> 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/substructure-ex1-cug.md).

# Substructure

This section defines all substructure components for the Concrete U Girder Bridge, including end bents, piers, columns, foundations, and piles.

{% hint style="info" %}
**Navigation:** Substructure
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## Overview

The substructure consists of:

* **End Bent:** Abutment structures at bridge ends
* **Pier:** Intermediate supports including pier caps and columns
* **Foundation:** Spread footing foundations
* **Pile:** Deep foundation elements

## Sections

| Section                                                                                                                      | Description                             |
| ---------------------------------------------------------------------------------------------------------------------------- | --------------------------------------- |
| [End Bent](/examples/concrete-bridge-examples/example-concrete-u-girder-bridge/substructure-ex1-cug/end-bent-ex1-cug.md)     | Define end bent geometry and properties |
| [Pier](/examples/concrete-bridge-examples/example-concrete-u-girder-bridge/substructure-ex1-cug/pier-ex1-cug.md)             | Configure pier caps and columns         |
| [Foundation](/examples/concrete-bridge-examples/example-concrete-u-girder-bridge/substructure-ex1-cug/foundation-ex1-cug.md) | Define spread footings                  |
| [Pile](/examples/concrete-bridge-examples/example-concrete-u-girder-bridge/substructure-ex1-cug/pile-ex1-cug.md)             | Configure pile properties               |

{% hint style="success" %}
Complete each section to fully define the substructure before proceeding to Tendon.
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---

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