Anchoring into Stone/Marble 5

[Mistieats]

I am trying to find a good way to anchor into stone/marble. Has anyone had any experience with the type of anchor used? I have used Keil undercut anchor before for bigger projects, but I wonder if Hilti epoxy anchor can do the job for smaller projects even if they don't have test data for anchoring into stone...

Thanks!

JC
Structural EIT

 

[StructuralAddict]

I believe it's a good question for Hilti Technical support. I believe they should be able to answer this.

 

[jayrod12]

The last time I asked them (Hilti) they recommended their Hilti 500RE adhesive but were clear to indicate that there's no published testing. My application was non-crucial and therefore I designed using the weakest concrete capacities they gave, and left myself a bunch of room even in that scenario.

 

[jjl317]

Are you trying to anchor something to stone / marble or trying to anchor something new made of stone / marble?

Some thoughts -

a) Hilti may do free field tension tests, but I don't believe that they have a way to do field shear tests.
b) Besides Keil anchors, they are a number of other proprietary back of stone anchorage options - stone fabricators will generally have a preference.
c) There are other stone specific epoxies that are often used with anchoring to stone. For these and the other proprietary anchorage products, the choices in terms of analysis are either anchorage specific stone testing per ASTM C1252 (which is not very common), or some sort of "first principles" analysis based on more general stone ASTM test information (modulus of rupture, flexural strength, compressive strength) which are generally available for most commercially available stone.
d) Each stone type has peculiarities, and marble may have more than most (especially exterior).

Stone facade engineering is one of core businesses (based on US), so we are very familiar with this issue.

Hope this helps

 

[Mistieats]

Thank you Jayrod12 and jjl317. Jjl317, what are some stone-specific epoxies you have used before? I am trying to anchor a newly made marble piece to a steel structure.

 

[jjl317]

Both Bonstone and Akemi have multiple products that might be appropriate, depending on loading, set time, installation orientation, environmental conditions, etc.

To be honest, we generally avoid epoxy anchors as much as possible. If needed, we would generally try and avoid supporting the dead load directly by the epoxy, with some sort of hidden gravity support. We will use bent threaded rods, to not rely exclusively on the epoxy. And we will often also used snug-tight threaded washers directly on the back face of the stone, to try and prevent potential over-tightening of the nuts failing the joint.

Is this some kind of statue / sculpture? Or just flat panels?

 

[dik]

where I prefer to use epoxy anchors... just make sure you check the adhesive for creep characteristics. I've treated them as low strength concrete, and generally use stainless steel.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[jjl317]

Oh, that's a big one I forgot to mention thanks dik - definitely stainless

 

[dik]

I kinda like the Hilti HAS TZ anchors...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[JedClampett]

Another company that's very knowledgeable is Hohman and Barnard.

 

[wth]

Not sure if applicable, but here's a table for bond strength to different types of bedrock. Copied and translated (chatgpt) from a Norwegian guideline for bedrock anchoring.

Page 25

https://publikasjoner.nve.no/retningslinjer/2005/retningslinjer2005_01.pdf