> 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/examples/concrete-bridge-examples/example-prestressed-i-girder-concrete-bridge-ex1-pig/bridge-geometry-ex1-pig/support-lines-ex1-pig.md).
# Support Lines
This section defines the support line locations for abutments and piers along the bridge alignment, including stations and skew angles.
{% hint style="info" %}
**Navigation:** Bridge Geometry > Support Lines
For detailed parameter explanations, see the [Support Lines Reference](https://docs.openbrim.org/templates/precast-i-girder-bridge-workflow/bridge-geometry-pig/support-lines-pig).
{% endhint %}
## Steps
### Step 1: Navigate to Support Lines
Navigate to **Bridge Geometry > Support Lines** in the tree view.
### Step 2: Create First Support Line (Abutment 1)
Click the **three-dots icon** on the first cell and set the bridge to **"Bridge1"**. Enter Station **23846 ft** for the first abutment.
### Step 3: Create Remaining Support Lines
Create support lines for the remaining structures at their respective stations:
| Support | Station (ft) |
| ------- | ------------ |
| Abut1 | 23846 |
| Pier1 | 23897 |
| Pier2 | 23982 |
| Abut2 | 24027 |
### Step 4: Define Skew Angles
Enter the skew angle for each support line as shown in the figure below.
Quick Tip: Transverse Offset Direction
Offset values use the Profile Grade Line (PGL) as the reference point.
## Verification
{% hint style="success" %}
After completing these steps, your Support Lines should match the view shown below.
{% endhint %}
### Video Walkthrough
---
# 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/examples/concrete-bridge-examples/example-prestressed-i-girder-concrete-bridge-ex1-pig/bridge-geometry-ex1-pig/support-lines-ex1-pig.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.