First rock anchor tests in the Red

Post by **Paul3eb** » Mon Apr 04, 2005 2:47 pm

according to that link TradMike, the harness would fail before the bolts that weber tested would fail..

it's not the best rock in the world.. but it'll hold.

Post by **Ascentionist** » Mon Apr 04, 2005 3:03 pm

Gaar wrote:All of this can be prevented with a.................? (Who can guess it?)

SOFT CATCH

We can go out to Roadside this weekend and I'll give you a soft catch on C Sharp. Sound fun?

Post by **alien2** » Mon Apr 04, 2005 3:26 pm

B Flat!

Post by **tomdarch** » Mon Apr 04, 2005 9:26 pm

I thought the answer to "what kind of fall will generate enough force to break a normal bolt?" was "the knid of fall that generates enough force to break the falling climber." In other words, if the fall would break the (normal/good) bolt, then it would surely kill the climber before the bolt breaks.

Are there situations where the bolt/hanger takes high forces that the climber doesn't?

Post by **rockclimbingdude** » Tue Apr 05, 2005 2:49 am

http://climbing.com/techtips/trad/tttrad234/

Here is some more to read about falll factors.

Post by **weber** » Tue Apr 05, 2005 4:28 am

tomdarch wrote:I thought the answer to "what kind of fall will generate enough force to break a normal bolt?" was "the knid of fall that generates enough force to break the falling climber." In other words, if the fall would break the (normal/good) bolt, then it would surely kill the climber before the bolt breaks.

Are there situations where the bolt/hanger takes high forces that the climber doesn't?

Yes, there are many situations where the bolted hanger takes a significantly higher force than does the climber. For just one, refer to page 1 of this thread and the example I posted on April 3 at 11:24 PM. In this case the rope sees a shock load of 1575 pounds. The topmost quickdraw (and bolted hanger) sees a force of 1350 pounds. The belayer feels a pull of 450 pounds. And, the leader experiences a force of 900 pounds.

Nevertheless, I agree with your presumption that a fall that is severe enough to break a normal bolt would make a real mess of the climber's innerds.

Rick

Post by **Alan Evil** » Wed Apr 06, 2005 12:39 am

Rick, I really want to see/take part in one of these tests. How much are tickets?

Are you planning on doing some with explosives? Explosions are cool. Maybe you could simulate when a bolt is used for target practice by a drunk deer hunter. That would be great. I volunteer to "pretend" to be a drunk deer hunter. I'll need a loaded rifle and a case of cheap beer... and a chair.

I'm curious, how hard is it to sink a 6" hole as opposed to a 3.75" hole. I've never driven a hammer drill into Corbin sandstone but I've drilled a lot of different kinds of concrete and even the soft stuff is a work out for a hole that big, especially when perched awkwardly. For roof bolts might an angled placement with an angled chock between the bolthead and the hanger provide a far stronger arrangement? (the chock would keep the hanger forces distributed evenly from the flat hanger to the angled bolt head)

Also, shouldn't the UIAA standards be somewhere below the force that would break a person in half or cause them to become eviscerated (uh... sp?) and turned inside out? Or are they guessing that that is the force resistance required to prevent failure after repeated, smaller forces?

Post by **ynot** » Wed Apr 06, 2005 2:04 am

Does the leader usually experience a more violent force than the belay? It seems more violent to me catching someone than the falls I have taken.

Post by **weber** » Wed Apr 06, 2005 3:12 am

Alan Evil wrote:...I'm curious, how hard is it to sink a 6" hole as opposed to a 3.75" hole. I've never driven a hammer drill into Corbin sandstone but I've drilled a lot of different kinds of concrete and even the soft stuff is a work out for a hole that big, especially when perched awkwardly.

About twice as hard, i.e. proportional to the depth of the hole.

Alan Evil wrote:...For roof bolts might an angled placement with an angled chock between the bolthead and the hanger provide a far stronger arrangement? (the chock would keep the hanger forces distributed evenly from the flat hanger to the angled bolt head)

We'll have to give that one some thought. One trick some of the old timers, like Lurkist, use is to turn the hanger bracket upside down on really steep rock faces. This presents a better geometry to the draw and has a little less tendancy to peal back the hanger from the wall under a shock load.

Alan Evil wrote:...Also, shouldn't the UIAA standards be somewhere below the force that would break a person in half or cause them to become eviscerated (uh... sp?) and turned inside out? Or are they guessing that that is the force resistance required to prevent failure after repeated, smaller forces?

I don't have an answer for that one. Guess it's best to ask them. I do know that I sure don't want to see my fragile body subjected to forces even close to the UIAA 123 specs!

Rick

Post by **Kiribell** » Wed Apr 06, 2005 3:26 pm

Would someone be kind enough to translate all that into a simple estimation of what percent chance there is for a bolt to fail on a lead fall in the Red?

I realize that is an extremely simplistic question but please humor me..