W310x129 G40.21 350W — Canadian W-Shape Section Properties

Approximate equivalent of W12X87 per AISC A6. Approx. equivalent of W12X87. Verify against CISC Handbook.

Dimensions (Metric)

Elastic Section Properties (Metric)

Torsional Properties

Imperial Reference

Section Profile Summary

Hot-rolled W-shape with Sx = 1,934 cm³. The section is appropriate for primary framing in multi-storey buildings, crane girders, and bridge stringers.

At 317.5 mm deep, this section is common for floor beams, portal frame rafters, and columns in commercial and industrial buildings.

Key Design Checks (CSA S16)

Design Notes

• Compactness: Most W-shapes in ASTM A992 satisfy the compact limits in CSA S16 Table B4.1b for flexure (λ ≤ λp). This allows full plastic moment Mp development before local buckling occurs.
• Flange local buckling (FLB): The flange slenderness ratio bf/2tf is compared against λpf = 0.38√(E/Fy) ≈ 9.0 for compact sections.
• Web local buckling (WLB): h/tw is checked against λpw = 3.76√(E/Fy) ≈ 72 for flexure, and a more restrictive limit for uniform compression.
• Lateral-torsional buckling (LTB): Lp ≈ 328.2 cm (plastic limit). For unbraced lengths ≤ Lp, the full plastic moment is available. Between Lp and Lr, linear interpolation per CSA S16 Eq. F2-2 applies.

Verification (CSA S16): 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: Residential floor beam — w310x129

Scenario: Residential apartment floor — partition allowance included in dead load. Simply supported wide flange, 7.3 m span, 3 m tributary width. Service loads: 3.0 kPa dead + 2.0 kPa live (15.0 kN/m total).

Given:

• Span L = 7303 mm (7.3 m)
• Total service load w = 15.0 kN/m
• Live load portion w_L = 6.0 kN/m
• Section w310x129: Ix = 308.0 × 10⁶ mm⁴, Sx = 1,934,000 mm³, Zx = 2,163,000 mm³
• Steel: fy = 350 MPa, E = 200,000 MPa
• Design moment resistance: φMn = 0.9 × Zx × fy = 681 kN·m

Step 1 — Live load deflection:

Δ_LL = 5 w_L L⁴ / (384 E Ix)

Δ_LL = 5 × 6.0 × (7303)⁴ / (384 × 200000 × 308,010,000)

Δ_LL = 3.6 mm

Step 2 — Deflection limit (L/360):

Δ_limit = L / 360 = 7303 / 360 = 20.3 mm

Step 3 — Dead + live deflection:

Δ_total = 9.0 mm

Step 4 — Design check:

✓ Live load deflection is within the L/360 limit.

Verify the design moment M*_Ed (from factored loads 1.35G + 1.5Q per CSA S16) does not exceed φMn = 681 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 CSA S16 Manual and mill certificates before design. Results are PRELIMINARY — NOT FOR CONSTRUCTION.