Rock bolting

Therrin

Was wondering if any of you have a working knowledge of rock bolting. Specifically for setting rock bolts as anchor points for a series of tyrolean type traverses spanning about 60ft down to about 20ft.

I'm trying to figure stuff like, minimum distance from one bolt to another, how many anchors I should use (in granite), if I might need bolts larger than 3/8"?

I'm lookin at using 3/8 x 16,SS Hex Head Cap Screw bolts, with SS hangers. Looking at about 200lb working load, which I guess at perfect horizontal would exert what, 1300lb roughly on the anchor system. Closer bolt spacing will keep the angles small on the wire leads that lead to the main anchor mallion for each side. Planning on using a 3:1 to pull slack out of the traverse ropes. The holes for these bolts will likely be hand drilled using a climbers drill & hammer, and carbide bits. (yeah, it'll take a while, but its doable.)

There 'should be' no shock loading on this system. It's a static transfer system between areas where I can clip in myself, and use to transfer gear across some natural pools and over a couple sets of waterfalls.

If anyone has experience with this kind of stuff and needs more info, just ask.

Thanks!

Eric Frei

Bolts will have ratings.

Here's a half decent site, look around.

Safer Cliffs Australia - Photos

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Jeff Darby

All bolts that are rated have marks on them that indicate to you their tensile strength, chain has a grading systems aswell, then there is wear factors to consider before discarding the bolt or chain, generally 10% or more wear, elongation of the chain link, diameter of wire rope times the amount of broken strands in a given measurement etc...etc, slings tears and how its used can reduce it SWLL to around 50% of rated strenght...know your stuff and stay safe.

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Therrin

Oh great link Ekka thx!

That has tons of info.

I've bolted before for climbing, but only for some lead stuff, not dedicated placements for a tyro.

Therrin

Just to repeat... Thanks a TON for that link Ekka.

I'd been looking around for a while before mentioning it on here but that link gives most of the info I was looking for, and alot I hadn't thought of.

Cheers

Eric Frei

Yeah, the gluing was new to me and the right and wrong way to have the "eye" set.

I dare say they'd be decent to you too if you emailed them. They have a legit looking role.

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