W14×159 Steel Beam
A W14×159 is a wide flange steel beam 15 inches deep with 15.6-inch flanges, weighing 159 pounds per foot. In ASTM A992 steel (Fy = 50 ksi) it has a design bending strength of 1,076 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 335 kips.
Design a W14×159 beam Opens a 24 ft span in the free beam designer.
W14×159 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 15.0 in |
| Flange width, bf | 15.6 in |
| Flange thickness, tf | 1.19 in |
| Web thickness, tw | 0.745 in |
| Distance to web toe of fillet, kdes | 1.79 in |
| Distance between flange centroids, ho | 13.81 in |
| Cross-sectional area, A | 46.7 in2 |
| Weight | 159 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W14×159 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 1900 in4 | 748 in4 |
| Elastic section modulus, S | 254 in3 | 96.2 in3 |
| Plastic section modulus, Z | 287 in3 | 146 in3 |
| Radius of gyration, r | 6.38 in | 4.00 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 19.7 in4 |
| Warping constant, Cw | 35600 in6 |
| Effective radius of gyration, rts | 4.51 in |
| Flange slenderness, bf/2tf | 6.54 |
| Web slenderness, h/tw | 15.3 |
W14×159 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 = 1,076 kip-ft | Mn/Ω = 716 kip-ft |
| Shear | φVn = 335 kips | Vn/Ω = 224 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 14.1 ft between braces it keeps its full strength; past Lr = 66.6 ft it buckles elastically. With uniform moment between braces (Cb = 1.0):
| Unbraced length, Lb | φMn (LRFD) | Mn/Ω (ASD) |
|---|---|---|
| Braced | 1,076 kip-ft | 716 kip-ft |
| 10 ft | 1,076 kip-ft | 716 kip-ft |
| 14.1 ft (Lp) | 1,076 kip-ft | 716 kip-ft |
| 20 ft | 1,030 kip-ft | 686 kip-ft |
| 30 ft | 952 kip-ft | 634 kip-ft |
| 40 ft | 874 kip-ft | 582 kip-ft |
| 50 ft | 796 kip-ft | 530 kip-ft |
| 60 ft | 718 kip-ft | 478 kip-ft |
| 66.6 ft (Lr) | 666 kip-ft | 443 kip-ft |
| 70 ft | 632 kip-ft | 421 kip-ft |
| 80 ft | 549 kip-ft | 365 kip-ft |
| 90 ft | 486 kip-ft | 323 kip-ft |
| 100 ft | 435 kip-ft | 290 kip-ft |
| 110 ft | 395 kip-ft | 263 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.
W14×159 load table by span
The largest uniform load a simply supported W14×159 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 0.159 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 8 ft | 83.8* | 55.9* | 159.4 | 239.1 |
| 10 ft | 67.1* | 44.7* | 81.6 | 122.4 |
| 12 ft | 55.9* | 37.3* | 47.2 | 70.9 |
| 14 ft | 43.9 | 29.2 | 29.7 | 44.6 |
| 16 ft | 33.6 | 22.4 | 19.9 | 29.9 |
| 18 ft | 26.6 | 17.7 | 14.0 | 21.0 |
| 20 ft | 21.5 | 14.3 | 10.2 | 15.3 |
| 22 ft | 17.8 | 11.8 | 7.67 | 11.5 |
| 24 ft | 14.9 | 9.95 | 5.90 | 8.86 |
| 26 ft | 12.7 | 8.47 | 4.64 | 6.97 |
| 28 ft | 11.0 | 7.31 | 3.72 | 5.58 |
| 30 ft | 9.57 | 6.37 | 3.02 | 4.53 |
| 32 ft | 8.41 | 5.59 | 2.49 | 3.74 |
| 34 ft | 7.45 | 4.96 | 2.08 | 3.12 |
| 36 ft | 6.64 | 4.42 | 1.75 | 2.62 |
| 38 ft | 5.96 | 3.97 | 1.49 | 2.23 |
- 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 24 ft span, a W14×159 carries a factored load of 14.9 kips per foot (LRFD) or an allowable load of 9.95 kips per foot (ASD). A live load of 5.90 kips per foot would deflect it span/360, which is 0.80 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.
W14×159 questions
What does W14×159 mean?
W means a wide flange shape. 14 is its nominal depth in inches (the actual depth is 15.0 in) and 159 is its weight in pounds per foot.
How much does a W14×159 weigh?
159 pounds per foot, so a 20 ft W14×159 weighs about 3,180 pounds.
How far can a W14×159 span?
It depends on the load. Braced along its length, it carries 83.8 kips per foot of factored load at 8 ft and 5.96 kips per foot at 38 ft; the load table has the spans in between. Floor beams are often 23 to 30 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W14×159 a compact section?
Yes. Its flanges (bf/2tf = 6.54) and web (h/tw = 15.3) are both compact for bending in 50 ksi steel.