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ceramiclover
Mar 29, 2010, 10:44 PM
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I am looking to bolt the climbing tower at the local ropes course and am looking for advice on the type of bolt I should use. I plan on using FIXE hangers because they are cheap and stainless. If there a better choice i would like to know.
The main problem is that I need a a bolt that will take a nut at the back, rather than a concrete expansion bolt. I was also advised by a ropes course inspector to put a metal plate on the back to spread the force. Thoughts on this?
The wall is composed of vertical 2X6's, screwed into horizontal 4X6's. Intuition tells me that I should bolt through the 4X6's, but the 2X6's would suffice, I would be open.
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acorneau
Mar 30, 2010, 2:11 AM
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ceramiclover wrote: I am looking to bolt the climbing tower at the local ropes course and am looking for advice on the type of bolt I should use. I plan on using FIXE hangers because they are cheap and stainless. If there a better choice i would like to know. The main problem is that I need a a bolt that will take a nut at the back, rather than a concrete expansion bolt. I was also advised by a ropes course inspector to put a metal plate on the back to spread the force. Thoughts on this? The wall is composed of vertical 2X6's, screwed into horizontal 4X6's. Intuition tells me that I should bolt through the 4X6's, but the 2X6's would suffice, I would be open.
First, I would recommend you contact these guys for real answers:
http://www.acctinfo.org/
For my personal opinion, use grade 8 bolts through the 4x6 and use some nice large fender washers on both sides of the beam.
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USnavy
Mar 30, 2010, 8:40 AM
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ceramiclover wrote: The main problem is that I need a a bolt that will take a nut at the back, rather than a concrete expansion bolt.
Are you bolting the wall for lead climbing? What are the bolts going to be used for?
(This post was edited by USnavy on Mar 30, 2010, 8:41 AM)
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ceramiclover
Mar 30, 2010, 8:28 PM
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Yes, we will be leading. We might also put in a pair of anchors for multi-pitch practice.
What is the danger with mixing stainless hangars and non-stainless? I had not expected to do this, given that the wall is outdoors, but would still like to know the danger.
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johnwesely
Mar 30, 2010, 8:41 PM
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ceramiclover wrote: Yes, we will be leading. We might also put in a pair of anchors for multi-pitch practice. What is the danger with mixing stainless hangars and non-stainless? I had not expected to do this, given that the wall is outdoors, but would still like to know the danger.
Galvanic corrosion.
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acorneau
Mar 30, 2010, 8:42 PM
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ceramiclover wrote: Yes, we will be leading. We might also put in a pair of anchors for multi-pitch practice. What is the danger with mixing stainless hangars and non-stainless? I had not expected to do this, given that the wall is outdoors, but would still like to know the danger.
Galvanic corrosion:
http://en.wikipedia.org/wiki/Galvanic_corrosion
One other thing you have to consider would be the reaction between the fasteners and treated wood.
Again, your best information is going to come from ACCT.
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ceramiclover
Mar 30, 2010, 8:52 PM
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Thanks for the corrosion info. I haven't found anything on the websites, so I am going to just contact the guy who inspects our course.
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mojomonkey
Mar 30, 2010, 9:59 PM
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ceramiclover wrote: I am looking to bolt the climbing tower at the local ropes course and am looking for advice on the type of bolt I should use. I plan on using FIXE hangers because they are cheap and stainless. If there a better choice i would like to know. The main problem is that I need a a bolt that will take a nut at the back, rather than a concrete expansion bolt. I was also advised by a ropes course inspector to put a metal plate on the back to spread the force. Thoughts on this? The wall is composed of vertical 2X6's, screwed into horizontal 4X6's. Intuition tells me that I should bolt through the 4X6's, but the 2X6's would suffice, I would be open.
Yep, cruising this forum seems like the best way to make important safety decisions for the equipment that other people will be relying...
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mojomonkey
Mar 30, 2010, 10:05 PM
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ceramiclover wrote: Thanks for the corrosion info. I haven't found anything on the websites, so I am going to just contact the guy who inspects our course.
Assuming the inspector is not just some other random guy winging it, why would you not be going with his guidelines? If the plates to distribute force are required to pass inspection, why would you be trying to find alternate approaches? I assume the plates are mandated by the climbing wall insurance regulations as well; I'm pretty sure that is what our gym uses. Though I have no idea what the required dimensions would be or any other regulations cause I'm just some other random guy on the internet you shouldn't be asking how to safely equip your wall...
Just think, if mixing metals and possible dangers wouldn't have been on your radar, what else might you do that is dangerous without knowing?
