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Toprope Anchor in Concrete
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wiki


Sep 14, 2007, 4:52 AM
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Toprope Anchor in Concrete
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Hi!
At the Gym I work at, we are putting up a new wall. We are using an existing concrete wall (about 40 years old).

The Toprope anchor we propose to put up is 5-6" sqare with a bolt in each corner and we want to use expansion/glue-in bolts in the concrete.

I am not sure whether I a) trust the bolts (the bolts we use in concrete for the holds tend to wiggle loose and pop out every now and then) or b) trust the integrity of the 6" square of concrete we are bolting our anchor to.

Bearing in mind we are a commercial gym and this wall will get a lot of use, what are your thoughts?


chossmonkey


Sep 14, 2007, 5:19 AM
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Re: [wiki] Toprope Anchor in Concrete [In reply to]
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Hire an engineer.

For what its worth, bolts have been holding stuff onto concrete long before they were holding climbers onto the sides of cliffs.


reg


Sep 14, 2007, 5:24 AM
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Re: [wiki] Toprope Anchor in Concrete [In reply to]
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wiki wrote:
Hi!
At the Gym I work at, we are putting up a new wall. We are using an existing concrete wall (about 40 years old).

ok, so far - so good. how tall?

wiki wrote:
The Toprope anchor we propose to put up is 5-6" sqare with a bolt in each corner

wha? lost me

wiki wrote:
and we want to use expansion/glue-in bolts in the concrete.

wha?? two different systems, wik

wiki wrote:
I am not sure whether I a) trust the bolts (the bolts we use in concrete for the holds tend to wiggle loose and pop out every now and then)

wha??? somebody's doin somethin wrong

wiki wrote:
or b) trust the integrity of the 6" square of concrete we are bolting our anchor to.


i gotta see this "5-6" square of concrete

wiki wrote:
Bearing in mind we are a commercial gym and this wall will get a lot of use, what are your thoughts?

i'll get back to ya on that


wiki


Sep 14, 2007, 5:44 AM
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Re: [reg] Toprope Anchor in Concrete [In reply to]
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Hire an engineer? Can't afford one - climbing gyms don't make money here!

reg wrote:
wiki wrote:
Hi!
At the Gym I work at, we are putting up a new wall. We are using an existing concrete wall (about 40 years old).

ok, so far - so good. how tall?

15m don't know what that is in feet (45' maybe?)

In reply to:
wiki wrote:
The Toprope anchor we propose to put up is 5-6" square with a bolt in each corner

wha? lost me

It is a 6" metal plate with a loop on it that the toprope goes through. We call them 'D' rings because they look like a 'D' attached to a square of metal. (I would draw you a diagram but I haven't figured out his whole image posting thing yet)


In reply to:
wiki wrote:
and we want to use expansion/glue-in bolts in the concrete.

wha?? two different systems, wik

I know I know! my boss wants to glue the expansion bolts in (he is talking about epoxy resin) - this all sounds dodgy to me... bolting is the one thing I have never been interested in and now I kinda wish that I knew more!

In reply to:
wiki wrote:
I am not sure whether I a) trust the bolts (the bolts we use in concrete for the holds tend to wiggle loose and pop out every now and then)

wha??? somebody's doin somethin wrong

They are always good at first but after 6 months or so they pop... I think it is because the drilled hole gets bigger from stress and the concrete is so old (concrete gets more friable with age right?)

In reply to:
wiki wrote:
or b) trust the integrity of the 6" square of concrete we are bolting our anchor to.


i gotta see this "5-6" square of concrete

Well... the patch of concrete that is the same size of the plate we are bolting to it - it doesn't really matter how big the rest of the concrete is, we are only interested in the bit we are bolting to! Oh with a bolt in each corner to make it weaker of course!

In reply to:
wiki wrote:
Bearing in mind we are a commercial gym and this wall will get a lot of use, what are your thoughts?

i'll get back to ya on that

Only if you feel like it - this is the internet after all! Thanks for pointing out my incoherence Smile

<edited for clarity - wiki xxx>


(This post was edited by wiki on Sep 14, 2007, 5:59 AM)


reg


Sep 14, 2007, 5:58 AM
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Re: [wiki] Toprope Anchor in Concrete [In reply to]
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nothin wrong with 40 year old concrete!
where'd ya get these plates with the "D" on um?
my advice is to use only porducts designed for climbing and certified as such by UIAA and CE, etc.
have you ok'd your designs with your insurance company?
glue ins are gawd awlfull strong as are expansion bolts - IF - put in correctly.
take a trip to some other gyms - see how they do it.
don't "jerry rig" when peoples lives and limbs are at risk!
who's runnin this thing anyway?

p.s. -
wiki wrote:
Thanks for pointing out my incoherence Smile

didn't mean to do that - sorry


(This post was edited by reg on Sep 14, 2007, 5:59 AM)


wiki


Sep 14, 2007, 6:13 AM
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Re: [reg] Toprope Anchor in Concrete [In reply to]
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In reply to:
reg wrote:
nothin wrong with 40 year old concrete!
where'd ya get these plates with the "D" on um?
Gym got em welded sometime before I was even thought of!

