I would really love to see bigger spacing between the holes, the breaks tend to go to the Already destroyed hole. I understand that you don't want to pour and remove new slab for every few bolts, but I would suggest trying reinforced prefabricated panels. Thank you for this content. It is revolutionary in certain way as I don't know any other creator who would approach it in similar "scientific" way.
I think that once the rock begins to cone it's already failed, so as long as the cone doesn't intersect the next bolt you're super good enough, but yeah in an ideal world you'd have a new same size mini slab for every test.
If the spacing of bolts were about 3 times the depth of the embedment there, it will give more independent results as the previous break test is affecting the available concrete to break for the next.
I agree, as interesting as this test is, it seems to me that every break already compromises the next bolt in line, and therefore possible invalid data. that being said, we can never be entirely sure if there isn't a hidden crack in the rock either, so it's not totally unrealistic...
The concrete is failing, not the bolts. Leaving a space around the bolt with radius equal to the bolt length (or higher) should help to preserve the rock / concrete's integrity. It's important that the areas don't overlap, so if the bolts are 7 cm long I should have at least 14 cm between the two bolts.
There was more than the bolt length spacing between each hole. They are 2.5 inches deep, and the holes were spaced more than 2.5" apart. They need 2-3x depth/length of bolt radius.
@@littlejackalo5326 that's incorrect. Bolt spacing should be at least 2x imbedded depth + bolt diameter. In this case, that's 2x (2.5) + .5 = 5.5". Otherwise the cones of fracture overlap. You can see here that the cone of fracture for the first bolt significantly overlaps into where the cone of fracture for the second bolt would have been, which makes the second bolt much weaker.
Ryan - you asked about concrete testing companies and my suggestion is to call the company that poured your concrete and ask them. Concrete testing is very routine and the lowest cost company is going to be local to you. If you want to know the actual strength of your concrete they will have to remove a core sample. I would suggest first calling the concrete company, tell them the date they poured your slab, and ask if they have any 28 day breaks from that mix and time frame. The concrete will continue to get stronger over time, but the 28 day break is pretty close to fully cured.
It's astonishing how strong these 3/8" Powers anchors are in the straight pullout, especially since all the force is transmitting to the expansion cone through a 5/16" or smaller diameter Grade 5 capscrew. Before Climbtech quit selling this size anchor to rock climbers they went to a supposedly stronger Power Bolt design that counterintuitively used an even smaller 1/4" diameter but Grade 8 equivalent capscrew and this concerned me a little so I stopped using them just to stay conservative. Looks like either way it's not an issue after all. In limestone sport routes in TX I've mostly used 1/2" diameter Rawl or Powers "5-piece" style bolts and only a relative few of the 3/8" size where I knew there would hardly ever be falls taken on a particular bolt. In these "consumer-oriented" climbs it is comforting to know that the 3/8" are super good enough and the 1/2" are no doubt absolutely bombalacious. Thanks guys!
My boys! I LOVE the work you do and the videos you make! One suggestion, when discussing torque, please include units. 12 ft/lb is very different from 12 in/lb. Which are both very different from 12nm or 12kg/m. I assume you always speak in ft/lbs but as a mechanic, 12 torque pounds is a phrase that leads to danger. In all fairness though, the work you do and the videos speak for themselves, and anybody who's bolting will know their stuff just fine. No real need to include units in something that isn't a tech manual, thanks so much for what you do.
Big fan of the channel and what you do, but it seemed like the bolts were way to close in this one, making them compromised before their pull even started.
Test again with them further apart. They were too close and the broken concrete affects the other ones. Also, concrete softens a bit when wet. Keep it dry for a few days.
A good way to measure whether a bolt has failed is bolt stretch. You mic the difference in stretch and if it's too high (read: long) the bolt is considered failed. We do this with rod bolts in racing engine to measure if they're still good. Overtorque or mechanical forces can both stretch a bolt to where it can't provide as much clamping force. The reason a bolt clamps is because you're stretching it slighty along its length by torquing it, go too far and it plastically deforms along its length.
Ryan, did you pour your test slab yourself or have it poured? It is very poor concrete and I would bet it’s compressive strength is no more than 2000 psi. Normal readymix is more like 3000 psi and structural concrete (that used with rebar for bridges/buildings) is twice that (4000-5000 psi). I’m guessing whoever poured the slab undercut the amount of cement used. If you mixed it in a wheelbarrow or it got overly wet because of improper formulation or rain, that would explain it. I know the slab is history now that you have moved but as an engineer I was curious…
13:40 I would call that a failed test result, The bolt continued to hold its ground and remained in the concrete,... it was the concrete that failed holding, not the bolt. You’d have to perform that test again and get the strength required to pull the bolt out with the concrete intact. Ah nm,... you address it at 15:25
I work on rope rescue team for the fire department. We have a rule for anchor placement that all anchor bolts must be a minimum of 6 bolt lengths away from each other and any (concrete) edges. That is because the compressive forces radiate outward. I'm curious if you ran the test again with the anchors spaced out more if the values would be different. Potentially the concrete that some of your anchors were in could have gave way prematurely due to the stress induced by the anchors on either side of it.
