W40×327 Steel Beam
A W40×327 is a wide flange steel beam 40.8 inches deep with 12.1-inch flanges, weighing 327 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 1,444 kips.
Design a W40×327 beam Opens a 62 ft span in the free beam designer.
W40×327 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 40.8 in |
| Flange width, bf | 12.1 in |
| Flange thickness, tf | 2.13 in |
| Web thickness, tw | 1.18 in |
| Distance to web toe of fillet, kdes | 3.31 in |
| Distance between flange centroids, ho | 38.67 in |
| Cross-sectional area, A | 96.0 in2 |
| Weight | 327 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W40×327 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 24500 in4 | 640 in4 |
| Elastic section modulus, S | 1200 in3 | 105 in3 |
| Plastic section modulus, Z | 1410 in3 | 170 in3 |
| Radius of gyration, r | 16.0 in | 2.58 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 103 in4 |
| Warping constant, Cw | 239000 in6 |
| Effective radius of gyration, rts | 3.21 in |
| Flange slenderness, bf/2tf | 2.85 |
| Web slenderness, h/tw | 29.0 |
W40×327 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 = 1,444 kips | Vn/Ω = 963 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 9.1 ft between braces it keeps its full strength; past Lr = 33.7 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 |
| 9.1 ft (Lp) | 5,288 kip-ft | 3,518 kip-ft |
| 10 ft | 5,210 kip-ft | 3,467 kip-ft |
| 20 ft | 4,339 kip-ft | 2,887 kip-ft |
| 30 ft | 3,469 kip-ft | 2,308 kip-ft |
| 33.7 ft (Lr) | 3,147 kip-ft | 2,094 kip-ft |
| 40 ft | 2,543 kip-ft | 1,692 kip-ft |
| 50 ft | 1,958 kip-ft | 1,303 kip-ft |
| 60 ft | 1,596 kip-ft | 1,062 kip-ft |
| 70 ft | 1,349 kip-ft | 897 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.
W40×327 load table by span
The largest uniform load a simply supported W40×327 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 0.327 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 20 ft | 105.8 | 70.4 | 131.6 | 197.4 |
| 22 ft | 87.4 | 58.1 | 98.9 | 148.3 |
| 24 ft | 73.4 | 48.9 | 76.1 | 114.2 |
| 26 ft | 62.6 | 41.6 | 59.9 | 89.8 |
| 28 ft | 54.0 | 35.9 | 47.9 | 71.9 |
| 30 ft | 47.0 | 31.3 | 39.0 | 58.5 |
| 32 ft | 41.3 | 27.5 | 32.1 | 48.2 |
| 34 ft | 36.6 | 24.3 | 26.8 | 40.2 |
| 36 ft | 32.6 | 21.7 | 22.6 | 33.8 |
| 38 ft | 29.3 | 19.5 | 19.2 | 28.8 |
| 40 ft | 26.4 | 17.6 | 16.4 | 24.7 |
| 42 ft | 24.0 | 16.0 | 14.2 | 21.3 |
| 44 ft | 21.8 | 14.5 | 12.4 | 18.5 |
| 46 ft | 20.0 | 13.3 | 10.8 | 16.2 |
| 48 ft | 18.4 | 12.2 | 9.52 | 14.3 |
| 50 ft | 16.9 | 11.3 | 8.42 | 12.6 |
| 52 ft | 15.6 | 10.4 | 7.49 | 11.2 |
| 54 ft | 14.5 | 9.65 | 6.68 | 10.0 |
| 56 ft | 13.5 | 8.97 | 5.99 | 8.99 |
| 58 ft | 12.6 | 8.37 | 5.39 | 8.09 |
| 60 ft | 11.8 | 7.82 | 4.87 | 7.31 |
| 62 ft | 11.0 | 7.32 | 4.42 | 6.62 |
| 64 ft | 10.3 | 6.87 | 4.02 | 6.02 |
| 66 ft | 9.71 | 6.46 | 3.66 | 5.49 |
| 68 ft | 9.15 | 6.09 | 3.35 | 5.02 |
| 70 ft | 8.63 | 5.74 | 3.07 | 4.60 |
| 72 ft | 8.16 | 5.43 | 2.82 | 4.23 |
| 74 ft | 7.72 | 5.14 | 2.60 | 3.90 |
| 76 ft | 7.32 | 4.87 | 2.40 | 3.60 |
| 78 ft | 6.95 | 4.63 | 2.22 | 3.33 |
| 80 ft | 6.61 | 4.40 | 2.06 | 3.08 |
| 82 ft | 6.29 | 4.19 | 1.91 | 2.86 |
| 84 ft | 5.99 | 3.99 | 1.78 | 2.66 |
| 86 ft | 5.72 | 3.81 | 1.65 | 2.48 |
| 88 ft | 5.46 | 3.63 | 1.54 | 2.32 |
| 90 ft | 5.22 | 3.47 | 1.44 | 2.17 |
| 92 ft | 5.00 | 3.33 | 1.35 | 2.03 |
| 94 ft | 4.79 | 3.19 | 1.27 | 1.90 |
| 96 ft | 4.59 | 3.05 | 1.19 | 1.78 |
| 98 ft | 4.40 | 2.93 | 1.12 | 1.68 |
| 100 ft | 4.23 | 2.81 | 1.05 | 1.58 |
| 102 ft | 4.07 | 2.71 | 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 62 ft span, a W40×327 carries a factored load of 11.0 kips per foot (LRFD) or an allowable load of 7.32 kips per foot (ASD). A live load of 4.42 kips per foot would deflect it span/360, which is 2.07 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.
W40×327 questions
What does W40×327 mean?
W means a wide flange shape. 40 is its nominal depth in inches (the actual depth is 40.8 in) and 327 is its weight in pounds per foot.
How much does a W40×327 weigh?
327 pounds per foot, so a 20 ft W40×327 weighs about 6,540 pounds.
How far can a W40×327 span?
It depends on the load. Braced along its length, it carries 105.8 kips per foot of factored load at 20 ft and 4.07 kips per foot at 102 ft; the load table has the spans in between. Floor beams are often 61 to 82 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W40×327 a compact section?
Yes. Its flanges (bf/2tf = 2.85) and web (h/tw = 29.0) are both compact for bending in 50 ksi steel.