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anchor testing rig


Teeds

7-Sep-2010
7:55:38 PM

The Hilti unit costs about $3,000 to purchase. But we buy a lot of Hilti gear, so we get a good discount. General public purchase is likely to be more.

J.C.

7-Sep-2010
11:24:41 PM

Just some input if anyone is looking at buying one I have used the Hilti ones (a couple generations of it and tested thousands of anchors with em) and I'm not the biggest fan, thought the Hydrajaws one was much nicer to use.

Tommo

8-Sep-2010
1:03:18 AM

Awesome Mikl, I wish I was still around to take part, but look forward to hearing the results. I think testing different glue types in eg. Blueys sandstone will be interesting, as there are so many opinions (and very little fact) going around regarding viscosity of different glues in porous rock etc. This will no doubt improve on the data from Steve's thesis, which although admirable, seemed somewhat limited in its laboratory approach.

I assume it tests with a static ie. gradually increasing load? If you can get some skinny spectra type slings donated, I'd love to see you equalise and load DBB simulation with self-equalising 'twisted-x' vs knotted, in a 120cm sling. Again, so much rumour going around. But I digress - the aim is testing anchors in rock types, not the other links in the system. But you could mix it up and occasionally kill two birds with one stone, given the comments above about wire rope and chain rigs.

mikllaw

8-Sep-2010
12:04:39 PM

On 6/09/2010 mik wrote:
>Hilti already make one of these. I used the "tester 4" on high access anchors
>high rise/industrial etc. It tests to 20kn and they make one that goes
>to 40kn, weighs about 4kg including frame and tester.

I wanted something a bit more flexible, particulary for shear testing, but the dedicated small anchor testers are good.

mikllaw

8-Sep-2010
12:13:34 PM

On 8/09/2010 Tommo wrote:
I think testing different glue types in eg. Blueys
>sandstone will be interesting, as there are so many opinions (and very
>little fact) going around regarding viscosity of different glues in porous
>rock etc.

>If you can get some skinny spectra type slings donated, I'd love to see you equalise
>and load DBB simulation with self-equalising 'twisted-x' vs knotted, in
>a 120cm sling. But I digress - the aim is testing anchors in rock types, not the other links in the system.

No, I'm open to all types of testing, though dynamic / drop tower type testing is better done on an instrumented drop tower

grangrump

8-Sep-2010
1:56:11 PM

On 7/09/2010 J.C. wrote:
>Just some input if anyone is looking at buying one I have used the Hilti
>ones (a couple generations of it and tested thousands of anchors with em)

Out of curiousity: what is tested industrially? All anchors to a fraction of rated load? Or test anchors to destruction to check glue/bolt batches?

J.C.

8-Sep-2010
2:46:25 PM

It's going back a while now but from memory the manufacturers recommendation (no 'standards' exist for testing bolts as far as I'm aware, they just have to be deemed safe by a 'competent person', so we generally just went by manufacturers rec.) was in the vicinity of 10% of SWL for 3 or 4 minutes? I could be way off in my memory there, I'll have a look in my old notes when I'm at my folks' place next


ambyeok

9-Sep-2010
2:17:11 PM

You've lost me. Sorry, whats all this testing about? Whats the specific problem that your trying to solve?

mikllaw

10-Sep-2010
8:34:02 AM

read page 1?

grangrump

10-Sep-2010
10:01:36 AM

On 2/09/2010 mikllaw wrote:
>> A solid glue-in should pull out a big come of rock, I don’t want to leave craters on cliffs so any serious testing will be away from climbs.

In my limited understanding of Bluies sandstone, sedimentary variation and differences in localised surface hardening (from salt migration/precipitation??) may make bolt strength variable.
So I for one am glad Mikl is doing some tests in rock rather than lab tests in homogeneous concrete.
(But I think that bolts in granite will be stronger!)

J.C.

10-Sep-2010
10:13:01 AM

On 8/09/2010 davidn wrote:
>On 8/09/2010 J.C. wrote:
>>It's going back a while now but from memory the manufacturers recommendation
>>(no 'standards' exist for testing bolts as far as I'm aware, they just
>>have to be deemed safe by a 'competent person', so we generally just
>went
>>by manufacturers rec.) was in the vicinity of 10% of SWL for 3 or 4 minutes?
>>I could be way off in my memory there, I'll have a look in my old notes
>>when I'm at my folks' place next
>
>10% - wtf? 2 people and a pig could weigh more than that and would be
>on 'em for far more than 3-4 minutes. Not that I'm into that big-walling
>type malarkey.

