> For the complete documentation index, see [llms.txt](https://docs.enercalc.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.enercalc.com/sel-faq/using-the-software/calculation-modules/retaining-walls/cantilevered-retaining-wall/calculation-of-minimum-vertica.md).

# Calculation of Minimum Vertical Steel in Concrete Stems

What options exist for calculating minimum vertical steel in the Cantilevered Retaining Wall module's concrete stems.

## What options are available for calculation of minimum vertical steel in the Cantilevered Retaining Wall module?

The Cantilevered Retaining Wall module offers an input field for minimum ratio of vertical steel in concrete design segments.

![](https://1076748670-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FtBL2fEQRwrlKSM2irFL0%2Fuploads%2Fgit-blob-721be525aece17908809e32eaaff15ed15e99ccd%2FMinimum%20Vertical%20Steel%20Input.jpg?alt=media)

Because the code points us back to sections in Chapter 22 of ACI 318-14 for the flexural design of cantilevered retaining walls, many engineers interpret that to mean that the minimum steel ratios in Chapter 11 for walls don't apply to CRWs.

​

Instead, some feel that the minimum steel ratio should be governed by the rules for a one-way slab (per section 7.6.1.1).

​

Still others feel that the minimum steel ratio should be governed by the rules for a beam (ie. minimum steel should be as per section 9.6.1.2 and 9.6.1.3), which is what the program already does in the red box below:

![](https://1076748670-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FtBL2fEQRwrlKSM2irFL0%2Fuploads%2Fgit-blob-35c51395bf6c9a6bf711c691a5b4605dedf30f23%2FMinimum%20Vertical%20Steel.jpg?alt=media)

So based on your design philosophy, you can set that input for minimum vertical steel ratio however you like.

If you feel that the walls ratio is appropriate, you can pick the appropriate value from Table 11.6.1, split it in half if you have two identical mats, and enter that.

If you feel that the one-way slab ratio is appropriate, you can pick the appropriate value from Table 7.6.1.1, but **don't** split it in half because it references flexural steel not total steel, and enter that value.

And finally, if you feel that the beams analogy is appropriate, you can simply enter zero.

Update as of May 2022:

The logic used by ENERCALC is that we apply 200Fy/(bd) and 3sqrt(f'c)(bd)/fy to retaining walls, because they are essentially designed as vertical beams. Their design does not take advantage of any 2-way action. So their design should incorporate the same level of ductility that the code requires for a regular beam. You'll see this logic in sources like *Basics of Retaining Wall Design*, by Hugh Brooks.

It used to be that there was a clear path to this logic in ACI.

​

ACI 318-05, -08, and -11 Chapter 14 Walls included section 14.1.2, which stated, "Cantilevered retaining walls are designed according to flexural provisions of Chapter 10..."

And Chapter 10 included section 10.5.1, which was the reference to 200Fy/(bd) and 3sqrt(f'c)(bd)/fy.

Then in ACI 318-14 they changed it up a little. In ACI 318-14 they have Chapter 11 Walls.

11.1.4 Design of cantilever retaining walls shall be in accordance with 22.2 through 22.4...

​

(These sections relate to Design assumptions for moment and axial strength, Flexural strength, and Axial strength or combined flexural and axial strength.)

​

But for the first time, they don't make a reference back to Chapter 9 Beams, where the limit of 200Fy/(bd) and 3sqrt(f'c)(bd)/fy appears.

Then in ACI 318-19 the logic looks like this.

CHAPTER 11—WALLS

11.1.4 Design of cantilever retaining walls shall be in accordance with Chapter 13.

13.3.6.1 The stem of a cantilever retaining wall shall be designed as a one-way slab in accordance with the applicable provisions of Chapter 7.

(Chapter 7 is One-Way Slabs.)

So as you can see, ACI is in a state of flux as to how to treat cantilevered retaining walls. And as a software provider, we are very reluctant to remove a requirement that was clearly in place and serving well for many years.


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