W27×539 Steel Beam
A W27×539 is a wide flange steel beam 32.5 inches deep with 15.3-inch flanges, weighing 539 pounds per foot. In ASTM A992 steel (Fy = 50 ksi) it has a design bending strength of 7,088 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 1,921 kips.
Design a W27×539 beam Opens a 48 ft span in the free beam designer.
W27×539 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 32.5 in |
| Flange width, bf | 15.3 in |
| Flange thickness, tf | 3.54 in |
| Web thickness, tw | 1.97 in |
| Distance to web toe of fillet, kdes | 4.33 in |
| Distance between flange centroids, ho | 28.96 in |
| Cross-sectional area, A | 159 in2 |
| Weight | 539 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W27×539 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 25600 in4 | 2110 in4 |
| Elastic section modulus, S | 1570 in3 | 277 in3 |
| Plastic section modulus, Z | 1890 in3 | 437 in3 |
| Radius of gyration, r | 12.7 in | 3.65 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 496 in4 |
| Warping constant, Cw | 443000 in6 |
| Effective radius of gyration, rts | 4.41 in |
| Flange slenderness, bf/2tf | 2.15 |
| Web slenderness, h/tw | 12.1 |
W27×539 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 = 7,088 kip-ft | Mn/Ω = 4,716 kip-ft |
| Shear | φVn = 1,921 kips | Vn/Ω = 1,281 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 12.9 ft between braces it keeps its full strength; past Lr = 88.6 ft it buckles elastically. With uniform moment between braces (Cb = 1.0):
| Unbraced length, Lb | φMn (LRFD) | Mn/Ω (ASD) |
|---|---|---|
| Braced | 7,088 kip-ft | 4,716 kip-ft |
| 10 ft | 7,088 kip-ft | 4,716 kip-ft |
| 12.9 ft (Lp) | 7,088 kip-ft | 4,716 kip-ft |
| 20 ft | 6,809 kip-ft | 4,530 kip-ft |
| 30 ft | 6,418 kip-ft | 4,270 kip-ft |
| 40 ft | 6,026 kip-ft | 4,009 kip-ft |
| 50 ft | 5,635 kip-ft | 3,749 kip-ft |
| 60 ft | 5,243 kip-ft | 3,488 kip-ft |
| 70 ft | 4,851 kip-ft | 3,228 kip-ft |
| 80 ft | 4,460 kip-ft | 2,967 kip-ft |
| 88.7 ft (Lr) | 4,119 kip-ft | 2,741 kip-ft |
| 90 ft | 4,056 kip-ft | 2,699 kip-ft |
| 100 ft | 3,644 kip-ft | 2,424 kip-ft |
| 110 ft | 3,308 kip-ft | 2,201 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.
W27×539 load table by span
The largest uniform load a simply supported W27×539 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 0.539 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 16 ft | 221.5 | 147.4 | 268.5 | 402.8 |
| 18 ft | 175.0 | 116.4 | 188.6 | 282.9 |
| 20 ft | 141.8 | 94.3 | 137.5 | 206.2 |
| 22 ft | 117.1 | 77.9 | 103.3 | 154.9 |
| 24 ft | 98.4 | 65.5 | 79.6 | 119.3 |
| 26 ft | 83.9 | 55.8 | 62.6 | 93.9 |
| 28 ft | 72.3 | 48.1 | 50.1 | 75.2 |
| 30 ft | 63.0 | 41.9 | 40.7 | 61.1 |
| 32 ft | 55.4 | 36.8 | 33.6 | 50.3 |
| 34 ft | 49.0 | 32.6 | 28.0 | 42.0 |
| 36 ft | 43.8 | 29.1 | 23.6 | 35.4 |
| 38 ft | 39.3 | 26.1 | 20.0 | 30.1 |
| 40 ft | 35.4 | 23.6 | 17.2 | 25.8 |
| 42 ft | 32.1 | 21.4 | 14.8 | 22.3 |
| 44 ft | 29.3 | 19.5 | 12.9 | 19.4 |
| 46 ft | 26.8 | 17.8 | 11.3 | 16.9 |
| 48 ft | 24.6 | 16.4 | 9.95 | 14.9 |
| 50 ft | 22.7 | 15.1 | 8.80 | 13.2 |
| 52 ft | 21.0 | 14.0 | 7.82 | 11.7 |
| 54 ft | 19.4 | 12.9 | 6.98 | 10.5 |
| 56 ft | 18.1 | 12.0 | 6.26 | 9.39 |
| 58 ft | 16.9 | 11.2 | 5.64 | 8.46 |
| 60 ft | 15.8 | 10.5 | 5.09 | 7.64 |
| 62 ft | 14.8 | 9.81 | 4.61 | 6.92 |
| 64 ft | 13.8 | 9.21 | 4.20 | 6.29 |
| 66 ft | 13.0 | 8.66 | 3.83 | 5.74 |
| 68 ft | 12.3 | 8.16 | 3.50 | 5.25 |
| 70 ft | 11.6 | 7.70 | 3.21 | 4.81 |
| 72 ft | 10.9 | 7.28 | 2.95 | 4.42 |
| 74 ft | 10.4 | 6.89 | 2.71 | 4.07 |
| 76 ft | 9.82 | 6.53 | 2.51 | 3.76 |
| 78 ft | 9.32 | 6.20 | 2.32 | 3.48 |
| 80 ft | 8.86 | 5.89 | 2.15 | 3.22 |
- 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 48 ft span, a W27×539 carries a factored load of 24.6 kips per foot (LRFD) or an allowable load of 16.4 kips per foot (ASD). A live load of 9.95 kips per foot would deflect it span/360, which is 1.60 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.
W27×539 questions
What does W27×539 mean?
W means a wide flange shape. 27 is its nominal depth in inches (the actual depth is 32.5 in) and 539 is its weight in pounds per foot.
How much does a W27×539 weigh?
539 pounds per foot, so a 20 ft W27×539 weighs about 10,780 pounds.
How far can a W27×539 span?
It depends on the load. Braced along its length, it carries 221.5 kips per foot of factored load at 16 ft and 8.86 kips per foot at 80 ft; the load table has the spans in between. Floor beams are often 49 to 65 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W27×539 a compact section?
Yes. Its flanges (bf/2tf = 2.15) and web (h/tw = 12.1) are both compact for bending in 50 ksi steel.