S12X31.8 Steel S-shape — Section Properties
Dimensions
| Property | Value | Unit |
|---|---|---|
| Depth (d) | 12 | 304.8 mm |
| Flange Width (bf) | 5 | 12.70 cm |
| Flange Thickness (tf) | 0.544 | 13.8 mm |
| Web Thickness (tw) | 0.35 | 8.9 mm |
| Area (A) | 9.31 in² | 60.1 cm² |
| Weight | 31.8 lb/ft | 47.3 kg/m |
Elastic Section Properties
| Property | Strong Axis (X-X) | Weak Axis (Y-Y) | Unit |
|---|---|---|---|
| Moment of Inertia (I) | 217 | 9.33 | in⁴ |
| Elastic Section Modulus (S) | 36.2 | 3.73 | in³ |
| Plastic Section Modulus (Z) | 41.8 | 6.44 | in³ |
| Radius of Gyration (r) | 4.83 | 1 | in |
Torsional Properties
| Property | Value | Unit |
|---|---|---|
| Torsional Constant (J) | 0.878 | in⁴ |
| Warping Constant (Cw) | 306 | in⁶ |
| Distance Between Flange Centroids (ho) | 11.5 | in |
| Effective Radius (rts) | 1.21 | in |
Design Resources
- Beam Capacity Calculator — Check S12X31.8 for your span and loads
- Column Capacity Calculator — Check S12X31.8 as a column
- Section Properties Database — Compare with other sections
- Steel Beam Sizes Reference — Full dimension table
- Steel Grades Reference — Material properties
Frequently Asked Questions
What is the weight of a S12X31.8 beam? 31.8 lb/ft (47.3 kg/m).
What is the section modulus of S12X31.8? Sx = 36.2 in³, Zx = 41.8 in³ (strong axis). Sy = 3.73 in³, Zy = 6.44 in³ (weak axis).
What steel grade is standard for S12X31.8? ASTM A36 (Fy = 36 ksi) for S-shapes. Verify with mill certificate.
What is the moment of inertia of S12X31.8? Ix = 217 in⁴ about the strong axis and Iy = 9.33 in⁴ about the weak axis. The radius of gyration is rx = 4.83 in and ry = 1 in.
Related Pages
Educational reference only. Verify all section properties against the current AISC Manual and mill certificates before design. Results are PRELIMINARY — NOT FOR CONSTRUCTION.