Discussion Topic |
|
This thread has been locked |
dirtineye
Trad climber
the south
|
|
Sport climbers are people too.... well sort of.
|
|
the kid
Trad climber
fayetteville, wv
|
|
this looks like a standard weld shut to me..
Here at the new river gorge, when we use glue in's they are petzl stainless steel units.. i would take stainless over ti any day..
ks
|
|
Hardman Knott
Gym climber
Muir Woods National Monument, Mill Valley, Ca
|
|
All the discussion of metallurgy and sport-dogging is interesting, but is completely irrelevant to this case.
Take another look, and please explain WTF is going on here:
There's no question that that is an improperly placed bolt (assuming that that bolt was actually placed somewhere).
Failing an explanation, I'm inclined to suspect that this whole story is a Bullshít Troll™ (or part of a smear-campaign against
Ushba). I'd love to hear from the person who actually "placed" that bolt, but I'm knott holding my breath...
|
|
Greg Barnes
climber
|
|
Kurt, any day except when you're climbing in warm seaside environments, I hope? I've seen glue-ins broken off at the surface of the rock in Thailand, and Petzl folks went down there years ago to confirm that stainless steel bolts were shattering within only a few years. The exact mechanism is still being investigated, so there's a slight chance that you could see similar results with stainless steel in non-seaside warm environments if there are just the right chemicals present. http://www.safeclimbing.org/education/deepbluesea.htm
Both the Petzl and the Ushba 10mm glue-ins are rated to 25kN, so unless you're using the giant Petzl glue-ins (14mm, 50kN), they should be the same strength.
That picture sure looks weird. I can't imagine any scenario that would result in the bolt breaking deep in the hole with a bend, since it shouldn't be possible to break through the epoxy and the rock to that depth on a properly installed glue-in.
|
|
Hardman Knott
Gym climber
Muir Woods National Monument, Mill Valley, Ca
|
|
Thanks for clearing that up. I think it goes without saying that "properly placed" includes
placing the bolt in suitable rock, since crumbling rock is the only thing that makes sense.
But even then, I simply can't picture the bolt bending to that extent, that far from the eye,
knott to mention the bolt bending in the wrong direction. So again I ask, WTF?
|
|
klk
Trad climber
cali
|
|
Well, if the bolt as originally placed could pass visual inspection, one possible scenario is that the soft rock at the surface gradually eroded away as folks twisted and dangled on that bolt. (Thus providing the weird angle stresses that the op describes.) Then the snap line would represent that place where the rock was just good enough not to pulverize under that sort of stress. In that case, the bolt before it broke would've looked pretty manky-- a chossy, fracture scoop around the eye, some of the shaft probably visible. I have seen bolts that bad in serious choss.
|
|
Hardman Knott
Gym climber
Muir Woods National Monument, Mill Valley, Ca
|
|
To my mind, if the bolt was properly oriented, the loop itself would be resting against the rock,
and even if the rock inside crumbled, the rock outside would support it and prevent bending.
That is why I suspect it was placed upside down, or in a manner so that it was opposite to the direction of loading.
|
|
scuffy b
climber
Zeno's Paradise
|
|
Placed in a roof, HK.
This explains the direction of bend.
|
|
Hardman Knott
Gym climber
Muir Woods National Monument, Mill Valley, Ca
|
|
So how would the bolt be loaded if it was rotated 180 degrees?
|
|
klk
Trad climber
cali
|
|
Maybe I wasn't clear-- it was placed upward into a roof (unless I read incorrectly) made of complete choss. So when folks dangled and spun, the surface rock gradually broke and eroded away, exposing part of the shaft. The better rock didn't erode, thereby creating a fulcrum line right, which is where it sheared. One would have to have rock so crummy that you could crunch away the surface with not much more than a fingernail scraping at it, but from the quotes, it sounds like that's the scene there. I'm not crazy about this scenario, but can't think of a likelier one.
I am presuming here that, if it had been fixed with the eye that far stuck out from the original surface, that someone would've said something.
|
|
dirtineye
Trad climber
the south
|
|
Must.. See.. Cross section!!! (choke) (gasp)
|
|
Brian in SLC
Social climber
Salt Lake City, UT
|
|
Would really like to see a cross section straight on photo of the break.
My bet is that if it was repeatedly dogged on, and it was originally placed so that part of the shaft of the bolt was in contact with the rock (or it got that way when the rock busted around it), then it eventually got a scratch/dent on it which bloomed into a stress riser. Fatigue then fast fracture failure when the crack became big enough to not withstand the load.
