> 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/loading-tb/loads-tb/element-loads-tb/truss-load-tb.md).

# Truss Load \[TB]

The Truss Load workflow item applies a concentrated load to every node of a selected truss's finite element group at a chosen construction stage. The input force and moment components are split evenly between the two nodes of each truss element (the internal formulation applies `Fx/2`, `Fy/2`, `-Fz/2`, `Mx/2`, `My/2`, `Mz/2` to the associated node group), so the entered values represent the total load delivered per truss element along the gravity-downward convention for Fz.

## Truss Load

**Truss:** Select the truss to which the load will be applied. The user must provide a truss pick; the truss's FE node group and alignment are pulled from the selected object.

**Stage:** Choose the construction stage at which to apply the truss load. When left empty, the load is defined but not activated on any construction stage (activation is guarded by a non-empty stage).

**Fx:** Force in the longitudinal direction along the truss alignment.

**Fy:** Force in the direction perpendicular to the truss alignment.

**Fz (Gravity):** Force in the vertical direction. A positive value indicates a load in the global -Z (gravity) direction. For typical gravity-type loads (utility loads, attached equipment, miscellaneous dead load), the user should enter positive values.

**Mx:** Moment about the longitudinal axis along the truss alignment.

**My:** Moment about the axis perpendicular to the truss alignment.

**Mz:** Moment about the vertical axis.

{% hint style="info" %}
Although **Fz** is applied in the direction of gravity (positive values correspond to the downward direction), **Mz** is positive relative to the **+Z** axis (upward direction by the right-hand rule).
{% endhint %}


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