I love your videos and I understand your desire to maximize the number of tests you can use the concrete slab for, but I'd really like it if you guys would give a good bit more spacing between bolts especially with how that concrete dinner plates off the surface. While 10x bolt diameter is "spec" for normal use, that's assuming that you're not actively compromising the substrate around each bolt.
Looking at your testing methodology it looks like the concrete failed before most of the bolts. I would say that the values that you recorded are not valid as a bolt test but it does a nice job of testing your concrete.
On our car, some larger bolts require a light torque to snug + turn an additional angle to get the required "clamping force". Smaller bolts seem to be just torque spec. Dirty or lubricated bolts have an impact on torque.
Those specs are far too stringent for this type of bolt. As you can see from the video, there is no real difference between 10 lbf, 15 lbf, 25 lbf, 2 turns, 3 turns, any turns between 2-3 turns, etc. As long as you pre load it some, it will be enough to drive the forcing cone into the sleeve and make it tighter as you pull. Doing 1 test at each torque/number of turns is statistically irrelevant. 1 test means absolutely nothing. You'd need to do 5 tests for it to even start to become relevant. You could put 10 pins in that slab, all tightened to 20 lbf with a calibrated digital tq wrench, and they'll all pop at a different force between 10-20 lbf. There are too many other variables to consider for things like you mentioned to play a role.
You can see the hanger gets really bent at 14 kN, but when it cuts back to the close up, the hanger is fine, so it must be footage accidentally edited in from one of the other samples
I think it'd be interesting to see break testing on self tending prusiks for like a top rope solo. We did one over the weekend and end up using a pulley with a Petzl ascension but I've seen them with a tibloc, grigri, and the micro traxion too.
For anyone else confused about the units of torque in the video, they show it as 12 ft-lbs in the spreadsheet at the end. I recommend you say the actual units instead of "torque pounds" since there are at least 3 common units to measure torque.
I'm clearly no expert but I would like to see this test done further apart from each hole it seems like when you're breaking the concrete you're weakening the next bolt in progression
I've had situations where I have hammered the dynabolts in. Super tight like yours. And then I had to pull them out. No way ! Even using a pichbar, the more you yank on the pichbar it just locks up. I always have to grind them off. I'm glad I stumbled upon your channel! I always wanted to see real life scenario! I'm a bit of a nerd. Lol
Dynabolts can be removed if the hole they are installed in is deep enough for the bolt shank to be driven below the surface. If the sleeve can be gripped the entire bolt can be removed in two pieces.
That blue plastic stopper piece that you said was missing from the 5 piece bolt is not actually to keep you from overscrewing it before installation, but to keep dust and debris from getting in the cone threads which could prevent it from tightening.
Good to know. Seems to function as stopper to warn against installing the bolt if the cone is screwed to far up the sleeve as well. The blue tape might serve the same function?
Love the channel, gotta send some support as I have definitely learned a lot. These results weren't expected. I have been referring to 3/8ths 5-pieces as "removables" atop some TR solo bouldering projects as I seem to be able to break them not too far above torque (with a calibrated wrench), and just pull the pieces out with my finger (granatic gneiss) leaving just the tip behind buried in epoxy and dust like I was never there. I am wondering of the concrete wasn't hard enough to break them especially after seeing that bell shape on one of them.
The more torque you apply to the bolt the more outward pressure the wedge is exerting on the surrounding concrete. This could cause damage to the concrete that should be holding the bolt in the hole? That might explain why higher torque loads on the bolt (above 50%) reduced the max load before pullout. I also agree that spacing the bolts further apart will reduce skewed date. Really cool test!
the reason why they are called 5 piece, is simple, 5 metal parts. The more you know. 1. stopper, 2. bolt, 3. washer, 4. crusher, 5. expanding shafttube.
As a Millwright with 45 years in the field, most of these anchors are used to keep things bolted to a factory floor to keep them aligned , for example, conveyors, storage racks, ext. The practical application is in shear not pul! out. as far as torque just simply use a box wrench and without jerking apply pressure on the wrench with a steady pull until the wrench stops, check the result with a torque wrench and you are probably very close and adjust accordingly. as far as anchoring overhead long bolts are required as well as a multiple hole anchor plate used in well cured concrete with reinforcement with rebar is necessary. In granite with a shear application a stainless anchor and clip should be all you need but use bigger diameter and longer bolts. lication
Ive never climbed, but I do tighten stuff to torque. If youre taking a spanner wrench and not a torque I dunno why you dont just bring a single open end wrench since its lighter and a better wrench. If youre taking a torque wrench, I like the one that makes a click after you set the torque on the handle. Its more compact and gives torque by feel rather than sight. Also, you can train your hand to feel torque spec more or less by repetition. 7-8 lbs. is a oil pan bolt and I would say thats good and cinched so 12 I would describe as "jam it on in there, jerk it on down" But it depends on the length of your bar for leverage also. I think this is good data and what the data says is the manufacturers lawyers are right saying "3 to 4 turns should be good" and the danger is not torqueing it at all.
The concrete breakout cone is 30 degrees off horiz from the tip of the anchor. You need to space your bolts out such that your cones do not overlap. -structural engineer
Thanks for this. I've installed bolts with a 6" wrench, tightened about as hard as I could turn it.Not sure the torque but I tap the hanger checking for how it sounds & bounce test each one.I tried a click wrench but doesn't seem to work well. Do they make a torque wrench with a "clutch" that would not allow you to torque above the setting ?