Er something like that.
Anyhoo, a good close up photograph of the surface of the busted area would be super revealing.
-Brian in SLC
|
|
Hardman Knott
Gym climber
Muir Woods National Monument, Mill Valley, Ca
|
|
I will Paypal $10.00 (the cost of 2 beers with tip) to the first person who posts close-up
pics of the hole of the broken bolt (alternately, they can be e-mailed to me).
The eye of the bolt should have been resting against the rock in the direction of force,
preventing the bending shown in the pic. If pics are knott too much trouble, beers on me!
Edit: Brian - we were composing our posts at the same time - LOL!
|
|
scuffy b
climber
Zeno's Paradise
|
|
"So how would the bolt be loaded if it was rotated 180 degrees?"
It would be loaded the same.
The bend is a result of loading in pull, not shear.
The bolt was placed in a roof, not near a roof, not before or
after a roof.
The direction of the bend is OK. The location of the bend, so
far from the eye, indicates soft rock or crappy hole.
|
|
bwancy1
Trad climber
|
|
Let me fix that for you...
The direction of the bend is OK. The location of the bend, so
far from the eye, indicates soft rock or crappy hole"
That makes sense to me too...
...or not being set deep enough.
|
|
JLP
Social climber
The internet
|
|
There appear to be no witness marks anywhere on the bolt. Assuming the bolt was photo'd sometime reasonably soon after the break, I would assume the thing was sticking out of it's hole up to near the "glue ring"
It looks like it broke pretty close to the first "glue ring" feature. The bolt "cross section" will be thinner here - significantly less strong. Depending on how the ring feature was manufactured into the bolt, there will certainly be additional stresses, the magnitude of which depend on the process.
I'm therefore concerned about the glue ring.
Sigma = My/I, I = pi r^4/4. Let's say the ring is 5cm dx from the load point, so 1kN force fall is 50 N-m @ break. Let's call the ID of the ring @ 5mm, so r = .0025 m. Solving, we get Sigma = ~8E10 Pa, not accounting for the additional stress imposed by the "glue ring" geometry and manf. process, and additional likely torsional stresses. Titanium Alloy snaps at 9E9 Pa. My numbers are guesses, but they show that it is certainly possible. Have fun speculating - or stick the real #'s in and see what you get.
Don't really need to see much else in the pic, just dimensions of a similar bolt. Looks like a design/installation issue to me - both. Direction of loading shouldn't matter beyond inducing torsion - ie, doesn't matter if they placed it upside down - sideways might matter more.
Lesson to self: bolts sticking out of rock = bad - these glue ins are probably best with the ring pointing down, seated against the rock and into some of the epoxy that oozes out of the hole.
|
|
healyje
Trad climber
Portland, Oregon
|
|
Notice how most bolts of this variety are best installed in a recessed manner as opposed to just drilling a hole and sticking it in.
|
|
Chiloe
Trad climber
Lee, NH
|
|
Here's an Ushba titanium bolt, which looks more similar to the one that broke.
Mounted flush with the rock:
|
|
Nor Cal
Trad climber
San Mateo
|
|
Knott,
yes, a simple back-up would have prevented his accident. Sad part is he had two ropes hanging, he could have easily tied in shrot on the second. he grabbed the rope during his fall and this prevented his ushba from camming into place. The device was only attached to his belay loop. A device such as the mini traxion would not have needed to cam into place.
He and I each logged over 10k feet using the ushba, most of that was in the valley and at our local rock (where he got hurt) it was rare that we did not back it up and we have take many falls with the device. I figure that if he had further to fall he would have let go of the rope and the device would have caught him. I guess that is why it's an accident. one that should not have happened.
|
|
neebee
Social climber
calif/texas
|
|
hey there nor cal and all... say, this whole bolt stuff is very interesting... i was just sitting here taking it all in...
i am only posting, just to say to nor cal:
say, i hope your friend is doing well... my grandkids have a step mom, and her DAD was a roofer... he fell and landed on his feet and broke both feet too... long after, he has still had trouble and has never been able to work again---thus, it has been very hard on him.... sure hope your friend recovered well, and if not, sure hope some good will come his way...
*back to the bolt-stuff, you all... (i really DID enjoying listening to everyone take on it) ...
|
|
|
SuperTopo on the Web
|
Let us know!