> 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/restrained-retaining-wall/calculation-of-top-and-bottom.md).

# Calculation of Top and Bottom Lateral Reactions

How the Restrained Retaining Wall module calculates top and slab lateral reactions for pinned and fixed stems.

## How does the Restrained Retaining Wall module calculate the reactions at the support and at the slab?

When the stem is pinned to the footing:

1. Consider the lateral load that applies to the stem-only.
2. Determine the top reaction by summing moments about the stem-footing joint.
3. Now consider the total lateral load applied to the stem and footing.
4. Determine the slab reaction by sum of forces in the horizontal direction.

When the stem is fixed to the footing:

1. Consider the lateral load that applies to the stem-only.
2. Determine the shear at the bottom of the stem by integrating the load over the full height of the stem and applying formulas for a propped cantilever.
3. Determine the top reaction by sum of forces in the horizontal direction.
4. Determine the slab reaction by summing shear at bottom of stem with active pressure on heel and on key.


---

# 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/restrained-retaining-wall/calculation-of-top-and-bottom.md?ask=<question>&goal=<endgoal>
```

`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.