W24×306 Steel Beam
A W24×306 is a wide flange steel beam 27.1 inches deep with 13.4-inch flanges, weighing 306 pounds per foot. In ASTM A992 steel (Fy = 50 ksi) it has a design bending strength of 3,458 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 1,024 kips.
Design a W24×306 beam Opens a 42 ft span in the free beam designer.
W24×306 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 27.1 in |
| Flange width, bf | 13.4 in |
| Flange thickness, tf | 2.28 in |
| Web thickness, tw | 1.26 in |
| Distance to web toe of fillet, kdes | 2.78 in |
| Distance between flange centroids, ho | 24.82 in |
| Cross-sectional area, A | 89.8 in2 |
| Weight | 306 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W24×306 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 10700 in4 | 919 in4 |
| Elastic section modulus, S | 789 in3 | 137 in3 |
| Plastic section modulus, Z | 922 in3 | 214 in3 |
| Radius of gyration, r | 10.9 in | 3.20 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 117 in4 |
| Warping constant, Cw | 142000 in6 |
| Effective radius of gyration, rts | 3.81 in |
| Flange slenderness, bf/2tf | 2.94 |
| Web slenderness, h/tw | 17.1 |
W24×306 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 = 3,458 kip-ft | Mn/Ω = 2,300 kip-ft |
| Shear | φVn = 1,024 kips | Vn/Ω = 683 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 11.3 ft between braces it keeps its full strength; past Lr = 57.8 ft it buckles elastically. With uniform moment between braces (Cb = 1.0):
| Unbraced length, Lb | φMn (LRFD) | Mn/Ω (ASD) |
|---|---|---|
| Braced | 3,458 kip-ft | 2,300 kip-ft |
| 10 ft | 3,458 kip-ft | 2,300 kip-ft |
| 11.3 ft (Lp) | 3,458 kip-ft | 2,300 kip-ft |
| 20 ft | 3,198 kip-ft | 2,128 kip-ft |
| 30 ft | 2,900 kip-ft | 1,929 kip-ft |
| 40 ft | 2,602 kip-ft | 1,731 kip-ft |
| 50 ft | 2,303 kip-ft | 1,533 kip-ft |
| 57.8 ft (Lr) | 2,070 kip-ft | 1,377 kip-ft |
| 60 ft | 1,989 kip-ft | 1,324 kip-ft |
| 70 ft | 1,692 kip-ft | 1,126 kip-ft |
| 80 ft | 1,473 kip-ft | 980 kip-ft |
| 90 ft | 1,305 kip-ft | 868 kip-ft |
| 100 ft | 1,172 kip-ft | 780 kip-ft |
| 110 ft | 1,063 kip-ft | 707 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.
W24×306 load table by span
The largest uniform load a simply supported W24×306 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 0.306 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 14 ft | 141.1 | 93.9 | 167.5 | 251.3 |
| 16 ft | 108.0 | 71.9 | 112.2 | 168.3 |
| 18 ft | 85.4 | 56.8 | 78.8 | 118.2 |
| 20 ft | 69.2 | 46.0 | 57.5 | 86.2 |
| 22 ft | 57.1 | 38.0 | 43.2 | 64.8 |
| 24 ft | 48.0 | 31.9 | 33.3 | 49.9 |
| 26 ft | 40.9 | 27.2 | 26.2 | 39.2 |
| 28 ft | 35.3 | 23.5 | 20.9 | 31.4 |
| 30 ft | 30.7 | 20.4 | 17.0 | 25.5 |
| 32 ft | 27.0 | 18.0 | 14.0 | 21.0 |
| 34 ft | 23.9 | 15.9 | 11.7 | 17.5 |
| 36 ft | 21.3 | 14.2 | 9.85 | 14.8 |
| 38 ft | 19.2 | 12.7 | 8.38 | 12.6 |
| 40 ft | 17.3 | 11.5 | 7.18 | 10.8 |
| 42 ft | 15.7 | 10.4 | 6.20 | 9.31 |
| 44 ft | 14.3 | 9.51 | 5.40 | 8.09 |
| 46 ft | 13.1 | 8.70 | 4.72 | 7.08 |
| 48 ft | 12.0 | 7.99 | 4.16 | 6.24 |
| 50 ft | 11.1 | 7.36 | 3.68 | 5.52 |
| 52 ft | 10.2 | 6.81 | 3.27 | 4.90 |
| 54 ft | 9.49 | 6.31 | 2.92 | 4.38 |
| 56 ft | 8.82 | 5.87 | 2.62 | 3.93 |
| 58 ft | 8.22 | 5.47 | 2.36 | 3.53 |
| 60 ft | 7.68 | 5.11 | 2.13 | 3.19 |
| 62 ft | 7.20 | 4.79 | 1.93 | 2.89 |
| 64 ft | 6.75 | 4.49 | 1.75 | 2.63 |
| 66 ft | 6.35 | 4.22 | 1.60 | 2.40 |
| 68 ft | 5.98 | 3.98 | 1.46 | 2.19 |
- 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 42 ft span, a W24×306 carries a factored load of 15.7 kips per foot (LRFD) or an allowable load of 10.4 kips per foot (ASD). A live load of 6.20 kips per foot would deflect it span/360, which is 1.40 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.
W24×306 questions
What does W24×306 mean?
W means a wide flange shape. 24 is its nominal depth in inches (the actual depth is 27.1 in) and 306 is its weight in pounds per foot.
How much does a W24×306 weigh?
306 pounds per foot, so a 20 ft W24×306 weighs about 6,120 pounds.
How far can a W24×306 span?
It depends on the load. Braced along its length, it carries 141.1 kips per foot of factored load at 14 ft and 5.98 kips per foot at 68 ft; the load table has the spans in between. Floor beams are often 41 to 54 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W24×306 a compact section?
Yes. Its flanges (bf/2tf = 2.94) and web (h/tw = 17.1) are both compact for bending in 50 ksi steel.