In reply to:
my advice is to use only porducts designed for climbing and certified as such by UIAA and CE, etc.
have you ok'd your designs with your insurance company?
My thoughts exactly... I have a very wilful boss... caught beween a rock and a hard place - makes me feel like a kayaker <though there is nothing wrong with that of course>

In reply to:
glue ins are gawd awlfull strong as are expansion bolts - IF - put in correctly.
take a trip to some other gyms - see how they do it.
don't "jerry rig" when peoples lives and limbs are at risk!
who's runnin this thing anyway?
Don't even ask! I just want to do the right thing but the boss is adamant and I can't do a thing about it except quit (and then the only climbing in our region would be screwed and I would be job-less!)

p.s. -
In reply to:
wiki wrote:
Thanks for pointing out my incoherence Smile

didn't mean to do that - sorry

No thats ok... A couple of glasses of wine and finishing work at 9pm on Friday night and all that... I'm not surprised that I'm incoherent!!!


pseudolith


Sep 14, 2007, 6:15 AM
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Re: [wiki] Toprope Anchor in Concrete [In reply to]
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Wow. It sounds like any money you save on hiring an engineer will be lost the first time somebody gets hurt/killed by safety equipment failure.

I understand that climbing is inherently risky, and I would never consider it anybody's fault but my own if I fell and broke an ankle/leg/whatever while bouldering at the gym. Likewise, if my belayer happened to do something stupid and drop me, then that's not the gym's fault. That boils down to poor communication, or a poor choice of belayer.

BUT those examples are completely different from mechanical failure of some portion of the gym's structure. Put up bolts that rip out when in use by a customer, and in today's overly letigious society, you can pretty much count on legal action being taken against the gym.

This is people's safety that you're messing with, and as the proprieter of the gym, your boss has the responsibility of putting up an anchoring system that is absolutely bomb-proof.

Suck it up and spend the $$ to consult with a structural engineer.


aarong


Sep 14, 2007, 6:24 AM
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Re: [wiki] Toprope Anchor in Concrete [In reply to]
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In reply to:
my boss wants to glue the expansion bolts in

Don't glue expansion bolts in. Contact Fixe and go with a proper glue-in system. http://www.fixeusa.com/gluein.htm

It's difficult to address this w/o a picture. Sounds like you have a "6" square of concrete" ( are you also saying it is 6" thick?) that you are bolting a 6" plate to - the same size? Is this just a concrete block embedded in the building? You need to make sure that whatever you are attaching your bolts to is sufficiently strong.

Not sure what you are bolting your holds to the wall with - but they shouldn't be wiggling out. Do you use steel drop-ins?

And the use of what sounds like a homemade steel "D-ring" plate for a top anchor is sketch. Probably better to go with two Fixe ring top anchors than the metal plate idea.


lodi5onu


Sep 14, 2007, 8:15 AM
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Re: [aarong] Toprope Anchor in Concrete [In reply to]
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Hey I converted a 55' silo into a climbing wall this year and it works very well. I used stainless steel expandable drop-ins (as shown above) reinforced by epoxy on the ends so they didn't twist. These were ONLY used for the holds. DO NOT use expansion bolts or glue-ins for the top anchors or hangers (if you're making it sport climb-able as i did) 6" concrete will blow out in a second with an expansion bolt. You need to thru-bold into the other side and put a plate on the back so it spreads out the force over a much larger area. I also double-nutted the bolts on the plate side so there was no way of them un-screwing. I've taken decent falls on the bolts (spaced roughly 10 feet apart as i used 5 bolts on a 55' silo) and everything has been solid so far. I can't stress enough to you though DO NOT ANCHOR WITH EXPANSION OR GLUE-INS INTO CONCRETE good luck!


aarong


Sep 14, 2007, 12:14 PM
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Re: [lodi5onu] Toprope Anchor in Concrete [In reply to]
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If you are talking 4000+ psi concrete an appropriate length expansion bolt (or proper glue-in) is safe.

We have 8" walls at our silo gym and use 4" expansion bolts and they are solid.

That said, you cannot make a blanket statement either way - it totally depends on the makeup (psi strength of concrete, structure, thickness, firability, etc.) of what you are placing anchors in.


lodi5onu


Sep 14, 2007, 12:28 PM
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Re: [aarong] Toprope Anchor in Concrete [In reply to]
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you're a hypocrite making blanket statements yourself
In reply to:
If you are talking 4000+ psi concrete an appropriate length expansion bolt (or proper glue-in) is safe.

In my opinion it's not safe to use expansion bolts or glue-ins in 40 year old concrete. I looked at your profile. You're a screenwriter. I'm a construction project manager. Using expansion bolts isn't even acceptable for non-weight bearing applications. Newsflash buddy, your silo anchors aren't as "solid" as you would like to believe.


glytch


Sep 14, 2007, 12:33 PM
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Re: [lodi5onu] Toprope Anchor in Concrete [In reply to]
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lodi5onu wrote:

You're a screenwriter. I'm a construction project manager .... Newsflash buddy, your silo anchors aren't as "solid" as you would like to believe.

