> 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/box-culvert-workflow/loading-bc/culvert-element-load-bc.md).

# Culvert Element Load \[BC]

Culvert Element Load applies a user-defined uniform pressure to one face of the culvert. It covers the loads that are not produced by one of the dedicated earth or live load objects — a wearing surface on the top slab, water inside the barrel, or any pressure a project-specific check calls for.

## General

**Box Culvert:** The culvert barrel this load is applied to. A selection is required.

**Stage:** The construction stage this load is activated in. Leave it empty for a model that is not staged.

**Surface \[Top Slab/Bottom Slab/Left Exterior Wall/Right Exterior Wall]:** Which face of the culvert carries the pressure. Interior webs are not available — they carry no external face.

**Coordinate System \[Element Local/Global]:** Whether the direction below is read in the element's own axes or in global axes. Element Local follows the surface, so a pressure normal to a wall stays normal to it as the barrel curves; Global keeps a fixed direction regardless of the surface, which is what a gravity-type load needs.

**Direction \[X/Y/Z]:** The axis the pressure acts along, in the chosen coordinate system. In global axes Z is vertical, so a downward wearing-surface load is a global Z pressure with a negative magnitude.

**Pressure Magnitude:** The pressure applied over the selected face. The sign follows the chosen direction: a negative value acts opposite to the axis. For a wearing surface on the top slab, apply it downward; for internal water pressure on a wall, apply it outward from the cell.


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