W27×307 Steel Beam
A W27×307 is a wide flange steel beam 29.6 inches deep with 14.4-inch flanges, weighing 307 pounds per foot. In ASTM A992 steel (Fy = 50 ksi) it has a design bending strength of 3,863 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 1,030 kips.
Design a W27×307 beam Opens a 45 ft span in the free beam designer.
W27×307 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 29.6 in |
| Flange width, bf | 14.4 in |
| Flange thickness, tf | 2.09 in |
| Web thickness, tw | 1.16 in |
| Distance to web toe of fillet, kdes | 2.88 in |
| Distance between flange centroids, ho | 27.51 in |
| Cross-sectional area, A | 90.4 in2 |
| Weight | 307 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W27×307 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 13100 in4 | 1050 in4 |
| Elastic section modulus, S | 887 in3 | 146 in3 |
| Plastic section modulus, Z | 1030 in3 | 227 in3 |
| Radius of gyration, r | 12.0 in | 3.41 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 101 in4 |
| Warping constant, Cw | 199000 in6 |
| Effective radius of gyration, rts | 4.04 in |
| Flange slenderness, bf/2tf | 3.46 |
| Web slenderness, h/tw | 20.6 |
W27×307 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 = 3,863 kip-ft | Mn/Ω = 2,570 kip-ft |
| Shear | φVn = 1,030 kips | Vn/Ω = 687 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 12.0 ft between braces it keeps its full strength; past Lr = 52.5 ft it buckles elastically. With uniform moment between braces (Cb = 1.0):
| Unbraced length, Lb | φMn (LRFD) | Mn/Ω (ASD) |
|---|---|---|
| Braced | 3,863 kip-ft | 2,570 kip-ft |
| 10 ft | 3,863 kip-ft | 2,570 kip-ft |
| 12.0 ft (Lp) | 3,863 kip-ft | 2,570 kip-ft |
| 20 ft | 3,561 kip-ft | 2,369 kip-ft |
| 30 ft | 3,182 kip-ft | 2,117 kip-ft |
| 40 ft | 2,803 kip-ft | 1,865 kip-ft |
| 50 ft | 2,424 kip-ft | 1,612 kip-ft |
| 52.5 ft (Lr) | 2,328 kip-ft | 1,549 kip-ft |
| 60 ft | 2,009 kip-ft | 1,337 kip-ft |
| 70 ft | 1,702 kip-ft | 1,132 kip-ft |
| 80 ft | 1,478 kip-ft | 983 kip-ft |
| 90 ft | 1,306 kip-ft | 869 kip-ft |
| 100 ft | 1,171 kip-ft | 779 kip-ft |
| 110 ft | 1,061 kip-ft | 706 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.
W27×307 load table by span
The largest uniform load a simply supported W27×307 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 0.307 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 15 ft | 137.3 | 91.4 | 166.8 | 250.1 |
| 17 ft | 106.9 | 71.1 | 114.6 | 171.8 |
| 19 ft | 85.6 | 56.9 | 82.1 | 123.1 |
| 21 ft | 70.1 | 46.6 | 60.8 | 91.2 |
| 23 ft | 58.4 | 38.9 | 46.3 | 69.4 |
| 25 ft | 49.4 | 32.9 | 36.0 | 54.0 |
| 27 ft | 42.4 | 28.2 | 28.6 | 42.9 |
| 29 ft | 36.7 | 24.4 | 23.1 | 34.6 |
| 31 ft | 32.2 | 21.4 | 18.9 | 28.3 |
| 33 ft | 28.4 | 18.9 | 15.7 | 23.5 |
| 35 ft | 25.2 | 16.8 | 13.1 | 19.7 |
| 37 ft | 22.6 | 15.0 | 11.1 | 16.7 |
| 39 ft | 20.3 | 13.5 | 9.49 | 14.2 |
| 41 ft | 18.4 | 12.2 | 8.17 | 12.2 |
| 43 ft | 16.7 | 11.1 | 7.08 | 10.6 |
| 45 ft | 15.3 | 10.2 | 6.18 | 9.26 |
| 47 ft | 14.0 | 9.31 | 5.42 | 8.13 |
| 49 ft | 12.9 | 8.56 | 4.78 | 7.18 |
| 51 ft | 11.9 | 7.90 | 4.24 | 6.36 |
| 53 ft | 11.0 | 7.32 | 3.78 | 5.67 |
| 55 ft | 10.2 | 6.80 | 3.38 | 5.07 |
| 57 ft | 9.51 | 6.33 | 3.04 | 4.56 |
| 59 ft | 8.88 | 5.91 | 2.74 | 4.11 |
| 61 ft | 8.30 | 5.53 | 2.48 | 3.72 |
| 63 ft | 7.79 | 5.18 | 2.25 | 3.38 |
| 65 ft | 7.31 | 4.87 | 2.05 | 3.07 |
| 67 ft | 6.88 | 4.58 | 1.87 | 2.81 |
| 69 ft | 6.49 | 4.32 | 1.71 | 2.57 |
| 71 ft | 6.13 | 4.08 | 1.57 | 2.36 |
| 73 ft | 5.80 | 3.86 | 1.45 | 2.17 |
- 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 45 ft span, a W27×307 carries a factored load of 15.3 kips per foot (LRFD) or an allowable load of 10.2 kips per foot (ASD). A live load of 6.18 kips per foot would deflect it span/360, which is 1.50 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.
W27×307 questions
What does W27×307 mean?
W means a wide flange shape. 27 is its nominal depth in inches (the actual depth is 29.6 in) and 307 is its weight in pounds per foot.
How much does a W27×307 weigh?
307 pounds per foot, so a 20 ft W27×307 weighs about 6,140 pounds.
How far can a W27×307 span?
It depends on the load. Braced along its length, it carries 137.3 kips per foot of factored load at 15 ft and 5.80 kips per foot at 73 ft; the load table has the spans in between. Floor beams are often 44 to 59 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W27×307 a compact section?
Yes. Its flanges (bf/2tf = 3.46) and web (h/tw = 20.6) are both compact for bending in 50 ksi steel.