I'm a concrete contractor and can tell you drilling holes in a linear line that close together severely compromises the structural strength of the concrete. Not sure what psi your pad is or the mix you used or the cure time allowed before testing but the testing is flawed in this video.
Thank you for the videos, very informative. A video where they are spaced further apart, or in granite like you suggested would be interesting. This type of cone failure of the concrete is absolutely expected. Google image search "concrete breakout cone" and scroll through the images to see what's theoretically expected and images of the real thing, like you got. One thing with these bolts is that they are designed for use in concrete, and frequently have to meet certain requirements with respect to performance in an earthquake to be used in certain jurisdictions, since it would suck re designing a bolt for every location, a lot of them just meet it anyway. One of those requirements is a certain amount of ductility (stretching) before you expect the concrete to fail, but it's not definitely universal in all bolts.
the concrete failed and that's mostly the case for over torqueing the bolt. too much expansion of the bolt will compromise the material (rock or concrete) and leads to a quick fail. it is possible for the bolt itself to loose its threads and become weaker, but remember that you are working with hardened metal.
Yup. Steel is stronger than concrete, and stronger than rock. So by overtightening, you're adding stress to the rock even before you start pulling, which you have to subtract out of the total load capacity. This is also why the undertensioned bolt was actually the "strongest" - it was putting the least stress on the rock in its unweighted state. Of course, if a bolt is too loose, it'll just pop right out because of a lack of friction, so the recommended torqueing is a compromise between too much torque stressing the rock and too little resulting in the bolt becoming loose as its used.
Almost seems torquing might have added to the "stressing" factor which allowed for easier coning. Water might have made the effect even more pronounced. Hard to say because the coning definitely would make it easier for the adjacent bolts to also cone. Would be interesting to know how the 67.79nm (50ft pounds) of rotational force translates to upward/outward force. You should figure out some way to hook the dyno up to the nut and torque it. Either way, was expecting to see the bolts themselves fail... Good to see that there seems to be quite a bit of wiggle room from the spec.
I found a calculator here... www.engineersedge.com/calculators/torque_calc.htm If I did it right, the "clamping force" of 50ft-lb would be ~8000lb. Not sure how impactful that is since it's a compressive force between the nut and hanger
Very interesting tests. In vertical tension torque would not play much of a role in breaking the bolt if over tightened, as pulling the bolt vertically releases the torque tension. Over tightening might crack the rock at the expansion point and this presents it's own issues, but I would wager in stable Granite this will not be observed. But over tightening might actually affect shear strength, as the torque tension in the bolt is compounded with the shear tension added and this is a known failure mode. There are of course many variables, and any slip-up of the bolt in the rock will release the torque tension, so it will not be necessarily easy to observe. The zero torque bolt should be the strongest in shear, if it does not slip out.
A few things needs to be done to make these tests better. 1st. The spacing needs to be increased to the point where the damage doesn't spread out into the general area of the next bolt. In short, after the pull tests, there needs to be an unaffected area between each test, otherwise the failures overlaps and you don't know what measured value you would have actually gotten. 2nd. The tests needs to be repeated a few times to account for error margins in both the material strength of the slab, bolt, and also hole size. I can however accept these issues, the tests are done on a relatively small budget, and they are still indicating a lower line.
I'm assuming you mean ft-lbs.. (since any torque on the scale of in-lbs seems dangerously loosenable by typical dynamic loads of one or more climbers), but it's still helpful to clarify that explicitly.
Hi, I see that in your concrete you do not respect the tearing cones of the moorings. A video to see the effect of the tear-off cones on two points that are too close would be great.
I'd like to see offwidth nuts get tested in real rock. It's hard to find anything online about what constitutes a good or bad placement for offwidth nuts, and I feel like you would be able to demonstrate it well in a video. Willing to donate a set of the bd offwidth stoppers if you bust em!
Anecdotal data point: last year I was installing a 3/8” SS 5-piece with a torque wrench (yes, I brought a torque wrench for route development). That worked against me as at the time, the bolt manufacturer’s website had a typo spec of 45 ft-lbs. Tightening the first bolt to that twisted it off (bolt twisted apart down by the cone at the threads). I redrilled and for the rest of the route used Fixe wedge bolts. So the danger is that severely over tightening could get the bolt close to snapping off and it would fail in tension at quite a low value.
This is serious dedication. destroying your concrete in the back your house. It also depends on how deep that concrete goes usually it's about 4 to 6 and is that the same as a granite wall? Also the spacing doesn't make a lot of sense. Plus using a substrate that doesn't work as well as granite . But I love the video
Not to rain on your parade Ryan but I am a fellow concrete guy here and I would say you need thicker concrete and better spacing to get better accuracy.
You can get a concrete strengthening chemical. They use it in Australia for bottle shop where forklifts drive over. It etches 10 mm into the concrete and raises overall MPA rating. But when using it has an extremely high flashpoint! I've done a lot of concreting in the past. I've seen where the truck driver will water it down so much that when it cures after about a month I'm doing the carpentry framing and crazy cracks everywhere! I'm not making fun of your concrete. Just saying there is a lot of variables in concrete.
