# Internal Diaphragm

This section defines solid internal diaphragms inside the tub girders.

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**Navigation:** Superstructure > Bracing > Internal Diaphragm

For detailed parameter explanations, see the [Internal Diaphragm Reference](https://docs.openbrim.org/templates/steel-tub-girder-bridge-workflow/superstructure-stg/bracing-stg/internal-diaphragm-stg).
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## Steps

### Step 1: Navigate to Internal Diaphragm

Navigate to **Bracing > Internal Diaphragm** in the tree view.

![Internal Diaphragm navigation](https://openbrim.atlassian.net/wiki/download/attachments/2169438209/image-20230220-151002.png?api=v2)

### Step 2: Assign Girder

Click the **three-dot icon** on **Girder** cell and select the tub girder where the diaphragm will be located.

### Step 3: Define Diaphragm Locations

Internal diaphragms are placed at the same stations as external diaphragms. For this example, there are 10 internal diaphragms total (5 per girder).

![Diaphragm layout](https://openbrim.atlassian.net/wiki/download/attachments/2169438209/image-20230220-163656.png?api=v2)

### Step 4: Enter Location Parameters

Enter Skew Angle, Station, materials, and type (Pier-End or Intermediate) similar to external diaphragm values.

### Step 5: Optional Settings

Modify **Section Details** and **3D Details** tabs if desired.

![Section details](https://openbrim.atlassian.net/wiki/download/attachments/2169438209/image-20230220-164138.png?api=v2)

![3D details](https://openbrim.atlassian.net/wiki/download/attachments/2169438209/image-20230220-164202.png?api=v2)

## Verification

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The completed internal diaphragms are shown below.
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![Completed internal diaphragm plan](https://openbrim.atlassian.net/wiki/download/attachments/2169438209/image-20230220-165041.png?api=v2)

![Completed internal diaphragm 3D](https://openbrim.atlassian.net/wiki/download/attachments/2169438209/image-20230220-165111.png?api=v2)

![Completed internal diaphragm detail](https://openbrim.atlassian.net/wiki/download/attachments/2169438209/image-20230220-165141.png?api=v2)