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ceramiclover
Mar 30, 2010, 11:37 PM
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The plate on the back wall was the recommendation of a guy who inspects a gym I climb at. I am having trouble contacting him and was wondering if other people on these forums had experience on the matter. The ACCT guy that inspects our course will ultimately have to approve of the method, though I suspect that he may not be the best help, given that sport climbing is atypical of ropes courses.
That is why I asked on a climbing forum, which can point me toward alternate resources.
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bill413
Mar 31, 2010, 4:28 AM
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USnavy wrote: ceramiclover wrote: The main problem is that I need a a bolt that will take a nut at the back, rather than a concrete expansion bolt. Yea that’s called a machine bolt, AKA the most popular bolt in the world, AKA the bolt type that can be found at any hardware store in the world. I would use 3/8" stainless steel bolts if it’s outside or 3/8" grade eight bolts if inside. If you place stainless steel hangers you MUST place stainless steel bolts. DO NOT mix grade 8, 5, or 2 bolts with stainless steel hangers.?
Don't use cheapo/non-grade bolts.
Also, to avoid galvanic corrosion, the plates & nuts should probably also be ss.
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USnavy
Mar 31, 2010, 9:17 AM
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ceramiclover wrote: Yes, we will be leading.
If you attach the bolts to 2x4's or spreader plates and a bolt pulls, it’s almost guaranteed any law suit filed against you would result in a judgment in the plaintiff's favor. Additionally, your insurance company may decline to cover any damages from the incident when they find out you were using 2x4's to hold lead falls. Even if the "wall inspector" green lights your wall, an investigation would show that any major climbing wall manufacturer uses steel and that no manufacturer would recommend the use of wood to support a lead fall.
That said I would look at rebuilding the frame of your wall if you really want to lead on this wall. Lastly, be careful if you do a multi-pitch class on the wall. Factor two falls are not forgiving and if someone takes one, I can almost guarantee you an injury is going to come with it.
(This post was edited by USnavy on Mar 31, 2010, 9:19 AM)
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johnwesely
Mar 31, 2010, 12:22 PM
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USnavy wrote: ceramiclover wrote: Yes, we will be leading. Well then you are going to have some issues. I would not use a piece of steel on the back of the wall to distribute the force. They did this back in the old days but I wouldn’t do that now. Eldorado Climbing Walls builds the entire exoskeleton of their walls with 3/16" steel. Also those Pine Wood 2x4's are not something I would trust to hold a lead fall, they are not that strong. If you intend to lead on the wall, the wall must have a frame designed to hold lead falls. I have never heard of a wall with lead climbing that has a frame built of anything else other then steel. If you attach the bolts to 2x4's or spreader plates and a bolt pulls, it’s almost guaranteed any law suit filed against you would result in a judgment in the plaintiff's favor. Additionally, your insurance company may decline to cover any damages from the incident when they find out you were using 2x4's to hold lead falls. Even if the "wall inspector" green lights your wall, an investigation would show that any major climbing wall manufacturer uses steel and that no manufacturer would recommend the use of wood to support a lead fall. That said I would look at rebuilding the frame of your wall if you really want to lead on this wall. Lastly, be careful if you do a multi-pitch class on the wall. Factor two falls are not forgiving and if someone takes one, I can almost guarantee you an injury is going to come with it.
He said he was going to use 4X6s not 2X4s. Those are pretty beefy pieces of wood. That being said, if anything were to happen, I am sure it would be a nightmare.
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USnavy
Mar 31, 2010, 12:25 PM
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Yes, 4x6's, none the less unacceptable IMO. I would not trust a 4x6 to take 10 kN across its width.
(This post was edited by USnavy on Mar 31, 2010, 12:28 PM)
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johnwesely
Mar 31, 2010, 12:35 PM
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USnavy wrote: Yes, 4x6's, none the less unacceptable IMO. I would not trust a 4x6 to take 10 kN across its width.
You would probably know better than me.
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I_do
Mar 31, 2010, 1:40 PM
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johnwesely wrote: USnavy wrote: Yes, 4x6's, none the less unacceptable IMO. I would not trust a 4x6 to take 10 kN across its width. You would probably know better than me.
I would beg to differ.
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angry
Mar 31, 2010, 1:50 PM
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USnavy wrote: Yes, 4x6's, none the less unacceptable IMO. I would not trust a 4x6 to take 10 kN across its width.
I wish a 4x6 was the smallest tree I'd rapped off. Or slung and fallen on. Or dyno'd to. Or set up a hanging belay off of.
If I'd built myself a big home wall and intended to lead, I wouldn't hesitate to use 2x6's to anchor the bolts.
