> For the complete documentation index, see [llms.txt](https://docs.openbrim.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.openbrim.org/templates/cable-stayed-bridge-workflow/loading-csb/loads-csb/element-loads-csb/girder-load-csb.md).

# Girder Load \[CSB]

## Girder Load

Girder loads are applied as line loads along the top or bottom flange of a selected girder. The magnitude is entered in terms of per-unit-length forces and moments, and the load is activated at a user-selected construction stage.

**Girder:** Select the girder to which the load will be applied. The user must provide a girder selection; the bridge alignment and flange reference points are pulled from the selected girder.

**Stage:** Choose the construction stage at which to apply the line load. When left empty, the load is defined but not activated on any construction stage.

**Applied Flange \[Top/Bottom]:** Specify whether the line load is applied along the top flange (1, default) or the bottom flange (2) of the selected girder.

**Fx:** Force per unit length in the longitudinal direction along the girder alignment.

**Fy:** Force per unit length in the direction perpendicular to the girder alignment.

**Fz (Gravity):** Force per unit length in the vertical direction. A positive value indicates a load in the global -Z (gravity) direction. For typical self-weight-like loads (wearing surface, stay-in-place formwork, utility lines), enter positive values.

**Mx:** Moment per unit length about the longitudinal axis along the girder alignment.

**My:** Moment per unit length about the axis perpendicular to the girder alignment.

**Mz:** Moment per unit length about the vertical axis.

{% hint style="info" %}
Although **Fz** is applied in the direction of gravity (positive values for **Fz** correspond to the downward direction), **Mz** is positive relative to the **+Z** axis (upward direction by the right-hand rule).
{% endhint %}


---

# 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.openbrim.org/templates/cable-stayed-bridge-workflow/loading-csb/loads-csb/element-loads-csb/girder-load-csb.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.