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AS 4600:2005Australia

Cold-Formed Steel Beam (old AS 4600:2005)

Beam reactions link to the columns and footings below so load changes propagate downstream automatically. Structural engineers designing cold-formed steel beams, rafters, and lintels for projects required to comply with AS 4600:2005 - useful for checking legacy designs or jurisdictions that have not adopted the 2018 edition. Uses the same Australian CFS section library including Cee, Zed, top-hat, and furring sections.

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What it calculates

Beam reactions link to the columns and footings below, so load changes propagate downstream automatically. Design cold-formed steel beams to AS 4600:2005 using the Direct Strength Method with a full library of Australian CFS sections. Suitable for projects required to comply with the earlier code edition.

Code standards

  • AS 4600:2005

How it calculates

The CFS Steel Beam (old AS 4600:2005) calculator performs integrated load analysis and member capacity design for cold-formed steel beams. It combines an FEA beam solver with Direct Strength Method checks from AS 4600:2005.

Structural analysis

The calculator resolves moment, shear, and deflection across simple or continuous spans using a stiffness-based beam FEA. Dead load (G), live load (Q), wind (service Ws and ultimate Wu, both up and down), and alternative imposed loads can each be entered as separate load types. AS 1170 load combinations are applied internally to find the governing strength and serviceability demands.

Moment capacity

Moment section capacity phiM_s sets the absolute upper bound. Positive and negative moment member capacities phiM_b+ and phiM_b- account for lateral-torsional buckling:

utilization = |M| / phiM_b ≤ 1.0*

Separate effective lengths are specified for top-flange lateral bracing, bottom-flange lateral bracing, and torsional bracing, reflecting real framing conditions where one flange may be more restrained than the other.

Shear capacity

Shear capacity follows AS 4600 Clause 3.3.4:

utilization = |V| / phiV_v ≤ 1.0*

When web holes are present, a reduced shear capacity at holes is calculated using the q_s reduction factor dependent on hole geometry and spacing.

Bearing capacity

End and interior bearing capacities are checked for standard Cee and Zed sections. The bearing demand is the factored support reaction:

utilization = R / phiR_b ≤ 1.0*

Combined action checks

Combined bending and shear interaction (MV_int) and combined bending and bearing interaction (MR_int) are evaluated at the governing cross-sections per AS 4600. Both interaction ratios must remain at or below 1.0.

Deflection

Short-term, long-term, and imposed-load deflections are each checked against span-based limits (default L/250 for interior spans) and an absolute hard limit. Wind-induced deflections are included in the serviceability combinations.

Related calculators

Cold-Formed Steel Beam (AS/NZS 4600:2018)→Cold-Formed Steel Stud / Column→Cold-Formed Steel Member→Cold-Formed Steel Beam→

Frequently asked questions

What design standard does this calculator use?
This calculator uses AS 4600:2005 (with Amendment 1) as the base design standard. It is intended for projects where the earlier code edition applies. For new work to the current standard, the CFS Beam AS/NZS 4600:2018 calculator is recommended.
What inputs does the calculator require?
You enter span and support conditions, distributed and concentrated loads (dead, live, wind uplift and downward as separate load types), lateral bracing intervals for top flange, bottom flange, and torsional restraint, deflection limits, and bearing lengths at each support. The section is selected from the Australian CFS library.
What design checks does it perform?
The calculator checks positive and negative moment capacity (including lateral-torsional buckling), shear capacity at the web and at web holes, bearing capacity at end and interior supports, combined bending and shear interaction, and combined bending and bearing interaction. Deflection is checked against span-based (L/250) and absolute hard limits.
Does it handle roof and floor framing presets?
Yes. Built-in presets for rafter, roof bearer, underpurlin, strutting beam, verandah beam, and hanging beam pre-populate typical load types, tributary widths, wind pressure coefficients, and bracing configurations so you can get to results quickly.
What is the difference between this calculator and the AS/NZS 4600:2018 version?
This calculator targets the 2005 edition of AS 4600, which predates the 2018 revision's updated DSM provisions and section library additions. If your project specifies the current Australian standard, use the CFS Beam AS/NZS 4600:2018 calculator instead.
How do beam reactions link to other calculators?
Support reactions are exported as linkable outputs. In a Calcs.com project you can connect them to a CFS column, timber column, or concrete column calculator below the beam. Changes to span or loading automatically push updated reactions downstream without manual re-entry.

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