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section-property-calculator skill

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This skill computes cross-sectional properties for standard and custom shapes, including area, inertia, and section moduli, empowering accurate structural

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SKILL.md

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---
name: section-property-calculator
description: Cross-sectional property calculation skill for structural sections including standard and custom shapes
allowed-tools:
  - Read
  - Write
  - Glob
  - Grep
  - Edit
  - Bash
metadata:
  specialization: civil-engineering
  domain: science
  category: Structural Analysis
  skill-id: CIV-SK-002
---

# Section Property Calculator Skill

## Purpose

The Section Property Calculator Skill calculates cross-sectional properties for structural sections including area, moment of inertia, section modulus, and plastic modulus for both standard and custom shapes.

## Capabilities

- Calculate cross-sectional properties (A, I, S, Z, r)
- Support for standard shapes (W, HSS, C, L, pipe)
- Custom section analysis
- Composite section properties
- Cracked section analysis for concrete
- Plastic section modulus calculation
- Effective section properties
- Built-up section analysis

## Usage Guidelines

### When to Use
- Determining section properties for design
- Analyzing composite sections
- Evaluating cracked concrete sections
- Designing built-up members

### Prerequisites
- Section geometry defined
- Material properties specified
- Cracking criteria established (for concrete)
- Effective width defined (for composites)

### Best Practices
- Use correct axis orientation
- Account for holes and penetrations
- Consider effective sections per code
- Verify against published values

## Process Integration

This skill integrates with:
- Reinforced Concrete Design
- Structural Steel Design
- Bridge Design LRFD

## Configuration

```yaml
section-property-calculator:
  standard-shapes:
    - W-shapes
    - HSS-rectangular
    - HSS-round
    - channels
    - angles
    - pipes
  analysis-types:
    - gross
    - net
    - effective
    - cracked
```

## Output Artifacts

- Section property tables
- Cross-section drawings
- Calculation summaries
- Composite section analysis

Overview

This skill computes cross-sectional properties for structural sections, covering standard shapes and custom geometries. It returns area, centroid location, moments of inertia, section and plastic moduli, radii of gyration, and effective properties for composite or cracked sections. Outputs include tabular summaries and cross-section drawings to support design checks and documentation.

How this skill works

Provide a section definition (standard shape parameters or polygonal geometry), material properties, and analysis type (gross, net, effective, cracked). The skill builds a geometric model, performs area-based integration or shape-specific closed-form calculations, applies transformation for composites, and computes plastic and effective section moduli where required. Results are validated against common published values and exported as tables and drawing assets.

When to use it

Sizing and checking steel members during preliminary and detailed design
Evaluating composite beams or built-up sections for stiffness and strength
Performing cracked-section analysis for reinforced concrete elements
Calculating plastic section modulus for limit-state or plastic design
Generating section properties for finite element or hand calculations

Best practices

Define axis orientation and units consistently before analysis
Model holes, cutouts, and weld attachments explicitly to capture net properties
Use effective width and code provisions for flanged elements when computing effective properties
Validate results for standard shapes against published tables as a quick check
Specify cracking criteria and reinforcement layout for reliable concrete cracked-section outputs

Example use cases

Compute gross and net section modulus for a W-shape used in beam design
Determine transformed properties of a composite steel-concrete beam for serviceability checks
Analyze a custom built-up column section made from plates and angles to obtain elastic and plastic capacities
Evaluate cracked moment of inertia for a reinforced concrete slab to estimate deflections
Generate cross-section drawings and property tables for inclusion in shop drawings or design reports

FAQ

Which shapes are supported out of the box?

Common shapes like W-shapes, rectangular and round HSS, channels, angles, and pipes are supported with dedicated parameter sets.

Can I analyze an arbitrary custom section?

Yes. You can supply polygonal coordinates or a composite of standard shapes; the skill will integrate area and compute section properties.

Does it handle composite and cracked-section analysis?

It supports transformed-section calculations for composites and cracked concrete section analysis when cracking criteria and reinforcement are provided.