> 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/steel-bridge-examples/example-steel-i-girder-bridge-ex1-sig/loading-ex1-sig/load-geometry-definitions-ex1-sig/surface-ex1-sig/quadrilateral-ex1-sig.md).
# Quadrilateral
{% hint style="info" %}
**Navigation:** Loading > Load Geometry Definitions > Surface > Quadrilateral
For detailed parameter explanations, see the [Quadrilateral Reference](https://docs.openbrim.org/templates/steel-i-girder-bridge-workflow/loading-sig/load-geometry-definitions-sig/surface-sig/quadrilateral-sig).
{% endhint %}
**Step 1:** Click the **three-dots icon** on the **Bridge** cell, and then set **BRG1**.
**Step 2:** Enter the **Start Station** as **0.**
**Step 3:** Enter the **End Station** as **530.**
**Step 4:** Keep the **Start** **Transverse Offset** and **End Transverse Offset** as default.
Quick Tip: Transverse Offset
Offset values use PGL as the reference point.
-20221025-123233.png?api=v2)
**Step 5:** Enter the **Surface Width** as **36.**
**Step 6:** Keep the **Start** **Skew** and **End Skew** as default.
Quick Tip: Skew Angle
Quick Tip: Skew Angle 2
**Step 7:** Keep the **Graphics parameters** as default.
{% hint style="success" %}
The completed surface load geometry is illustrated below. Please verify that you have the same model on your end by examining each view provided here. For more information on how to perform visual checks, refer to the quick tips.
{% endhint %}
{% hint style="success" %}
To view the entire procedure explained on this page, please watch the recorded Video below.
{% endhint %}
{% embed url="" %}
Surface
{% endembed %}
---
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