Gear Failure on West Face Leaning Tower results in whipper.
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OK, one of the pieces pulled. So only 2 biners actually failed. |
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ROFL!!!!! I'm glad to not b the only one who gets bored at belays. The 'jerk on my head' & 'well the only hand' thing is hilarious |
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Russ Walling wrote:As for the biners breaking.... In the spirit of internet speculation, I'd go with bad luck, open gates, the Devil needing more souls, and probably some other factor yet injected into the conversation.I got ya worried, huh Russ. I mean, probably neither you nor I are as light as Shern's partner. ;-) No, really, you are right that the precise way it failed is hard to say. |
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Caprinae monkey wrote: There is a site you can check what kN force the falling climber generated: myoan.net/climbart/climbfor…That calculator is completely bogus---it can't even get the fall factor right, and who knows what it is doing with the numbers after that. (I wrote them years ago but they have never taken it down.) The only online calculator I know of right now that is "accurate" in the sense that the mathematical model is correctly implemented is at jt512.dyndns.org/impactcalc. The pictured broken biner is interesting. A cross-loaded biner will typically blow the gate out but not break the rest of the body. Open and closed-gate failures can break the carabiner spine at the narrow end as occurred here, or nearer to the wide end. I wonder whether the location of the break in tests has to do with different testing protocols. In the closed-gate failure, the wide end is held in place by the gate and gets deformed into a sharper curve by the load until the spine breaks. It is hard to get such loads, even with a grigri and well-used rope. In the open-gate failure, the wide end gets bent down to a shallower curve until the spine breaks---this type of failure is far more likely because the forces required are much lower. The picture looks like a gate-open failure since the curve of the wide part hasn't been noticeably narrowed. Still, it makes me wonder if the biners were used for sport climbing and if so, if they were gouged by a bolt hanger. |
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rgold wrote:The only online calculator I know of right now that is "accurate" in the sense that the mathematical model is correctly implemented is at [[ jt512.dyndns.org/impactcalc.Just to be clear, the above calculator is the same one I linked with the text "JT's Force Calculator" and "JT's Impact Force Calculator". All three of these references lead to the same web page. |
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were the biners in contacts with a crack? ... its easy to have biners loaded in a crack |
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Russ Walling wrote: 2 hour lead is nothing. On those 6 hour leads I'd put the rope under my head and pull out a few feet of slack. They pull on the rope, it jerks on my head, I wake up and they never see me sleeping. I'd also put a Jumar down the line a few feet from the belay as a third hand... well, the only hand if If I'm sleeping. This was using a Fig. 8 rig or an ATC. .Haha, I originally was going to say a 3 hour lead but I didn't want to be accused of exaggerating on the internet. I can't even imagine a 6 hour lead, I could drain an Ipod battery watching movies in that kind of time. I like the rope under the head trick, it could avoid my partner getting mad from having to repeatedly tug on the gri-gri to wake me up. |
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First off, glad to hear you guys are OK!!! |
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After reviewing the added picture of the fractured surface, the angle of the fracture, some examples from my "Failure Analysis of Engineering Materials" book, and the BD blog listed above . . . my mildly educated SWAG would be failure due to torsional stress with the gate closed that started at a notch as one person mentioned from clipping to a bolt or other similar damage. |
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About the actual failure mechanisms, the thing that seems the most inexplicable to me is that the cam pulled out but the bent gate biner for its sling was missing. Any damage to the cam lobes? |
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JoelO wrote:Here in Europe half ropes are a lot more frequently used also for rock climbing and they really do generate smaller forces on the gear (handy for sketchy winter gear, but maybe also when avoiding breaking biners). Single ropes >10mm usually have a UIAA impact force of >8kN and for <8.5mm half ropes this force is usually <5kN.The impact force ratings for half and single ropes aren´t comparable as the test is different, a dual rated rope like a Sterling Fusion gets 8.5kN as a single strand and 6.4kN as a half rope. |
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Also...this is an aid climb, pretty much nobody is using half ropes for aid climbing. |
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Not saying everyone should start to use half ropes, especially for aid-climbs, but there is a point in minimizing impact fores and half-ropes is one way to go, even in climbs where you have one or two odd aid pitches, if the rest is free climbing. |
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" Also--Anthony found the .5 c4 and draw minus the bent gate hung up on one of his aiders by some kind of luck. It was not clipped to it--it was tangled in it and he found it after the fall when he went to set up to jug. So on the way down, we figure his aider hooked the cam and pulled it as well." |
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Hopefully someone checks this ... Using * Jay T's Impact Force Calculator |
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Torsional forces? On a rope-end biner that is floating in a sewn sling, not straight into a hanger? Just not seeing the mechanism there for any real torsion without the biner somehow being pinned. |
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I'm saying a little Occam's razor mixed with Murphy's law...what could of went wrong did go wrong, and why?...really bad luck. You guys should have doubled down on black that day instead. The good news...a situation like this probably won't happen again for at least 30-40 years so we're all in the clear thanks for getting it out of the way for everyone else. Kind of like two commercial jets haven't crashed in the same week, month, year or whatever. |
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Were there any batch numbers visible on the failed biners? |
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agree with willS, not seeing what will act as a reaction force to the torsion, as a sling has very little torsional stiffness. |
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Ah yes sorry about the bogus falling force calculator... I didn't know it was messed up. But it's crazy yet good that they would have the FF messed up (I think this crossed my mind but figured who would create a faulty calculator), if they didn't, it would be difficult to verify the kN force is also unreliable. |