This test tells me the concrete cure fails before the bolt. This is testing the durability of the concrete. Test again in another material. Obviously this test tells us do not forget to torque the bolts. I think a larger depth concrete and different length bolts would be better test here. That would show climbers a better understanding of how to avoid failure in softer (wet) material.
Not trying to be that guy. But there is "foot pounds of torque" and "inch pounds of torque" (at least for American scales). "Torque pounds" is not a scale as it does not specify which of these 2 your talking about. Again not trying to knit pick here. Great video as always cheers.
I'm a big fan of you guys testing all sorts of stuff, but this one seems a waste of time and equipment due to poor setting. (inadequate bolt spacing, the concrete condition, and the lack of 6-point socket) I've personally broken off a head of stainless steel bolts by over tightening it.
People aren't talking torque wrenches out into the field to set bolts. It's just not happening. It's called a generalization. Just because 1 in 10k people might bring a tq wrench into the field, it still means that no one is bringing tq wrenches into the field. There's a reason why the manufacturer says 3-4 turns. It's because the torque is pretty inconsequential. You could put in 10 bolts with a calibrated digital tq wrench, and they'll all pull out at drastically different forces.
Concrete gets harder harder over time, indefinitely. At least this is the lore in the trades. So a newer slab like this will be weaker than something that has been around for 10 years. That said, seems to me once you get large chunks of concrete blowing out so close to the other bolts I think you’d lose some compressive strength on the bolt.
I don't think you managed to show any difference (50, 100, 200%). Those numbers feel likely to be covered by concrete strength variablility. As for 400% isn't it likely an effect of the bolt effectively shortening by almost half an inch or so? (less concrete to crater) Also, 3KN is more than bodyweight! 🤔😅😉
You guys are putting the bolts way to close to each other. When one bolt pulls out the area it compromised the other hole next to it .. Put the bolts further apart
I don't think the test has any informative value, Looks like the bolts are too close together and the breaking of the previous changed the outcome of the next. I think the conclusion that this kind of bolt is as good as the medium you put it in is a valid claim. Thanks for the hard work, keep busting!
Да , лучше создать динамический тест - с фактором падения от 0,5 - до 2 ( и добавлять не каждый тест шаг 0,25) с использованием и без спускового устройства = тогда видео будет ещё интереснее!
I just noticed that bolt buster rig looks very similar to that monilith Andy pulled out of the desert which is speculated to be a stunt for that slackline reality show... Potential conspiracy?
The data is trash at this point because the concrete failed all around the other bolts. They need to be spaced like a foot apart to make this test legit. Also there’s a considerable strength difference between plated steel and stainless.
results: zero torque bolt: ~3kN concrete: 10-16kN (next time yout test bolts in rock, pls place them further apart. but i'm sure you came to the same conclusion
Find a local civil engineer on Facebook, they’d ought to have a portable tester and probably wouldn’t mind swinging around for a beer or two. They’re quality control machines for when they pour structural concrete to make sure they’re within spec
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I would really love to see bigger spacing between the holes, the breaks tend to go to the Already destroyed hole. I understand that you don't want to pour and remove new slab for every few bolts, but I would suggest trying reinforced prefabricated panels.
Thank you for this content. It is revolutionary in certain way as I don't know any other creator who would approach it in similar "scientific" way.
I think that once the rock begins to cone it's already failed, so as long as the cone doesn't intersect the next bolt you're super good enough, but yeah in an ideal world you'd have a new same size mini slab for every test.
If the spacing of bolts were about 3 times the depth of the embedment there, it will give more independent results as the previous break test is affecting the available concrete to break for the next.
I agree, as interesting as this test is, it seems to me that every break already compromises the next bolt in line, and therefore possible invalid data. that being said, we can never be entirely sure if there isn't a hidden crack in the rock either, so it's not totally unrealistic...
Tension pulls seem to need bigger spacing than side-pulls.
@@KrishnaDase more like 2D
The concrete is failing, not the bolts. Leaving a space around the bolt with radius equal to the bolt length (or higher) should help to preserve the rock / concrete's integrity. It's important that the areas don't overlap, so if the bolts are 7 cm long I should have at least 14 cm between the two bolts.
This is interesting to note that wild bolting should not be too close either?
yeah, the test is voided when the first bolt already ruined the integrity of the concrete around it. They put the bolts too close together.
There was more than the bolt length spacing between each hole. They are 2.5 inches deep, and the holes were spaced more than 2.5" apart. They need 2-3x depth/length of bolt radius.
@@littlejackalo5326 that's incorrect. Bolt spacing should be at least 2x imbedded depth + bolt diameter. In this case, that's 2x (2.5) + .5 = 5.5". Otherwise the cones of fracture overlap. You can see here that the cone of fracture for the first bolt significantly overlaps into where the cone of fracture for the second bolt would have been, which makes the second bolt much weaker.
Ryan - you asked about concrete testing companies and my suggestion is to call the company that poured your concrete and ask them. Concrete testing is very routine and the lowest cost company is going to be local to you. If you want to know the actual strength of your concrete they will have to remove a core sample. I would suggest first calling the concrete company, tell them the date they poured your slab, and ask if they have any 28 day breaks from that mix and time frame. The concrete will continue to get stronger over time, but the 28 day break is pretty close to fully cured.
