W24×103 Steel Beam
A W24×103 is a wide flange steel beam 24.5 inches deep with 9-inch flanges, weighing 103 pounds per foot. In ASTM A992 steel (Fy = 50 ksi) it has a design bending strength of 1,050 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 404 kips.
Design a W24×103 beam Opens a 36 ft span in the free beam designer.
W24×103 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 24.5 in |
| Flange width, bf | 9.00 in |
| Flange thickness, tf | 0.980 in |
| Web thickness, tw | 0.550 in |
| Distance to web toe of fillet, kdes | 1.48 in |
| Distance between flange centroids, ho | 23.52 in |
| Cross-sectional area, A | 30.3 in2 |
| Weight | 103 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W24×103 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 3000 in4 | 119 in4 |
| Elastic section modulus, S | 245 in3 | 26.5 in3 |
| Plastic section modulus, Z | 280 in3 | 41.5 in3 |
| Radius of gyration, r | 10.0 in | 1.99 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 7.07 in4 |
| Warping constant, Cw | 16600 in6 |
| Effective radius of gyration, rts | 2.40 in |
| Flange slenderness, bf/2tf | 4.59 |
| Web slenderness, h/tw | 39.2 |
W24×103 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 = 1,050 kip-ft | Mn/Ω = 699 kip-ft |
| Shear | φVn = 404 kips | Vn/Ω = 270 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 7.0 ft between braces it keeps its full strength; past Lr = 21.9 ft it buckles elastically. With uniform moment between braces (Cb = 1.0):
| Unbraced length, Lb | φMn (LRFD) | Mn/Ω (ASD) |
|---|---|---|
| Braced | 1,050 kip-ft | 699 kip-ft |
| 5 ft | 1,050 kip-ft | 699 kip-ft |
| 7.0 ft (Lp) | 1,050 kip-ft | 699 kip-ft |
| 10 ft | 969 kip-ft | 644 kip-ft |
| 15 ft | 831 kip-ft | 553 kip-ft |
| 20 ft | 694 kip-ft | 462 kip-ft |
| 21.9 ft (Lr) | 643 kip-ft | 428 kip-ft |
| 25 ft | 530 kip-ft | 353 kip-ft |
| 30 ft | 414 kip-ft | 275 kip-ft |
| 35 ft | 340 kip-ft | 226 kip-ft |
| 40 ft | 288 kip-ft | 192 kip-ft |
| 45 ft | 251 kip-ft | 167 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.
W24×103 load table by span
The largest uniform load a simply supported W24×103 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 0.103 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 12 ft | 58.3 | 38.8 | 74.6 | 111.9 |
| 14 ft | 42.9 | 28.5 | 47.0 | 70.5 |
| 16 ft | 32.8 | 21.8 | 31.5 | 47.2 |
| 18 ft | 25.9 | 17.2 | 22.1 | 33.2 |
| 20 ft | 21.0 | 14.0 | 16.1 | 24.2 |
| 22 ft | 17.4 | 11.5 | 12.1 | 18.2 |
| 24 ft | 14.6 | 9.70 | 9.32 | 14.0 |
| 26 ft | 12.4 | 8.27 | 7.33 | 11.0 |
| 28 ft | 10.7 | 7.13 | 5.87 | 8.81 |
| 30 ft | 9.33 | 6.21 | 4.77 | 7.16 |
| 32 ft | 8.20 | 5.46 | 3.93 | 5.90 |
| 34 ft | 7.27 | 4.83 | 3.28 | 4.92 |
| 36 ft | 6.48 | 4.31 | 2.76 | 4.14 |
| 38 ft | 5.82 | 3.87 | 2.35 | 3.52 |
| 40 ft | 5.25 | 3.49 | 2.01 | 3.02 |
| 42 ft | 4.76 | 3.17 | 1.74 | 2.61 |
| 44 ft | 4.34 | 2.89 | 1.51 | 2.27 |
| 46 ft | 3.97 | 2.64 | 1.32 | 1.99 |
| 48 ft | 3.65 | 2.43 | 1.17 | 1.75 |
| 50 ft | 3.36 | 2.24 | 1.03 | 1.55 |
| 52 ft | 3.11 | 2.07 | 0.92 | 1.37 |
| 54 ft | 2.88 | 1.92 | 0.82 | 1.23 |
| 56 ft | 2.68 | 1.78 | 0.73 | 1.10 |
| 58 ft | 2.50 | 1.66 | 0.66 | 0.99 |
| 60 ft | 2.33 | 1.55 | 0.60 | 0.90 |
- 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 36 ft span, a W24×103 carries a factored load of 6.48 kips per foot (LRFD) or an allowable load of 4.31 kips per foot (ASD). A live load of 2.76 kips per foot would deflect it span/360, which is 1.20 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.
W24×103 questions
What does W24×103 mean?
W means a wide flange shape. 24 is its nominal depth in inches (the actual depth is 24.5 in) and 103 is its weight in pounds per foot.
How much does a W24×103 weigh?
103 pounds per foot, so a 20 ft W24×103 weighs about 2,060 pounds.
How far can a W24×103 span?
It depends on the load. Braced along its length, it carries 58.3 kips per foot of factored load at 12 ft and 2.33 kips per foot at 60 ft; the load table has the spans in between. Floor beams are often 37 to 49 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W24×103 a compact section?
Yes. Its flanges (bf/2tf = 4.59) and web (h/tw = 39.2) are both compact for bending in 50 ksi steel.