My bad, it's all coming back to me :) we tested to about 50% which for a fall arrest anchor is 7kn & for an abseil anchor is 6kn. Not sure why I had 10% in my head?!

mikllaw

10-Sep-2010
12:06:55 PM

On 10/09/2010 grangrump wrote:
>>In my limited understanding of Bluies sandstone, sedimentary variation
>and differences in localised surface hardening (from salt migration/precipitation??)
>may make bolt strength variable.
-Black rock ok
-Vertcial orange rock good
-steep orange can be mud inside

>(But I think that bolts in granite will be stronger!)
-Almost always (except some carrots). The rock strength is about 10 times higher


nmonteith

10-Sep-2010
12:17:45 PM

On 10/09/2010 mikllaw wrote:
>-steep orange can be mud inside

Its wierd - the best quality rock from the outside (the polished limestone like orange stuff) is almost always oozing mud inside. I guess the slick outside is literally like a limestone coating formed by the water evaporating from the inside of the rock onto the surface and leaving minerals behind?

mikllaw

10-Sep-2010
1:22:00 PM

No, that stuff is mostly insanely hard, like most other sandstone...
Blueys sandstone is very weak for climbing rock. It's virtually identical to nowra sandstone except for age and burial temp (induration).

The strength is a combination of binding of grains by things flowing through it (and at temperature, silica is very mobile) and heat melting the points of the grains together.

Once you get to the gramps most of the rock is fully fused and dense. Blueys is wet sand held together with snot, with an attractive orange skin on it.

I still remember Neil's disbelief whern i hand drilled a rap anchor in 3 minutes

rod

10-Sep-2010
6:12:20 PM

On 10/09/2010 mikllaw wrote:
>3 minutes

holy shit, i'd start praying!

One Day Hero

13-Sep-2010
3:12:44 PM

On 10/09/2010 nmonteith wrote:
>On 10/09/2010 mikllaw wrote:
>>-steep orange can be mud inside
>
>Its wierd - the best quality rock from the outside (the polished limestone
>like orange stuff) is almost always oozing mud inside. I guess the slick
>outside is literally like a limestone coating formed by the water evaporating
>from the inside of the rock onto the surface and leaving minerals behind?

Shipley and Bowen's?

One Day Hero

13-Sep-2010
3:21:06 PM

On 10/09/2010 grangrump wrote:
>(But I think that bolts in granite will be stronger!)

This comment shits me. Who cares which is stronger?!

I had a friend who experimented with some glue bolting in the mountains about a decade ago. He put a bunch of bolts in 30cms off the deck and got a 2.5 ton car jack underneath them. Apparently he got oil to ooze out of the seals but none of the bolts budged. 2.5 tons is massive overkill for a bolt!

I really don't think there will ever be a "cone of rock" failure at a cliff. More important is how the glue ages. Whether the bolt held 1.5 tons or 2.5 tons new is irrelevent once the glue has transformed to dust.

One Day Hero

13-Sep-2010
4:37:37 PM

On 10/09/2010 mikllaw wrote:
>Blueys is wet sand held together with snot, with an attractive orange skin
>on it.
>
Sounds similar to those aging hollywood starlets enamored with silicon and fake tan!

mikllaw

13-Sep-2010
5:04:25 PM

On 13/09/2010 One Day Hero wrote:
>I really don't think there will ever be a "cone of rock" failure at a cliff.
There could be if we make the mistake of testing them to 5kN and destroy a good climb, thus we will not be testing "good " bolts. The dodgy ones are easy to pick

testing aging glue is important, the twist strength of rings is intersting also

mikllaw

17-Sep-2010
8:53:25 AM

Rob LeBreton had a pretty spectacular case of bolt failure (carrot failure, long fall, chopper ride) which subsequently fuelled the move to glue-in anchors. Rob has Graciously allowed me to call the testing rig “Robbie the robot”

There are 72 messages in this topic.