# Steel I Girder Bent Cap \[CUG]

The I-Girders of a bent cap can be modeled in both FEM and 3D by defining the required parameters listed below.

## I Girder Bent

The properties of the I Girder Bent can be specified using the parameters listed below. For a visual representation of each, refer to the figure below.

**Bearings:** Select the appropriate bearings to accurately determine the location of the steel I-girder bent cap.

**Top Elevation Offset from Alignment:** Specify the distance from the midpoint of the bent cap at the top to the PGL location, where 0 indicates that the midpoint of the pier cap is at the PGL location vertically. Generally, a value equivalent to the sum of the deck thickness, girder depth, bearing depth, and haunch depth is employed.

**Top Flange Width:** The width of the top flange can be specified by defining this parameter.

**Top Flange Thickness:** The thickness of the top flange can be specified by defining this parameter.

**Web Depth:** The depth of the web (vertical portion of the I-girder) can be specified using this parameter.

**Web Thickness:** The thickness of the web can be specified by defining this parameter.

**Bottom Flange Width:** The width of the bottom flange can be specified using this parameter.

**Bottom Flange Thickness:** The thickness of the bottom flange can be specified by defining this parameter.

**Top Flange Material:** Assign a material to the top flange. Materials can be selected from previously defined options or imported as needed.

**Web Material:** Assign a material to the web. Materials can be selected from previously defined options or imported as needed.

**Bottom Flange Material:** Assign a material to the bottom flange. Materials can be selected from previously defined options or imported as needed.

![image-20240913-121436.png](https://openbrim.atlassian.net/wiki/download/attachments/2575400970/image-20240913-121436.png?api=v2)

![image-20240913-121626.png](https://openbrim.atlassian.net/wiki/download/attachments/2575400970/image-20240913-121626.png?api=v2)

![image-20241010-111531.png](https://openbrim.atlassian.net/wiki/download/attachments/2575400970/image-20241010-111531.png?api=v2)

## FEM

**Rigid Section:** To connect the pier cap finite element to the bearing, the user needs to specify the properties of the rigid section. When bearings are longitudinally offset from the support line, rigid elements are automatically generated to link those bearings to the pier cap.

**Spring Depth:** Defines the depth of the spring between the steel bent and the column when a column is placed under a steel bent bearing.

**Initial Cantilever Length (from Right End):** Defines the cantilever length of the steel bent extending from the right end of the girder.

**End Cantilever Length of Girder (from Left End):** Defines the cantilever length of the steel bent extending from the left end of the girder.

![image-20250528-082647.png](https://openbrim.atlassian.net/wiki/download/attachments/2575400970/image-20250528-082647.png?api=v2)

**Mesh Size:** The maximum distance between nodes in the elements local X-direction is specified using the mesh size.

**Number of Result Extraction Stations:** The result extraction station settings are solely for viewing FEA composite results in either the spreadsheet or FEA view, and do not impact standard finite element analysis results like member end forces, node displacement, and node reactions.

**Flange FEM\[Beam/Shell]:** The finite model of the I-girder bent can be generated using both beam elements and shell elements, which can be specified by this parameter.

**Additional Result Extraction Point**: For results of Composite Element Forces at a specific point to be viewed, the location can be determined using this parameter by defining the distance of the point from the right of the cap (when looking up the station along PGL).