BoltBuster - Wave bolts, ac100 glue, tension break tests

Wave bolts pulled out of the AC100 polyester glue in our tension test at 31.26kn and 28.46kn and 27.72kn.  with Bobby Hutton.  We try to do 3 samples of each test, and in an effort to keep the videos short enough to be interesting but useful enough to be worth watching, we are sharing our results as a batch of 3 samples instead of just 1 fancy slow motion shot.  Yes we did this in epoxy, yes we did it in shear, yes we are doing every other bolt you can imagine and yes we will be using real rock soon.  Give us (constructive) feedback as we read all the comments and it does help shape our next tests.  Cheers! 

Mildly interesting.   Looks like the concrete you're using is fracturing/spalling, so your results are conflated, but everything is well above the UIAA standard, so no biggie.   I'd be mildly interested in elastic vs. plastic deformation of the bolt.   Also, a torque test would be interesting since I've never seen one done.  What's quite interesting is that the Wave Bolt doesn't conform to 2.2.1, below.

"2.2.For the award of the UIAA Label, the following additional safety requirements shall be met:
Design:2.2.1.The embedded part of any rock anchor held in place by a chemical bonding agent shall have deformations or roughness, intended to prevent extraction or rotation.
           2.2.2.When tested in accordance with 3.3all types of rock anchors shall have an axial load bearing capacity of 20 kN.
          2.2.3.When tested in accordance with 3.4 all types of rock anchors held in place by achemical bonding agent shall withstand a torque of 150 N-m for 60(0/+5) seconds without rotating in the hole."

AC-100 isn't as good as epoxy.  Yup, we knew that.  

Just FYI, one bolt tester I'm familiar with epoxies the bolts into a steel block (approx 1'x1'x1') for pull tests.   The block is unfazed, the epoxy doesn't fail, and he is able to isolate the bolt strength.   After the test the shaft can be heated with a torch, which softens the epoxy, and pulled out so you can reuse the block.

Thanks for posting  these!  I love seeing all these posts from y'all.  Super interesting that it deforms at 5Kn I had no idea!

Does it deform at 5kN when the pull is in the direction it’s designed for instead of straight out?

You’d have to place it upside down  in a foundation or  other vertical Surface near the floor so you could have your rig sitting on the floor pulling up on the bolt in the vertical surface. 

This is very satisfying to watch.

bus driver wrote: Does it deform at 5kN when the pull is in the direction it’s designed for instead of straight out?

You’d have to place it upside down  in a foundation or  other vertical Surface near the floor so you could have your rig sitting on the floor pulling up on the bolt in the vertical surface. 

We tested the Wave bolts in shear as well. They do deform in the same way in shear. Think about it, the SS wire is just bent into the P shape and it reshapes to whatever pulls it with enough force (all of the 6mm wire bolts we have tested so far started to deform in the 4 to 8 kn range.) 

We used another rig to test in shear. 

Cool. Thanks for the explanation and all the testing.  

John Byrnes wrote: Mildly interesting.   Looks like the concrete you're using is fracturing/spalling, so your results are conflated, but everything is well above the UIAA standard, so no biggie.   I'd be mildly interested in elastic vs. plastic deformation of the bolt.   Also, a torque test would be interesting since I've never seen one done.  What's quite interesting is that the Wave Bolt doesn't conform to 2.2.1, below.

"2.2.For the award of the UIAA Label, the following additional safety requirements shall be met:
Design:2.2.1.The embedded part of any rock anchor held in place by a chemical bonding agent shall have deformations or roughness, intended to prevent extraction or rotation.
           2.2.2.When tested in accordance with 3.3all types of rock anchors shall have an axial load bearing capacity of 20 kN.
          2.2.3.When tested in accordance with 3.4 all types of rock anchors held in place by achemical bonding agent shall withstand a torque of 150 N-m for 60(0/+5) seconds without rotating in the hole."

AC-100 isn't as good as epoxy.  Yup, we knew that.  

Just FYI, one bolt tester I'm familiar with epoxies the bolts into a steel block (approx 1'x1'x1') for pull tests.   The block is unfazed, the epoxy doesn't fail, and he is able to isolate the bolt strength.   After the test the shaft can be heated with a torch, which softens the epoxy, and pulled out so you can reuse the block.

They actually deform under far lower forces but it´s usually neither relevant nor a problem, the lower acceptable limit is when they bend under bodyweight as this kinda freaks climbers a bit! About 2.5kN is the ballpark but it´s hard to measure exactly.

