WT22X131 Steel WT-shape — Section Properties
Dimensions
| Property | Value | Unit |
|---|---|---|
| Depth (d) | 21.7 | 551.2 mm |
| Flange Width (bf) | 15.8 | 40.13 cm |
| Flange Thickness (tf) | 1.42 | 36.1 mm |
| Web Thickness (tw) | 0.785 | 19.9 mm |
| Area (A) | 38.5 in² | 248.4 cmÃÂò |
| Weight | 131 lb/ft | 194.9 kg/m |
Elastic Section Properties
| Property | Strong Axis (X-X) | Weak Axis (Y-Y) | Unit |
|---|---|---|---|
| Moment of Inertia (I) | 1640 | 462 | in⁴ |
| Elastic Section Modulus (S) | 99.4 | 58.6 | in³ |
| Plastic Section Modulus (Z) | 176 | 90.9 | in³ |
| Radius of Gyration (r) | 6.53 | 3.47 | in |
Torsional Properties
| Property | Value | Unit |
|---|---|---|
| Torsional Constant (J) | 18.6 | in⁴ |
| Warping Constant (Cw) | 200 | in⁶ |
Section Profile Summary
The centroid of a tee is closer to the flange, creating an inherent eccentricity in tension connections. For truss chords and bracing, account for this eccentricity in the connection design — the induced bending moment can be significant for slender members.
At 21.7" deep, this section is frequently specified for primary floor beams, girders, and moment frame columns in commercial and institutional buildings.
Key Design Checks (AISC 360)
| Check | Formula | This Section |
|---|---|---|
| Plastic moment | Mp = Zx × Fy | 8,800 kip-in |
| Deflection | Δ = 5wLâÃÂô/(384EIx) | Use Ix = 1,640 in⁴ |
| Torsion | St. Venant = GJ/L | J = 18.6 in⁴ |
| Column buckling | KL/r âÃÂàFcr | r_x = 6.53 in |
Design Notes
- Stem in tension for beams: Orient the tee so the flange is in compression (stem down for gravity loads). Per AISC 360 Section F9, the flexural capacity is significantly higher with the stem in tension.
- Flexural-torsional buckling for columns: Single-axis symmetry means the governing buckling mode may be flexural-torsional rather than pure flexural per AISC 360 Eq. E4-4.
- Connection eccentricity: The centroid is closer to the flange — tension connections must account for the induced bending when the work line differs from the centroidal axis.
Verification (AISC 360): All designs using this section must be verified by a licensed Professional Engineer. Before finalizing member selection, check beam-column interaction (P-M), lateral-torsional buckling, serviceability deflections, and all connection limit states. See Engineering Disclaimer.
Worked Example: Tension Capacity — wt22x131
Scenario: wt22x131 used as a bottom chord member in a roof truss. The member carries axial tension only under the governing load combination.
Given:
- wt22x131: gross area Ag = 38.5 in²
- Steel: Fy = 50 ksi, Fu = 65 ksi
- Connection: bolted through the flange with 4 bolts per line (standard holes)
Step 1 — Gross yield (AISC 360 Eq. D2-1):
φTn_yield = 0.9 × Ag × Fy = 0.9 × 38.5 × 50 = 1,733 kips
Step 2 — Net section fracture:
For bolted connections, deduct bolt holes from Ag: An = Ag − n × dh × tf
The effective net area Ae = U × An depends on the shear lag factor U per AISC 360 Table D3.1.
Check φTn_fracture = 0.75 × Ae × Fu per AISC 360 Eq. D2-2.
Step 3 — Stem-in-tension note:
For WT/ST sections loaded in axial tension, the eccentricity between the centroid and the connection plane introduces a bending moment that should be considered in the connection design. The stem is more flexible than the flange — verify the weld or bolt group can accommodate the induced prying action.
Related Resources
- Steel Beam Capacity Calculator
- Column Capacity Calculator
- Beam Deflection Calculator
- Section Properties Calculator
- Steel Grades Reference
- Section Comparison Tool
Design Resources
- Section Properties Lookup — Compare with similar sections
- Steel Beam Sizes Reference — Standard beam dimensions
Educational reference only. Verify all section properties against the current AISC 360 Manual and mill certificates before design. Results are PRELIMINARY — NOT FOR CONSTRUCTION.