# SteelSections EC3

> Steel Section Properties, Classification, and Selection per EN 1993

Canonical: https://www.ramcadds.com/products/steelsections-ec3
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Last verified: 2026-07-18
Categories: building-components

SteelSections EC3 is a steel section property database and classification tool per Eurocode 3. It provides structural engineers with comprehensive section properties, cross-section classification, and section selection capabilities for steel design to EN 1993 standards.

SteelSections EC3 is a steel-section database and classification program from RUNET Norway AS for design to Eurocode 3 (EN 1993-1-1:2005), supplied in India by RAM CADDSYS. It holds European, American and British profiles — channels, angles and hollow sections included — with full properties drawn to scale. Every section is automatically classified (Class 1-4) with tension, compression, bending, shear and buckling resistances computed.

SteelSections EC3 by Runet Software is a specialized tool for steel section analysis and selection per Eurocode 3 (EN 1993). It provides a comprehensive database of standard steel section properties, performs cross-section classification per EN 1993-1-1, and assists engineers in selecting optimal sections for given loading conditions. An essential companion tool for steel structural design to Eurocode standards.

## Key points

- SteelSections EC3 is Runet Software's design-table program for structural steel sections to Eurocode 3 (EN 1993-1-1:2005).
- It covers the full range of international standard profiles — European, American and British sections, channels, angles and hollow sections — with properties drawn to scale.
- Beyond listing dimensions, it automatically classifies every section (Class 1-4 per §5.5) and computes tension, compression, bending, shear, buckling and lateral-torsional buckling resistance.
- Steel grades and partial safety factors (γM0, γM1, γM2) are user-editable, so results can be aligned with a project specification or National Annex.
- Engineers can define non-standard or welded built-up sections and get the same automatic property and resistance computation as standard profiles.
- RAM CADDSYS supplies SteelSections EC3 in India with licensing, training and technical support.
- Tables of all international standard steel sections (European, British, American) with full geometric and mechanical properties, drawn to scale
- Automatic cross-section classification (Class 1-4) per EN 1993-1-1:2005 §5.5 for axial load and bending
- Computes design resistances — tension, compression, bending (y-y and z-z), and shear — per EN 1993-1-1:2005 §6.2
- Computes buckling resistance (§6.3.1) and lateral-torsional buckling resistance (§6.3.2) across a range of buckling lengths (1.0-15 m)
- Handles four steel grades (S235, S275, S355, S450) with parametric, user-editable yield/ultimate values
- User-editable partial safety factors (γM0, γM1, γM2) to suit a project or National Annex
- Supports non-standard sections (edit standard dimensions) and fully user-defined welded built-up sections with automatic property and resistance computation
- One-click analytical report for the classification, resistance and buckling values of any selected section

## Why engineers pick it

- **Comprehensive Section Database** — Tables of all international standard steel sections — European IPE, HE, IPN, HL, HD, HP, American W, British UB/UC, channels, equal and unequal angles, SHS, RHS and CHS — with full geometric and mechanical properties drawn to scale.
- **EC3 Cross-Section Classification** — Automatic cross-section classification per EN 1993-1-1:2005 §5.5 (Class 1 through Class 4), determined from the width-to-thickness ratios of the compression parts for axial load and bending.
- **Code-Based Resistance and Buckling** — Computes design tension, compression, bending and shear resistances per §6.2, plus compression buckling (§6.3.1) and lateral-torsional buckling (§6.3.2) with Mcr per Annex F — not just section properties.
- **Editable Materials and Custom Sections** — Four steel grades (S235, S275, S355, S450) with user-editable yield/ultimate values and partial factors (γM0, γM1, γM2), plus non-standard and fully user-defined welded built-up sections with automatic property and resistance computation.

