Muir Madness
Interesting thread. We've struggled with virtually all the questions and concerns expressed here during our first year of establishing guidelines for bolting routes in Muir Valley.
First off, please note the word "guidelines." That doesn't read: "rules."
I've been working on a book, "Bolting in the Red", the first edition of which should be offered on line soon as a free downloadable pdf file. Although, I'm an engineer (retired) I am in NO WAY offering this information as my take on how bolting must be done. Rather, it is a COMPILATION of how many other experienced route developers bolt. This book provides detailed answers to the questions posted here. The book will be an ongoing project and will be added to and modified as better data and new hardware becomes available.
Several prominent RRG route developers, including Tim Powers, Terry Kindred, Blake Bowling, Hugh Loeffler, and others to be named later, have contributed to and helped with the editing of this book. We really appreciate their contributions as well as those gleaned from the American Safe Climbing Association.
It will be apparent to anyone picking up a copy of the book that there is no one perfect bolting technique or type of hardware presented as the "gospel." Furthermore, significantly different hardware and techniques are used for different types of rock. For that reason, quite a bit of research was done on how sandstone is bolted in other parts of the world. Much testing of anchor bolts has been done on the Swinburne cliffs of South Africa and also on crags in Australia. Because we didn't find any testing done on rock-mounted hardware in the Red, we are building our knowledge base on what we are learning from the S. Africa and Australia studies.
I've just finished building a monster of a hydraulic test instrument that will be used this spring to do destructive testing of anchor systems and bolted hangers installed in the Corbin Sandstone that comprises our Crags here in the Red. Much of the testing will be done to glue-in bolts, which are becoming more widely used internationally -- especially in softer rock. Got an anchor bolt or hanger/bolt combo that you would like to see tested for shear (downward force) and tensile strength (resistance to pull-out) when mounted in Corbin Sandstone? PM me and I'll tell you how to get it here for free testing.
Please stay tuned to this forum for an announcement where you can download a free copy of this book. For those of you who really want to see a preliminary copy and are willing to respond with comments and suggestions, you can PM me with reasons why you just gotta have it, and I'll email one to you.
I'll post more info later on Rawl Powerbolts vs. Redhead Dynabolts, stainless steel vs. zinc plated carbon steel, and glue-ins vs. mechanical bolts.
Rick
First off, please note the word "guidelines." That doesn't read: "rules."
I've been working on a book, "Bolting in the Red", the first edition of which should be offered on line soon as a free downloadable pdf file. Although, I'm an engineer (retired) I am in NO WAY offering this information as my take on how bolting must be done. Rather, it is a COMPILATION of how many other experienced route developers bolt. This book provides detailed answers to the questions posted here. The book will be an ongoing project and will be added to and modified as better data and new hardware becomes available.
Several prominent RRG route developers, including Tim Powers, Terry Kindred, Blake Bowling, Hugh Loeffler, and others to be named later, have contributed to and helped with the editing of this book. We really appreciate their contributions as well as those gleaned from the American Safe Climbing Association.
It will be apparent to anyone picking up a copy of the book that there is no one perfect bolting technique or type of hardware presented as the "gospel." Furthermore, significantly different hardware and techniques are used for different types of rock. For that reason, quite a bit of research was done on how sandstone is bolted in other parts of the world. Much testing of anchor bolts has been done on the Swinburne cliffs of South Africa and also on crags in Australia. Because we didn't find any testing done on rock-mounted hardware in the Red, we are building our knowledge base on what we are learning from the S. Africa and Australia studies.
I've just finished building a monster of a hydraulic test instrument that will be used this spring to do destructive testing of anchor systems and bolted hangers installed in the Corbin Sandstone that comprises our Crags here in the Red. Much of the testing will be done to glue-in bolts, which are becoming more widely used internationally -- especially in softer rock. Got an anchor bolt or hanger/bolt combo that you would like to see tested for shear (downward force) and tensile strength (resistance to pull-out) when mounted in Corbin Sandstone? PM me and I'll tell you how to get it here for free testing.
Please stay tuned to this forum for an announcement where you can download a free copy of this book. For those of you who really want to see a preliminary copy and are willing to respond with comments and suggestions, you can PM me with reasons why you just gotta have it, and I'll email one to you.
I'll post more info later on Rawl Powerbolts vs. Redhead Dynabolts, stainless steel vs. zinc plated carbon steel, and glue-ins vs. mechanical bolts.
Rick
We cannot change the cards we are dealt, just how we play the hand. - Randy Pausch
None are so old as those who have outlived enthusiasm. - Henry David Thoreau
None are so old as those who have outlived enthusiasm. - Henry David Thoreau
As we discuss and debate hardware for sport routes, we need to remember an important point.
