W12×336 Steel Beam
A W12×336 is a wide flange steel beam 16.8 inches deep with 13.4-inch flanges, weighing 336 pounds per foot. In ASTM A992 steel (Fy = 50 ksi) it has a design bending strength of 2,261 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 897 kips.
Design a W12×336 beam Opens a 26 ft span in the free beam designer.
W12×336 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 16.8 in |
| Flange width, bf | 13.4 in |
| Flange thickness, tf | 2.96 in |
| Web thickness, tw | 1.78 in |
| Distance to web toe of fillet, kdes | 3.55 in |
| Distance between flange centroids, ho | 13.84 in |
| Cross-sectional area, A | 98.8 in2 |
| Weight | 336 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W12×336 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 4060 in4 | 1190 in4 |
| Elastic section modulus, S | 483 in3 | 177 in3 |
| Plastic section modulus, Z | 603 in3 | 274 in3 |
| Radius of gyration, r | 6.41 in | 3.47 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 243 in4 |
| Warping constant, Cw | 57000 in6 |
| Effective radius of gyration, rts | 4.13 in |
| Flange slenderness, bf/2tf | 2.26 |
| Web slenderness, h/tw | 5.47 |
W12×336 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 = 2,261 kip-ft | Mn/Ω = 1,504 kip-ft |
| Shear | φVn = 897 kips | Vn/Ω = 598 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 12.3 ft between braces it keeps its full strength; past Lr = 150.1 ft it buckles elastically. With uniform moment between braces (Cb = 1.0):
| Unbraced length, Lb | φMn (LRFD) | Mn/Ω (ASD) |
|---|---|---|
| Braced | 2,261 kip-ft | 1,504 kip-ft |
| 10 ft | 2,261 kip-ft | 1,504 kip-ft |
| 12.3 ft (Lp) | 2,261 kip-ft | 1,504 kip-ft |
| 20 ft | 2,205 kip-ft | 1,467 kip-ft |
| 30 ft | 2,133 kip-ft | 1,419 kip-ft |
| 40 ft | 2,061 kip-ft | 1,371 kip-ft |
| 50 ft | 1,989 kip-ft | 1,323 kip-ft |
| 60 ft | 1,917 kip-ft | 1,275 kip-ft |
| 70 ft | 1,845 kip-ft | 1,228 kip-ft |
| 80 ft | 1,773 kip-ft | 1,180 kip-ft |
| 90 ft | 1,701 kip-ft | 1,132 kip-ft |
| 100 ft | 1,629 kip-ft | 1,084 kip-ft |
| 110 ft | 1,557 kip-ft | 1,036 kip-ft |
| 150.1 ft (Lr) | 1,268 kip-ft | 844 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.
W12×336 load table by span
The largest uniform load a simply supported W12×336 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 0.336 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 8 ft | 224.3* | 149.5* | 340.7 | 511.0 |
| 10 ft | 179.4* | 119.6* | 174.4 | 261.6 |
| 12 ft | 125.6 | 83.6 | 100.9 | 151.4 |
| 14 ft | 92.3 | 61.4 | 63.6 | 95.4 |
| 16 ft | 70.7 | 47.0 | 42.6 | 63.9 |
| 18 ft | 55.8 | 37.1 | 29.9 | 44.9 |
| 20 ft | 45.2 | 30.1 | 21.8 | 32.7 |
| 22 ft | 37.4 | 24.9 | 16.4 | 24.6 |
| 24 ft | 31.4 | 20.9 | 12.6 | 18.9 |
| 26 ft | 26.8 | 17.8 | 9.92 | 14.9 |
| 28 ft | 23.1 | 15.4 | 7.95 | 11.9 |
| 30 ft | 20.1 | 13.4 | 6.46 | 9.69 |
| 32 ft | 17.7 | 11.8 | 5.32 | 7.98 |
| 34 ft | 15.6 | 10.4 | 4.44 | 6.66 |
| 36 ft | 14.0 | 9.29 | 3.74 | 5.61 |
| 38 ft | 12.5 | 8.34 | 3.18 | 4.77 |
| 40 ft | 11.3 | 7.52 | 2.73 | 4.09 |
| 42 ft | 10.3 | 6.82 | 2.35 | 3.53 |
- 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 26 ft span, a W12×336 carries a factored load of 26.8 kips per foot (LRFD) or an allowable load of 17.8 kips per foot (ASD). A live load of 9.92 kips per foot would deflect it span/360, which is 0.87 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.
W12×336 questions
What does W12×336 mean?
W means a wide flange shape. 12 is its nominal depth in inches (the actual depth is 16.8 in) and 336 is its weight in pounds per foot.
How much does a W12×336 weigh?
336 pounds per foot, so a 20 ft W12×336 weighs about 6,720 pounds.
How far can a W12×336 span?
It depends on the load. Braced along its length, it carries 224.3 kips per foot of factored load at 8 ft and 10.3 kips per foot at 42 ft; the load table has the spans in between. Floor beams are often 25 to 34 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W12×336 a compact section?
Yes. Its flanges (bf/2tf = 2.26) and web (h/tw = 5.47) are both compact for bending in 50 ksi steel.