> 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/properties-ex1-sig.md).

# 3. Properties

This section defines the material properties, sections, rebars, and bolt properties used throughout the bridge model.

{% hint style="info" %}
Define these properties before modeling structural components. Once imported, they appear in property selection dropdowns throughout the workflow.
{% endhint %}

## Properties to Define

| Property Type                                        | Description                                                        |
| ---------------------------------------------------- | ------------------------------------------------------------------ |
| [Materials](broken://pages/z5q19ul1eM9pWYHSE1PW)     | Steel and concrete material definitions (A709 Grade 50, f'c=4 ksi) |
| [Rebars](broken://pages/fPzsETOEB4Zqqvqlevj4)        | Reinforcement bar definitions for deck and substructure            |
| [Sections](broken://pages/9UkLRPfv7sA4BH2YKAjT)      | Cross-frame member sections and other structural shapes            |
| [Bolt Property](broken://pages/QOT86cp6HvJ6gP3xLFYZ) | Bolt specifications for field splices and connections              |

## Materials Used in This Example

* **Structural Steel**: AASHTO M270, Grade 50 (Fy=50 ksi, Fu=65 ksi)
* **Concrete**: f'c=4 ksi, unit weight=150 pcf
* **Reinforcing Steel**: AASHTO M31, Grade 60 (Fy=60 ksi)


---

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