There is a SAFETY CHAIN of "items" that keep us from decking. (This is not to be confused with a metal anchor chain.) If any link in this safety chain fails, we fall.
A typical safety chain includes the following:
Rock
Anchor bolt
Hanger bracket
Steel chain
Quick link
Quickdraw
Climber's Harness
Climbing rope
Belay device
Belayer's harness
Belayer's expertise
Climber's expertise
The failure of any one of these "links" in the safety chain can result in a climber's fall. If we can identify the weakest link, then it can be replaced or modified to increase the safety of the whole system. Of course, if this weakest link meets or exceeds our system's strength requirements, then it is not necessary to replace it.
Which links do you think are the most important? Which ones have historically had the highest failure rate?
As I research bolting here in the Red, it is becoming more and more apparent that the expertises of the climber and belayer are the weaker links. But, let's put these aside to concentrate on the non-human links in the safety chain.
Next in line may be the rock itself. After our tests of this hypothesis this Spring, we will know more. If destructive testing shows that the rock is significantly weaker than two different bolts, then little value is gained from debating the finer points of strength between these two bolt examples. Unfortunately, we can "upgrade" every link except the rock.
If we find that a particular piece of hardware fails before the rock fails, we can probably find a stronger replacement.
But, if the rock itself turns out to be the weakest link, then to specify stronger hardware for the other links in the safety chain will only increase costs and offer no additional safety. Of course, this is predicated on the requirement that all hardware links meet or exceed minimum strength requirements for the system.
What do you think the minimum system strength for YOUR safety chain should be? (For example, UIAA Standard 123 requires all types of rock anchors to have both an axial and radial load bearing capacity of 20 kN (approx 4,500 pounds.)
After all this thought, analysis, and discussion, very few of us give more than a second thought to the strength of hardware on a particular RRG route. We saunter up to the crag, squint up in the sun to see if we can figure out where the hangers are, then go for it. We sure put a lot of trust-- no, make that "blind faith" --in the folks who put this stuff up!
Rick
There is a SAFETY CHAIN of "items" that keep us from decking. (This is not to be confused with a metal anchor chain.) If any link in this safety chain fails, we fall.
A typical safety chain includes the following:
Rock
Anchor bolt
Hanger bracket
Steel chain
Quick link
Quickdraw
Climber's Harness
Climbing rope
Belay device
Belayer's harness
Belayer's expertise
Climber's expertise
The failure of any one of these "links" in the safety chain can result in a climber's fall. If we can identify the weakest link, then it can be replaced or modified to increase the safety of the whole system. Of course, if this weakest link meets or exceeds our system's strength requirements, then it is not necessary to replace it.
Which links do you think are the most important? Which ones have historically had the highest failure rate?
As I research bolting here in the Red, it is becoming more and more apparent that the expertises of the climber and belayer are the weaker links. But, let's put these aside to concentrate on the non-human links in the safety chain.
Next in line may be the rock itself. After our tests of this hypothesis this Spring, we will know more. If destructive testing shows that the rock is significantly weaker than two different bolts, then little value is gained from debating the finer points of strength between these two bolt examples. Unfortunately, we can "upgrade" every link except the rock.
If we find that a particular piece of hardware fails before the rock fails, we can probably find a stronger replacement.
But, if the rock itself turns out to be the weakest link, then to specify stronger hardware for the other links in the safety chain will only increase costs and offer no additional safety. Of course, this is predicated on the requirement that all hardware links meet or exceed minimum strength requirements for the system.
What do you think the minimum system strength for YOUR safety chain should be? (For example, UIAA Standard 123 requires all types of rock anchors to have both an axial and radial load bearing capacity of 20 kN (approx 4,500 pounds.)
After all this thought, analysis, and discussion, very few of us give more than a second thought to the strength of hardware on a particular RRG route. We saunter up to the crag, squint up in the sun to see if we can figure out where the hangers are, then go for it. We sure put a lot of trust-- no, make that "blind faith" --in the folks who put this stuff up!
Rick
We cannot change the cards we are dealt, just how we play the hand. - Randy Pausch
None are so old as those who have outlived enthusiasm. - Henry David Thoreau
None are so old as those who have outlived enthusiasm. - Henry David Thoreau
I wonder if it would be possible to drill a hole, insert a temporary device which would leach a chemical or adhesive which would absorb into the microscopic pores of the rock thereby hardening it and making it more resistant to shearing? One could then insert the bolt in the rock and the rock, at least in a small region around the bolt, would behave like a harder stone. I am sure there are epoxy formulations which could do this and not adhere to the metal or plastic applicator. Hmm, anyone know a patent attorney?
The theory of evolution is just as stupid as the theories of gravity and electromagnetism.