> 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-concrete-u-girder-bridge/superstructure-ex1-cug/diaphragm-ex1-cug/internal-diaphragm-ex1-cug.md).

# Internal Diaphragm

This section defines internal diaphragms within Concrete U Girders to provide stability at bearing locations.

{% hint style="info" %}
**Navigation:** Superstructure > Diaphragm > Internal Diaphragm

For detailed parameter explanations, see the [Internal Diaphragm Reference](https://docs.openbrim.org/templates/concrete-u-girder-bridge-workflow/superstructure-cug/diaphragm-cug/internal-diaphragm-cug).
{% endhint %}

## Steps

### Step 1: Navigate to Internal Diaphragm

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

![Internal Diaphragm navigation](https://openbrim.atlassian.net/wiki/download/attachments/2258337911/image-20230828-151037.png?api=v2)

![Internal Diaphragm spreadsheet](https://openbrim.atlassian.net/wiki/download/attachments/2258337911/image-20230828-151102.png?api=v2)

{% hint style="info" %}
Internal diaphragms within Concrete U Girders mitigate torsional stability issues at bearing locations.
{% endhint %}

### Step 2: Assign Girder

Click the **three-dots icon** on the **Girder** cell and select **CUG1** (Concrete U Girder).

### Step 3: Define Diaphragm Locations

Enter the **Girder** and **Station** values for all internal diaphragms:

![Girder and Station](https://openbrim.atlassian.net/wiki/download/attachments/2258337911/image-20230828-152232.png?api=v2)

### Step 4: Set Thickness and Skew

Configure the diaphragm geometry:

| Parameter  | Value       |
| ---------- | ----------- |
| Thickness  | As required |
| Start Skew | 0           |
| End Skew   | 0           |

![Thickness and Skew](https://openbrim.atlassian.net/wiki/download/attachments/2258337911/image-20230828-153323.png?api=v2)

### Step 5: Assign Material

Click the **three-dots icon** on the **Material** cell and assign the appropriate material for all internal diaphragms.

![Material Assignment](https://openbrim.atlassian.net/wiki/download/attachments/2258337911/image-20230828-154050.png?api=v2)

## Verification

{% hint style="success" %}
The completed internal diaphragms are shown below.
{% endhint %}

![Completed Internal Diaphragms](https://openbrim.atlassian.net/wiki/download/attachments/2258337911/image-20230828-154354.png?api=v2)


---

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