have broke if he had rigged his daisies differently.  The only lesson from his tragedy is not to use a harness that is literally in tatters.  I think the climbing world had an understandable but entirely unjustified panic attack over that accident, which seems to be the source of the idea that you shouldn't girth-hitch to the belay loop.  Personally, I just don't buy it; belay loops have been demonstrated to be among the most robust and strong links in the chain.

You can use either the belay loop or the harness tie-in points for attaching a daisy or PAS.  "Triaxial loading" (however defined, the usual sense in the climbing world is not the 3d interpretation) is of no consequence in this context.  I rather doubt there is anything intrinsically problematic about the triaxial loading of an oval link either, the problem is that with a carabiner, one of the "axes" (meaning force vectors) might load the gate.    

Inspect your harness, since the belay loop rubs against the tie-in points when rappelling and belaying as well, and that wear isn't well-distributed over time because of the stiffness of the belay loop sewing.  The wear, if you ever see any at all, will generally be at two opposite points on the belay loop, but most people don't do enough jugging and daisy-bounce testing to produce any noticeable belay loop wear before it is appropriate to retire the harness.  Moreover, when wear happens, it is usually not the belay loop, but the bottom hard point of the harness that suffers noticeable abrasion, which is why some harnesses have a plastic insert to protect that part.

You can't tri-axial load two "soft" points of contact that will be pulled together as soon as you cinch up the girth hitch.  The gym employee is confused.

Nate Tastic wrote:

Okay, I checked the book I saw this in. This is what is said:

• Always load the carabiner in the proper direction--on the major, or long, axis.
• Do not cross-load a carabiner (on the minor axis) or load it in three directions (called triaxial loading.)

"Rock Climbing - The AMGA Single Pitch Manual - Bob Gaines and Jason D. Martin"

So you're telling me that's actually biaxial loading? At what point should the technical term be overridden by the sensical term and this for the sake of clarity and or particularly safety? Especially in a book for newcomers?

triaxial = having or relating to three axes, especially in mechanical or astronomical contexts. 

axis = an imaginary straight line passing through the center of a symmetrical solid, and about which a plane figure can be conceived as rotating to generate the solid. OR a fixed reference line for the measurement of coordinates.  OR a straight central part in a structure to which other parts are connected. OR others don't really matter.

The way it is used generally when dealing with carabiners is 3 directions. Alot of physics / eng considers it 3 spacial dimensions such as Up / Down, Left / Right, and Forward / Back aka x, y, z.

Honestly if you really want to go by pure definition of the word the way carabiners use it meaning 3 lines that go through the center of the biner it works for how they want to for triaxial. However if you want to go by fixed reference lines for coordinates which is more of what physics / eng does than the way biners use it is wrong because there is only 2 needed (biaxial) for the coordinates cross / standard loading directions. The way biner people use biaxial loading is totally wrong / impossible because cross loading = single axial loading and standard loading direction = single axial loading.

Nate Tastic wrote:

Okay, I checked the book I saw this in. This is what is said:

• Always load the carabiner in the proper direction--on the major, or long, axis.
• Do not cross-load a carabiner (on the minor axis) or load it in three directions (called triaxial loading.)

"Rock Climbing - The AMGA Single Pitch Manual - Bob Gaines and Jason D. Martin"

So you're telling me that's actually biaxial loading? At what point should the technical term be overridden by the sensical term and this for the sake of clarity and or particularly safety? Especially in a book for newcomers?

If they had simply left off the "(called triaxial loading)" they would have been technically correct which is a desirable trait in a technical manual by a national organisation, nobody would or could have been confused and clarity and safety would have been enhanced  

Jim Titt wrote:

If they had simply left off the "(called triaxial loading)" they would have been technically correct which is a desirable trait in a technical manual by a national organisation, nobody would or could have been confused and clarity and safety would have been enhanced  

Technically by the definition of the word it isn't wrong. All it really means is 3 different lines that go through the middle of an object that it can rotate around. It is only when you go to the physics / eng side of the word where it starts to mean a coordinate system direction that it no longer would work.

Really the people who I would say really screwed up the terms is BD. They call this quad-axis loading, which I guess it is sorta pulling in 4 different axes but really I would call this closer to biaxial since the top left and bottom right are pulling close enough to the same that it is more like an X pulling on the biner.

ViperScale . wrote:

Technically by the definition of the word it isn't wrong. All it really means is 3 different lines that go through the middle of an object that it can rotate around.

I would add, that the addition of subsequent axes cannot inhibit the rotation of already existing axis (-es). They either exist together or they don't.  You don't get to pick and choose when to apply the laws of physics to meet your misnomer.  

ViperScale . wrote:

Technically by the definition of the word it isn't wrong. All it really means is 3 different lines that go through the middle of an object that it can rotate around. It is only when you go to the physics / eng side of the word where it starts to mean a coordinate system direction that it no longer would work.

Really the people who I would say really screwed up the terms is BD. They call this quad-axis loading, which I guess it is sorta pulling in 4 different axes but really I would call this closer to biaxial since the top left and bottom right are pulling close enough to the same that it is more like an X pulling on the biner.

We live in a world that is Euclidean at human scale, including the stress testing you are showing images of. Anyone describing planar force distributions as triaxial is in a very small minority using a non-standard convention.

ConorCarroll wrote:

I would add, that the addition of subsequent axes cannot inhibit the rotation of already existing axis (-es). They either exist together or they don't.  You don't get to pick and choose when to apply the laws of physics to meet your misnomer.  

Your not talking about axis anymore, you are talking about a three-dimensional space cartesian coordinate system. Which is build of 3 axes that do not overlap each other.

We live in a world that is Euclidean at human scale  including the stress testing you are showing images of.

What in the world does that mean?  How about not ending sentences with a preposition?