The Wave Bolt does conform, the bends in the rods are the mechanical resistance. However as you can see from the video they straighten out under load and in reality all that is then holding it in is the weld at the bottom. Our twisted leg bolts also do this to a certain extent but at higher forces, it´s kinda complicated what actually happens under load. Paragraph 2.2.1 is simply requiring that the resistance to extraction must be purely mechanical, that is just depending on the resin bond is not permitted.

The torque test is basically ignored, it´s there to require there is some design feature of the bolt intended to prevent rotation and all two-legged bolts have this automatically. The intepretation of this test is flexible! The requirement is as usual poorly written as it doesn´t doesn´t consider a bolt which is strong enough in all respects but the eye twists without the bolt coming loose. Ours look like this after 100Nm;

But it still hasn´t come loose, this one is twisted 360° but you can go further, 540° and it would probably snap off. Even brutalised like this it still held 32.6kN axial pull.

Sure it´s weaker than normal and failed in a different place but still vastly stronger than needed. And it´s kind of difficult to visualise a climbing circumstance where this would occur!

Just to test the bolt strength we either use longer bolts resined in to granite blocks or for routine testing clamp them in a split metal block. The new EN959 discourages the use of polyester resin BUT a) this is in fact outside the remit of the standard, b) ignoring the real world since the majority of bolts are installed with this or more likely nowadays vinylester. Therefore we certify with all the common resin systems.

Jim Titt wrote:

They actually deform under far lower forces but it´s usually neither relevant nor a problem, the lower acceptable limit is when they bend under bodyweight as this kinda freaks climbers a bit! About 2.5kN is the ballpark but it´s hard to measure exactly.

Yup.  We know that you can take a hard fall on a glue-in and it will not have any permanent (plastic) deformation afterwards, so I was just interested (academically)  in where that threshold was.  

The Wave Bolt does conform, the bends in the rods are the mechanical resistance. However as you can see from the video they straighten out under load and in reality all that is then holding it in is the weld at the bottom. 

Yes, and in my opinion, this is a design defect.  The hole for the Wavebolt must be drilled deeper than you'd expect because the bolt lengthens as you pound it in.  So it's really no surprise that the same thing (straightening of the bends) happens coming out.  And, IMO, it does not conform because of this deformation, and the tests here show that.

Our twisted leg bolts also do this to a certain extent but at higher forces, it´s kinda complicated what actually happens under load. Paragraph 2.2.1 is simply requiring that the resistance to extraction must be purely mechanical, that is just depending on the resin bond is not permitted.

Yes.  The standard allows for binding mortars to be used, which hold purely via mechanical action.   Thus, if you used a binding mortar with a Wavebolt, I have serious doubts that it would meet the pull-out standard.

The torque test is basically ignored, it´s there to require there is some design feature of the bolt intended to prevent rotation and all two-legged bolts have this automatically. The intepretation of this test is flexible! The requirement is as usual poorly written as it doesn´t doesn´t consider a bolt which is strong enough in all respects but the eye twists without the bolt coming loose. Ours look like this after 100Nm;

But it still hasn´t come loose, this one is twisted 360° but you can go further, 540° and it would probably snap off. Even brutalised like this it still held 32.6kN axial pull.

Sure it´s weaker than normal and failed in a different place but still vastly stronger than needed. And it´s kind of difficult to visualise a climbing circumstance where this would occur!

I got to place more of your bolts recently.  I like them FAR better than the Wavebolt, which has all sorts of bad attributes.   By the way, your 5/8" version is a fucking beast!

Really awesome.  Thanks!

John Byrnes wrote: I got to place more of your bolts recently.  I like them FAR better than the Wavebolt, which has all sorts of bad attributes.  

This has been my experience as well.  The fact they seize 1/3 of the way into the hole and need to be pounded is a PITA and does result in botched placements.  I tested this and found you need a 14mm hole for the waves to be more or less frustration free.  BP bolts work with 12mm or 1/2".

John Byrnes wrote: Yup.  We know that you can take a hard fall on a glue-in and it will not have any permanent (plastic) deformation afterwards, so I was just interested (academically)  in where that threshold was.  

Yes, and in my opinion, this is a design defect.  The hole for the Wavebolt must be drilled deeper than you'd expect because the bolt lengthens as you pound it in.  So it's really no surprise that the same thing (straightening of the bends) happens coming out.  And, IMO, it does not conform because of this deformation, and the tests here show that.

Yes.  The standard allows for binding mortars to be used, which hold purely via mechanical action.   Thus, if you used a binding mortar with a Wavebolt, I have serious doubts that it would meet the pull-out standard.

I got to place more of your bolts recently.  I like them FAR better than the Wavebolt, which has all sorts of bad attributes.   By the way, your 5/8" version is a fucking beast!

