W33×263 Steel Beam
A W33×263 is a wide flange steel beam 34.5 inches deep with 15.8-inch flanges, weighing 263 pounds per foot. In ASTM A992 steel (Fy = 50 ksi) it has a design bending strength of 3,900 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 900 kips.
Design a W33×263 beam Opens a 51 ft span in the free beam designer.
W33×263 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 34.5 in |
| Flange width, bf | 15.8 in |
| Flange thickness, tf | 1.57 in |
| Web thickness, tw | 0.870 in |
| Distance to web toe of fillet, kdes | 2.36 in |
| Distance between flange centroids, ho | 32.93 in |
| Cross-sectional area, A | 77.5 in2 |
| Weight | 263 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W33×263 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 15900 in4 | 1040 in4 |
| Elastic section modulus, S | 919 in3 | 131 in3 |
| Plastic section modulus, Z | 1040 in3 | 202 in3 |
| Radius of gyration, r | 14.3 in | 3.66 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 48.7 in4 |
| Warping constant, Cw | 281000 in6 |
| Effective radius of gyration, rts | 4.31 in |
| Flange slenderness, bf/2tf | 5.03 |
| Web slenderness, h/tw | 34.3 |
W33×263 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 = 3,900 kip-ft | Mn/Ω = 2,595 kip-ft |
| Shear | φVn = 900 kips | Vn/Ω = 600 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 12.9 ft between braces it keeps its full strength; past Lr = 41.6 ft it buckles elastically. With uniform moment between braces (Cb = 1.0):
| Unbraced length, Lb | φMn (LRFD) | Mn/Ω (ASD) |
|---|---|---|
| Braced | 3,900 kip-ft | 2,595 kip-ft |
| 10 ft | 3,900 kip-ft | 2,595 kip-ft |
| 12.9 ft (Lp) | 3,900 kip-ft | 2,595 kip-ft |
| 20 ft | 3,533 kip-ft | 2,351 kip-ft |
| 30 ft | 3,015 kip-ft | 2,006 kip-ft |
| 40 ft | 2,496 kip-ft | 1,661 kip-ft |
| 41.6 ft (Lr) | 2,410 kip-ft | 1,603 kip-ft |
| 50 ft | 1,888 kip-ft | 1,256 kip-ft |
| 60 ft | 1,501 kip-ft | 999 kip-ft |
| 70 ft | 1,248 kip-ft | 831 kip-ft |
| 80 ft | 1,070 kip-ft | 712 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.
W33×263 load table by span
The largest uniform load a simply supported W33×263 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 0.263 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 17 ft | 105.9* | 70.6* | 139.0 | 208.6 |
| 19 ft | 86.4 | 57.5 | 99.6 | 149.4 |
| 21 ft | 70.7 | 47.1 | 73.8 | 110.6 |
| 23 ft | 59.0 | 39.2 | 56.1 | 84.2 |
| 25 ft | 49.9 | 33.2 | 43.7 | 65.6 |
| 27 ft | 42.8 | 28.5 | 34.7 | 52.1 |
| 29 ft | 37.1 | 24.7 | 28.0 | 42.0 |
| 31 ft | 32.5 | 21.6 | 22.9 | 34.4 |
| 33 ft | 28.7 | 19.1 | 19.0 | 28.5 |
| 35 ft | 25.5 | 16.9 | 15.9 | 23.9 |
| 37 ft | 22.8 | 15.2 | 13.5 | 20.2 |
| 39 ft | 20.5 | 13.6 | 11.5 | 17.3 |
| 41 ft | 18.6 | 12.3 | 9.91 | 14.9 |
| 43 ft | 16.9 | 11.2 | 8.59 | 12.9 |
| 45 ft | 15.4 | 10.3 | 7.50 | 11.2 |
| 47 ft | 14.1 | 9.40 | 6.58 | 9.87 |
| 49 ft | 13.0 | 8.65 | 5.81 | 8.71 |
| 51 ft | 12.0 | 7.98 | 5.15 | 7.72 |
| 53 ft | 11.1 | 7.39 | 4.59 | 6.88 |
| 55 ft | 10.3 | 6.86 | 4.11 | 6.16 |
| 57 ft | 9.60 | 6.39 | 3.69 | 5.53 |
| 59 ft | 8.96 | 5.96 | 3.33 | 4.99 |
| 61 ft | 8.38 | 5.58 | 3.01 | 4.51 |
| 63 ft | 7.86 | 5.23 | 2.73 | 4.10 |
| 65 ft | 7.38 | 4.91 | 2.49 | 3.73 |
| 67 ft | 6.95 | 4.62 | 2.27 | 3.41 |
| 69 ft | 6.55 | 4.36 | 2.08 | 3.12 |
| 71 ft | 6.19 | 4.12 | 1.91 | 2.86 |
| 73 ft | 5.85 | 3.90 | 1.76 | 2.63 |
| 75 ft | 5.55 | 3.69 | 1.62 | 2.43 |
| 77 ft | 5.26 | 3.50 | 1.50 | 2.24 |
| 79 ft | 5.00 | 3.33 | 1.39 | 2.08 |
| 81 ft | 4.76 | 3.16 | 1.29 | 1.93 |
| 83 ft | 4.53 | 3.01 | 1.19 | 1.79 |
| 85 ft | 4.32 | 2.87 | 1.11 | 1.67 |
- 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 W33×263 carries a factored load of 12.0 kips per foot (LRFD) or an allowable load of 7.98 kips per foot (ASD). A live load of 5.15 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.
W33×263 questions
What does W33×263 mean?
W means a wide flange shape. 33 is its nominal depth in inches (the actual depth is 34.5 in) and 263 is its weight in pounds per foot.
How much does a W33×263 weigh?
263 pounds per foot, so a 20 ft W33×263 weighs about 5,260 pounds.
How far can a W33×263 span?
It depends on the load. Braced along its length, it carries 105.9 kips per foot of factored load at 17 ft and 4.32 kips per foot at 85 ft; the load table has the spans in between. Floor beams are often 52 to 69 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W33×263 a compact section?
Yes. Its flanges (bf/2tf = 5.03) and web (h/tw = 34.3) are both compact for bending in 50 ksi steel.