Well, that was some call-out. rough.

Seriously, though, this is an interesting topic. Why do expansion bolts (or glue ins) not hold in older concrete? Not that I have any use for the answer... just curious.

G


chossmonkey


Sep 14, 2007, 12:40 PM
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Re: [lodi5onu] Toprope Anchor in Concrete [In reply to]
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lodi5onu wrote:
you're a hypocrite making blanket statements yourself
In reply to:
If you are talking 4000+ psi concrete an appropriate length expansion bolt (or proper glue-in) is safe.

In my opinion it's not safe to use expansion bolts or glue-ins in 40 year old concrete. I looked at your profile. You're a screenwriter. I'm a construction project manager. Using expansion bolts isn't even acceptable for non-weight bearing applications. Newsflash buddy, your silo anchors aren't as "solid" as you would like to believe.
Care to explain? And who are you to making design calls? You are after all just the project manager not an engineer. You should be shuffling papers and scheduling.


aarong


Sep 14, 2007, 1:17 PM
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Re: [chossmonkey] Toprope Anchor in Concrete [In reply to]
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wow - somehow I got under someone's skin when I didn't even mean to. oh well. that's rc.com for you.

please don't assume that because you read something in my profile that i decided to volunteer to an online community that you know everything about me.

i made the comment based on data such as this (specifically pg. 4,5 columns under 4000 psi concrete and above for 3/8" and 1/2"). http://www.powers.com/...mechanical/06914.pdf

you will find similar charts for other anchors such as Fixe and glue-ins

i stand by what i said - even if the concrete is 40 yrs old if it still tests out at 4000+ psi it shouldn't matter. obviously this assumes you can test it at that level - which, in this case it doesn't sound like they have done or are going to do.

we agree it goes back to the concrete condition.


onceahardman


Sep 14, 2007, 1:17 PM
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1/2" threaded bolt-thru, to a 1/4" 6X6 plate on the outside of the wall...

the fact that your existing bolts "loosen and pop out" with use does not bode well for the project.

where is the gym? i will be sure to not go there.


codhands


Sep 14, 2007, 1:51 PM
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Run a three inch steel pipe the length of the wall set off the wall about six inches and suspended below the rafters every other rafter and on both ends. I have seen this at a couple places and it works slick. Just run your rope over the pipe, very low impact on the rope and allows for more route versatility.


wiki


Sep 14, 2007, 4:24 PM
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Re: [codhands] Toprope Anchor in Concrete [In reply to]
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codhands wrote:
Run a three inch steel pipe the length of the wall set off the wall about six inches and suspended below the rafters every other rafter and on both ends. I have seen this at a couple places and it works slick. Just run your rope over the pipe, very low impact on the rope and allows for more route versatility.

That is a great idea - Thank you! I like the idea of Fixe anchors too!

I think I will show this thread to my boss to show him it isn't just me being paranoid about bolts in concrete!

Thanks for your help.

(as to where the gym is - if I tell you I will have to kill you Wink)


socalbolter


Sep 14, 2007, 4:58 PM
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The continuous toprope bar is the best idea in this thread. Hanging it from the roof structure also eliminates the concerns about the integrity of the concrete.

Second place would go to the through-bolting idea with a bearing plate on the inside and outside of the wall. Although I would suggest using this to anchor some sort of toprope bar as well. Your "D" rings will wear quickly due to their narrow radius and will need to be replaced at regular intervals.

It sounds as though your hold (drop in) anchor holes are not being cleaned thoroughly before placing the anchors. They should be brushed inside with a wire hole brush and then blown out completely. Not doing this can lead to anchors spinning and/or pulling out. It also sounds as though your walls are probably not 4000 psi concrete (as assumed above), but probably 2500 psi or less. Building codes were considerably different 40 years ago than they are now.

Put the word out to your member base that you are in need of a Structural Engineer's input. You might be surprised to know that you have one as a member. If so, offer him/her a free year's extension membership and take his advice.

I'm a climbing wall builder and a concrete contractor and there are many ways to tackle this, but without seeing it firsthand, it's difficult to tell you absolutely how to approach this.

Kudos for voicing your concerns and looking for the best solution. Good luck getting this resolved.

- Louie


vegastradguy


Sep 14, 2007, 5:46 PM
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make it a 5-6" pipe- a 3" pipe would create too much friction if you double rap the rope (which is ideal, because it makes it easy for anyone to belay, regardless of the weight difference).

this is what my gym uses, and its pretty sweet and user friendly.


talnlnky


Sep 26, 2007, 9:34 PM
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my gym back home in the states uses the bar.... probably a 5-6" bar. Works great for adding friction thus increase safety a bit. However. It does seem to cause sheath slippage more so than you would otherwise get.

I believe this might be due to the rope basically not rotating on the bar. The same side is almost always touching the bar. now, figure in the difference in distance in circumfrence of a large and small circle.(large being outside edge of the rope... small being the side of the rope touching the bar).... over time your bound to have some slippage.


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