Understand though, for instructional use, there is basically no implied risk. You have to everything so outrageously overbuilt that there is no chance of a failure. You can't go with 'good enough', even though it is. You have to go with industry standard for institutional use, which is way stronger.
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USnavy
Mar 31, 2010, 2:02 PM
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I_do
Mar 31, 2010, 2:04 PM
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USnavy wrote: I_do wrote: johnwesely wrote: USnavy wrote: Yes, 4x6's, none the less unacceptable IMO. I would not trust a 4x6 to take 10 kN across its width. You would probably know better than me. I would beg to differ. Because you clearly know the answer... 
I disagree
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shoo
Mar 31, 2010, 2:07 PM
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angry wrote: USnavy wrote: Yes, 4x6's, none the less unacceptable IMO. I would not trust a 4x6 to take 10 kN across its width. I wish a 4x6 was the smallest tree I'd rapped off. Or slung and fallen on. Or dyno'd to. Or set up a hanging belay off of. If I'd built myself a big home wall and intended to lead, I wouldn't hesitate to use 2x6's to anchor the bolts. Understand though, for instructional use, there is basically no implied risk. You have to everything so outrageously overbuilt that there is no chance of a failure. You can't go with 'good enough', even though it is. You have to go with industry standard for institutional use, which is way stronger.
My main concern isn't with the wood being thick enough; it's with the wooden construction of the wall itself. Ropes course walls are typically not built for this kind of force. What are the chances that the beam is going to rip out altogether?
Personally, I wouldn't lead on any man-made climbing wall that wasn't built and bolted using a steel skeleton, and absolutely wouldn't make an addition like this for institutional use. If things go wrong, it's your fault. Period. Forget any of this waiver BS. None of it will hold in court. Gross negligence cannot be signed away, and that'll be the item that gets you.
Can I ask what kind of ropes course this is? Who uses it? What kind of program?
Forget about trying to teach people or practice multi-pitch on this kind of thing. A ropes course is woefully inadequate for this kind of thing. The only thing you can accomplish is a false sense of security for when people want to actually climb multi-pitch.
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angry
Mar 31, 2010, 2:12 PM
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Another thing.
Galvanic corrosion is real. For an outdoor wall in South Dakota (not Bermuda), regularly maintained, I think the wood would rot away before the swapping of ions caught up to you.
Throw a lot more water, some salt, some limestone, and constant humidity into the mix and we've got a different story all together.
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ceramiclover
Mar 31, 2010, 11:37 PM
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It is a standard, static ropes course. We work for the YMCA, though, and occasionally use the climbing wall for our climbing program, lead by AMGA SPI's. The leading aspect would never come into play with people going through the course, only those learning to climb.
As for the factor 2 comment, we could theoretically go through the 20" telephone polls if that were necessary.
And again, with respect to the wood:
The wall is made of vertical telephone poles, with horizontal 4X6's and 2X6's decked onto the front of them. A steel plate could theoretically spread across multiple 2X6's, but i am realizing that the connections to the 4X6's would probably not be sufficient unless we beefed them up.
Again, thanks for the comments
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acorneau
Apr 1, 2010, 12:55 AM
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ceramiclover wrote: but i am realizing that the connections to the 4X6's would probably not be sufficient unless we beefed them up.
If you went through the intersection of a horizontal 4x6 and a vertical 2x6 I think you'd be fine, but that's just my guess.
Yes, going through the telephone poles would be perfectly bomber.
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benmoreite
Apr 1, 2010, 1:00 AM
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Just contact the ACCT. They can tell you what does and does not meet the standards for challenge courses. That being said, something like the Project Adventure LEAP anchor found about a third of the way down this page: http://www.pa.org/...uipment_chcourse.php might be worth looking into.
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JimTitt
Apr 1, 2010, 6:35 AM
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Plenty of wood framed commercial wall manufacturers out there, people like http://www.experientialsystems.com
for example.
Any static engineer who works in timber frame construction can give you the correct backing washer dimensions and bolt size as well as the allowable load on the beam, or you can look this up yourself.
Repeated radial loading may give problems with the bolt tearing down through the wood and bending in softwood, there are tube inserts available to spread the load or you get a suitable sized thick walled tube and make your own.
In the boat building industry we would only use a 2X6 to hold the boat up in the workshop! We would have no problems with just glueing a bolt into the wood and there is enough research into this from both the marine and aircraft industry, glued fittings are commonplace in the wooden boat industry these days. For the sort of quality timber used in the construction industry a pull-out strength of 5N/mm² would be a reasonable value.
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