Bobby Hutton and I are sitting in front of about $5000 worth of bolts and glue (not sponsored!). We plan to break test everything one can imagine - the goal is 1000 break tests. Some of the best tests out there are not filmed or filmed well and the well filmed tests are not thorough. We plan on doing 3 in tension and 3 in shear of every variable and question we can think of and publish them in an easy and quick to understand way. This is research for The Bolting Bible as I realized how much we don't know ( slackademics.com/boltingbible ). I post a few times a week now on instagram.com/hownottohighl… IG single results and on youtube ( youtube.com/c/hownottohighline ) we will be posting full episodes about our conclusions over the next year. We already have 700 samples done (mostly for slackline related gear) for SlackSnap which is the machine in the picture. WHAT WOULD YOU LIKE TO SEE TESTED???
Not sure if this is possible to do/simulate with the setup you’ve got, but I’ve always wondered about the strength of bolts that have been exposed by weathered sandstone.
Whatever tests you do, it would be great to publish the results. You’ve got enough reps to be systematic and do some good science.
Frankly, it seems like a waste of money/time to be testing a bunch of modern bolts and glue ... I'm trying to understand what the best case scenario of your testing data would be.
some of the posters above-described various suboptimal bolting scenarios where they be interested in the strength reduction. For example expired glue, not enough glue, excetera. It seems quite easy to do small sample experiments, but extremely hard to make generalizable statements. For example, in the not enough glue situation, the answer may depend on the exact type of glue and bolt, the exact amount of glue, distribution of glue, the type of rock, excetera.
Modern bolts, if placed correctly, just don't break. And, given that most people placing bolts do it right, meaning the correct bolt for the rock type and proper tightening, I think the only thing worth testing are edge conditions. That means stuff where people really screw it up. But, then when you think about that scenario it's either really easy to spot a poorly placed bolt or it's very difficult. There really is no in-between. This means that it is really pretty difficult in the field to assess the installation quality of a bolt so testing numbers don't really mean much for edge conditions because you can't really determine if it is an edge condition.
I guess that means I am not sure what your testing is going to prove.
Having said that maybe you could test certain popular wedge bolts to see if any one brand is better than another though probably all of them hold at some reasonable spec. I would also be interested to know if a wedge bolt with "rolled" threads is stronger than one with "cut" threads, especially in shear.
What good does it do to test for over torquing? Unless the installer realizes that they have over torqued the bolt and they replace it then and there, there is no way for a climber on a route to inspect a bolt and know if it is over torqued. As I said above, it is too difficult in the field to do a proper inspection of the installation. All you can do is hope that the person placing the bolt knew what they were doing.
3/8" Power-Bolt+ (carbon steel, the new ones which people shouldn't be using for climbing!)
3/8" x 2.25" 5-piece (carbon steel) paired straight with chain links/washer piles and maybe Metolius rap hangers (those are both really thick, so the bolt depth is not too deep in the rock)
3/8" x 1 7/8" 4-piece (carbon steel) paired with any standard hanger (I have some of these, they were only made for a short bit before Powers discontinued the 5-piece lineup in carbon steel)
Bruce Hildenbrand wrote: What good does it do to test for over torquing? Unless the installer realizes that they have over torqued the bolt and they replace it then and there, there is no way for a climber on a route to inspect a bolt and know if it is over torqued. As I said above, it is too difficult in the field to do a proper inspection of the installation. All you can do is hope that the person placing the bolt knew what they were doing.
I think some people would like an answer to the question do I actually need a torque wrench. I'd be really curious to know, both under and over torqued. Especially for 5 piece sleeve bolts. Many people do not use a torque wrench and until someone provides some actual science and data neither side will "win" the argument
I'd be curious about 1/2 vs 3/8 overtorqued.
I imagine some of this study will help developers and not climbers trying to make a judgment in situ. After all when you find a bad bolt you often have no choice but to trust it. Often there is no bail or backup option
Ryan Jenks wrote:Bobby Hutton and I are sitting in front of about $5000 worth of bolts and glue (not sponsored!). .... WHAT WOULD YOU LIKE TO SEE TESTED???
Are you asking about 1) How to test the "$5000 worth of bolts", or are you asking about 2) Testing other bolts and related anchor gear that you might not have purchased yet?
These are all great ideas. Of course we have 100s of our own but these ideas help guide us to what is most interesting to others. We will test under torquing, over torquing, twisting of all sorts with all sorts of glues, backward P bolts, chain links on bolts pulling unfavorably on the top of stud, and expired glue (mostly because this is cheaper for us to buy to do a lot of our testing haha). Keep the ideas coming. FYI. We are already 108 break tests done and will be starting to release our data in bite size pieces now. IG will be single breaks and Youtube will be 12 to 24 breaks to show an entire concept/question tested. We have super slow motions, 3 camera angles and will have easy to read charts. And no, we won't make you watch the whole break test but the best 3 seconds of each one! :). Here is a teaser. Guess that KN! What did this 12mm solid leg "Crux Monster" MBS 60kn break at pulling in tension? Hint: concrete and glue were fine.
Bruce Hildenbrand wrote: Modern bolts, if placed correctly, just don't break. And, given that most people placing bolts do it right, meaning the correct bolt for the rock type and proper tightening, I think the only thing worth testing are edge conditions. That means stuff where people really screw it up. But, then when you think about that scenario it's either really easy to spot a poorly placed bolt or it's very difficult. There really is no in-between. This means that it is really pretty difficult in the field to assess the installation quality of a bolt so testing numbers don't really mean much for edge conditions because you can't really determine if it is an edge condition.
I guess that means I am not sure what your testing is going to prove.
