W21X122 Steel Beam — Section Properties
Dimensions
| Property | Value | Unit |
|---|---|---|
| Depth (d) | 21.70 | in (551.2 mm) |
| Flange Width (bf) | 12.40 | in (315.0 mm) |
| Flange Thickness (tf) | 0.96 | in |
| Web Thickness (tw) | 0.60 | in |
| Area (A) | 35.90 | in² (231.6 cm²) |
| Weight | 122 | lb/ft (182 kg/m) |
Elastic Section Properties
| Property | Strong Axis (X-X) | Weak Axis (Y-Y) | Unit |
|---|---|---|---|
| Moment of Inertia (I) | 2,960 | 305 | in⁴ |
| Elastic Section Modulus (S) | 273 | 49.20 | in³ |
| Plastic Section Modulus (Z) | 307 | 75.60 | in³ |
| Radius of Gyration (r) | 9.09 | 2.92 | in |
Torsional Properties
| Property | Value | Unit |
|---|---|---|
| Torsional Constant (J) | 8.98 | in⁴ |
| Warping Constant (Cw) | 32,700 | in⁶ |
| Distance Between Flange Centroids (ho) | 20.70 | in |
| Effective Radius (rts) | 3.40 | in |
Design Resources
- Beam Capacity Calculator — Check W21X122 for your span and loads
- Column Capacity Calculator — Check W21X122 as a column
- Section Properties Database — Compare with other sections
- Steel Beam Sizes Reference — Full W-shape dimension table
- Steel Grades Reference — A992/A572 material properties
Frequently Asked Questions
What is the weight of a W21X122 beam? 122 lb/ft (182 kg/m). A 40-ft length weighs approximately 4,880 lbs.
What is the section modulus of W21X122? Sx = 273 in³ (strong axis) and Sy = 49.2 in³ (weak axis). The plastic section modulus Zx = 307 in³ and Zy = 75.6 in³.
What steel grade is standard for W21X122? Typically ASTM A992 (Fy = 50 ksi, Fu = 65 ksi) for W-shapes. Also available in A572 Grade 50 or A36. Verify with mill certificate.
What is the moment of inertia of W21X122? Ix = 2960 in⁴ about the strong axis and Iy = 305 in⁴ about the weak axis. The radius of gyration is rx = 9.09 in and ry = 2.92 in.
Related Pages
- Steel Beam Sizes Reference
- Beam Capacity Calculator
- Column Capacity Calculator
- Section Properties Database
Educational reference only. Verify all section properties against the current AISC Manual and mill certificates before design. Results are PRELIMINARY — NOT FOR CONSTRUCTION.