W33×241 Steel Beam
A W33×241 is a wide flange steel beam 34.2 inches deep with 15.9-inch flanges, weighing 241 pounds per foot. In ASTM A992 steel (Fy = 50 ksi) it has a design bending strength of 3,525 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 852 kips.
Design a W33×241 beam Opens a 51 ft span in the free beam designer.
W33×241 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 34.2 in |
| Flange width, bf | 15.9 in |
| Flange thickness, tf | 1.40 in |
| Web thickness, tw | 0.830 in |
| Distance to web toe of fillet, kdes | 2.19 in |
| Distance between flange centroids, ho | 32.80 in |
| Cross-sectional area, A | 71.0 in2 |
| Weight | 241 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W33×241 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 14200 in4 | 933 in4 |
| Elastic section modulus, S | 831 in3 | 118 in3 |
| Plastic section modulus, Z | 940 in3 | 182 in3 |
| Radius of gyration, r | 14.1 in | 3.62 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 36.2 in4 |
| Warping constant, Cw | 251000 in6 |
| Effective radius of gyration, rts | 4.29 in |
| Flange slenderness, bf/2tf | 5.66 |
| Web slenderness, h/tw | 35.9 |
W33×241 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 = 3,525 kip-ft | Mn/Ω = 2,345 kip-ft |
| Shear | φVn = 852 kips | Vn/Ω = 568 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 12.8 ft between braces it keeps its full strength; past Lr = 39.8 ft it buckles elastically. With uniform moment between braces (Cb = 1.0):
| Unbraced length, Lb | φMn (LRFD) | Mn/Ω (ASD) |
|---|---|---|
| Braced | 3,525 kip-ft | 2,345 kip-ft |
| 10 ft | 3,525 kip-ft | 2,345 kip-ft |
| 12.8 ft (Lp) | 3,525 kip-ft | 2,345 kip-ft |
| 20 ft | 3,166 kip-ft | 2,106 kip-ft |
| 30 ft | 2,668 kip-ft | 1,775 kip-ft |
| 39.8 ft (Lr) | 2,181 kip-ft | 1,451 kip-ft |
| 40 ft | 2,160 kip-ft | 1,437 kip-ft |
| 50 ft | 1,587 kip-ft | 1,056 kip-ft |
| 60 ft | 1,254 kip-ft | 834 kip-ft |
| 70 ft | 1,038 kip-ft | 691 kip-ft |
| 80 ft | 886 kip-ft | 590 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.
W33×241 load table by span
The largest uniform load a simply supported W33×241 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 0.241 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 17 ft | 97.6 | 64.9 | 124.2 | 186.3 |
| 19 ft | 78.1 | 52.0 | 88.9 | 133.4 |
| 21 ft | 63.9 | 42.5 | 65.9 | 98.8 |
| 23 ft | 53.3 | 35.5 | 50.1 | 75.2 |
| 25 ft | 45.1 | 30.0 | 39.0 | 58.6 |
| 27 ft | 38.7 | 25.7 | 31.0 | 46.5 |
| 29 ft | 33.5 | 22.3 | 25.0 | 37.5 |
| 31 ft | 29.3 | 19.5 | 20.5 | 30.7 |
| 33 ft | 25.9 | 17.2 | 17.0 | 25.5 |
| 35 ft | 23.0 | 15.3 | 14.2 | 21.3 |
| 37 ft | 20.6 | 13.7 | 12.0 | 18.1 |
| 39 ft | 18.5 | 12.3 | 10.3 | 15.4 |
| 41 ft | 16.8 | 11.2 | 8.85 | 13.3 |
| 43 ft | 15.3 | 10.1 | 7.67 | 11.5 |
| 45 ft | 13.9 | 9.27 | 6.69 | 10.0 |
| 47 ft | 12.8 | 8.49 | 5.88 | 8.81 |
| 49 ft | 11.7 | 7.81 | 5.19 | 7.78 |
| 51 ft | 10.8 | 7.21 | 4.60 | 6.90 |
| 53 ft | 10.0 | 6.68 | 4.10 | 6.15 |
| 55 ft | 9.32 | 6.20 | 3.67 | 5.50 |
| 57 ft | 8.68 | 5.77 | 3.29 | 4.94 |
| 59 ft | 8.10 | 5.39 | 2.97 | 4.46 |
| 61 ft | 7.58 | 5.04 | 2.69 | 4.03 |
| 63 ft | 7.11 | 4.73 | 2.44 | 3.66 |
| 65 ft | 6.67 | 4.44 | 2.22 | 3.33 |
| 67 ft | 6.28 | 4.18 | 2.03 | 3.04 |
| 69 ft | 5.92 | 3.94 | 1.86 | 2.79 |
| 71 ft | 5.59 | 3.72 | 1.70 | 2.56 |
| 73 ft | 5.29 | 3.52 | 1.57 | 2.35 |
| 75 ft | 5.01 | 3.34 | 1.45 | 2.17 |
| 77 ft | 4.76 | 3.16 | 1.34 | 2.00 |
| 79 ft | 4.52 | 3.01 | 1.24 | 1.86 |
| 81 ft | 4.30 | 2.86 | 1.15 | 1.72 |
| 83 ft | 4.09 | 2.72 | 1.07 | 1.60 |
| 85 ft | 3.90 | 2.60 | 0.99 | 1.49 |
- 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 W33×241 carries a factored load of 10.8 kips per foot (LRFD) or an allowable load of 7.21 kips per foot (ASD). A live load of 4.60 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.
W33×241 questions
What does W33×241 mean?
W means a wide flange shape. 33 is its nominal depth in inches (the actual depth is 34.2 in) and 241 is its weight in pounds per foot.
How much does a W33×241 weigh?
241 pounds per foot, so a 20 ft W33×241 weighs about 4,820 pounds.
How far can a W33×241 span?
It depends on the load. Braced along its length, it carries 97.6 kips per foot of factored load at 17 ft and 3.90 kips per foot at 85 ft; the load table has the spans in between. Floor beams are often 51 to 68 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W33×241 a compact section?
Yes. Its flanges (bf/2tf = 5.66) and web (h/tw = 35.9) are both compact for bending in 50 ksi steel.