Australian Universal Beam Guide — UB 150 to 610 per AS/NZS 3679.1

Complete engineering reference for Australian universal beam (UB) sections manufactured to AS/NZS 3679.1:2016. Covers the full OneSteel/InfraBuild rolling range from 150UB14.0 to 610UB125, including section properties, design capacities, grade selection, worked examples, and comparison with international equivalents. All values in metric units consistent with AS 4100:2020.

Related pages: AU Beam Sizes Table | AU Universal Column Guide | Beam Design Worked Example | Beam Capacity Calculator

Universal Beam Section Properties — Full Range Table

Australian UB sections are designated by nominal depth (mm) followed by mass per metre (kg/m). The designation 310UB40.4 indicates a universal beam approximately 310 mm deep with a mass of 40.4 kg/m. All sections are hot-rolled from Grade 300 steel unless Grade 350 is specified.

150 UB Series

180 UB Series

200 UB Series

250 UB Series

310 UB Series

360 UB Series

410 UB Series

460 UB Series

530 UB Series

610 UB Series

700 UB Series — Heavy Beams

Grade 300 Mechanical Properties — AS/NZS 3679.1

Australian universal beams are supplied to Grade 300 with the following minimum mechanical properties:

Section Designation System

Australian UB designations follow a logical system:

310UB40.4 decodes as:

• 310 = Nominal depth in mm (actual depth 300 mm for this specific section)
• UB = Universal Beam (parallel flange, depth > flange width)
• 40.4 = Mass per metre in kg/m

Comparison: Australian UB vs International Equivalent Beams

Worked Example: UB Selection for Simply Supported Beam

Problem: Select a suitable UB section for a simply supported floor beam spanning 9.0 m. Dead load G = 4.5 kN/m, live load Q = 3.0 kPa x 2.5 m tributary width = 7.5 kN/m. Use Grade 300 steel. Assume full lateral restraint from composite slab. Deflection limit = span/250 under live load.

Step 1: Design loads (factored)

w* = 1.2G + 1.5Q = 1.2 x 4.5 + 1.5 x 7.5 = 5.4 + 11.25 = 16.65 kN/m

Step 2: Maximum bending moment

M* = w* x L^2 / 8 = 16.65 x 9.0^2 / 8 = 16.65 x 81 / 8 = 168.6 kNm

Step 3: Required section modulus

Zx >= M* / (phi x fy) = 168.6 x 10^6 / (0.90 x 300) = 168.6 x 10^6 / 270 = 624,400 mm^3 = 624 x 10^3 mm^3

Step 4: Trial section

Try 360UB44.7: Zx = 510 x 10^3 mm^3 — too small.

Try 360UB50.7: Zx = 582 x 10^3 mm^3 — still below requirement.

Try 360UB56.7: Zx = 645 x 10^3 mm^3 > 624 — strength OK.

Step 5: Check shear capacity

V* = w* x L / 2 = 16.65 x 9.0 / 2 = 74.9 kN

Web area: Aw = d1 x tw = (350 - 2 x 12.0) x 7.0 = 326 x 7.0 = 2282 mm^2

phi Vv = phi x 0.6 x fy x Aw = 0.90 x 0.6 x 300 x 2282 / 1000 = 369.6 kN >> 74.9 kN — shear OK.

Step 6: Check deflection (serviceability)

w_service = G + psi_s x Q = 4.5 + 0.7 x 7.5 = 9.75 kN/m

delta = 5 x 9.75 x 9000^4 / (384 x 200,000 x 113 x 10^6) = 5 x 9.75 x 6.561e15 / (384 x 200,000 x 113e6) = 31.99e16 / 8.678e15 = 36.9 mm

Deflection limit = span/250 = 9000/250 = 36 mm

delta = 36.9 mm slightly exceeds 36 mm. Either increase section or rely on composite action.

Try 410UB53.7: Ix = 128 x 10^6 mm^4

delta = 31.99e16 / (384 x 200,000 x 128e6) = 31.99e16 / 9.830e15 = 32.6 mm < 36 mm — OK.

Result: Select 410UB53.7 Grade 300. Final check: phi Ms = 0.90 x 300 x 647 x 10^3 / 10^6 = 174.7 kNm > 168.6 kNm — strength OK. Shear OK. Deflection OK.

