> 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/max-permissible-reinforcement.md). # Max Permissible Reinforcement Spacing What maximum reinforcement spacing ENERCALC SEL applies to cantilever retaining wall footings and stems per ACI 318. What is the maximum permissible reinforcement spacing for cantilever retaining wall footings (heel, toe, and key)? According to ACI 318 Section **13.3.2.1**, "the design and detailing of one-way shallow foundations \[...] shall be in accordance with this section and the applicable provisions of Chapter 7 and Chapter 9." Per Section **7.7.2.3**, the "maximum spacing s of deformed longitudinal reinforcement shall be the lesser of 3h and 18 in." In ENERCALC SEL, the maximum permissible reinforcement spacing for cantilever retaining wall footings (heel, toe, and key) is taken as the lesser of 3h or 18 inches, where "h" refers to the thickness of the respective footing component. What is the maximum permissible reinforcement spacing for cantilever retaining wall stems? According to ACI 318 Section **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." Per Section **7.7.2.3**, the "maximum spacing s of deformed longitudinal reinforcement shall be the lesser of 3h and 18 in." In ENERCALC SEL, the maximum permissible reinforcement spacing for cantilever retaining wall stems is the lesser of 3h or 18 inches, where "h" is the thickness of the stem. For more details on ENERCALC's interpretation of the "applicable provisions" phrasing in the ACI 318, refer to the [Shallow Foundation "Applicable Provisions"](/sel-faq/using-the-software/calculation-modules/foundations2/shallow-foundation-applicable.md) section in the help documentation. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.enercalc.com/sel-faq/using-the-software/calculation-modules/retaining-walls/cantilevered-retaining-wall/max-permissible-reinforcement.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.