I think he poured the slab himself but this answer is still relevant.
interesting, thank you!
It's astonishing how strong these 3/8" Powers anchors are in the straight pullout, especially since all the force is transmitting to the expansion cone through a 5/16" or smaller diameter Grade 5 capscrew. Before Climbtech quit selling this size anchor to rock climbers they went to a supposedly stronger Power Bolt design that counterintuitively used an even smaller 1/4" diameter but Grade 8 equivalent capscrew and this concerned me a little so I stopped using them just to stay conservative. Looks like either way it's not an issue after all. In limestone sport routes in TX I've mostly used 1/2" diameter Rawl or Powers "5-piece" style bolts and only a relative few of the 3/8" size where I knew there would hardly ever be falls taken on a particular bolt. In these "consumer-oriented" climbs it is comforting to know that the 3/8" are super good enough and the 1/2" are no doubt absolutely bombalacious. Thanks guys!
My boys! I LOVE the work you do and the videos you make!
One suggestion, when discussing torque, please include units. 12 ft/lb is very different from 12 in/lb. Which are both very different from 12nm or 12kg/m. I assume you always speak in ft/lbs but as a mechanic, 12 torque pounds is a phrase that leads to danger.
In all fairness though, the work you do and the videos speak for themselves, and anybody who's bolting will know their stuff just fine. No real need to include units in something that isn't a tech manual, thanks so much for what you do.
To piggyback on that, torque is force x distance. So it is written as ft•lbs or ft-lbs, not ft/lbs. Same thing for N•m and kg•m.
@@coltonmuri3672 Good point! ft/lbs could imply division or something entirely different. Always good to be as specific as possible :D
This has turned into basically the inverse of the hydraulic press channel. They crush things, you rip things apart.
You could do a video testing ice screws or snow anchors like the dead mans
I offered screws a while ago for testing
Not sure they have any real access to significant enough ice to run that test. But I have no idea.
travel to some ice and test for science!
Thanks!
Big fan of the channel and what you do, but it seemed like the bolts were way to close in this one, making them compromised before their pull even started.
Test again with them further apart. They were too close and the broken concrete affects the other ones. Also, concrete softens a bit when wet. Keep it dry for a few days.
A good way to measure whether a bolt has failed is bolt stretch. You mic the difference in stretch and if it's too high (read: long) the bolt is considered failed. We do this with rod bolts in racing engine to measure if they're still good. Overtorque or mechanical forces can both stretch a bolt to where it can't provide as much clamping force. The reason a bolt clamps is because you're stretching it slighty along its length by torquing it, go too far and it plastically deforms along its length.
YES! i think i asked about this a while ago. thanks for coming through
Yo bobby is lowkey my hero! Would love to be a routesetter and climber like him some day!
Ryan, did you pour your test slab yourself or have it poured? It is very poor concrete and I would bet it’s compressive strength is no more than 2000 psi. Normal readymix is more like 3000 psi and structural concrete (that used with rebar for bridges/buildings) is twice that (4000-5000 psi). I’m guessing whoever poured the slab undercut the amount of cement used. If you mixed it in a wheelbarrow or it got overly wet because of improper formulation or rain, that would explain it. I know the slab is history now that you have moved but as an engineer I was curious…
13:40 I would call that a failed test result, The bolt continued to hold its ground and remained in the concrete,... it was the concrete that failed holding, not the bolt.
You’d have to perform that test again and get the strength required to pull the bolt out with the concrete intact.
Ah nm,... you address it at 15:25
I work on rope rescue team for the fire department. We have a rule for anchor placement that all anchor bolts must be a minimum of 6 bolt lengths away from each other and any (concrete) edges. That is because the compressive forces radiate outward. I'm curious if you ran the test again with the anchors spaced out more if the values would be different. Potentially the concrete that some of your anchors were in could have gave way prematurely due to the stress induced by the anchors on either side of it.
I love your videos and I understand your desire to maximize the number of tests you can use the concrete slab for, but I'd really like it if you guys would give a good bit more spacing between bolts especially with how that concrete dinner plates off the surface. While 10x bolt diameter is "spec" for normal use, that's assuming that you're not actively compromising the substrate around each bolt.
Looking at your testing methodology it looks like the concrete failed before most of the bolts. I would say that the values that you recorded are not valid as a bolt test but it does a nice job of testing your concrete.
On our car, some larger bolts require a light torque to snug + turn an additional angle to get the required "clamping force". Smaller bolts seem to be just torque spec. Dirty or lubricated bolts have an impact on torque.
Those specs are far too stringent for this type of bolt. As you can see from the video, there is no real difference between 10 lbf, 15 lbf, 25 lbf, 2 turns, 3 turns, any turns between 2-3 turns, etc. As long as you pre load it some, it will be enough to drive the forcing cone into the sleeve and make it tighter as you pull. Doing 1 test at each torque/number of turns is statistically irrelevant. 1 test means absolutely nothing. You'd need to do 5 tests for it to even start to become relevant. You could put 10 pins in that slab, all tightened to 20 lbf with a calibrated digital tq wrench, and they'll all pop at a different force between 10-20 lbf. There are too many other variables to consider for things like you mentioned to play a role.
