AISC 360-22ASTM A992 / A6W21 Series
AISC W21x55 Properties & Dimensions
Standard wide flange I-beam cross-section properties, geometric dimensions, and LRFD design capacities per AISC Steel Construction Manual 15th/16th Edition.
Cross-Section Technical Schematic
Dual Units: Imperial (US) · SI MetricGeometric Dimensions & Area
| Property | Symbol | Imperial (US) | Metric (SI) |
|---|---|---|---|
| Nominal Weight | w | 55 lb/ft | 81.8 kg/m |
| Cross-Sectional Area | A | 16.2 in² | 10452 mm² |
| Overall Depth | d | 20.8 in | 528.3 mm |
| Flange Width | bf | 8.22 in | 208.8 mm |
| Flange Thickness | tf | 0.522 in | 13.3 mm |
| Web Thickness | tw | 0.375 in | 9.5 mm |
| Flange Centroid Distance | ho | 20.3 in | 515.6 mm |
Bending & Buckling Properties
| Property | Symbol | Imperial (US) | Metric (SI) |
|---|---|---|---|
| Strong-Axis Inertia | Ix | 1140 in⁴ | 474.5 ×10⁶ mm⁴ |
| Strong-Axis Elastic Modulus | Sx | 110 in³ | 1803 ×10³ mm³ |
| Strong-Axis Plastic Modulus | Zx | 126 in³ | 2065 ×10³ mm³ |
| Strong-Axis Radius of Gyration | rx | 8.4 in | 213.4 mm |
| Weak-Axis Inertia | Iy | 48.4 in⁴ | 20.1 ×10⁶ mm⁴ |
| Weak-Axis Elastic Modulus | Sy | 11.8 in³ | 193 ×10³ mm³ |
| Weak-Axis Plastic Modulus | Zy | 18.4 in³ | 302 ×10³ mm³ |
| Weak-Axis Radius of Gyration | ry | 1.73 in | 43.9 mm |
| Torsional Constant | J | 1.24 in⁴ | 516 ×10³ mm⁴ |
| Warping Constant | Cw | 7838.2 in⁶ | 1337.3 ×10⁹ mm⁶ |
| Effective Radius of Gyration | rts | 2.11 in | 53.6 mm |
AISC 360-22 Design Capacities (Fy = 50 ksi / 345 MPa)
Plastic Moment Capacity (φMp)
472.5 kip-ft
641.1 kN·m (φ = 0.90)Nominal Shear Capacity (φVn)
210.6 kips
937.5 kN (φ = 0.90)Flange Slenderness (λf = bf / 2tf)
7.87
✓ Compact Flange (λf ≤ 9.15)Web Slenderness (λw = h / tw)
52.7
✓ Compact Web (λw ≤ 90.5)