# Truss Construction \[TB]

The Truss Construction workflow item activates truss members in the staged construction model. Starting at the selected stage the truss members either all trusses on the bridge, or only a user-selected subset become structurally active, contribute stiffness, and carry their own self-weight.

## Truss Construction

**Stage:** Select the [Construction Stage \[TB\]](/templates/truss-bridge-workflow/construction-tb/construction-stage-tb.md) at which the truss members will be constructed. The truss FE group is activated from this stage onward.

**Bridge:** Select the [Bridge Alignment \[TB\]](/templates/truss-bridge-workflow/bridge-geometry-tb/bridge-alignment-tb.md) whose truss elements are being constructed. The truss FE group associated with that bridge is used when constructing all trusses.

**Construct All/Selection \[All/Selection]:** Choose whether to construct every truss on the bridge (**All**) or only a specific set of trusses (**Selection**). When **All** is selected the full truss FE group of the bridge is activated; when **Selection** is selected only the trusses listed below are activated.

**Selected Trusses:** Pick the individual trusses to be constructed at this stage. This list is only used when **Construct All/Selection** is set to **Selection**.

**Truss Self Weight Factor:** Factor applied to the truss members' own weight during this construction stage. A value of `1.0` applies the full self-weight; a value greater than `1.0` scales the self-weight up (e.g. to account for connection hardware or sacrificial elements), while a value less than `1.0` reduces it. The factor is applied as a downward (negative Z) body-force multiplier on the activated truss FE group.

**Stiffness \[No/Yes]:** Choose whether the truss members contribute stiffness to the FE model from this stage onward. In most construction scenarios this is set to **Yes** so that the trusses start resisting load at their construction stage; **No** can be used when the trusses are present but not yet structurally engaged (e.g. for weight-only staging).


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.openbrim.org/templates/truss-bridge-workflow/construction-tb/superstructure-construction-tb/truss-construction-tb.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.