250UB81 AS/NZS 3679.1 Grade 300 — Australian Universal Beam Section Properties
250UB81 is an Australian UB (Universal Beam) per AS/NZS 3679.1 hot-rolled structural steel section. Standard Australian UB dimensions. Verify against Liberty OneSteel / InfraBuild section catalog.
Dimensions (Metric)
| Property | Value | Unit |
|---|---|---|
| Depth (d) | 250 | mm |
| Flange Width (bf) | 150 | mm |
| Flange Thickness (tf) | 18.0 | mm |
| Web Thickness (tw) | 8.5 | mm |
| Cross-Sectional Area (A) | 72.2 | cm² |
| Mass | 81.0 | kg/m |
Elastic Section Properties (Metric)
| Property | Strong Axis (X-X) | Weak Axis (Y-Y) | Unit |
|---|---|---|---|
| Moment of Inertia (I) | 7,975 | 1,014 | cm⁴ |
| Elastic Section Modulus (S) | 638 | 135 | cm³ |
| Plastic Section Modulus (Z) | 724 | 206 | cm³ |
| Radius of Gyration (r) | 10.51 | 3.75 | cm |
Torsional Properties
| Property | Value | Unit |
|---|---|---|
| Torsional Constant (J) | 63 | cm⁴ |
| Distance Between Flange Centroids (ho) | 23.20 | cm |
Design Resources
- Australian Steel Design Guide — AS 4100 overview
- Australian Steel Beam Sizes — Full UB/UC dimension table
- AS/NZS 3679.1 Steel Grades — Grade 300, 350, 400 properties
- Beam Capacity Calculator — Check 250UB81 for your loads
- Column Capacity Calculator — Check 250UB81 as a column
- Section Properties Database — Compare with other sections
Frequently Asked Questions
What is the 250UB81 section depth? The 250UB81 has a nominal depth of 250mm and a flange width of 150mm. The UB is part of the 250mm depth series.
What steel grade is standard for 250UB81? Typically AS/NZS 3679.1 Grade 300 per AS/NZS 3679.1. Also available as Grade 300PLUS, Grade 350, Grade 400. Verify grade requirements with project specifications.
What is the mass of a 250UB81 beam? 81.0 kg/m. A 12m length weighs approximately 972 kg.
What is the section modulus of 250UB81? Sx = 638 cm³ (strong axis) and Sy = 135 cm³ (weak axis). The plastic section modulus Zx = 724 cm³.
Related Pages
- Australian Steel Beam Sizes Reference
- AS 4100 Steel Design Guide
- Australian Steel Grades
- Beam Capacity Calculator
- Column Capacity Calculator
Educational reference only. Verify all section properties against the current Liberty OneSteel / InfraBuild section catalog and AS/NZS 3679.1 before design. Results are PRELIMINARY — NOT FOR CONSTRUCTION.