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Greg Barnes
climber
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Topic Author's Original Post - Jan 27, 2009 - 11:51am PT
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Short version: stud bolt pulls, climber falls, rope gets cut on dike/edge. Upon investigation, other bolts pull easily - in fact the rope cutting might have prevented the single belay bolt from pulling.
Report by Simon Carter (the photographer):
http://www.onsight.com.au/news-blog/index.php
What I get from this: stud bolts can pull easily in soft sandstone. These particular ones were skinny (8mm = 5/16") and may have been improperly installed (insufficient hole cleaning?), but this should give pause to those who use stud bolts in soft sandstone or other soft rock (glue-ins are the standard in that area).
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Moof
Big Wall climber
A cube at my soul sucking job in Oregon
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Jan 27, 2009 - 12:46pm PT
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Schiza!
I've been spoiled by basalt and granite...
I did get an interesting response from a dude after I replaced an ancient anchor consisting of two 1/4" jobs (one threaded, one button head) with two 3/8x2.25" stainless bolts in solid basalt. He wanted to know why I didn't use some of my 3.5" ones (purchased for Pinnacles, but never used). Confusing. It's on a route for which probably hadn't seen an ascent in 10-20 years, and might not see another one for another 10-20 years.
Local ethics were also bizarre to negotiate, advocating leaving old bolt in place to remind the young bucks how burly the haz-bins used to be, back when they weren't sporting dentures. Thankfully these bolts were "nothing special", and I was allowed to pull them and reuse the holes.
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Wes Allen
Boulder climber
KY
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Jan 27, 2009 - 01:10pm PT
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Greg, from what it sounds like to me, is the equipper didn't have the right sized bit for the bolts they were using. Total and complete user error. I know that people will jump on the soft rock / need glue ins wagon, but studs are fine when used correctly. And, if you use the right bit, even non-tightened expansion bolts are "pretty" solid for a downward fall, and are not all that easy to get out.
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Mighty Hiker
Social climber
Vancouver, B.C.
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Jan 27, 2009 - 01:19pm PT
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I read the report. There undoubtedly are concerns about the kind of rock, the type of bolts that were placed, and whether they were placed properly. The immediate cause here, though, was a rope under tension being cut by a sharp edge. Something that happens occasionally, and which can be caused by many things. The chain in this accident seems to have been: off route climbers (guidebook? unknown new route?) - attempt to bypass unexpectedly hard section with aid - bolt failed - fall - rope cut - remaining bolts not severely loaded, and so belayer spared.
It sounds like one way or another, one or more of the bolts was likely to fail, probably precipitating severe consequences. A very sad business.
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bhilden
Trad climber
Mountain View, CA
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Jan 27, 2009 - 03:01pm PT
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I read the report on Simon Carter's website. I have never liked wedge bolts in soft rock. At Pinnacles National Monument I have tightened existing wedge bolts right out of the rock. Sure, wedge bolts are probably the cheapest climbing anchors, but they need to be used properly.
Bruce
ps - in the above accident these guys are very lucky it wasn't a triple fatality.
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Juan Maderita
Trad climber
San Diego, CA
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Jan 27, 2009 - 03:06pm PT
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Before getting into a technical discussion of bolt types, we should get away from using the casually used term "stud" bolt. The bolt in question is, in the USA, referred to as a "wedge anchor" type bolt. The term "stud" refers to the outer exposed threads, and a hex nut is tightened over the hanger.
There are other types of bolts which have exposed threads and therefore could be generically called stud bolts, but are not wedge anchors.
The Raumer 8mm wedge anchors which pulled out were of the double-cone type which may provide increased holding power in "less than hard" rock or pocketed limestone. That does not mean they should be used in soft rock.
Numerous sources, including the manufacturers, indicate that wedge anchors should only be used in hard material. That would include granite, basalt, and quartzite. The expansion collar of a wedge anchor has a very small contact/surface area. The pressure exerted by the collar will crush softer rock.
Additionally, small diameter bolts (such as the 8mm in question) are inferior for softer rock types, including sandstone.
It is interesting to note that Raumer's website has this to say about their 8mm wedge anchor: "Has two expanding elements, therefore it is recommended for use as an anchor device even on rock not too hard and compact."
Their recommendation is poorly worded and dead-wrong, per the recent bolt failures and fatality.
I will contact Raumer regarding their deadly description.
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mdavid
Big Wall climber
CA, CO, TX
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Jan 27, 2009 - 04:20pm PT
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very sad
every one of those crappy bolts should be yanked immediately. Either put in the right equipment or don't fing drill....damn
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Clint Cummins
Trad climber
SF Bay area, CA
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Jan 27, 2009 - 04:28pm PT
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Juan,
Excellent points - I agree completely.
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cragnshag
Social climber
san joser
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Jan 27, 2009 - 04:34pm PT
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From the Hilti Tech Guide: a 1/4" dia wedge bolt in 2000 psi lightweight concrete fails in tension at about 2,040 lbs. It does not say what the method of failure (pulled out of hole or shear cone failure of concrete). Definitely not tension yielding of the steel itself, though. It appears that these bolts (somewhat larger than 1/4") pulled at 20-40 lbs tension.
Accoding to the following website data http://www.mininglife.com/Miner/rockmech/UCS_Field_Index.htm
Sandstone uniaxial compressive strength (using typical concrete cylinder test method) is in the range of 7,000 psi to over 20,000 psi.