The standard is confused as well, it refers to "glue" and "adhesive"  when a purely glued in bolt is unnaceptable and the test lab would rightly fail it.  The only system is using a mortar and that's why mechanical engagement is required.

mattm wrote:

This has been my experience as well.  The fact they seize 1/3 of the way into the hole and need to be pounded is a PITA and does result in botched placements.  I tested this and found you need a 14mm hole for the waves to be more or less frustration free.  BP bolts work with 12mm or 1/2".

I haven’t placed the wave bolts but I thought the interference fit was on purpose  for bolting on lead with them and having a decent placement even if the glue wasn’t dry.  

bus driver wrote:

I haven’t placed the wave bolts but I thought the interference fit was on purpose  for bolting on lead with them and having a decent placement even if the glue wasn’t dry.  

The main purpose is to keep the bolt in place so it doesn't slide out when on overhanging terrain.  While people claim you can "bolt on lead" with this I'm not aware of ANY ONE who would want to do this.  Yeah, you could I guess but bolting glue ins on lead is about as painful an experience as I could imagine...  BPs slight interference is much better IME

Thanks. I’ll stick to mechanicals for bolting on lead. 

mattm wrote:

This has been my experience as well.  The fact they seize 1/3 of the way into the hole and need to be pounded is a PITA and does result in botched placements.  I tested this and found you need a 14mm hole for the waves to be more or less frustration free.  BP bolts work with 12mm or 1/2".

Pounding isn't the only PITA part.  They have a tendency to twist as you pound, resulting in a non-vertical eye orientation which is almost impossible to fix once the bolt is fully seated.  I've tried orienting the eye at 1/2 depth, again at 3/4, but it seems the further in  they go, the more twist occurs.  So it's really a PITA to get them oriented the way you want.    

Following. Thanks for the effort and taking on the expense. Very curious how the Twist Bolts do. Placed about 60 now and I like them a LOT more than the Wavebolts.

John Byrnes wrote: Mildly interesting.   Looks like the concrete you're using is fracturing/spalling, so your results are conflated, but everything is well above the UIAA standard, so no biggie.   I'd be mildly interested in elastic vs. plastic deformation of the bolt.   Also, a torque test would be interesting since I've never seen one done.  What's quite interesting is that the Wave Bolt doesn't conform to 2.2.1, below.

"2.2.For the award of the UIAA Label, the following additional safety requirements shall be met:
Design:2.2.1.The embedded part of any rock anchor held in place by a chemical bonding agent shall have deformations or roughness, intended to prevent extraction or rotation.
           2.2.2.When tested in accordance with 3.3all types of rock anchors shall have an axial load bearing capacity of 20 kN.
          2.2.3.When tested in accordance with 3.4 all types of rock anchors held in place by achemical bonding agent shall withstand a torque of 150 N-m for 60(0/+5) seconds without rotating in the hole."

AC-100 isn't as good as epoxy.  Yup, we knew that.  

Just FYI, one bolt tester I'm familiar with epoxies the bolts into a steel block (approx 1'x1'x1') for pull tests.   The block is unfazed, the epoxy doesn't fail, and he is able to isolate the bolt strength.   After the test the shaft can be heated with a torch, which softens the epoxy, and pulled out so you can reuse the block.

We will be testing in rock of all types as we now have our hydraulic systems working smoothly (know that we know what we are doing haha)

That steel block idea has my wheels turning.  I do want to test a whole lot in real rock but that could be nice for some of the testing (when it's raining outside and the stoke is still high).  
What we noticed was it was elastic up to 5kn then permanently deformed after that.

bus driver wrote: Does it deform at 5kN when the pull is in the direction it’s designed for instead of straight out?

You’d have to place it upside down  in a foundation or  other vertical Surface near the floor so you could have your rig sitting on the floor pulling up on the bolt in the vertical surface. 

It does deform at 5kn in shear as well but it takes a lot more to get it to break or pull out

We have a hydraulic cylinder that we anchor on one side and pull our samples on the other side for shear testing

bus driver wrote:

I haven’t placed the wave bolts but I thought the interference fit was on purpose  for bolting on lead with them and having a decent placement even if the glue wasn’t dry.  

Spoiler alert... in tension they come out at 1.5 to 2.5kn with no glue and all over the place when pulled in shear with no glue (but mostly high enough).  I'd hesitate whipping on one with uncured glue.

Ma Ja wrote: Following. Thanks for the effort and taking on the expense. Very curious how the Twist Bolts do. Placed about 60 now and I like them a LOT more than the Wavebolts.

We have and are testing them.  We like them too.  Sharing 3 to 6 tests a week takes a surprisingly long time to share all the data haha