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Proof loading bolts 19-Jul-2009 At 7:56:42 PM contactgav

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I have been climbing since the early 90’s and since moved into the fall protection business and now I’m doing a lot of work & consultation in fall protection.

I have seen the video footage of Mikl pulling the sleeved anchors with the draw up in the mountains. Which I found completely horrifying.
The other thing is that we generally assume that most bolts are good and we only give them a visual inspection or maybe a tap or a tug. We don't know the history of the bolts and how many falls they have taken and if there have been any major falls on them.

I would think that as bolts are more likely to be loaded compared to commercial fall protection anchors, climbing anchors should be put to a proof load test.
I’m not saying that all anchors on every route new and old undergo an annual pull test, however if there are any concerns about any bolts, when checking them, I think this would be the best way to test them.

Given the field of my work, i'm fortunate to gain a sound knowledge of anchors and proof loading.
the rig pictured is an anchor pull tester. i use it on all the routes that i bolt and also on routes that i feel have a questionable bolt(s).
it is capable of pull testing 25kN, more than the UIAA standard of 22kN. however this could destroy the rock and bolt.

After liasing with Mikl about pull testing / proof loading bolts, i feel that with this rig, i can accurately check the strength of bolts in a controlled reliable manner.

Under AS1891, all chemical and sleeved fall arrest anchors must be tested under AS1891, this being, Fall Arrest anchors for single users must be proof loaded to 15kN. The concern is to avoid testing at a level that might weaken an otherwise good anchor or allow some time dependent degradation to occur (such as cracking the glue leading to further cracking during falls). Testing should try to remove the small number of faulty anchors (at about 5kN) and not damage the strong 20kN + ones.

The method i use is pull testing the bolt to 6kN for a period of 3minutes.
i have chosen 6kN as this is the proof load for fall restraint anchors under AS1891

At 6kN for 3 minutes, this will identify any poor bolts without effecting the glue of the bolt and its safety. The imposed load is a coaxial load, ie, pulling directly out. This is when the bolt is at is most weakest.

It is good pull testing the bolts before use. I get a feeling of reassurance that everything has gone right and the route is safe for public use.

much better than the often used patch samples before and after gluing the line.

if you have any questions or comments about this, please feel free to contact me. as you see the rig is very portable, if you have some bolts you'd like tested i maybe able to help out. the only cost, would be belaying me on a route or two...