W36×256 Steel Beam
A W36×256 is a wide flange steel beam 37.4 inches deep with 12.2-inch flanges, weighing 256 pounds per foot. In ASTM A992 steel (Fy = 50 ksi) it has a design bending strength of 3,900 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 1,077 kips.
Design a W36×256 beam Opens a 57 ft span in the free beam designer.
W36×256 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 37.4 in |
| Flange width, bf | 12.2 in |
| Flange thickness, tf | 1.73 in |
| Web thickness, tw | 0.960 in |
| Distance to web toe of fillet, kdes | 2.48 in |
| Distance between flange centroids, ho | 35.67 in |
| Cross-sectional area, A | 75.4 in2 |
| Weight | 256 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W36×256 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 16800 in4 | 528 in4 |
| Elastic section modulus, S | 895 in3 | 86.5 in3 |
| Plastic section modulus, Z | 1040 in3 | 137 in3 |
| Radius of gyration, r | 14.9 in | 2.65 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 52.9 in4 |
| Warping constant, Cw | 168000 in6 |
| Effective radius of gyration, rts | 3.24 in |
| Flange slenderness, bf/2tf | 3.53 |
| Web slenderness, h/tw | 33.8 |
W36×256 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 = 3,900 kip-ft | Mn/Ω = 2,595 kip-ft |
| Shear | φVn = 1,077 kips | Vn/Ω = 718 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 9.4 ft between braces it keeps its full strength; past Lr = 31.5 ft it buckles elastically. With uniform moment between braces (Cb = 1.0):
| Unbraced length, Lb | φMn (LRFD) | Mn/Ω (ASD) |
|---|---|---|
| Braced | 3,900 kip-ft | 2,595 kip-ft |
| 9.4 ft (Lp) | 3,900 kip-ft | 2,595 kip-ft |
| 10 ft | 3,855 kip-ft | 2,565 kip-ft |
| 20 ft | 3,155 kip-ft | 2,099 kip-ft |
| 30 ft | 2,455 kip-ft | 1,634 kip-ft |
| 31.5 ft (Lr) | 2,350 kip-ft | 1,563 kip-ft |
| 40 ft | 1,717 kip-ft | 1,143 kip-ft |
| 50 ft | 1,308 kip-ft | 870 kip-ft |
| 60 ft | 1,059 kip-ft | 704 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.
W36×256 load table by span
The largest uniform load a simply supported W36×256 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 0.256 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 19 ft | 86.4 | 57.5 | 105.2 | 157.8 |
| 21 ft | 70.7 | 47.1 | 77.9 | 116.9 |
| 23 ft | 59.0 | 39.2 | 59.3 | 89.0 |
| 25 ft | 49.9 | 33.2 | 46.2 | 69.3 |
| 27 ft | 42.8 | 28.5 | 36.7 | 55.0 |
| 29 ft | 37.1 | 24.7 | 29.6 | 44.4 |
| 31 ft | 32.5 | 21.6 | 24.2 | 36.3 |
| 33 ft | 28.7 | 19.1 | 20.1 | 30.1 |
| 35 ft | 25.5 | 16.9 | 16.8 | 25.3 |
| 37 ft | 22.8 | 15.2 | 14.2 | 21.4 |
| 39 ft | 20.5 | 13.6 | 12.2 | 18.3 |
| 41 ft | 18.6 | 12.3 | 10.5 | 15.7 |
| 43 ft | 16.9 | 11.2 | 9.08 | 13.6 |
| 45 ft | 15.4 | 10.3 | 7.92 | 11.9 |
| 47 ft | 14.1 | 9.40 | 6.95 | 10.4 |
| 49 ft | 13.0 | 8.65 | 6.14 | 9.20 |
| 51 ft | 12.0 | 7.98 | 5.44 | 8.16 |
| 53 ft | 11.1 | 7.39 | 4.85 | 7.27 |
| 55 ft | 10.3 | 6.86 | 4.34 | 6.51 |
| 57 ft | 9.60 | 6.39 | 3.90 | 5.85 |
| 59 ft | 8.96 | 5.96 | 3.51 | 5.27 |
| 61 ft | 8.38 | 5.58 | 3.18 | 4.77 |
| 63 ft | 7.86 | 5.23 | 2.89 | 4.33 |
| 65 ft | 7.38 | 4.91 | 2.63 | 3.94 |
| 67 ft | 6.95 | 4.62 | 2.40 | 3.60 |
| 69 ft | 6.55 | 4.36 | 2.20 | 3.30 |
| 71 ft | 6.19 | 4.12 | 2.02 | 3.02 |
| 73 ft | 5.85 | 3.90 | 1.86 | 2.78 |
| 75 ft | 5.55 | 3.69 | 1.71 | 2.57 |
| 77 ft | 5.26 | 3.50 | 1.58 | 2.37 |
| 79 ft | 5.00 | 3.33 | 1.46 | 2.20 |
| 81 ft | 4.76 | 3.16 | 1.36 | 2.04 |
| 83 ft | 4.53 | 3.01 | 1.26 | 1.89 |
| 85 ft | 4.32 | 2.87 | 1.18 | 1.76 |
| 87 ft | 4.12 | 2.74 | 1.10 | 1.64 |
| 89 ft | 3.94 | 2.62 | 1.02 | 1.54 |
| 91 ft | 3.77 | 2.51 | 0.96 | 1.44 |
| 93 ft | 3.61 | 2.40 | 0.90 | 1.35 |
- 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 57 ft span, a W36×256 carries a factored load of 9.60 kips per foot (LRFD) or an allowable load of 6.39 kips per foot (ASD). A live load of 3.90 kips per foot would deflect it span/360, which is 1.90 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.
W36×256 questions
What does W36×256 mean?
W means a wide flange shape. 36 is its nominal depth in inches (the actual depth is 37.4 in) and 256 is its weight in pounds per foot.
How much does a W36×256 weigh?
256 pounds per foot, so a 20 ft W36×256 weighs about 5,120 pounds.
How far can a W36×256 span?
It depends on the load. Braced along its length, it carries 86.4 kips per foot of factored load at 19 ft and 3.61 kips per foot at 93 ft; the load table has the spans in between. Floor beams are often 56 to 75 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W36×256 a compact section?
Yes. Its flanges (bf/2tf = 3.53) and web (h/tw = 33.8) are both compact for bending in 50 ksi steel.