W33×141 Steel Beam
A W33×141 is a wide flange steel beam 33.3 inches deep with 11.5-inch flanges, weighing 141 pounds per foot. In ASTM A992 steel (Fy = 50 ksi) it has a design bending strength of 1,928 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 604 kips.
Design a W33×141 beam Opens a 51 ft span in the free beam designer.
W33×141 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 33.3 in |
| Flange width, bf | 11.5 in |
| Flange thickness, tf | 0.960 in |
| Web thickness, tw | 0.605 in |
| Distance to web toe of fillet, kdes | 1.66 in |
| Distance between flange centroids, ho | 32.34 in |
| Cross-sectional area, A | 41.6 in2 |
| Weight | 141 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W33×141 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 7450 in4 | 246 in4 |
| Elastic section modulus, S | 448 in3 | 42.7 in3 |
| Plastic section modulus, Z | 514 in3 | 66.9 in3 |
| Radius of gyration, r | 13.4 in | 2.43 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 9.70 in4 |
| Warping constant, Cw | 64400 in6 |
| Effective radius of gyration, rts | 2.98 in |
| Flange slenderness, bf/2tf | 6.01 |
| Web slenderness, h/tw | 49.6 |
W33×141 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 = 1,928 kip-ft | Mn/Ω = 1,282 kip-ft |
| Shear | φVn = 604 kips | Vn/Ω = 403 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 8.6 ft between braces it keeps its full strength; past Lr = 25.0 ft it buckles elastically. With uniform moment between braces (Cb = 1.0):
| Unbraced length, Lb | φMn (LRFD) | Mn/Ω (ASD) |
|---|---|---|
| Braced | 1,928 kip-ft | 1,282 kip-ft |
| 5 ft | 1,928 kip-ft | 1,282 kip-ft |
| 8.6 ft (Lp) | 1,928 kip-ft | 1,282 kip-ft |
| 10 ft | 1,863 kip-ft | 1,239 kip-ft |
| 15 ft | 1,634 kip-ft | 1,087 kip-ft |
| 20 ft | 1,405 kip-ft | 935 kip-ft |
| 25.0 ft (Lr) | 1,176 kip-ft | 783 kip-ft |
| 25 ft (Lr) | 1,174 kip-ft | 781 kip-ft |
| 30 ft | 875 kip-ft | 582 kip-ft |
| 35 ft | 691 kip-ft | 460 kip-ft |
| 40 ft | 569 kip-ft | 379 kip-ft |
| 45 ft | 483 kip-ft | 321 kip-ft |
| 50 ft | 419 kip-ft | 279 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.
W33×141 load table by span
The largest uniform load a simply supported W33×141 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 0.141 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 17 ft | 53.4 | 35.5 | 65.1 | 97.7 |
| 19 ft | 42.7 | 28.4 | 46.7 | 70.0 |
| 21 ft | 35.0 | 23.3 | 34.6 | 51.8 |
| 23 ft | 29.1 | 19.4 | 26.3 | 39.5 |
| 25 ft | 24.7 | 16.4 | 20.5 | 30.7 |
| 27 ft | 21.2 | 14.1 | 16.3 | 24.4 |
| 29 ft | 18.3 | 12.2 | 13.1 | 19.7 |
| 31 ft | 16.0 | 10.7 | 10.7 | 16.1 |
| 33 ft | 14.2 | 9.42 | 8.91 | 13.4 |
| 35 ft | 12.6 | 8.38 | 7.47 | 11.2 |
| 37 ft | 11.3 | 7.49 | 6.32 | 9.48 |
| 39 ft | 10.1 | 6.75 | 5.40 | 8.09 |
| 41 ft | 9.17 | 6.10 | 4.64 | 6.97 |
| 43 ft | 8.34 | 5.55 | 4.03 | 6.04 |
| 45 ft | 7.61 | 5.07 | 3.51 | 5.27 |
| 47 ft | 6.98 | 4.64 | 3.08 | 4.62 |
| 49 ft | 6.42 | 4.27 | 2.72 | 4.08 |
| 51 ft | 5.93 | 3.94 | 2.41 | 3.62 |
| 53 ft | 5.49 | 3.65 | 2.15 | 3.22 |
| 55 ft | 5.10 | 3.39 | 1.92 | 2.89 |
| 57 ft | 4.75 | 3.16 | 1.73 | 2.59 |
| 59 ft | 4.43 | 2.95 | 1.56 | 2.34 |
| 61 ft | 4.14 | 2.76 | 1.41 | 2.12 |
| 63 ft | 3.89 | 2.58 | 1.28 | 1.92 |
| 65 ft | 3.65 | 2.43 | 1.17 | 1.75 |
| 67 ft | 3.44 | 2.29 | 1.06 | 1.60 |
| 69 ft | 3.24 | 2.15 | 0.97 | 1.46 |
| 71 ft | 3.06 | 2.04 | 0.89 | 1.34 |
| 73 ft | 2.89 | 1.93 | 0.82 | 1.23 |
| 75 ft | 2.74 | 1.82 | 0.76 | 1.14 |
| 77 ft | 2.60 | 1.73 | 0.70 | 1.05 |
| 79 ft | 2.47 | 1.64 | 0.65 | 0.97 |
| 81 ft | 2.35 | 1.56 | 0.60 | 0.90 |
| 83 ft | 2.24 | 1.49 | 0.56 | 0.84 |
- 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 W33×141 carries a factored load of 5.93 kips per foot (LRFD) or an allowable load of 3.94 kips per foot (ASD). A live load of 2.41 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.
W33×141 questions
What does W33×141 mean?
W means a wide flange shape. 33 is its nominal depth in inches (the actual depth is 33.3 in) and 141 is its weight in pounds per foot.
How much does a W33×141 weigh?
141 pounds per foot, so a 20 ft W33×141 weighs about 2,820 pounds.
How far can a W33×141 span?
It depends on the load. Braced along its length, it carries 53.4 kips per foot of factored load at 17 ft and 2.24 kips per foot at 83 ft; the load table has the spans in between. Floor beams are often 50 to 67 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W33×141 a compact section?
Yes. Its flanges (bf/2tf = 6.01) and web (h/tw = 49.6) are both compact for bending in 50 ksi steel.