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Cold-Formed Steel Design Calculator

The SkyCiv Cold-Formed Steel Design Software assist structural engineers in determining member capacities and performing limit state design in accordance with the selected design code. The tools support all standard AS/NZS and AISI cold-formed steel sections, and also allow for custom standards and steel grades to be designed using the Direct Strength Method (DSM). This method typically results in approximately 10% higher member capacities compared to the Effective Width Method (EWM). The Cold-Formed Steel Design Software is part of the SkyCiv Quick Design module.

Versions of the Cold-Formed Steel Design Calculator are available for:

  • Australia and New Zealand – AS/NZS 4600:2018
  • United States, Canada, and Mexico – AISI S100-16 (North American Specification)

This is a preview of our full version cold-formed steel design software, which also includes the following premium features when you subscribe to either our Quick Design Module or SkyCiv Professional:

  • Premium: Integration with SkyCiv’s analysis software for more comprehensive analysis.
  • Premium: Full results, no lockouts.
  • Premium: Full reporting capabilities and analysis of sections.
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Contents

About the Cold-Formed Steel Design Software

Which cross-sections are supported?

The cold-formed steel design software by SkyCiv supports a diverse range of cold-formed steel sections and grades from the SkyCiv Australian, New-Zealand and AISI Section Library. It adheres to AS/NZS 4600:2018 and AISI S100-16 standards, providing an efficient tool for structural design and analysis.

AS/NZS 4600:2018

The calculator includes support for the following standard cold-formed steel section types commonly used in Australia and New Zealand:

  • Channels
  • Lipped Channels
  • Double Lipped Channels
  • Lipped Z Sections
  • Hat Sections
Cross-section illustrations for AS/NZS 4600:2018 showing Channels, Lipped Channels, Lipped Double Channels, Z‑Sections, and Topspan (Hat) sections with SkyCiv logo.

AISI S100-16

The calculator supports the majority of steel sections in the AISI Cold-Formed Steel Design manual, listed below:

  • C-Sections with Lips (I-1, I-2)
  • C-Sections without Lips (I-3)
  • Z-Sections with Lips (I-4)
  • Z-Sections without Lips (I-5)
  • Hat Sections (I-8)
Cross-section illustrations for AS/NZS 4600:2018 showing Channels, Lipped Channels, Lipped Double Channels, Z‑Sections, and Topspan (Hat) sections with SkyCiv logo.

What design checks are carried out?

The cold-formed steel calculator performs a comprehensive range of section and member capacity checks.

In accordance with AS/NZS 4600:2018:

  • Section Symmetry – Clause 2.1.1
  • Compression Capacity – Clause 2.3.1
  • Tension and Biaxial Bending Capacity – Clause 3.2
  • Lateral-Torsional Buckling – Clause 3.3.2
  • Local and Distortional Buckling – Clause 3.3.3
  • Shear Moment Compression / Tension Factor – Clause 3.3.3.2.1
  • Member Pre-Qualification – Table 7.1
  • Capacity Factors – Clause 7.2
  • Section Moment Capacity – Clause 7.2.1
  • Member Moment Capacity – Clause 7.2.2
  • Shear Capacity – Clause 7.2.3
  • Unequal End Moment Factor – Clause D2.1.1
  • Moment Compression Face Factors – Clause D2.1.1.2

In accordance with AISI S100-16:

  • Tension Strength – Appendix 1.1.1(a) and Section E3.1
  • Compression Strength – Section E2 / E3 / E4 and Appendix 2
  • Distortional Buckling – Section E4 and F4
  • Flexure Strength – Section F2 / F3 / F4 and Appendix 2
  • Shear Strength – Section G2.1 and G5
  • Combined Tensile Axial Load and Bending – Section H1.1
  • Combined Compressive Axial Load and Bending – Section H1.1
  • Combined Bending and Shear – Section H2

What are DSM Factors?

In the cold-formed steel design software, DSM factors are used to determine the elastic buckling capacities of each section. These factors form a key part of cold-formed steel design, allowing the software to account for local, distortional, and flexural buckling effects in accordance with relevant design standards.

The calculator displays the following Direct Strength Method (DSM) factors for each section.
These are elastic buckling stresses (MPa) in accordance with AS/NZS 4600 Clause 7 and AISI S100-16 Appendix 2.

Factor Description Units
fo,l,c Local buckling stress under axial compression ksi / MPa
fo,d,c Distortional buckling stress under axial compression ksi / MPa
fo,l,bx,pos Local buckling stress under positive bending about x-axis ksi / MPa
fo,l,bx,neg Local buckling stress under negative bending about x-axis ksi / MPa
fo,d,bx,pos Distortional buckling stress under positive bending about x-axis ksi / MPa
fo,d,bx,neg Distortional buckling stress under negative bending about x-axis ksi / MPa
fo,l,by,pos Local buckling stress under positive bending about y-axis ksi / MPa
fo,l,by,neg Local buckling stress under negative bending about y-axis ksi / MPa
fo,d,by,pos Distortional buckling stress under positive bending about y-axis ksi / MPa
fo,d,by,neg Distortional buckling stress under negative bending about y-axis ksi / MPa

Note:
l = local,
d = distortional.

