> 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/spliced-i-girder-bridge-workflow/organization-spig/cross-project-data-spig/analysis-results-spig/top-of-pile-layout-forces-spig.md).

# Top of Pile Layout Forces \[SPIG]

The Top of Pile Layout Forces workflow item extracts forces at the top of every pile in a selected pile layout (pile group) and identifies the critical pile based on a user-chosen force or moment component. The extracted forces are used by downstream pile interaction and pile capacity checks.

## General

**Pile Layout:** Pick the pile group (layout) from which forces are extracted at each pile's top. Required; exactly one pile group must be selected.

**Find Critical Pile According To: \[Fx/Fy/Fz/Mx/My/Mz]:** Component used to select the critical pile inside the picked layout. The pile whose absolute value of the selected component is largest becomes the reported "critical" pile; the extracted forces correspond to that pile.

**Extract From \[Result Case/Load Combination Table]:** Source of the extracted forces. Result Case (0) pulls the envelope from a single analysis case. Load Combination Table (1) applies AASHTO limit-state factors before extraction.

**Result Case:** Analysis case whose result is read when Extract From is Result Case.

**Load Combination Table:** Limit-state table used when Extract From is Load Combination Table.

**Limit State \[Strength I/Strength II/Strength III/Strength IV/Strength V/Extreme Event I/Extreme Event II/Service I/Service II/Service III/Service IV/Fatigue I/Fatigue II]:** AASHTO limit state whose combined forces are extracted. Only enabled when Extract From is Load Combination Table.

## Force Extraction Settings

**Maximize Force \[All/Fx/Fy/Fz/Mx/My/Mz]:** Component used to identify the critical result for each pile before the critical pile is selected. All computes each component independently.

**Min/Max \[Abs. max/Max/Min]:** Sorting convention for the component search. Abs. max picks the largest magnitude; Max picks most positive; Min picks most negative.

**Set Max Target \[Self/Target]:** (Read-only) Indicates the max target mode used. Shown for reference.

## Extracted Forces

All values in this group are computed from the most recent result extraction — they are displayed read-only for inspection.

**Extracted From:** (Read-only) Result case or load combination used.

**Force Settings:** (Read-only) Summary of the Maximize Force and Min/Max selections.

**Last Result Extraction:** (Read-only) Date and time of the last result extraction.

**Fx:** (Read-only) Extracted axial force at the critical pile top.

**Fy:** (Read-only) Extracted transverse shear force.

**Fz:** (Read-only) Extracted vertical force.

**Mx:** (Read-only) Extracted moment about X.

**My:** (Read-only) Extracted moment about Y.

**Mz:** (Read-only) Extracted moment about Z.

**Coordinate System:** (Read-only) Coordinate system in which the forces are reported.

**Pile Index:** (Read-only) Zero-based index of the critical pile inside the picked pile layout.


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