Nice work. As they say, plagiarism is another form of flattery!
A few points:
Fig 1.5 is of one of my bolts (a belay bolt, hence the relatively large eye) and above this it is stated:-
"In some configurations one spiral can ride up over the other spiral and jam the bolt in its hole; however this probably depends on the direction of pull and can’t be relied on. There is no weld to crack or corrode."
The movement of the two legs in the hole after glue failure is NOT dependent on the direction of pull and CAN be relied on. We have tested hundreds of these bolts and it always occurs, both radial and axial testing. The movement produces a wedging action and raises the pull-out resistance by an enormous amount,this size of bolt getting up to 49kN pulled straight out in granite. We even perform and publish no-glue pull-out tests, the model shown holding 12kN straight out and 20kN radial.
How effective this is is well illustrated by Fig 2 on page 4 which is another of my bolts being tested in very soft ("We purposely chose a softer, weaker piece of sandstone for this test") sandstone in the U.S.A. Rick Weber of Red River Climbing has not been able to pull any of these test bolts out and states they are the strongest bolts he has ever tested. The same results are obtained in tests by the British Mountaineering Council who have not been able to pull out any of our bolts.
The highest value we have yet achieved is 102,9kN for a bolt glued with polyester in granite with a straight out (axial)test.
The section on fatigue (Appendix 6) shows how important correct anchor design is, we have performed repeat axial pulls on our bolts, our test protocol being 1000 x 25kN pulls then raising the force in 5kN steps with 100 pulls each. After 1,362 pulls the test block (granite) failed at 44,6kN. This is with the smallest bolt we produce.
We also perform high frequency fatigue tests with a load of 800N being applied 1500 times minute, we have had no bolt failures and one is still going strong after over 130.000.000 cycles (which reminds me to do something about it).
That is amazing! What a great resource and only 52 pages!
After reading about the latest tradgedy downunder, I think
this should be required reading for those "visitors" that
want to bolt in soft rock!
I was actually really impressed with the baby angle solution in Zion. It doesn't seem like they are prone to the erosional problems of expansion bolts. But possibly Piton Ron would know more on that subject! I only climbed there in short spurts, during different years! So maybe some were replced periodically?
That reminds me of a funny story, well not at the time, I was sitting in a lawn chair racking up for "Days of No Future" in Zion when Olevesky and Bridwell got out of the car (silver Mercedes?) with a spotting scope. They walked over to us and I looked up and said, Middendorf! Well Bridwell gave me an irritated blank stare and I quickly said, Birdman! I am not sure that broke the ice, but they chatted it up with us for awhile anyway! Damn. hope I got all the details right this time!
I know nobody wants to hear it, but I normally get at least one of those every season in Yosemite.
Only one this season in TM. First or second hit while trying to start the tuning fork under one cornor of the hanger. This bolt protected a ground fall and I guess no one ever fell there. I am betting that a lot of the bolts on easier routes have never experienced the force of a fall.