W36×330 Steel Beam
A W36×330 is a wide flange steel beam 37.7 inches deep with 16.6-inch flanges, weighing 330 pounds per foot. In ASTM A992 steel (Fy = 50 ksi) it has a design bending strength of 5,288 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 1,154 kips.
Design a W36×330 beam Opens a 57 ft span in the free beam designer.
W36×330 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 37.7 in |
| Flange width, bf | 16.6 in |
| Flange thickness, tf | 1.85 in |
| Web thickness, tw | 1.02 in |
| Distance to web toe of fillet, kdes | 2.80 in |
| Distance between flange centroids, ho | 35.85 in |
| Cross-sectional area, A | 97.0 in2 |
| Weight | 330 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W36×330 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 23300 in4 | 1420 in4 |
| Elastic section modulus, S | 1240 in3 | 171 in3 |
| Plastic section modulus, Z | 1410 in3 | 265 in3 |
| Radius of gyration, r | 15.5 in | 3.83 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 84.3 in4 |
| Warping constant, Cw | 456000 in6 |
| Effective radius of gyration, rts | 4.53 in |
| Flange slenderness, bf/2tf | 4.49 |
| Web slenderness, h/tw | 31.4 |
W36×330 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 = 5,288 kip-ft | Mn/Ω = 3,518 kip-ft |
| Shear | φVn = 1,154 kips | Vn/Ω = 769 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 13.5 ft between braces it keeps its full strength; past Lr = 45.5 ft it buckles elastically. With uniform moment between braces (Cb = 1.0):
| Unbraced length, Lb | φMn (LRFD) | Mn/Ω (ASD) |
|---|---|---|
| Braced | 5,288 kip-ft | 3,518 kip-ft |
| 10 ft | 5,288 kip-ft | 3,518 kip-ft |
| 13.5 ft (Lp) | 5,287 kip-ft | 3,518 kip-ft |
| 20 ft | 4,876 kip-ft | 3,244 kip-ft |
| 30 ft | 4,240 kip-ft | 2,821 kip-ft |
| 40 ft | 3,604 kip-ft | 2,398 kip-ft |
| 45.5 ft (Lr) | 3,255 kip-ft | 2,166 kip-ft |
| 50 ft | 2,877 kip-ft | 1,914 kip-ft |
| 60 ft | 2,293 kip-ft | 1,526 kip-ft |
| 70 ft | 1,910 kip-ft | 1,271 kip-ft |
| 80 ft | 1,639 kip-ft | 1,090 kip-ft |
| 90 ft | 1,436 kip-ft | 956 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.
W36×330 load table by span
The largest uniform load a simply supported W36×330 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 0.330 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 19 ft | 117.2 | 78.0 | 145.9 | 218.9 |
| 21 ft | 95.9 | 63.8 | 108.1 | 162.1 |
| 23 ft | 80.0 | 53.2 | 82.3 | 123.4 |
| 25 ft | 67.7 | 45.0 | 64.1 | 96.1 |
| 27 ft | 58.0 | 38.6 | 50.9 | 76.3 |
| 29 ft | 50.3 | 33.5 | 41.0 | 61.6 |
| 31 ft | 44.0 | 29.3 | 33.6 | 50.4 |
| 33 ft | 38.8 | 25.8 | 27.9 | 41.8 |
| 35 ft | 34.5 | 23.0 | 23.3 | 35.0 |
| 37 ft | 30.9 | 20.6 | 19.8 | 29.6 |
| 39 ft | 27.8 | 18.5 | 16.9 | 25.3 |
| 41 ft | 25.2 | 16.7 | 14.5 | 21.8 |
| 43 ft | 22.9 | 15.2 | 12.6 | 18.9 |
| 45 ft | 20.9 | 13.9 | 11.0 | 16.5 |
| 47 ft | 19.1 | 12.7 | 9.64 | 14.5 |
| 49 ft | 17.6 | 11.7 | 8.51 | 12.8 |
| 51 ft | 16.3 | 10.8 | 7.55 | 11.3 |
| 53 ft | 15.1 | 10.0 | 6.72 | 10.1 |
| 55 ft | 14.0 | 9.30 | 6.02 | 9.03 |
| 57 ft | 13.0 | 8.66 | 5.41 | 8.11 |
| 59 ft | 12.2 | 8.08 | 4.87 | 7.31 |
| 61 ft | 11.4 | 7.56 | 4.41 | 6.62 |
| 63 ft | 10.7 | 7.09 | 4.00 | 6.01 |
| 65 ft | 10.0 | 6.66 | 3.65 | 5.47 |
| 67 ft | 9.42 | 6.27 | 3.33 | 4.99 |
| 69 ft | 8.88 | 5.91 | 3.05 | 4.57 |
| 71 ft | 8.39 | 5.58 | 2.80 | 4.20 |
| 73 ft | 7.94 | 5.28 | 2.57 | 3.86 |
| 75 ft | 7.52 | 5.00 | 2.37 | 3.56 |
| 77 ft | 7.13 | 4.75 | 2.19 | 3.29 |
| 79 ft | 6.78 | 4.51 | 2.03 | 3.05 |
| 81 ft | 6.45 | 4.29 | 1.88 | 2.83 |
| 83 ft | 6.14 | 4.09 | 1.75 | 2.63 |
| 85 ft | 5.85 | 3.90 | 1.63 | 2.45 |
| 87 ft | 5.59 | 3.72 | 1.52 | 2.28 |
| 89 ft | 5.34 | 3.55 | 1.42 | 2.13 |
| 91 ft | 5.11 | 3.40 | 1.33 | 1.99 |
| 93 ft | 4.89 | 3.25 | 1.24 | 1.87 |
- 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 57 ft span, a W36×330 carries a factored load of 13.0 kips per foot (LRFD) or an allowable load of 8.66 kips per foot (ASD). A live load of 5.41 kips per foot would deflect it span/360, which is 1.90 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.
W36×330 questions
What does W36×330 mean?
W means a wide flange shape. 36 is its nominal depth in inches (the actual depth is 37.7 in) and 330 is its weight in pounds per foot.
How much does a W36×330 weigh?
330 pounds per foot, so a 20 ft W36×330 weighs about 6,600 pounds.
How far can a W36×330 span?
It depends on the load. Braced along its length, it carries 117.2 kips per foot of factored load at 19 ft and 4.89 kips per foot at 93 ft; the load table has the spans in between. Floor beams are often 57 to 75 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W36×330 a compact section?
Yes. Its flanges (bf/2tf = 4.49) and web (h/tw = 31.4) are both compact for bending in 50 ksi steel.