# 6. Substructure

This section covers the substructure components that support the bridge superstructure, including piers, foundations, and piles.

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Substructure elements are essential for load transfer from the superstructure to the ground. Each component must be properly dimensioned for the design loads.
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## Components to Model

| Component                                                                                                                                            | Description                                   |
| ---------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------- |
| [Pier](https://docs.openbrim.org/examples/steel-bridge-examples/example-steel-i-girder-bridge-ex1-sig/substructure-ex1-sig/pier-ex1-sig)             | Pier caps and columns supporting the bearings |
| [Foundation](https://docs.openbrim.org/examples/steel-bridge-examples/example-steel-i-girder-bridge-ex1-sig/substructure-ex1-sig/foundation-ex1-sig) | Rectangular footings for load distribution    |
| [Pile](https://docs.openbrim.org/examples/steel-bridge-examples/example-steel-i-girder-bridge-ex1-sig/substructure-ex1-sig/pile-ex1-sig)             | Deep foundation elements beneath footings     |

## Substructure Elements

* **Pier Caps**: Horizontal members that distribute loads from bearings to columns
* **Pier Columns**: Vertical members transferring loads from caps to foundations
* **Rectangular Footings**: Spread footings for foundation support
* **Piles**: Deep foundation elements for load transfer to bearing strata

## Model Views

![Pier Cap](https://openbrim.atlassian.net/wiki/download/attachments/2101903451/image-20250117-141559.png?api=v2)

![Pier Column](https://openbrim.atlassian.net/wiki/download/attachments/2101903451/image-20250117-141720.png?api=v2)

![Foundation](https://openbrim.atlassian.net/wiki/download/attachments/2101903451/image-20250117-141829.png?api=v2)

![Complete Substructure](https://openbrim.atlassian.net/wiki/download/attachments/2101903451/image-20250117-141927.png?api=v2)