300PFC AS/NZS 3679.1 Grade 300 — Australian Parallel Flange Channel Section Properties

300PFC is an Australian PFC (Parallel Flange Channel) per AS/NZS 3679.1 hot-rolled structural steel section. Standard Australian PFC dimensions. Verify against Liberty OneSteel / InfraBuild section catalog.

Dimensions (Metric)

Elastic Section Properties (Metric)

Torsional Properties

Section Profile Summary

Channels are efficient for bracing, girts, and stair stringers where loads align near the shear center. At 45 kg/m, this channel is a practical choice for secondary framing in industrial and commercial structures.

At 300 mm deep, this is a mid-range section for secondary beams, roof purlins, and bracing in standard framing.

Key Design Checks (AS 4100)

Design Notes

• Section asymmetry: The shear center lies outside the web. Loads not applied through the shear center produce torsion. Provide intermediate torsional restraints or stiffeners when the load eccentricity is significant.
• Lateral-torsional buckling: Check Cb (moment modification factor) per AS 4100 Chapter F — channels are more sensitive to load height effects than doubly-symmetric sections.
• Web crippling at supports: For channels used as beams, bearing stiffeners may be needed at concentrated load points per AS 4100 Section J10.

Verification (AS 4100): All designs using this section must be verified by a licensed Professional Engineer. Before finalizing member selection, check beam-column interaction (P-M), lateral-torsional buckling, serviceability deflections, and all connection limit states. See Engineering Disclaimer.

Worked Example: Retail floor beam — 300pfc

Scenario: Retail space — higher live load for public occupancy per EN 1991-1-1. Simply supported channel, 7.5 m span, 2.4 m tributary width. Service loads: 4.5 kPa dead + 5.0 kPa live (22.8 kN/m total).

Given:

• Span L = 7500 mm (7.5 m)
• Total service load w = 22.8 kN/m
• Live load portion w_L = 12.0 kN/m
• Section 300pfc: Ix = 65.0 × 10⁶ mm⁴, Sx = 433,000 mm³, Zx = 508,000 mm³
• Steel: fy = 300 MPa, E = 200,000 MPa
• Design moment resistance: φMn = 0.9 × Zx × fy = 137 kN·m

Step 1 — Live load deflection:

Δ_LL = 5 w_L L⁴ / (384 E Ix)

Δ_LL = 5 × 12.0 × (7500)⁴ / (384 × 200000 × 64,990,000)

Δ_LL = 38.0 mm

Step 2 — Deflection limit (L/300):

Δ_limit = L / 300 = 7500 / 300 = 25.0 mm

Step 3 — Dead + live deflection:

Δ_total = 72.3 mm

Step 4 — Design check:

⚠ Live load deflection exceeds L/300 — consider a deeper section, reduce tributary, or shorten the span.

Verify the design moment M*_Ed (from factored loads 1.35G + 1.5Q per AS 4100) does not exceed φMn = 137 kN·m. Also confirm shear resistance and bearing details at the supports.

Related Resources

• Steel Beam Capacity Calculator
• Column Capacity Calculator
• Beam Deflection Calculator
• Section Properties Calculator
• Steel Grades Reference
• Section Comparison Tool

Design Resources

• Section Properties Lookup — Compare with similar sections
• Steel Beam Sizes Reference — Standard beam dimensions

Educational reference only. Verify all section properties against the current AS 4100 Manual and mill certificates before design. Results are PRELIMINARY — NOT FOR CONSTRUCTION.