Reinforcing in ICF walls

[archeng59]

I am working with a few architects who are determined to use ICF for storm shelters and other projects. After going through the construction process on a few projects, it is my opinion that ICF contractors are clueless about how to install reinforcing for concrete walls and beams. I am fighting installers to get vertical bars located in the required location. They build the wall to about 10 feet and install the vertical bars with no means of securing the bars against movement during the concrete pour. After the concrete is poured, the vertical bars are no longer vertical.

The ICF manufacturers provide support for horizontal bars but so far, I have found no ICF manufacturers that provide positioners for vertical bars. The installers do not want to use standard masonry rebar positioners for vertical bars, even though I've specified and detailed them in the construction documents. I have detailed splice couplers for vertical bars, too, which the installers do not want to use.

Just curious if anyone else has experience with this issue. It's getting to the point that I am about to refuse to do ICF projects because the installers simply do not cooperate.

 

[dik]

Many ICF products have their own prescribed reinforcing. Other than that, I've generally treated them as an RC wall.

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

-Dik

 

[archeng59]

I am a licensed structural engineer and design the wall as a conventional reinforced concrete wall. Likewise, with ICF beams when the architect and/or owner wanted to use that system for a roof.

I don't let the ICF installer/manufacturer specify the reinforcing.

My issue is with the lack of control for vertical bar placement with the ICF installers. How do any of you enforce rebar placement in ICF since the installers do not want to comply with the construction documents and details?

 

[dik]

Just a caution... if the manufacturer/supplier specifies something that is different than what you provide, there can be issues. I design as RC, but keep this in mind. My first ICF building was nearly 50 years ago and was a 'three storey walkup' (actually 2-1/2 stories to avoid an elevator), and likely one of the first in Manitoba... there was no guidance at the time.

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

-Dik

 

[XR250]

I think you just have to be conservative with your design.
Kinda like when I design retaining walls - design for bars in the middle, detail them on the edge. I figure on average the bars will be about right.

 

[phamENG]

Also keep in mind that the IRC and the ICF reinforcement tables are based on ACI 332, Code Requirements for Residential Concrete and not ACI 318. They are less onerous as the buildings tend to be much smaller and the comparative reliability requirements are a bit lower (max risk category 2 with maybe 8 people in it vs structures up to and including risk category 4/high rise structures).

I'm going through some similar headaches. Installer is insisting on being able to epoxy bars rather than cast in. You can but the demands on the joint are such that the footing (already excavated) would have to get thicker. About to head out to do an inspection...we'll see how it goes...

 

[Brad805]

The verts are dropped in after. Most alter the location of the horizontal bars each course so the verts fit nicely between. It is impossible to tie them as you go for many reasons. You will have to deal with that, along with the reality of non-contact splices at the bottom. Some forms work better with certain rebar sizes.