Seismic Application for Insulated CMU Walls

[HDStructural]

Hello all,

I am working on a project on the west coast (SDC D) and the architect wants to use insulated CMU walls, see attached. I have not used these before and am curious if they are often used in high seismic applications or if they even meet the requirements for special reinforced masonry shear walls or need specific code approval.


I am just starting my research now but figured I would ask if any of you have experience with these.

 

[driftLimiter]

With solid grout I don't see any reason why they cant work as a special reinforced wall for seismic areas.
When I used Hi-R in the past they provided an analysis tool for out of plane that takes into account the unique section properties.

 

[bIockhead]

Who makes these units? I've had my run-ins with Omni block. Doesn't strike me as a very effective solution, and those ones weigh a ton for the poor mason on the line putting them in, but they can technically work. These just look like inserts for standard CMU.

I don't see why you can't meet seismic code objectives, although I'd worry about the effectiveness of the reinforcement if the grout has a layer of foam between the core are and the unit (which it's supposedly coupling with).

I would reach out to CMHA (formerly NCMA) or IMI. You don't want to be a guinea pig on this. I wouldn't be surprised if like omni block, this has been done a fair bit and seems fine, but I don't love it.

There's a reason we put the insulation on the outside as a continuous layer... It's far more effective there.

 

[hawkaz]

Do they have a current ICC report that lists limitations?

 

[strucbells]

This has come up for me at various points on a few projects, we've always pushed back and ultimately gone with either an EIFS system or a cavity wall construction depending on the client's budget and architectural look they wanted. We had concerns about the bond between the grout and the face shell, and almost all of my projects are in high seismic areas, and many have been RC III/IV.

If you search for Hi R Structural Design Manual, there is a document they developed that gives some additional information. In it, they have a vague claim that testing shows it still works compositely due to the bond of the other 3 sides. But I've never seen an ICC/IAPMO/3rd party report on it.

And within the same document they note that the reduction of grout space due to the foam means your development length/lap splices can go through the roof. So need to plan/detail around that. Also, need to modify all your usual CMU design equations to account for the asymmetry of the sections. Just seems like a hassle, not worth whatever savings you might theoretically get.