## Capabilities

- **Standard section database with properties** — A left-tree picker for IPE, HE, IPN, HL, HD, HP, American W, British UB/UC, UPN/UAP/UPE channels, equal/unequal angles, SHS, RHS (hot-rolled and cold-formed) and CHS. The table lists every standard size with A, Iy, Iz, Wy, Wz, Wpl, iy, iz, Avz, Avy, It, Iw and a scaled section drawing.
- **EN 1993-1-1 cross-section classification** — Classifies each section into Class 1-4 per §5.5 (Table 5.2) from the width-to-thickness ratios of the compression parts, for axial loading and loading with bending — determining whether plastic or elastic (and effective, for Class 4) resistance applies.
- **Cross-section resistance verification** — Computes design resistances per §6.2: tension (Npl,Rd, Nu,Rd at fastener holes), compression (Nc,Rd), bending about both axes (My,Rd, Mz,Rd), shear parallel to web and flanges (Vz,Rd, Vy,Rd), with shear-bending interaction and bi-axial bending checks.
- **Member buckling and lateral-torsional buckling** — Computes compression buckling resistance (Nb,Rd) per §6.3.1 using the appropriate buckling curve (a0-d), and lateral-torsional buckling resistance (Mb,Rd) per §6.3.2 with Mcr from Annex F — tabulated for buckling/restraint lengths from 1.0 to 15 m, for uniform and parabolic moment diagrams.
- **Non-standard and welded user sections** — Lets engineers edit the basic dimensions of standard sections or define welded built-up I/H sections; geometric, strength and buckling properties are recomputed automatically.
- **Parametric materials and safety factors** — Steel grade values (S235/S275/S355/S450) and the partial factors γM0, γM1, γM2 used for classification and resistance are user-editable.
- **Section Property Lookup** — Instant access to full geometric properties (area, moments of inertia, section moduli, radii of gyration) and mechanical properties.
- **Cross-Section Classification** — Automatic classification of steel sections per EN 1993-1-1 Table 5.2 for compression, bending, and combined loading with Class 1-4 determination.
- **Section Comparison Tool** — Side-by-side comparison of multiple sections for resistance, stiffness, and weight optimization to identify the most efficient profile for a given application.
- **Custom Section Input** — Input and analysis of custom welded or built-up section profiles with automatic property calculation and Eurocode 3 classification.

## Applications

- **Fast section sizing during steel design** — Look up a candidate profile and immediately read its EC3 class, axial/bending/shear resistances and buckling capacities.
- **Verifying members to Eurocode 3** — Confirm that a chosen beam or column satisfies EN 1993-1-1 cross-section and buckling checks across realistic unrestrained lengths.
- **Designing welded and built-up sections** — Define a custom welded I/H section by its plate dimensions and obtain its classification, resistances and buckling values to Eurocode 3.
- **Section property reference for analysis software** — Provide consistent EC3 section properties (A, I, W, Wpl, i, shear areas, torsion and warping constants) for hand checks or for feeding frame-analysis tools.
- **Teaching and learning Eurocode 3 steel design** — A transparent, clause-referenced tool that shows how classification, resistance and buckling are derived — useful for training engineers and students on EN 1993-1-1 procedures.

## In depth

### Why not just hand-calculate a section's Eurocode 3 classification and resistance?

Because deriving a section's EC3 class, resistance and buckling capacity by hand is slow and repetitive across dozens of candidate profiles, and SteelSections EC3 returns them instantly from a shared, code-referenced database.

Selecting a steel section to Eurocode 3 means more than reading its dimensions off a catalogue. Before a profile can be checked against a real design case, an engineer must classify its cross-section (Class 1 through 4 per EN 1993-1-1:2005 §5.5), because the class determines whether plastic, elastic or effective section properties apply — and then work through the §6.2 resistance and §6.3 buckling checks by hand, selecting the appropriate buckling curve and, for lateral-torsional buckling, the critical moment from Annex F.

SteelSections EC3 replaces that manual sequence with a lookup: pick a section from the international database — IPE, HE, IPN, HL, HD, HP, W, UB/UC, channels, angles, or hollow sections — and it reports the classification, design resistances and buckling capacities directly, drawn to scale and backed by a one-click analytical report suitable for design documentation.

### How does SteelSections EC3 turn a section choice into a Eurocode 3 check?

You pick a profile from the tree of standard international sections, or define a non-standard or welded one, and the program applies EN 1993-1-1 classification and resistance rules automatically using the steel grade and safety factors you set.

The interface presents a left-tree picker for every supported family — European IPE, HE, IPN, HL, HD, HP, American W, British UB/UC, channels (UPN/UAP/UPE), equal and unequal angles, and hot-rolled or cold-formed SHS, RHS and CHS. Selecting a size returns its full geometric and mechanical properties (A, Iy, Iz, Wy, Wz, Wpl, iy, iz, shear areas, torsion and warping constants) alongside its EN 1993-1-1 §5.5 classification for axial load and bending.

