W24×250 Steel Beam
A W24×250 is a wide flange steel beam 26.3 inches deep with 13.2-inch flanges, weighing 250 pounds per foot. In ASTM A992 steel (Fy = 50 ksi) it has a design bending strength of 2,790 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 821 kips.
Design a W24×250 beam Opens a 39 ft span in the free beam designer.
W24×250 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 26.3 in |
| Flange width, bf | 13.2 in |
| Flange thickness, tf | 1.89 in |
| Web thickness, tw | 1.04 in |
| Distance to web toe of fillet, kdes | 2.39 in |
| Distance between flange centroids, ho | 24.41 in |
| Cross-sectional area, A | 73.5 in2 |
| Weight | 250 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W24×250 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 8490 in4 | 724 in4 |
| Elastic section modulus, S | 644 in3 | 110 in3 |
| Plastic section modulus, Z | 744 in3 | 171 in3 |
| Radius of gyration, r | 10.7 in | 3.14 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 66.6 in4 |
| Warping constant, Cw | 108000 in6 |
| Effective radius of gyration, rts | 3.71 in |
| Flange slenderness, bf/2tf | 3.49 |
| Web slenderness, h/tw | 20.7 |
W24×250 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 = 2,790 kip-ft | Mn/Ω = 1,856 kip-ft |
| Shear | φVn = 821 kips | Vn/Ω = 547 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 11.1 ft between braces it keeps its full strength; past Lr = 48.7 ft it buckles elastically. With uniform moment between braces (Cb = 1.0):
| Unbraced length, Lb | φMn (LRFD) | Mn/Ω (ASD) |
|---|---|---|
| Braced | 2,790 kip-ft | 1,856 kip-ft |
| 10 ft | 2,790 kip-ft | 1,856 kip-ft |
| 11.1 ft (Lp) | 2,790 kip-ft | 1,856 kip-ft |
| 20 ft | 2,529 kip-ft | 1,683 kip-ft |
| 30 ft | 2,236 kip-ft | 1,488 kip-ft |
| 40 ft | 1,944 kip-ft | 1,293 kip-ft |
| 48.7 ft (Lr) | 1,691 kip-ft | 1,125 kip-ft |
| 50 ft | 1,639 kip-ft | 1,091 kip-ft |
| 60 ft | 1,344 kip-ft | 894 kip-ft |
| 70 ft | 1,141 kip-ft | 759 kip-ft |
| 80 ft | 992 kip-ft | 660 kip-ft |
| 90 ft | 877 kip-ft | 584 kip-ft |
| 100 ft | 787 kip-ft | 524 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.
W24×250 load table by span
The largest uniform load a simply supported W24×250 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 0.250 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 13 ft | 126.2* | 84.2* | 166.0 | 249.0 |
| 15 ft | 99.2 | 66.0 | 108.1 | 162.1 |
| 17 ft | 77.2 | 51.4 | 74.2 | 111.4 |
| 19 ft | 61.8 | 41.1 | 53.2 | 79.8 |
| 21 ft | 50.6 | 33.7 | 39.4 | 59.1 |
| 23 ft | 42.2 | 28.1 | 30.0 | 45.0 |
| 25 ft | 35.7 | 23.8 | 23.3 | 35.0 |
| 27 ft | 30.6 | 20.4 | 18.5 | 27.8 |
| 29 ft | 26.5 | 17.7 | 15.0 | 22.4 |
| 31 ft | 23.2 | 15.5 | 12.2 | 18.4 |
| 33 ft | 20.5 | 13.6 | 10.1 | 15.2 |
| 35 ft | 18.2 | 12.1 | 8.51 | 12.8 |
| 37 ft | 16.3 | 10.8 | 7.20 | 10.8 |
| 39 ft | 14.7 | 9.76 | 6.15 | 9.22 |
| 41 ft | 13.3 | 8.83 | 5.29 | 7.94 |
| 43 ft | 12.1 | 8.03 | 4.59 | 6.88 |
| 45 ft | 11.0 | 7.33 | 4.00 | 6.00 |
| 47 ft | 10.1 | 6.72 | 3.51 | 5.27 |
| 49 ft | 9.30 | 6.19 | 3.10 | 4.65 |
| 51 ft | 8.58 | 5.71 | 2.75 | 4.12 |
| 53 ft | 7.95 | 5.29 | 2.45 | 3.68 |
| 55 ft | 7.38 | 4.91 | 2.19 | 3.29 |
| 57 ft | 6.87 | 4.57 | 1.97 | 2.95 |
| 59 ft | 6.41 | 4.27 | 1.78 | 2.66 |
| 61 ft | 6.00 | 3.99 | 1.61 | 2.41 |
| 63 ft | 5.62 | 3.74 | 1.46 | 2.19 |
| 65 ft | 5.28 | 3.51 | 1.33 | 1.99 |
- 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 39 ft span, a W24×250 carries a factored load of 14.7 kips per foot (LRFD) or an allowable load of 9.76 kips per foot (ASD). A live load of 6.15 kips per foot would deflect it span/360, which is 1.30 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.
W24×250 questions
What does W24×250 mean?
W means a wide flange shape. 24 is its nominal depth in inches (the actual depth is 26.3 in) and 250 is its weight in pounds per foot.
How much does a W24×250 weigh?
250 pounds per foot, so a 20 ft W24×250 weighs about 5,000 pounds.
How far can a W24×250 span?
It depends on the load. Braced along its length, it carries 126.2 kips per foot of factored load at 13 ft and 5.28 kips per foot at 65 ft; the load table has the spans in between. Floor beams are often 39 to 53 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W24×250 a compact section?
Yes. Its flanges (bf/2tf = 3.49) and web (h/tw = 20.7) are both compact for bending in 50 ksi steel.