# Bridge Geometry

This section defines the geometric layout of the Steel Tub Girder Bridge including alignment, supports, and girder positions.

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**Navigation:** Bridge Geometry
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## Overview

Bridge geometry establishes the spatial framework for the entire model:

* **Roadway Alignment:** Horizontal, vertical, and transverse geometry
* **Bridge Alignment:** Associates alignment with the bridge
* **Support Lines:** Defines abutment and pier locations
* **Insertion Points:** Positions for girder placement
* **Girder Layout:** Connects insertion points to define girder paths

## Sections

| Section                                                                                                                                                                 | Description                                          |
| ----------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------- |
| [Roadway Alignment](https://docs.openbrim.org/examples/steel-bridge-examples/example-steel-tub-girder-bridge-ex1-stg/bridge-geometry-ex1-stg/roadway-alignment-ex1-stg) | Define horizontal curves, grades, and cross-sections |
| [Bridge Alignment](https://docs.openbrim.org/examples/steel-bridge-examples/example-steel-tub-girder-bridge-ex1-stg/bridge-geometry-ex1-stg/bridge-alignment-ex1-stg)   | Assign alignment to bridge                           |
| [Support Lines](https://docs.openbrim.org/examples/steel-bridge-examples/example-steel-tub-girder-bridge-ex1-stg/bridge-geometry-ex1-stg/support-lines-ex1-stg)         | Define abutment and pier stations                    |
| [Insertion Point](https://docs.openbrim.org/examples/steel-bridge-examples/example-steel-tub-girder-bridge-ex1-stg/bridge-geometry-ex1-stg/insertion-point-ex1-stg)     | Position girders on support lines                    |
| [Girder Layout](https://docs.openbrim.org/examples/steel-bridge-examples/example-steel-tub-girder-bridge-ex1-stg/bridge-geometry-ex1-stg/girder-layout-ex1-stg)         | Connect insertion points for girder paths            |

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Complete Bridge Geometry before defining Properties and Superstructure components.
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