# 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.

![Navigation](https://openbrim.atlassian.net/wiki/download/attachments/2235858977/image-20230711-155749.png?api=v2)

### 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**

![Import Material](https://openbrim.atlassian.net/wiki/download/attachments/2235858977/image-20230712-075002.png?api=v2)

![Material Library](https://openbrim.atlassian.net/wiki/download/attachments/2235858977/image-20230712-075148.png?api=v2)

### 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**

![Concrete Materials](https://openbrim.atlassian.net/wiki/download/attachments/2235858977/image-20230712-082429.png?api=v2)

### 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 %}

![Custom Material](https://openbrim.atlassian.net/wiki/download/attachments/2235858977/image-20230803-120258.png?api=v2)

### 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 %}

<details>

<summary><strong>Quick Tip:</strong> Stress-Strain Curves</summary>

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

![Stress-Strain Model](https://openbrim.atlassian.net/wiki/download/attachments/2235858977/image-20230803-114343.png?api=v2)

![Stress-Strain Curve](https://openbrim.atlassian.net/wiki/download/attachments/2235858977/image-20230803-115753.png?api=v2)

</details>

## Verification

{% hint style="success" %}
After completing these steps, your material definitions should match the view shown below.
{% endhint %}

![Completed Materials](https://openbrim.atlassian.net/wiki/download/attachments/2235858977/image-20230803-120032.png?api=v2)