> 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/properties-ex1-pig/materials-ex1-pig.md).
# Materials
This section defines the material properties for concrete, reinforcing steel, structural steel, and prestressing strands used in the bridge model.
{% hint style="info" %}
**Navigation:** Properties > Materials
For detailed parameter explanations, see the [Materials Reference](https://docs.openbrim.org/templates/precast-i-girder-bridge-workflow/properties-pig/materials-pig).
{% endhint %}
## Steps
### Step 1: Navigate to Materials
Navigate to **Properties > Materials** in the tree view.
### Step 2: Import Steel Materials
Click the **three-dots icon** on the first cell under **Name** and select **Import Material**.
Import the following steel materials from the OpenBrIM Library:
**Reinforcement Steel:**
* OpenBrIM Bridge Objects > Steel Material Database (US) > Reinforcement Steel > **A615\_60**
**Structural Steel:**
* OpenBrIM Bridge Objects > Steel Material Database (US) > Structural Steel > **A709\_50**
### Step 3: Import Concrete Materials
Import the following concrete materials:
* OpenBrIM Bridge Objects > Concrete Material Database (US) > US AASHTO > **Fc\_3\_1/2ksi**
* OpenBrIM Bridge Objects > Concrete Material Database (US) > US AASHTO > **Fc\_4ksi**
* OpenBrIM Bridge Objects > Concrete Material Database (US) > US AASHTO > **Fc\_4\_1/2ksi**
* OpenBrIM Bridge Objects > Concrete Material Database (US) > US AASHTO > **Fc\_5\_1/2ksi**
* OpenBrIM Bridge Objects > Concrete Material Database (US) > US AASHTO > **Fc\_6ksi**
* OpenBrIM Bridge Objects > Concrete Material Database (US) > US AASHTO > **Fc\_8\_1/2ksi**
### Step 4: Import Prestressing Steel
Import the prestressing strand material:
* OpenBrIM Bridge Objects > Steel Material Database (US) > Prestressing Steel > **A416\_270low\_relaxation**
### Step 5: Define Custom Concrete Material
Create a custom material named **Fc\_3\_1/2ksi\_NoStiffness**.
{% hint style="info" %}
This material is used for components like barriers where stiffness should be excluded during construction analysis.
{% endhint %}
### Step 6: Define Rigid Material
Add a new row and create a **RigidMaterial** for rigid connections.
{% hint style="warning" %}
Always set the unit weight of rigid materials to **0** to avoid adding artificial mass to the model.
{% endhint %}
Quick Tip: Stress-Strain Curves
Each material type includes a default stress-strain curve used for section capacity calculations based on the strain compatibility method.
To view or modify curves:
1. Click the three-dots icon on a material and select **Edit**
2. Select **Stress/Strain Model** from the dropdown
3. The corresponding **Stress/Strain Curve** will update automatically
## Verification
{% hint style="success" %}
After completing these steps, your material definitions should match the view shown below.
{% endhint %}
---
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