From there the program computes design resistances per §6.2 — tension, compression, bending about both axes and shear — plus compression buckling per §6.3.1 and lateral-torsional buckling per §6.3.2 with Mcr from Annex F, tabulated across buckling lengths from 1.0 to 15 m. Steel grade (S235, S275, S355, S450) and the partial factors γM0, γM1, γM2 are editable to match a project specification or National Annex, and the same automatic computation applies to non-standard or user-defined welded sections.

## Design codes

- **EN (Eurocode)** — EN 1993-1-1:2005 (Eurocode 3, Part 1-1) / Cross-section classification §5.5 (Table 5.2) / Cross-section resistance §6.2 / Member buckling resistance §6.3.1 / Lateral-torsional buckling §6.3.2 / Critical moment Mcr per Annex F

## Questions

### What is SteelSections EC3?

It is a Runet Software program that provides design tables of structural steel sections to Eurocode 3 (EN 1993-1-1:2005). For any section it gives the dimensions and properties, the EC3 cross-section class, and the design tension, compression, bending, shear, buckling and lateral-torsional-buckling resistances.

### Which design code does it follow?

EN 1993-1-1:2005 (Eurocode 3, Part 1-1). It applies §5.5 for classification, §6.2 for cross-section resistance, §6.3.1 for compression buckling, and §6.3.2 for lateral-torsional buckling, with the critical moment Mcr computed per Annex F.

### Does it actually design to the code, or just list properties?

Both. Beyond geometric properties it performs code-based verification — computing Npl,Rd, Nc,Rd, My,Rd, Mz,Rd, Vz,Rd, Vy,Rd, Nb,Rd and Mb,Rd per the EN 1993-1-1 clauses — so it determines resistances, not just section dimensions.

### Which steel section types are included?

European I-beams (IPE, IPE A/O/V), wide-flange beams and columns (HE A/AA/B, HEM, HD, HP, HL), European standard beams (IPN), American wide-flange (W), British universal beams and columns (UB, UC), channels (UPN, UAP, UPE), equal and unequal angles, square and rectangular hollow sections (hot-rolled and cold-formed), and circular hollow sections.

### Which steel grades are supported?

Four grades by default — S235, S275, S355 and S450. The yield and ultimate strength values for each grade are parametric and can be edited under Parameters / Structural steel.

### Can I change the partial safety factors for a National Annex?

Yes. The partial factors for materials (γM0, γM1, γM2) used in classification and resistance are user-editable under Parameters / Partial factors, so results can be aligned with a project specification or National Annex.

### Does it handle slender Class 4 sections?

Yes. Classification distinguishes Class 1-4 per §5.5; for Class 4 sections the resistances use effective cross-section properties (Aeff, Weff), consistent with EN 1993-1-1's effective-section approach for slender cross-sections.

### Can I analyse welded or non-standard sections?

Yes. You can edit the basic dimensions of standard sections, or define user welded built-up sections by their plate dimensions; the program automatically recomputes the geometric, strength and buckling properties and lets you reuse the section like a standard one.

### Does it calculate buckling and lateral-torsional buckling?

Yes. It computes compression buckling resistance Nb,Rd (§6.3.1) using the appropriate buckling curve, and lateral-torsional buckling resistance Mb,Rd (§6.3.2) with Mcr per Annex F, tabulated for buckling and restraint lengths from about 1.0 to 15 m, for both uniform and parabolic moment diagrams.

### What output does it produce?

Selecting (or double-clicking) a section produces an analytical report covering its classification, resistance values and buckling resistance — suitable as a reference for design calculations. The same EC3 section tables are also used by Runet's FRAME2Dexpress.

### How does it relate to Runet's other steel tools?

It is the section-database engine behind Runet's steel suite — the same EC3 tables are activated inside FRAME2Dexpress, and Runet also offers STEELexpress for element design and Steel Portal Frame EC3 for portal-frame design to Eurocode 3.

### Is SteelSections EC3 available in India through RAM CADDSYS?

Yes. RAM CADDSYS is an authorised distributor of Runet Software and lists Runet's Eurocode building-component tools on its catalogue, providing licensing, training and technical support for structural engineering firms in India and the wider region.

### What platform does it run on?

It is a Windows desktop application, distributed in English (the Runet suite is offered in English and Bulgarian), with free internet updates provided by the vendor.

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