RRC Archives

Here are some numbers in terms of the amount of force you can hold before slippage occurs. As you can see the grigri holds alot of force before slipping, thereby not decreasing any energy for a long time.

Body belay 1 kN (250 lb.)
Figure of eight in rappel mode 1.5 kN (350 lb.)
Slot devices (ATC, Sticht plate, etc.) 2 kN (450 lb.)
Slot device with 2 carabiners 3 kN (700 lb.)
Müenter hitch 3 kN (675 lb.)
Grigri 9 kN (2025 lb.)

There were some really interesting abstracts in the conference agenda. Especially the three dimensional analysis of climbers at the Innsbruck world comp. I would love to see the entire paper/presentation of these. It looks like there has been two of these conferences already. Really interesting stuff!!

Eric, please don't all abstract on us. All this science I don't understand. It's just my job five days a week.

Eric wrote:There were some really interesting abstracts in the conference agenda. Especially the three dimensional analysis of climbers at the Innsbruck world comp. I would love to see the entire paper/presentation of these. It looks like there has been two of these conferences already. Really interesting stuff!!

We'll try to get copies.

Rick

I have already emailed the University to try to obtain copies from the two conferences.

This thread makes me giddy!

Nothing like talk of forces and vectors to get the old juices flowing.

Hi There in America.
A friend put me onto this thread. I wrote the stuff about bolting in climbargolis and have some more to add when it is finished which will answer most of your questions. We have done plenty of testing here and in Greece and the answer is that glue-ins are the way to go, cheap and long lasting.
To remove them heat them up to about 140°C and pull with a wrecking bar. Cost- we make them ourselves from stainless bar, with glue they cost around 60 US cents each. Durability. The constuction glues are certified here for 20 yrs and tests in Germany show no deterioration after 15 yrs. We get around 38kN pull out, in sandstone the German Alpine Club use 150mm long bolts. Don´t use staples.
Nice to see your forums drift off into re-inventing the wheel like everyone elses, impact testing is pointless, the bolt must hold a force of ca 20kN however it is applied and why test with static rope or maybe you climb differently in the U.S.? For easy to understand info on the forces in a fall check out the info pages from Petzl or Beal.
Good climbing and safe bolting.
Jim

jimtitt wrote:Hi There in America.
A friend put me onto this thread. I wrote the stuff about bolting in climbargolis and have some more to add when it is finished which will answer most of your questions. We have done plenty of testing here and in Greece and the answer is that glue-ins are the way to go, cheap and long lasting.
To remove them heat them up to about 140°C and pull with a wrecking bar. Cost- we make them ourselves from stainless bar, with glue they cost around 60 US cents each. Durability. The constuction glues are certified here for 20 yrs and tests in Germany show no deterioration after 15 yrs. We get around 38kN pull out, in sandstone the German Alpine Club use 150mm long bolts. Don´t use staples.
Nice to see your forums drift off into re-inventing the wheel like everyone elses, impact testing is pointless, the bolt must hold a force of ca 20kN however it is applied and why test with static rope or maybe you climb differently in the U.S.? For easy to understand info on the forces in a fall check out the info pages from Petzl or Beal.
Good climbing and safe bolting.
Jim

Thank you very much Jim for your input. Can you answer these questions:
1. What is the alloy composition of your stainless steel?
2. What diameter of s.s. rod are you using?
3. Are you using an "eye" type bolt or threaded rod?
4. And, if you are using an eye-bolt, then I assume you weld the loop closed?

We tried glue-in threaded rods with a nut and hanger bracket here, but ended up with the same problem of the hanger brackets loosening after repeated falls on them. When jerked they sometimes tend to crush the sandstone surface behind them, causing the hanger to loosen. The FIXE eye-bolt seems to solve this problem. But, this is a very expensive piece of hardware. We have considered making our own glue-ins, but have not done so. We are very interested in how you make and install yours.

jimtitt wrote: impact testing is pointless, the bolt must hold a force of ca 20kN however it is applied ...
Jim

Agreed that the radial and axial forces can be applied effectively in a non-impact manner. Many of us have been curious to see just how much force a climber and the hanger bracket experiences during actual falls of various fall factors. That is why we are going to be doing the falling tests with a load cell.

jimtitt wrote:... maybe you climb differently in the U.S.?
Jim

There are some in our climbing community who purposely take long falls at the end of each climb. Instead of clipping the top anchors, they just touch them and fall, putting an unnecessary stress on the last bolt below the top anchors. Often, a little extra rope is payed out to increase the length of the fall. These senseless acts of daring are referred to as "Victory Whippers" and "rope jumping." We have been unsuccessful in convincing these irresponsible climbers that they are putting unecessary stress on bolted hardware (which are mostly mechanical sleeve bolts here in this area.)

Thank you again, Jim for any information you can provide us.

Rick Weber

Rick, please do not refer to me as "irresponsible." If the forces of falling on the last bolt are so bad for the bolts, then we should have been seeing bolts fail left and right.

Thanks.

Wes