Having said that maybe you could test certain popular wedge bolts to see if any one brand is better than another though probably all of them hold at some reasonable spec. I would also be interested to know if a wedge bolt with "rolled" threads is stronger than one with "cut" threads, especially in shear.
I know the conclusion to this many break tests is that it is all "Super Good Enough" - something i say often. We have a huge margin of error installing bolts as they break stronger than almost anything I can connect to them. We want to find out how bad one needs to eff up before someone is actually at risk of dying. We get 5kn to 6kn on our highlines which isn't actually that much and we have redundancy but we also don't know what the limits are. We as slackliners are overbolting in my opinion because we don't know, when we could get away with 2 or 3 bolts instead of 4. The reason I named it the Bolting Bible because I find bolters treat other bolters like shit so often over petty details when in fact, as our testing is showing, isn't that big of a deal. So often people discuss details of bolting based on biases and not actually hard evidence, just like they use to when I was in church back in the day. So we shall find answers to all our questions! Cheers :).
mpech wrote: Frankly, it seems like a waste of money/time to be testing a bunch of modern bolts and glue ... I'm trying to understand what the best case scenario of your testing data would be.
some of the posters above-described various suboptimal bolting scenarios where they be interested in the strength reduction. For example expired glue, not enough glue, excetera. It seems quite easy to do small sample experiments, but extremely hard to make generalizable statements. For example, in the not enough glue situation, the answer may depend on the exact type of glue and bolt, the exact amount of glue, distribution of glue, the type of rock, excetera.
Best Matt
We do hope to find the edge of bad bolting and work our way up to what is acceptable even though we promote and teach best bolt practices. It is hard to quantify if a bad job is ok or not because the variables are endless but we can hopefully narrow down some deal breakers and use fun visuals of WHY people shouldn't do certain things.
I know the conclusion to this many break tests is that it is all "Super Good Enough" - something i say often. We have a huge margin of error installing bolts as they break stronger than almost anything I can connect to them. We want to find out how bad one needs to eff up before someone is actually at risk of dying. We get 5kn to 6kn on our highlines which isn't actually that much and we have redundancy but we also don't know what the limits are. We as slackliners are overbolting in my opinion because we don't know, when we could get away with 2 or 3 bolts instead of 4. The reason I named it the Bolting Bible because I find bolters treat other bolters like shit so often over petty details when in fact, as our testing is showing, isn't that big of a deal. So often people discuss details of bolting based on biases and not actually hard evidence, just like they use to when I was in church back in the day. So we shall find answers to all our questions! Cheers :).
The ASCA and Access Fund already have very good instructional videos and web pages on how to properly place bolts which were developed by some of the leading experts in this field. I am not sure how you are going to add to this body of work other than to reinforce what we already know that if a bolt isn't placed properly it isn't going to be as strong as it could be.
I applaud the goals of what you are trying to do, but a lot of this work has already been done, and documented by others. Besides organizations such as the Access Fund and ASCA named above, there have been a number of individuals such as Dan Merrick(a climber and retired college professor of engineering), as Clint mentioned, who have been doing good work in testing potentially bad bolting practices such as removing the blue plastic washer on 2.25" x 3/8" Powers bolts. Before you begin your work, I would suggest that you do a search of the internet, including You Tube, for work that has already been done in this area.
If it's a certified glue-in anchor and placed correctly in strong enough substrate then only the adhesive used and whether the eye is welded is going to make any difference.
Anchors won't fail until way past UIAA123 requirements (let alone EN959) when placed properly (as per conditions above).
E.g. Fixe welded rings with Hilti RE500 in limestone? You'll snap the weld but the anchor won't budge. Same anchor in the same rock with a weaker adhesive and you'll most likely extract it without a broken weld.
Only difference beyond that is the tensile strength of the anchor material versus the anchor design as to when the metal yields (or snaps) or does n't.
Too much variability with a glue-in anchor in terms of how it could be incorrectly installed to make it worth modelling sufficient times to get any statistical reliability and for what benefit? Any concerns during the installation absolutely require corrective action immediately rather than it'll be ok because...
Adhesive testing of different brands would be definitely beneficial because that's really the longterm unknown with current knowledge regarding the use of this (type) of anchor.
To clarify a few things (which on your website are also not quite accurate):- The "rated" strength of rock anchors for climbing is 15kN axial and 25kN radial (if the UIAA Safety Label is issued then 20kN axial. There is no requirement to mark this on the product and other numbers which may be in the literature or marked on the product are from testing and apply to the anchor tested, specifically the anchor is tested to the requirements of EN959 and then to failure and the manufacturer may publish this or not as they wish. We generally give this as an indication of what to expect and there is no guarantee the bolt you have clipped will hold this, the only "rating" is to the 15/25kN. CE marking is prohibited for rock anchors, anyone claiming or implying their anchors are CE approved doesn´t understand the system and is breaking the law if they are in Europe. The UIAA do not certify anchors, manufacturers may apply for the UIAA Safety Label and use the UIAA Logo if they wish (and pay the annual fee to do so). For rock anchors it has no real relevance. The testing conditions are quite specific for EN959 and the rate of pull (and whether it is continous or not) plays a major role in the ultimate strength of stainless steel anchors due to the work hardening which may occur, I can get values varying from 36 to 44.7kN from identical bolts tested in different ways. The test pin also makes a difference, the proof pins are 10mm in diameter but for a lot of bolts this is too small to achieve failure so larger ones are required, since we are talking about forces vastly over the requirements this is common practice. The standard is for bolts which may only be good for one fall, there is a repeat test requirement for EN959 and this is 10 pulls at 8kN but distortion is permitted. They are neither designed nor tested for continous loads.
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