Fiberglass or steel fibers mixed with the concrete may help with the spawling in tension tests
At 11:32 it looks like bolt 316 (no torque) reaches 14.86kn, much higher than the 2.96kn recorded
I think I saw this as well.
Me too.
You can see the hanger gets really bent at 14 kN, but when it cuts back to the close up, the hanger is fine, so it must be footage accidentally edited in from one of the other samples
yea, my editor put in the wrong footage right there. good eye!
I think it'd be interesting to see break testing on self tending prusiks for like a top rope solo. We did one over the weekend and end up using a pulley with a Petzl ascension but I've seen them with a tibloc, grigri, and the micro traxion too.
For anyone else confused about the units of torque in the video, they show it as 12 ft-lbs in the spreadsheet at the end. I recommend you say the actual units instead of "torque pounds" since there are at least 3 common units to measure torque.
I'm clearly no expert but I would like to see this test done further apart from each hole it seems like when you're breaking the concrete you're weakening the next bolt in progression
I've had situations where I have hammered the dynabolts in. Super tight like yours. And then I had to pull them out. No way ! Even using a pichbar, the more you yank on the pichbar it just locks up. I always have to grind them off. I'm glad I stumbled upon your channel! I always wanted to see real life scenario! I'm a bit of a nerd. Lol
Dynabolts can be removed if the hole they are installed in is deep enough for the bolt shank to be driven below the surface.
If the sleeve can be gripped the entire bolt can be removed in two pieces.
@@allangibson8494 yeah cheap shit!
Your hole spacing seem too close since the coning is close to the next bolt
That blue plastic stopper piece that you said was missing from the 5 piece bolt is not actually to keep you from overscrewing it before installation, but to keep dust and debris from getting in the cone threads which could prevent it from tightening.
Good to know. Seems to function as stopper to warn against installing the bolt if the cone is screwed to far up the sleeve as well. The blue tape might serve the same function?
Love the channel, gotta send some support as I have definitely learned a lot. These results weren't expected. I have been referring to 3/8ths 5-pieces as "removables" atop some TR solo bouldering projects as I seem to be able to break them not too far above torque (with a calibrated wrench), and just pull the pieces out with my finger (granatic gneiss) leaving just the tip behind buried in epoxy and dust like I was never there. I am wondering of the concrete wasn't hard enough to break them especially after seeing that bell shape on one of them.
Wow I want to try that. Ryan can you try this in concrete and granite?
The more torque you apply to the bolt the more outward pressure the wedge is exerting on the surrounding concrete. This could cause damage to the concrete that should be holding the bolt in the hole? That might explain why higher torque loads on the bolt (above 50%) reduced the max load before pullout. I also agree that spacing the bolts further apart will reduce skewed date. Really cool test!
the reason why they are called 5 piece, is simple, 5 metal parts. The more you know. 1. stopper, 2. bolt, 3. washer, 4. crusher, 5. expanding shafttube.
As a Millwright with 45 years in the field, most of these anchors are used to keep things bolted to a factory floor to keep them aligned , for example, conveyors, storage racks, ext. The practical application is in shear not pul! out.
as far as torque just simply use a box wrench and without jerking apply pressure on the wrench with a steady pull until the wrench stops, check the result with a torque wrench and you are probably very close and adjust accordingly. as far as anchoring overhead long bolts are required as well as a multiple hole anchor plate used in well cured concrete with reinforcement with rebar is necessary. In granite with a shear application a stainless anchor and clip should be all you need but use bigger diameter and longer bolts.
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none of the mounts failed, the concrete did. concrete is not good under "flex" or stretch it's only great with compression.
Ive never climbed, but I do tighten stuff to torque. If youre taking a spanner wrench and not a torque I dunno why you dont just bring a single open end wrench since its lighter and a better wrench. If youre taking a torque wrench, I like the one that makes a click after you set the torque on the handle. Its more compact and gives torque by feel rather than sight. Also, you can train your hand to feel torque spec more or less by repetition. 7-8 lbs. is a oil pan bolt and I would say thats good and cinched so 12 I would describe as "jam it on in there, jerk it on down" But it depends on the length of your bar for leverage also. I think this is good data and what the data says is the manufacturers lawyers are right saying "3 to 4 turns should be good" and the danger is not torqueing it at all.
The concrete breakout cone is 30 degrees off horiz from the tip of the anchor. You need to space your bolts out such that your cones do not overlap. -structural engineer
I think it would be interesting to pour a slab with large granite rock pieces. Then do some testing .
Thanks for this. I've installed bolts with a 6" wrench, tightened about as hard as I could turn it.Not sure the torque but I tap the hanger checking for how it sounds & bounce test each one.I tried a click wrench but doesn't seem to work well. Do they make a torque wrench with a "clutch" that would not allow you to torque above the setting ?
I'm a concrete contractor and can tell you drilling holes in a linear line that close together severely compromises the structural strength of the concrete. Not sure what psi your pad is or the mix you used or the cure time allowed before testing but the testing is flawed in this video.