OneSteel (InfraBuild) Procurement Guide

Standard Lengths

UB sections are typically supplied in stock lengths of 9.0 m, 10.5 m, 12.0 m, 13.5 m, 15.0 m, and 18.0 m. Some 610UB series sections available up to 20.0 m. Mill rolling lengths up to 24.0 m can be ordered subject to road transport constraints (maximum trailer length 24.0 m in most states).

Surface Condition

Standard supply is as-rolled with mill scale surface (Class 1 per AS 1627.4). Blast cleaning to Class 2.5 is performed at the fabricator's workshop. Shop primer (zinc phosphate or zinc-rich epoxy, 15-25 micron DFT) from the mill or service centre costs approximately AUD 80-120 per tonne additional.

Tolerances

Dimensional tolerances per AS/NZS 3679.1 Table G1: Depth (d): +/- 3 mm for d <= 300 mm; +/- 4 mm for d > 300 mm. Flange width (bf): +/- 3 mm for bf <= 200 mm; +/- 4 mm for bf > 200 mm. Web eccentricity: <= 3 mm at mid-depth. Mass per metre: +/- 4% of nominal. Straightness: L/1000 maximum.

Frequently Asked Questions

Can universal beams be used as columns in Australian practice?

Yes, but with caution. Universal beams are optimised for bending and have lower minor-axis stiffness (ry is significantly less than rx) compared to universal columns, which have approximately equal rx and ry. A UB used as a column will buckle about the weak axis at a lower load than an equivalent-weight UC. If a UB must be used as a column (common in portal frame leg members where strong-axis bending coexists with axial compression), the buckling capacity must be explicitly checked for both axes per AS 4100 Clause 6.3. In many cases, a UC section will provide better axial efficiency.

What is the difference between Grade 300 and Grade 300PLUS?

Grade 300PLUS is a trademarked designation from InfraBuild (OneSteel) for steel that meets the minimum requirements of Grade 300 per AS/NZS 3679.1 but with additional guaranteed properties: maximum carbon equivalent value (CEV <= 0.43) for assured weldability, guaranteed Charpy V-notch impact values (27 J at 0 degree C), and through-thickness ductility exceeding the minimum standard. For structural design calculations, fy and fu values are identical to Grade 300 — the difference is in quality assurance, not strength.

How do I calculate the self-weight deflection of a UB beam during erection?

The self-weight deflection of an unpropped UB beam is calculated using the mass per metre from the section table. Convert kg/m to kN/m by dividing by 101.97 (or multiply mass by 0.00981). For a 410UB53.7 (53.7 kg/m): self-weight = 53.7 x 9.81 / 1000 = 0.527 kN/m. This is typically much smaller than imposed dead and live loads but can be significant for long spans with light loading. Pre-cambering (typically 50-75% of self-weight deflection) can be specified to achieve a level floor after slab casting.

What minimum bearing length is required at UB supports?

Per AS 4100 Clause 5.13, the minimum bearing length for a UB at a support must satisfy web bearing (yielding and buckling) requirements. For beams supported on concrete or masonry, a minimum bearing length of 75 mm is typically specified for small beams (up to 310UB), 100 mm for medium beams (360UB to 460UB), and 150 mm for large beams (530UB and 610UB). For steel-to-steel bearing, the bearing plate must be designed for the web bearing capacity of both the supported and supporting members.

Are holes permitted in UB flanges?

Holes in the tension flange of a UB significantly reduce the flexural capacity and should be avoided unless explicitly designed. AS 4100 Clause 9.1.10 provides rules for holes in structural members: holes in the tension flange reduce the net section modulus, potentially shifting the failure mode from yielding to net section fracture. For simply supported beams, any hole in the bottom flange within the central half of the span should be treated as a net section check.

Educational reference only. All design values must be verified against the current edition of AS 4100:2020, AS/NZS 3679.1:2016, and the project specification. This information does not constitute professional engineering advice. Always consult a qualified structural engineer for design decisions.

Disclaimer: This content is for educational purposes only. Results must be verified by a licensed professional engineer. Steel Calculator provides preliminary design tools — NOT a substitute for professional engineering judgment.