I have no idea how strong the sandstone is at the Blue Mountains but if it is in that range, and the assumption is made that the anchor in concrete behaves similarly to sandstone, is reasonable to expect the wedge bolts in question should not have failed at 20 to 40 lbs. UNLESS THE HOLE WAS DRILLED TOO WIDE. Then all bets are off for tension capacity.
Whomever "tightened" the nut to set it should have known something was wrong when the nut wouldn't offer resistance.
Very sad. Condolences to the family and friends of the victim.
This really shows the magnitude of responsiblity that is placed in the hands of the FA party. If the FA party ever learns of this accident.... that would be a tough cross to bear for the rest of their days.
Edit: not an advocate of wedgies in sandstone
Edit: coversion 1MPa=145 psi for website listed above
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Greg Barnes
climber
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Topic Author's Reply - Jan 27, 2009 - 05:24pm PT
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Juan, I deliberately don't call this type of bolt "wedge bolt" anymore. The problem with "wedge bolt" is that in the past few years, a lot of people take that to mean Powers Wedge anchors or the like - which are those new screw-into-concrete bolts (that people keep on emailing the ASCA to ask if they are good for rock - they are NOT).
On the other hand, since "stud bolt" is also typically thought of as the bolt we're talking about (eg Power-Stud from Powers), and since there's no confusion with an entirely new type of bolt, I think it's the better option. Some people do call any threaded bolt sticking out of rock a "stud" which can lead to confusion.
Some brands call them stud bolts, some call them wedge bolts, but Hilti has its bases covered - they have both "wedge" and "stud" bolts that are this same basic design (eg HSA Stud, Kwikbolt 3 Wedge).
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Clint Cummins
Trad climber
SF Bay area, CA
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Jan 27, 2009 - 05:58pm PT
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Greg,
It's unfortunate that Powers uses the name "Power Stud" for what has traditionally been called a wedge bolt, and uses "Wedge-Bolt Screw Anchor" for what I'd call a "lag bolt" or "lag screw".
http://en.wikipedia.org/wiki/Screw
Best would be to find a name in use for what we have called "wedge bolt", and hope it is not redefined by Powers....
How about:
"wedge stud"
and
"double-wedge stud"
?
"stud" = hex nut on threaded shaft
"bolt" = hex head shaft
Too bad something like "cone and clip-ring stud" takes too long to say. Powers uses "mandrel" to describe the cone in their "Power-stud" description, but apparently that is another redefinition....
The newer "Power-Stud + SD2" has a longer clip-ring with more surface area - it is probably an improvement over the smaller ring version for softer rock (assuming proper hole diameter, proper cleaning/blowing/brushing, etc.):
http://www.powers.com/mechanical.html
However, the SD2 is a carbon-steel stud and stainless clip-ring!
High strength in hard rock/concrete, but not built to last.
And it still has the non-removable problem.
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Euroford
Trad climber
chicago
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"Juan, I deliberately don't call this type of bolt "wedge bolt" anymore. The problem with "wedge bolt" is that in the past few years, a lot of people take that to mean Powers Wedge anchors or the like - which are those new screw-into-concrete bolts (that people keep on emailing the ASCA to ask if they are good for rock - they are NOT). "
i've given powers a good bit of heat over their naming on that one. clearly attempting to muddy the waters. we've had SOOO many problems with those things. fortunately powers has addressed most of those issues for us and most concerns are now limited to use problems. (i'm talking about in construction btw)
but... i've always been VERY curious about using these in soft rock situations. it seams like a pretty darn good solution actually.
fyi: the typical term used in our industry for these types of anchors (several other manufacturers have jumped on board with simular designs) is an "LDT" or "large diameter tapcon".
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tradmanclimbs
Ice climber
Pomfert VT
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Only on the taco could a discussion of a climbing fatality turn into a rant about what a manufacturer choses to name a product:)
Carry on..........
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Scared Silly
Trad climber
UT
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Wow this is rather sad. Seems rather irresponsible of the blokes who put up the route as from what it seems they knew the bolts were suspect. I would say their egos got in the way of safety for others.
A few years back I removed a few bolts cause they were not put in correctly. Via friends the bolts got back to the original driller who I understand was rather PO'ed that I had taken them out. WTF should have I done leave them for someone other person to die on?
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tradmanclimbs
Ice climber
Pomfert VT
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Sometimes folks mean well but just don't know any better.. I have seen a few bolt jobs that were done by guys who can out climb me strengthwise 7 days a week but they just don't have the experience and skills to do a good bolt job.
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survival
Big Wall climber
A Token of My Extreme
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Very sad. My condolences go out to the families involved.
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mdavid
Big Wall climber
CA, CO, TX
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more than sad, this was totally preventable.
The guys who placed the bolts knew they were crap and it appears might have been warned not to use them at this location.
http://www.onsight.com.au/news-blog/articles/37/report-follow-up
"Cujic showed Andy the bolts he had with him and the Blue Mountains guidebook indicating where they intended to climb. Andy says he told Cujic not to use those bolts. Cujic has denied to me that he was clearly told "
One of these guys is full of crap, either they were warned or no, if they were, well i can't imagine being such an irresponsible ass....or how hard he deserves to be punched when visiting climbing areas...
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jbar
Social climber
land of the lost
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Seems like not only poor bolting practices but bad placement as far as location as well. Should have been something for a directional or a runner used to avoid the sharp edge. There was a great "soft rock bolting guide" link posted here recently. I can't find the link but I printed the guide.
Edit: Man those bolts in the video are barely body weight. The scale the guy is using is a fish scale. I use the same one to weigh my packs before I fly.
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Nudge Nudge
Trad climber
WI, now CA
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That bolt removal video made me sick. Scary.
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