Thank you for the videos, very informative. A video where they are spaced further apart, or in granite like you suggested would be interesting. This type of cone failure of the concrete is absolutely expected. Google image search "concrete breakout cone" and scroll through the images to see what's theoretically expected and images of the real thing, like you got. One thing with these bolts is that they are designed for use in concrete, and frequently have to meet certain requirements with respect to performance in an earthquake to be used in certain jurisdictions, since it would suck re designing a bolt for every location, a lot of them just meet it anyway. One of those requirements is a certain amount of ductility (stretching) before you expect the concrete to fail, but it's not definitely universal in all bolts.
5 pieces of metal with the hanger? also love you guys keep up the science!
the concrete failed and that's mostly the case for over torqueing the bolt. too much expansion of the bolt will compromise the material (rock or concrete) and leads to a quick fail. it is possible for the bolt itself to loose its threads and become weaker, but remember that you are working with hardened metal.
Yup. Steel is stronger than concrete, and stronger than rock. So by overtightening, you're adding stress to the rock even before you start pulling, which you have to subtract out of the total load capacity. This is also why the undertensioned bolt was actually the "strongest" - it was putting the least stress on the rock in its unweighted state. Of course, if a bolt is too loose, it'll just pop right out because of a lack of friction, so the recommended torqueing is a compromise between too much torque stressing the rock and too little resulting in the bolt becoming loose as its used.
Almost seems torquing might have added to the "stressing" factor which allowed for easier coning. Water might have made the effect even more pronounced. Hard to say because the coning definitely would make it easier for the adjacent bolts to also cone.
Would be interesting to know how the 67.79nm (50ft pounds) of rotational force translates to upward/outward force. You should figure out some way to hook the dyno up to the nut and torque it.
Either way, was expecting to see the bolts themselves fail... Good to see that there seems to be quite a bit of wiggle room from the spec.
I found a calculator here... www.engineersedge.com/calculators/torque_calc.htm
If I did it right, the "clamping force" of 50ft-lb would be ~8000lb. Not sure how impactful that is since it's a compressive force between the nut and hanger
I'd love to see this test done using wedge bolts, like the Hilti KB3!
Im interested too
Very interesting tests. In vertical tension torque would not play much of a role in breaking the bolt if over tightened, as pulling the bolt vertically releases the torque tension. Over tightening might crack the rock at the expansion point and this presents it's own issues, but I would wager in stable Granite this will not be observed.
But over tightening might actually affect shear strength, as the torque tension in the bolt is compounded with the shear tension added and this is a known failure mode. There are of course many variables, and any slip-up of the bolt in the rock will release the torque tension, so it will not be necessarily easy to observe. The zero torque bolt should be the strongest in shear, if it does not slip out.
A few things needs to be done to make these tests better.
1st. The spacing needs to be increased to the point where the damage doesn't spread out into the general area of the next bolt. In short, after the pull tests, there needs to be an unaffected area between each test, otherwise the failures overlaps and you don't know what measured value you would have actually gotten.
2nd. The tests needs to be repeated a few times to account for error margins in both the material strength of the slab, bolt, and also hole size.
I can however accept these issues, the tests are done on a relatively small budget, and they are still indicating a lower line.
I'm assuming you mean ft-lbs.. (since any torque on the scale of in-lbs seems dangerously loosenable by typical dynamic loads of one or more climbers), but it's still helpful to clarify that explicitly.
Break test a DMM XSRE biner. Its supposedly the smallest rated-carabiner on the market. 2oz and 4kn.
definitely need to test it in different materials since you're seeing the concrete fail before the bolt fails.
Hi,
I see that in your concrete you do not respect the tearing cones of the moorings. A video to see the effect of the tear-off cones on two points that are too close would be great.
I'd like to see offwidth nuts get tested in real rock. It's hard to find anything online about what constitutes a good or bad placement for offwidth nuts, and I feel like you would be able to demonstrate it well in a video. Willing to donate a set of the bd offwidth stoppers if you bust em!
Anecdotal data point: last year I was installing a 3/8” SS 5-piece with a torque wrench (yes, I brought a torque wrench for route development). That worked against me as at the time, the bolt manufacturer’s website had a typo spec of 45 ft-lbs. Tightening the first bolt to that twisted it off (bolt twisted apart down by the cone at the threads). I redrilled and for the rest of the route used Fixe wedge bolts. So the danger is that severely over tightening could get the bolt close to snapping off and it would fail in tension at quite a low value.
Interesting. Be interesting to see that replicated. That 45 ft/lb. Torque spec is for the 1/2" plated steel version of these bolts.
Would you ever test an ice screw?
0:56 did you just count the bolt head as a separate piece from the bolt threads? That can't be right.
Is it true when a body reaches maximum atmospheric velocity and splatters it turns into mist?
This is serious dedication. destroying your concrete in the back your house. It also depends on how deep that concrete goes usually it's about 4 to 6 and is that the same as a granite wall? Also the spacing doesn't make a lot of sense. Plus using a substrate that doesn't work as well as granite . But I love the video
Thx Ryan! Lets see it in granite! Do you have rock to use?
Tanks fron Brasil ... Legend preese ??!!! 🙏👍
In Granite with greater bolt spacing would be great !
Not to rain on your parade Ryan but I am a fellow concrete guy here and I would say you need thicker concrete and better spacing to get better accuracy.
