AISC 360-22ASTM A992 / A6W8 Series
AISC W8x21 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 | 21 lb/ft | 31.3 kg/m |
| Cross-Sectional Area | A | 6.16 in² | 3974 mm² |
| Overall Depth | d | 8.28 in | 210.3 mm |
| Flange Width | bf | 5.27 in | 133.9 mm |
| Flange Thickness | tf | 0.4 in | 10.2 mm |
| Web Thickness | tw | 0.25 in | 6.4 mm |
| Flange Centroid Distance | ho | 7.88 in | 200.2 mm |
Bending & Buckling Properties
| Property | Symbol | Imperial (US) | Metric (SI) |
|---|---|---|---|
| Strong-Axis Inertia | Ix | 75.3 in⁴ | 31.3 ×10⁶ mm⁴ |
| Strong-Axis Elastic Modulus | Sx | 18.2 in³ | 298 ×10³ mm³ |
| Strong-Axis Plastic Modulus | Zx | 20.4 in³ | 334 ×10³ mm³ |
| Strong-Axis Radius of Gyration | rx | 3.49 in | 88.6 mm |
| Weak-Axis Inertia | Iy | 9.8 in⁴ | 4.1 ×10⁶ mm⁴ |
| Weak-Axis Elastic Modulus | Sy | 3.7 in³ | 61 ×10³ mm³ |
| Weak-Axis Plastic Modulus | Zy | 5.7 in³ | 93 ×10³ mm³ |
| Weak-Axis Radius of Gyration | ry | 1.26 in | 32 mm |
| Torsional Constant | J | 0.282 in⁴ | 117 ×10³ mm⁴ |
| Warping Constant | Cw | 239.2 in⁶ | 40.8 ×10⁹ mm⁶ |
| Effective Radius of Gyration | rts | 1.46 in | 37.1 mm |
AISC 360-22 Design Capacities (Fy = 50 ksi / 345 MPa)
Plastic Moment Capacity (φMp)
76.5 kip-ft
103.8 kN·m (φ = 0.90)Nominal Shear Capacity (φVn)
55.9 kips
248.8 kN (φ = 0.90)Flange Slenderness (λf = bf / 2tf)
6.59
✓ Compact Flange (λf ≤ 9.15)Web Slenderness (λw = h / tw)
29.9
✓ Compact Web (λw ≤ 90.5)