Bonding Cor-ten plate to a concrete wall

He doesn't want to see fasteners but he doesn't mind seeing the rust bleed down all over the rest of the material?
What about welding pins to the back of the steel and then using epoxy to set those into holes in the wall>
Yes, you will need sealant across the top of the wall.
And this sealant will be a maintenance item requiring regular upkeep.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

Concrete has no tensile strength so adhering anything else on its surface is a no-go.

I think Ed is on the right track with studs and epoxy but getting all of the studs and holes to line up is too challenging. Instead, weld flat plates to the studs and epoxy them into the concrete. Once cured, you can apply epoxy to the flat plates then install your large plate.

Adhesive will not work.

Maybe an adaptation of a French cleat.

Can you use headed studs? Those sharp corners could be dangerous. One of the more interesting things I've seen...

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

-Dik

You might want to check with Masterbond... they have adhesives that secure strange stuff to even stranger stuff.

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

-Dik

Adhesives bond just fine to concrete. The problem is that concrete doesn't bond to itself. Under tension, the bonded to concrete layer will simply pull off. Studs put the concrete to adhesive connection in shear.

Thanks all. We are looking at a few options...
I like the French Cleat idea too!

There are numerous times when things are bonded to concrete... tiles, flooring, etc. The loads are light and there is a lot of surface area for adhesion. A couple of psi adhesion is several hundred psf...

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

-Dik

Why not provide studs on the back of the plate and cast it into the concrete?

As Ed said, I doubt the architect will like the rust bleeding down the rest of the installation. But then, architects often have silly ideas.

Put embeds in the concrete and plug weld thru holes in the weathering steel? I *believe* they make welding filler that matches the material.

1/2" plate for landscaping, so something purely esthetical? I've been doing this wrong my entire life, been using 3 mm plates for several similar applications and so far this has been more than enough...

I agree with putting studs on the back, drilling corresponding holes, filling those with chemical anchor and making the connection work in shear.
Still needs caulking all around, and probably maintenance yearly.

Yes, they make similar filler that's barely noticeable after time - but it needs the entire surface sandblasted so it can "grow" a uniform oxide scale. Welding on brown plates (only locally cleaned up) will have the weld stick out for it's entire lifetime. Don't ask me how I know.

Is that a bench? Looks like a bench.

Whomever sits on that bench is going to really like what it does to their pants.

I digress.

Welded studs as mentioned by others seems like the best solution.

There is also a Sika product in the Sikadur family which is specifically designed for structural bonding of steel to concrete. I've used it before, it's a good product. Doesn't require any weird prep, and does what the label says it will do.

It's actually a planting bed (I turned off the vegetation in the model) so we're trying to retain a couple feet of soil so... figuring on 1/2". Architect likes that look regardless.

The current approach is to tie the front and back walls together with a steel plate maybe 6" below the top of the lower plate (spaced about every 6ft) and provide a 4x4 steel angle "spike" embedded on a modest pier/footing at the same spacing.
anchoring the taller plate to the concrete wall with a french cleat. I will be working in coordination with the fabricator and the architect to figure out details for retaining the soil.

Fabricator (who is experienced with architects AND CorTen metals used like this) uses a sealer to reduce staining.

We will have some CorTen used as cosmetic cladding (like at the fireplace wall) and that will be 16 gage, glued to 3/4" substrate.

Oh man it's getting filled with dirt?

Mechanical anchors below the level of the dirt to the back wall. Shop weld punched angle inside each plate, bolted rib between the punched angle to hold it all together. Weld a few clips to the bottom of the outer plate on the inside, if you think you need it to be anchored. May be unnecessary.

Easy money.