W33×201 Steel Beam
A W33×201 is a wide flange steel beam 33.7 inches deep with 15.7-inch flanges, weighing 201 pounds per foot. In ASTM A992 steel (Fy = 50 ksi) it has a design bending strength of 2,899 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 723 kips.
Design a W33×201 beam Opens a 51 ft span in the free beam designer.
W33×201 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 33.7 in |
| Flange width, bf | 15.7 in |
| Flange thickness, tf | 1.15 in |
| Web thickness, tw | 0.715 in |
| Distance to web toe of fillet, kdes | 1.94 in |
| Distance between flange centroids, ho | 32.55 in |
| Cross-sectional area, A | 59.2 in2 |
| Weight | 201 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W33×201 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 11600 in4 | 749 in4 |
| Elastic section modulus, S | 686 in3 | 95.2 in3 |
| Plastic section modulus, Z | 773 in3 | 147 in3 |
| Radius of gyration, r | 14.0 in | 3.56 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 20.8 in4 |
| Warping constant, Cw | 198000 in6 |
| Effective radius of gyration, rts | 4.21 in |
| Flange slenderness, bf/2tf | 6.85 |
| Web slenderness, h/tw | 41.7 |
W33×201 bending and shear strength
For ASTM A992 steel (Fy = 50 ksi, E = 29,000 ksi) per AISC 360-16. Its flanges and web are compact for bending, so with its compression flange braced it reaches its full plastic moment.
| Strength | LRFD | ASD |
|---|---|---|
| Bending, compression flange braced | φMn = 2,899 kip-ft | Mn/Ω = 1,929 kip-ft |
| Shear | φVn = 723 kips | Vn/Ω = 482 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 12.6 ft between braces it keeps its full strength; past Lr = 36.8 ft it buckles elastically. With uniform moment between braces (Cb = 1.0):
| Unbraced length, Lb | φMn (LRFD) | Mn/Ω (ASD) |
|---|---|---|
| Braced | 2,899 kip-ft | 1,929 kip-ft |
| 10 ft | 2,899 kip-ft | 1,929 kip-ft |
| 12.6 ft (Lp) | 2,899 kip-ft | 1,929 kip-ft |
| 20 ft | 2,562 kip-ft | 1,705 kip-ft |
| 30 ft | 2,108 kip-ft | 1,403 kip-ft |
| 36.8 ft (Lr) | 1,798 kip-ft | 1,197 kip-ft |
| 40 ft | 1,582 kip-ft | 1,052 kip-ft |
| 50 ft | 1,142 kip-ft | 760 kip-ft |
| 60 ft | 891 kip-ft | 593 kip-ft |
| 70 ft | 731 kip-ft | 486 kip-ft |
A beam with a uniform load between braces has Cb above 1.0 (1.14 for a simple span braced only at its ends), so these values are conservative. The beam designer works out Cb for every segment between braces.
W33×201 load table by span
The largest uniform load a simply supported W33×201 can carry, in kips per foot, with its compression flange braced along its length (by a floor or roof deck, for example). The loads include the beam's own weight of 0.201 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 17 ft | 80.2 | 53.4 | 101.4 | 152.2 |
| 19 ft | 64.2 | 42.7 | 72.7 | 109.0 |
| 21 ft | 52.6 | 35.0 | 53.8 | 80.7 |
| 23 ft | 43.8 | 29.2 | 41.0 | 61.4 |
| 25 ft | 37.1 | 24.7 | 31.9 | 47.8 |
| 27 ft | 31.8 | 21.2 | 25.3 | 38.0 |
| 29 ft | 27.6 | 18.3 | 20.4 | 30.7 |
| 31 ft | 24.1 | 16.1 | 16.7 | 25.1 |
| 33 ft | 21.3 | 14.2 | 13.9 | 20.8 |
| 35 ft | 18.9 | 12.6 | 11.6 | 17.4 |
| 37 ft | 16.9 | 11.3 | 9.84 | 14.8 |
| 39 ft | 15.2 | 10.1 | 8.40 | 12.6 |
| 41 ft | 13.8 | 9.18 | 7.23 | 10.8 |
| 43 ft | 12.5 | 8.34 | 6.27 | 9.40 |
| 45 ft | 11.5 | 7.62 | 5.47 | 8.20 |
| 47 ft | 10.5 | 6.98 | 4.80 | 7.20 |
| 49 ft | 9.66 | 6.43 | 4.24 | 6.35 |
| 51 ft | 8.92 | 5.93 | 3.76 | 5.64 |
| 53 ft | 8.26 | 5.49 | 3.35 | 5.02 |
| 55 ft | 7.67 | 5.10 | 3.00 | 4.49 |
| 57 ft | 7.14 | 4.75 | 2.69 | 4.04 |
| 59 ft | 6.66 | 4.43 | 2.43 | 3.64 |
| 61 ft | 6.23 | 4.15 | 2.20 | 3.29 |
| 63 ft | 5.84 | 3.89 | 1.99 | 2.99 |
| 65 ft | 5.49 | 3.65 | 1.81 | 2.72 |
| 67 ft | 5.17 | 3.44 | 1.66 | 2.49 |
| 69 ft | 4.87 | 3.24 | 1.52 | 2.28 |
| 71 ft | 4.60 | 3.06 | 1.39 | 2.09 |
| 73 ft | 4.35 | 2.90 | 1.28 | 1.92 |
| 75 ft | 4.12 | 2.74 | 1.18 | 1.77 |
| 77 ft | 3.91 | 2.60 | 1.09 | 1.64 |
| 79 ft | 3.72 | 2.47 | 1.01 | 1.52 |
| 81 ft | 3.53 | 2.35 | 0.94 | 1.41 |
| 83 ft | 3.37 | 2.24 | 0.87 | 1.31 |
- Factored and allowable loads are limited by bending, or by shear where marked *.
- The deflection columns are the service loads that make the beam sag span/360 or span/240. Compare span/360 with the live load alone and span/240 with dead plus live load, the usual floor limits in IBC Table 1604.3.
Reading the table
At a 51 ft span, a W33×201 carries a factored load of 8.92 kips per foot (LRFD) or an allowable load of 5.93 kips per foot (ASD). A live load of 3.76 kips per foot would deflect it span/360, which is 1.70 in. The beam works if the factored load is under the first number and the live and total loads are under the deflection numbers. For other spans, supports or loads, open it in the beam designer, or follow the steel beam design guide to check one by hand.
W33×201 questions
What does W33×201 mean?
W means a wide flange shape. 33 is its nominal depth in inches (the actual depth is 33.7 in) and 201 is its weight in pounds per foot.
How much does a W33×201 weigh?
201 pounds per foot, so a 20 ft W33×201 weighs about 4,020 pounds.
How far can a W33×201 span?
It depends on the load. Braced along its length, it carries 80.2 kips per foot of factored load at 17 ft and 3.37 kips per foot at 83 ft; the load table has the spans in between. Floor beams are often 51 to 67 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W33×201 a compact section?
Yes. Its flanges (bf/2tf = 6.85) and web (h/tw = 41.7) are both compact for bending in 50 ksi steel.