W40×264 Steel Beam
A W40×264 is a wide flange steel beam 40 inches deep with 11.9-inch flanges, weighing 264 pounds per foot. In ASTM A992 steel (Fy = 50 ksi) it has a design bending strength of 4,238 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 1,152 kips.
Design a W40×264 beam Opens a 60 ft span in the free beam designer.
W40×264 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 40.0 in |
| Flange width, bf | 11.9 in |
| Flange thickness, tf | 1.73 in |
| Web thickness, tw | 0.960 in |
| Distance to web toe of fillet, kdes | 2.91 in |
| Distance between flange centroids, ho | 38.27 in |
| Cross-sectional area, A | 77.6 in2 |
| Weight | 264 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W40×264 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 19400 in4 | 493 in4 |
| Elastic section modulus, S | 971 in3 | 82.6 in3 |
| Plastic section modulus, Z | 1130 in3 | 132 in3 |
| Radius of gyration, r | 15.8 in | 2.52 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 56.1 in4 |
| Warping constant, Cw | 181000 in6 |
| Effective radius of gyration, rts | 3.12 in |
| Flange slenderness, bf/2tf | 3.45 |
| Web slenderness, h/tw | 35.6 |
W40×264 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 = 4,238 kip-ft | Mn/Ω = 2,819 kip-ft |
| Shear | φVn = 1,152 kips | Vn/Ω = 768 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 8.9 ft between braces it keeps its full strength; past Lr = 29.7 ft it buckles elastically. With uniform moment between braces (Cb = 1.0):
| Unbraced length, Lb | φMn (LRFD) | Mn/Ω (ASD) |
|---|---|---|
| Braced | 4,238 kip-ft | 2,819 kip-ft |
| 5 ft | 4,238 kip-ft | 2,819 kip-ft |
| 8.9 ft (Lp) | 4,238 kip-ft | 2,819 kip-ft |
| 10 ft | 4,148 kip-ft | 2,760 kip-ft |
| 15 ft | 3,742 kip-ft | 2,489 kip-ft |
| 20 ft | 3,335 kip-ft | 2,219 kip-ft |
| 25 ft | 2,929 kip-ft | 1,949 kip-ft |
| 29.7 ft (Lr) | 2,549 kip-ft | 1,696 kip-ft |
| 30 ft | 2,508 kip-ft | 1,668 kip-ft |
| 35 ft | 2,035 kip-ft | 1,354 kip-ft |
| 40 ft | 1,713 kip-ft | 1,140 kip-ft |
| 45 ft | 1,480 kip-ft | 985 kip-ft |
| 50 ft | 1,304 kip-ft | 867 kip-ft |
| 55 ft | 1,166 kip-ft | 776 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.
W40×264 load table by span
The largest uniform load a simply supported W40×264 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 0.264 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 20 ft | 84.8 | 56.4 | 104.2 | 156.3 |
| 22 ft | 70.0 | 46.6 | 78.3 | 117.4 |
| 24 ft | 58.9 | 39.2 | 60.3 | 90.4 |
| 26 ft | 50.1 | 33.4 | 47.4 | 71.1 |
| 28 ft | 43.2 | 28.8 | 38.0 | 57.0 |
| 30 ft | 37.7 | 25.1 | 30.9 | 46.3 |
| 32 ft | 33.1 | 22.0 | 25.4 | 38.2 |
| 34 ft | 29.3 | 19.5 | 21.2 | 31.8 |
| 36 ft | 26.2 | 17.4 | 17.9 | 26.8 |
| 38 ft | 23.5 | 15.6 | 15.2 | 22.8 |
| 40 ft | 21.2 | 14.1 | 13.0 | 19.5 |
| 42 ft | 19.2 | 12.8 | 11.2 | 16.9 |
| 44 ft | 17.5 | 11.7 | 9.78 | 14.7 |
| 46 ft | 16.0 | 10.7 | 8.56 | 12.8 |
| 48 ft | 14.7 | 9.79 | 7.54 | 11.3 |
| 50 ft | 13.6 | 9.02 | 6.67 | 10.0 |
| 52 ft | 12.5 | 8.34 | 5.93 | 8.89 |
| 54 ft | 11.6 | 7.73 | 5.29 | 7.94 |
| 56 ft | 10.8 | 7.19 | 4.75 | 7.12 |
| 58 ft | 10.1 | 6.70 | 4.27 | 6.41 |
| 60 ft | 9.42 | 6.27 | 3.86 | 5.79 |
| 62 ft | 8.82 | 5.87 | 3.50 | 5.25 |
| 64 ft | 8.28 | 5.51 | 3.18 | 4.77 |
| 66 ft | 7.78 | 5.18 | 2.90 | 4.35 |
| 68 ft | 7.33 | 4.88 | 2.65 | 3.98 |
| 70 ft | 6.92 | 4.60 | 2.43 | 3.64 |
| 72 ft | 6.54 | 4.35 | 2.23 | 3.35 |
| 74 ft | 6.19 | 4.12 | 2.06 | 3.09 |
| 76 ft | 5.87 | 3.90 | 1.90 | 2.85 |
| 78 ft | 5.57 | 3.71 | 1.76 | 2.63 |
| 80 ft | 5.30 | 3.52 | 1.63 | 2.44 |
| 82 ft | 5.04 | 3.35 | 1.51 | 2.27 |
| 84 ft | 4.80 | 3.20 | 1.41 | 2.11 |
| 86 ft | 4.58 | 3.05 | 1.31 | 1.97 |
| 88 ft | 4.38 | 2.91 | 1.22 | 1.83 |
| 90 ft | 4.19 | 2.78 | 1.14 | 1.71 |
| 92 ft | 4.01 | 2.66 | 1.07 | 1.61 |
| 94 ft | 3.84 | 2.55 | 1.00 | 1.51 |
| 96 ft | 3.68 | 2.45 | 0.94 | 1.41 |
| 98 ft | 3.53 | 2.35 | 0.89 | 1.33 |
| 100 ft | 3.39 | 2.26 | 0.83 | 1.25 |
- 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 60 ft span, a W40×264 carries a factored load of 9.42 kips per foot (LRFD) or an allowable load of 6.27 kips per foot (ASD). A live load of 3.86 kips per foot would deflect it span/360, which is 2.00 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.
W40×264 questions
What does W40×264 mean?
W means a wide flange shape. 40 is its nominal depth in inches (the actual depth is 40.0 in) and 264 is its weight in pounds per foot.
How much does a W40×264 weigh?
264 pounds per foot, so a 20 ft W40×264 weighs about 5,280 pounds.
How far can a W40×264 span?
It depends on the load. Braced along its length, it carries 84.8 kips per foot of factored load at 20 ft and 3.39 kips per foot at 100 ft; the load table has the spans in between. Floor beams are often 60 to 80 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W40×264 a compact section?
Yes. Its flanges (bf/2tf = 3.45) and web (h/tw = 35.6) are both compact for bending in 50 ksi steel.