Positive and negative bending directions correspond to the compression face as follows:

  • Positive Moment about X-axis → Compression at the bottom
  • Negative Moment about X-axis → Compression at the top
  • Positive Moment about Y-axis → Compression at the right
  • Negative Moment about Y-axis → Compression at the left

Light gauge steel vs cold formed steel

Light gauge steel (LGS) and cold-formed steel (CFS) are both terms for steel that is shaped at room temperature (cold-formed) without heat, relying on mechanical processes to achieve strength and shape. These steel sections are produced with a cold-rolling process that uses rollers to transform steel sheets into various profiles with different thicknesses. Light gauge steel (LGS), often discussed in the context of light gauge steel design, typically refers to thinner (typically less than 3mm or 0.12 in) steel sections often used for non-load-bearing elements in structures such as framing and partitions. In contrast, Cold Formed Steel (CFS) is used in more complex profiles like C-sections, Z-sections, and Hat-sections that are found in common structural members such as purlins, girts, and framing elements.

What can the cold-formed steel design software be used for?

The cold-formed steel software can be used to design a wide range of cold-formed steel structural beams, columns and members. This includes the design of the following in accordance with AS/NZS 4600 or AISI S100-16:

  • Purlins
  • Girts
  • Z-section beams
  • Steel Wall Studs
  • CFS tracks
  • Complex cold-formed framing and structural partition systems

Additionally, the tools support the design of other cold-formed steel profiles, such as C-sections (both plain and lipped) and Hat-sections ensuring compliance with the relevant standards for a variety of structural applications.

Axis Convention for Cold-Formed Steel Design

The axis conventions used in the cold formed steel design software are displayed graphically below.

For sections with an inclined principal axis (angles), the conventions displayed below are rotated counter clockwise by the principal axis angle (α).

Loading inputs will be converted to principal / geometric axis directions by the principal axis angle where required.

Four-panel illustration comparing major and minor axis conventions with colored axes: Y (green), Z (blue), TOP/BTM labels, and vectors V_y+ and V_z+ in each panel.

AS 4600 section symmetry

Clause 2.1.1 of AS/NZS 4600:2018 defines section symmetry, classifying sections as doubly, point, singly (monosymmetric) or non (asymmetric), which impacts their structural behaviour under loads. The figure below visually illustrates these classifications, highlighting how section geometry influences buckling resistance and load distribution.

Diagram of four symmetry types in sections: A) doubly-symmetric, B) point-symmetric, C) singly-symmetric (monosymmetric), D) non-symmetric (asymmetric); each panel shows x and y axes with representative shapes.

What shapes and material grades are supported by the Cold-Formed Steel Design Calculator?

The Cold-Formed Steel Design Calculator supports a wide range of standard and manufacturer-specific cold-formed steel shapes and material grades, in accordance with the relevant regional design codes.

AS/NZS 4600:2018 – Australia and New Zealand

This version includes extensive support for cold-formed steel sections used across Australian and New Zealand manufacturers. Supported manufacturers include:

  • Lysaght
  • Enduroframe
  • FrameCAD
  • Metalcraft
  • Metroll
  • Millform
  • Steeline
  • Stramit
  • Stratco
  • Studco

The calculator includes a comprehensive library of the following cold-formed steel shapes:

  • Channels
  • Channels (Lipped)
  • Double Channels (Lipped)
  • Z-Sections (Lipped)
  • Topspan (Hat)
  • Cee
  • U
  • MC Purlins
  • MZ Purlins
  • MS Tophats (Lipped)
  • Megaspan C Purlin
  • Megaspan Z Purlin
  • Extreme C Purlins
  • Extreme Z Purlins
  • Exacta Cee
  • Exacta Zee
  • Deflection Head Track
  • Steel Stud

The following material standards are available, each offering various material grades, and custom grades are also supported:

  • AS/NZS 1163
  • AS 1397
  • AS/NZS 1594
  • AS/NZS 1595
  • AS/NZS 3678

AISI S100-16 – United States, Canada, and Mexico

This version supports all standard AISI cold-formed steel sections in accordance with the North American Specification (AISI S100-16) as well as the following North American Manufacturers:

  • CEMCO
  • ClarkDietrich
  • MarinoWARE
  • SSMA
  • SUPREME

The calculator includes a comprehensive library of the following cold-formed steel shapes:

  • C-Sections W Lips (I-1)
  • C-Sections W Lips (I-2)
  • C-Sections WO Lips (I-3)
  • Z-Sections W Lips (I-4)
  • Z-Sections WO Lips (I-5)
  • Hat Sections (I-8)
  • Stud
  • Track
  • U-Channel
  • CR Channel
  • Track (T)
  • U-Channel (U)
  • Track (SFT)

The following material standards are available, each offering various material grades, and custom grades are also supported:

  • Gr. 33
  • Gr. 37
  • Gr. 40
  • Gr. 50
  • Gr. 55
  • Gr. 60
  • Gr. 70
  • Gr. 80

SkyCiv Quick Design Software

SkyCiv offers a wide range of Cloud Structural Analysis and Engineering Design Software, including:

As a constantly evolving tech company, we’re committed to innovating and challenging existing workflows to save engineers time in their work processes and designs.

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