You can get a concrete strengthening chemical. They use it in Australia for bottle shop where forklifts drive over. It etches 10 mm into the concrete and raises overall MPA rating. But when using it has an extremely high flashpoint! I've done a lot of concreting in the past. I've seen where the truck driver will water it down so much that when it cures after about a month I'm doing the carpentry framing and crazy cracks everywhere! I'm not making fun of your concrete. Just saying there is a lot of variables in concrete.
Great stuff!
Are your tests not only testing the strength of your concrete? It seems that this has a lot of statistical variance in it
This test tells me the concrete cure fails before the bolt. This is testing the durability of the concrete. Test again in another material. Obviously this test tells us do not forget to torque the bolts. I think a larger depth concrete and different length bolts would be better test here. That would show climbers a better understanding of how to avoid failure in softer (wet) material.
Side note, are you familiar with a German torque wrench?
I'd like to see the torque specs between 0 & 50%
Is lock-tite necessary?
Were these bolts stainless?
Do you re-patch the concrete after tests so you can use it again?
Very good 🙏👏👏👏🙏👍👏
how comparable is concrete to granite/sandstone?
Not very, Granite is far more dense.
I think you'd be surprised how many climbers do torque the bolts they install
Not trying to be that guy.
But there is "foot pounds of torque" and "inch pounds of torque" (at least for American scales). "Torque pounds" is not a scale as it does not specify which of these 2 your talking about. Again not trying to knit pick here. Great video as always cheers.
I'm a big fan of you guys testing all sorts of stuff, but this one seems a waste of time and equipment due to poor setting. (inadequate bolt spacing, the concrete condition, and the lack of 6-point socket) I've personally broken off a head of stainless steel bolts by over tightening it.
I know you are testing your set up as it would be used however I feel a true test of the bolt would be a straight pull not cantilevered
did your concrete get time to cure propperly? Should leave at least 2 -4 weeks to allow it to cure properly
Yes! Granite!
There should be a minimum spacing between bolts.
interesting test
what's a torque pound bud? inch and foot pounds I know, but torque pounds?
5:19 No one bolts with a torque wrench? Definitely not the case...
True but fixed wrench lengths are sized so that a standard 300 pound Gorilla would not be able to go much above the recommended torque.
People aren't talking torque wrenches out into the field to set bolts. It's just not happening. It's called a generalization. Just because 1 in 10k people might bring a tq wrench into the field, it still means that no one is bringing tq wrenches into the field. There's a reason why the manufacturer says 3-4 turns. It's because the torque is pretty inconsequential. You could put in 10 bolts with a calibrated digital tq wrench, and they'll all pull out at drastically different forces.
Concrete gets harder harder over time, indefinitely. At least this is the lore in the trades. So a newer slab like this will be weaker than something that has been around for 10 years.
That said, seems to me once you get large chunks of concrete blowing out so close to the other bolts I think you’d lose some compressive strength on the bolt.
I don't think you managed to show any difference (50, 100, 200%). Those numbers feel likely to be covered by concrete strength variablility.
As for 400% isn't it likely an effect of the bolt effectively shortening by almost half an inch or so? (less concrete to crater)
Also, 3KN is more than bodyweight! 🤔😅😉
You guys are putting the bolts way to close to each other. When one bolt pulls out the area it compromised the other hole next to it .. Put the bolts further apart
You should find older concrete or precast wall concrete. New concrete is weaker
There’s many things wrong with this test haha
After watching allot of bolt buster videos, I'm pretty sure something else in my system will fail before the bolt or anchor.
I don't think the test has any informative value,
Looks like the bolts are too close together and the breaking of the previous changed the outcome of the next.
I think the conclusion that this kind of bolt is as good as the medium you put it in is a valid claim.
Thanks for the hard work, keep busting!
I totally agree with you.
Да , лучше создать динамический тест - с фактором падения от 0,5 - до 2 ( и добавлять не каждый тест шаг 0,25) с использованием и без спускового устройства = тогда видео будет ещё интереснее!
Cmon!!! Could see from very beginning the bad bolt positioning, this test is no sense. Position them MUCH further apart. Thanks for your videos
Get a 6 bit socket then that 9 or 12 star socket
I just noticed that bolt buster rig looks very similar to that monilith Andy pulled out of the desert which is speculated to be a stunt for that slackline reality show... Potential conspiracy?
The data is trash at this point because the concrete failed all around the other bolts. They need to be spaced like a foot apart to make this test legit. Also there’s a considerable strength difference between plated steel and stainless.
Bring home some granite rocks, cement them together
pull them the same way as the weight of a climber would... pulling straight up is not the way to test those anchors...
results:
zero torque bolt: ~3kN
concrete: 10-16kN
(next time yout test bolts in rock, pls place them further apart. but i'm sure you came to the same conclusion
Atlantic testing canton NY
That concrete clearly isn't dry, no way that's accurate
Spacing is not enough. This test is not realistic.
Find a local civil engineer on Facebook, they’d ought to have a portable tester and probably wouldn’t mind swinging around for a beer or two. They’re quality control machines for when they pour structural concrete to make sure they’re within spec
Those welds on the aluminum 🤮
Get a better torque wrench! I’ll buy it and mail it to you!