W27×146 Steel Beam
A W27×146 is a wide flange steel beam 27.4 inches deep with 14-inch flanges, weighing 146 pounds per foot. In ASTM A992 steel (Fy = 50 ksi) it has a design bending strength of 1,740 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 497 kips.
Design a W27×146 beam Opens a 42 ft span in the free beam designer.
W27×146 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 27.4 in |
| Flange width, bf | 14.0 in |
| Flange thickness, tf | 0.975 in |
| Web thickness, tw | 0.605 in |
| Distance to web toe of fillet, kdes | 1.76 in |
| Distance between flange centroids, ho | 26.42 in |
| Cross-sectional area, A | 43.1 in2 |
| Weight | 146 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W27×146 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 5660 in4 | 443 in4 |
| Elastic section modulus, S | 414 in3 | 63.5 in3 |
| Plastic section modulus, Z | 464 in3 | 97.7 in3 |
| Radius of gyration, r | 11.5 in | 3.20 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 11.3 in4 |
| Warping constant, Cw | 77200 in6 |
| Effective radius of gyration, rts | 3.76 in |
| Flange slenderness, bf/2tf | 7.16 |
| Web slenderness, h/tw | 39.4 |
W27×146 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 = 1,740 kip-ft | Mn/Ω = 1,158 kip-ft |
| Shear | φVn = 497 kips | Vn/Ω = 332 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 11.3 ft between braces it keeps its full strength; past Lr = 33.3 ft it buckles elastically. With uniform moment between braces (Cb = 1.0):
| Unbraced length, Lb | φMn (LRFD) | Mn/Ω (ASD) |
|---|---|---|
| Braced | 1,740 kip-ft | 1,158 kip-ft |
| 10 ft | 1,740 kip-ft | 1,158 kip-ft |
| 11.3 ft (Lp) | 1,740 kip-ft | 1,158 kip-ft |
| 20 ft | 1,482 kip-ft | 986 kip-ft |
| 30 ft | 1,185 kip-ft | 789 kip-ft |
| 33.3 ft (Lr) | 1,087 kip-ft | 723 kip-ft |
| 40 ft | 829 kip-ft | 551 kip-ft |
| 50 ft | 609 kip-ft | 405 kip-ft |
| 60 ft | 482 kip-ft | 320 kip-ft |
| 70 ft | 399 kip-ft | 265 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.
W27×146 load table by span
The largest uniform load a simply supported W27×146 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 0.146 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 14 ft | 71.0 | 47.3 | 88.6 | 132.9 |
| 16 ft | 54.4 | 36.2 | 59.4 | 89.1 |
| 18 ft | 43.0 | 28.6 | 41.7 | 62.5 |
| 20 ft | 34.8 | 23.2 | 30.4 | 45.6 |
| 22 ft | 28.8 | 19.1 | 22.8 | 34.3 |
| 24 ft | 24.2 | 16.1 | 17.6 | 26.4 |
| 26 ft | 20.6 | 13.7 | 13.8 | 20.8 |
| 28 ft | 17.8 | 11.8 | 11.1 | 16.6 |
| 30 ft | 15.5 | 10.3 | 9.01 | 13.5 |
| 32 ft | 13.6 | 9.04 | 7.42 | 11.1 |
| 34 ft | 12.0 | 8.01 | 6.19 | 9.28 |
| 36 ft | 10.7 | 7.15 | 5.21 | 7.82 |
| 38 ft | 9.64 | 6.41 | 4.43 | 6.65 |
| 40 ft | 8.70 | 5.79 | 3.80 | 5.70 |
| 42 ft | 7.89 | 5.25 | 3.28 | 4.92 |
| 44 ft | 7.19 | 4.78 | 2.85 | 4.28 |
| 46 ft | 6.58 | 4.38 | 2.50 | 3.75 |
| 48 ft | 6.04 | 4.02 | 2.20 | 3.30 |
| 50 ft | 5.57 | 3.70 | 1.95 | 2.92 |
| 52 ft | 5.15 | 3.43 | 1.73 | 2.59 |
| 54 ft | 4.77 | 3.18 | 1.54 | 2.32 |
| 56 ft | 4.44 | 2.95 | 1.38 | 2.08 |
| 58 ft | 4.14 | 2.75 | 1.25 | 1.87 |
| 60 ft | 3.87 | 2.57 | 1.13 | 1.69 |
| 62 ft | 3.62 | 2.41 | 1.02 | 1.53 |
| 64 ft | 3.40 | 2.26 | 0.93 | 1.39 |
| 66 ft | 3.20 | 2.13 | 0.85 | 1.27 |
| 68 ft | 3.01 | 2.00 | 0.77 | 1.16 |
- 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 42 ft span, a W27×146 carries a factored load of 7.89 kips per foot (LRFD) or an allowable load of 5.25 kips per foot (ASD). A live load of 3.28 kips per foot would deflect it span/360, which is 1.40 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.
W27×146 questions
What does W27×146 mean?
W means a wide flange shape. 27 is its nominal depth in inches (the actual depth is 27.4 in) and 146 is its weight in pounds per foot.
How much does a W27×146 weigh?
146 pounds per foot, so a 20 ft W27×146 weighs about 2,920 pounds.
How far can a W27×146 span?
It depends on the load. Braced along its length, it carries 71.0 kips per foot of factored load at 14 ft and 3.01 kips per foot at 68 ft; the load table has the spans in between. Floor beams are often 41 to 55 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W27×146 a compact section?
Yes. Its flanges (bf/2tf = 7.16) and web (h/tw = 39.4) are both compact for bending in 50 ksi steel.