W24×176 Steel Beam
A W24×176 is a wide flange steel beam 25.2 inches deep with 12.9-inch flanges, weighing 176 pounds per foot. In ASTM A992 steel (Fy = 50 ksi) it has a design bending strength of 1,916 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 567 kips.
Design a W24×176 beam Opens a 39 ft span in the free beam designer.
W24×176 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 25.2 in |
| Flange width, bf | 12.9 in |
| Flange thickness, tf | 1.34 in |
| Web thickness, tw | 0.750 in |
| Distance to web toe of fillet, kdes | 1.84 in |
| Distance between flange centroids, ho | 23.86 in |
| Cross-sectional area, A | 51.7 in2 |
| Weight | 176 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W24×176 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 5680 in4 | 479 in4 |
| Elastic section modulus, S | 450 in3 | 74.3 in3 |
| Plastic section modulus, Z | 511 in3 | 115 in3 |
| Radius of gyration, r | 10.5 in | 3.04 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 23.9 in4 |
| Warping constant, Cw | 68400 in6 |
| Effective radius of gyration, rts | 3.57 in |
| Flange slenderness, bf/2tf | 4.81 |
| Web slenderness, h/tw | 28.7 |
W24×176 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 = 1,916 kip-ft | Mn/Ω = 1,275 kip-ft |
| Shear | φVn = 567 kips | Vn/Ω = 378 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 10.7 ft between braces it keeps its full strength; past Lr = 37.4 ft it buckles elastically. With uniform moment between braces (Cb = 1.0):
| Unbraced length, Lb | φMn (LRFD) | Mn/Ω (ASD) |
|---|---|---|
| Braced | 1,916 kip-ft | 1,275 kip-ft |
| 10 ft | 1,916 kip-ft | 1,275 kip-ft |
| 10.7 ft (Lp) | 1,916 kip-ft | 1,275 kip-ft |
| 20 ft | 1,661 kip-ft | 1,105 kip-ft |
| 30 ft | 1,386 kip-ft | 922 kip-ft |
| 37.4 ft (Lr) | 1,181 kip-ft | 786 kip-ft |
| 40 ft | 1,086 kip-ft | 722 kip-ft |
| 50 ft | 830 kip-ft | 552 kip-ft |
| 60 ft | 674 kip-ft | 448 kip-ft |
| 70 ft | 568 kip-ft | 378 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.
W24×176 load table by span
The largest uniform load a simply supported W24×176 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 0.176 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 13 ft | 87.2* | 58.2* | 111.1 | 166.6 |
| 15 ft | 68.1 | 45.3 | 72.3 | 108.5 |
| 17 ft | 53.0 | 35.3 | 49.7 | 74.5 |
| 19 ft | 42.5 | 28.3 | 35.6 | 53.4 |
| 21 ft | 34.8 | 23.1 | 26.4 | 39.5 |
| 23 ft | 29.0 | 19.3 | 20.1 | 30.1 |
| 25 ft | 24.5 | 16.3 | 15.6 | 23.4 |
| 27 ft | 21.0 | 14.0 | 12.4 | 18.6 |
| 29 ft | 18.2 | 12.1 | 10.0 | 15.0 |
| 31 ft | 16.0 | 10.6 | 8.19 | 12.3 |
| 33 ft | 14.1 | 9.37 | 6.79 | 10.2 |
| 35 ft | 12.5 | 8.33 | 5.69 | 8.54 |
| 37 ft | 11.2 | 7.45 | 4.82 | 7.23 |
| 39 ft | 10.1 | 6.71 | 4.11 | 6.17 |
| 41 ft | 9.12 | 6.07 | 3.54 | 5.31 |
| 43 ft | 8.29 | 5.52 | 3.07 | 4.60 |
| 45 ft | 7.57 | 5.04 | 2.68 | 4.02 |
| 47 ft | 6.94 | 4.62 | 2.35 | 3.53 |
| 49 ft | 6.38 | 4.25 | 2.07 | 3.11 |
| 51 ft | 5.89 | 3.92 | 1.84 | 2.76 |
| 53 ft | 5.46 | 3.63 | 1.64 | 2.46 |
| 55 ft | 5.07 | 3.37 | 1.47 | 2.20 |
| 57 ft | 4.72 | 3.14 | 1.32 | 1.98 |
| 59 ft | 4.40 | 2.93 | 1.19 | 1.78 |
| 61 ft | 4.12 | 2.74 | 1.08 | 1.61 |
| 63 ft | 3.86 | 2.57 | 0.98 | 1.46 |
- 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 W24×176 carries a factored load of 10.1 kips per foot (LRFD) or an allowable load of 6.71 kips per foot (ASD). A live load of 4.11 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.
W24×176 questions
What does W24×176 mean?
W means a wide flange shape. 24 is its nominal depth in inches (the actual depth is 25.2 in) and 176 is its weight in pounds per foot.
How much does a W24×176 weigh?
176 pounds per foot, so a 20 ft W24×176 weighs about 3,520 pounds.
How far can a W24×176 span?
It depends on the load. Braced along its length, it carries 87.2 kips per foot of factored load at 13 ft and 3.86 kips per foot at 63 ft; the load table has the spans in between. Floor beams are often 38 to 50 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W24×176 a compact section?
Yes. Its flanges (bf/2tf = 4.81) and web (h/tw = 28.7) are both compact for bending in 50 ksi steel.