> 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/e3d-training-manual/design/concrete-design/model-design-criteria2.md).

# RC Model Design Criteria

How to set concrete design criteria controlling column, beam, and slab parameters, codes, and capacity-check options.

Click **Concrete Design > RC Model Design Criteria** to open the *RC Design Criteria* dialog.

![](https://3750289988-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FlRZtG5Ynp58kYzLHYbR7%2Fuploads%2Fgit-blob-4524ca196d2bfd05ca8d8fa1dce0ffa090650d92%2FRC%20Design%20Criteria.jpg?alt=media)

This dialog controls many aspects of the concrete design process.

**Design Code:** Select the desired code.

***Column Design Parameters***

**Minimum and Maximum reinforcing ratio:** Enter values as whole number. Example: 1 for 1%, or 8 for 8%.

**Neutral axis steps for accuracy:** A control to balance accuracy with processing time. Do not use values less than 20.

**Biaxial angle steps:** Another control to balance accuracy with processing time. Must be a multiple of 4.

**Axial capacity steps for display:** A third control to balance accuracy with processing time. Must be 5 or more.

**Exclude concrete displaced by steel:** When selected, the program will exclude concrete displaced by rebar when calculating concrete capacity. This should be selected in practice. However, almost all examples in concrete textbooks include concrete displaced by rebar for calculation conveniences, so this can be useful if comparing program results to published examples.

**Always use 1.0 for Cm:** Uncheck this box to have the program compute Cm automatically.

**Sustained load combination for computing Beta d in columns:** Select the load combination that represents the sustained loads.

**Ignore compressive force in concrete shear capacity:** Offers the option to neglect the compressive force in a member when computing its shear capacity.

**Check capacity at column ends only:** If this is not selected, the concrete design procedure will check columns at every analysis segmental point along the member (more calculation time).

**Compute minimum moment Pu\*(0.6 + 0.03h):** When selected, the program uses Pu\*(0.6 + 0.03h) to calculate the minimum moment, and will consider both the minimum moment and the moment due to loading (whichever is larger). When this option is not selected, then the program will not compute the minimum moment and will use moment due to loading only.

***Beam Design Parameters***

**Automatically compute support widths:** Select this option so that flexural design starts at support faces and shear design starts at a distance of "d" from the face of support.

***Slab/Plate Design Parameters***

**Minimum reinforcing ratio for slab top/bottom steel:** The values entered will be treated as percentages. Example: 0.18 will be considered as 0.18% = 0.0018.


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