> 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/templates/truss-bridge-workflow/superstructure-tb/connections-tb/gusset-plate-tb.md).

# Gusset Plate \[TB]

A gusset plate connects multiple truss members that frame into a common Insertion Point. The plate can be defined from a predefined section or a custom polygonal shape, positioned in three dimensions, and optionally refined into a shell-element mesh for detailed analysis of the connection region.

## Plate

**Insertion Point:** Insertion Point at which the gusset plate is centered. The plate picks up all truss members connected to this insertion point. The user must provide a value.

**Select/Custom Section \[Select/Custom]:** Chooses how the plate outline is defined. **Select** uses a predefined section from **Properties > Sections**; **Custom** uses the user-defined polygon in **Custom Section**.

**Select Section:** Section used as the plate outline when **Select/Custom Section** is set to **Select**. Pick a previously defined section from **Properties > Sections**.

**Custom Section:** User-defined polygon (list of X,Y vertices in the plate's local plane) that defines the plate outline when **Select/Custom Section** is set to **Custom**. Used to draw gusset plates of any shape required by the truss geometry.

**Plate Material:** Material assigned to the plate when **Custom Section** is used. Pick from **Properties > Materials**.

**Plate Thickness:** Out-of-plane thickness of the gusset plate. Used both for the 3D model and for refined FEM computations.

## Position

**Rotate about X Axis:** Rotation of the plate about the local X axis of the Insertion Point. Use to orient the plate relative to the connecting members.

**Rotate about Y Axis:** Rotation of the plate about the local Y axis.

**Rotate about Z Axis:** Rotation of the plate about the local Z axis.

**Offset along X Axis:** Translation of the plate center along the local X axis of the Insertion Point. Use for eccentric placements relative to the connection.

**Offset along Y Axis:** Translation of the plate center along the local Y axis.

**Offset along Z Axis:** Translation of the plate center along the local Z axis.

## Bolt

**Bolt Arrangement:** Layout of bolts on the plate, entered as a list of bolt positions. Used to position bolt holes in the 3D model and to drive the bolt-group stiffness calculation in the refined FE analysis.

**Bolt Segment:** Number of segments used to discretize each bolt hole in the 3D model.

**Show Bolt Holes (Detailing) \[No/Yes]:** Toggles rendering of bolt holes in the 3D view. Visualization only.

## FEM

**Generate Refined Mesh \[Yes/No]:** Enables shell-element meshing of the gusset plate in the FE model. When **Yes**, the plate participates in the analysis as a shell mesh connected to the truss members via rigid links; when **No**, the plate is 3D-only and does not contribute to FEA. The FEM parameters below apply only when **Yes** is selected. Switching this on may significantly increase solve time.

**Rigid Section:** Section used to model rigid links between the plate mesh and the connecting truss members. The user must provide a value when refined mesh is enabled.

**Bolt Segment:** Number of mesh segments used around each bolt hole in the refined FE model.

**Mesh Size:** Target element size for the refined plate mesh.

**Mesh Option \[MeshAdapt/Automatic/Initial mesh only/Delaunay/Frontal-Delaunay/BAMG/Frontal-Delaunay for Quads/Packing of Parallelograms/Quasi-structured Quad]:** Selects the 2D meshing algorithm used to generate the shell mesh of the plate. Default is **Automatic**.

**Truss Restraints:** Optional list of restraints applied to individual truss members' ends at this gusset, overriding their global end releases for the refined analysis.

**Truss Loads:** Optional list of loads applied to individual truss members' ends at this gusset for the refined analysis.

## Transferable Data

**Compute Transferable Data:** Precomputed data (truss geometry, bolt layouts, section properties, material constants) used when the gusset plate is exported as a shared object for refined standalone analysis. Populate using the **Compute Elevations** cell action.

## 3D Detailing

**Display Local Axis \[No/Yes]:** Toggles display of the plate's local axis triad in the 3D view.

**Plate Opacity:** Opacity of the plate in the 3D view. Values from 0 (fully transparent) to 1 (fully opaque).

**Plate Color:** Color of the plate in the 3D view, entered as a hex color code (e.g., `#ffe6d1`).


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