W27×102 Steel Beam
A W27×102 is a wide flange steel beam 27.1 inches deep with 10-inch flanges, weighing 102 pounds per foot. In ASTM A992 steel (Fy = 50 ksi) it has a design bending strength of 1,144 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 419 kips.
Design a W27×102 beam Opens a 42 ft span in the free beam designer.
W27×102 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 27.1 in |
| Flange width, bf | 10.0 in |
| Flange thickness, tf | 0.830 in |
| Web thickness, tw | 0.515 in |
| Distance to web toe of fillet, kdes | 1.43 in |
| Distance between flange centroids, ho | 26.27 in |
| Cross-sectional area, A | 30.0 in2 |
| Weight | 102 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W27×102 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 3620 in4 | 139 in4 |
| Elastic section modulus, S | 267 in3 | 27.8 in3 |
| Plastic section modulus, Z | 305 in3 | 43.4 in3 |
| Radius of gyration, r | 11.0 in | 2.15 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 5.28 in4 |
| Warping constant, Cw | 24000 in6 |
| Effective radius of gyration, rts | 2.62 in |
| Flange slenderness, bf/2tf | 6.03 |
| Web slenderness, h/tw | 47.1 |
W27×102 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 = 1,144 kip-ft | Mn/Ω = 761 kip-ft |
| Shear | φVn = 419 kips | Vn/Ω = 279 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 7.6 ft between braces it keeps its full strength; past Lr = 22.2 ft it buckles elastically. With uniform moment between braces (Cb = 1.0):
| Unbraced length, Lb | φMn (LRFD) | Mn/Ω (ASD) |
|---|---|---|
| Braced | 1,144 kip-ft | 761 kip-ft |
| 5 ft | 1,144 kip-ft | 761 kip-ft |
| 7.6 ft (Lp) | 1,144 kip-ft | 761 kip-ft |
| 10 ft | 1,071 kip-ft | 712 kip-ft |
| 15 ft | 919 kip-ft | 612 kip-ft |
| 20 ft | 768 kip-ft | 511 kip-ft |
| 22.2 ft (Lr) | 700 kip-ft | 466 kip-ft |
| 25 ft | 580 kip-ft | 386 kip-ft |
| 30 ft | 440 kip-ft | 293 kip-ft |
| 35 ft | 352 kip-ft | 234 kip-ft |
| 40 ft | 294 kip-ft | 195 kip-ft |
| 45 ft | 252 kip-ft | 167 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.
W27×102 load table by span
The largest uniform load a simply supported W27×102 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 0.102 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 14 ft | 46.7 | 31.1 | 56.7 | 85.0 |
| 16 ft | 35.7 | 23.8 | 38.0 | 57.0 |
| 18 ft | 28.2 | 18.8 | 26.7 | 40.0 |
| 20 ft | 22.9 | 15.2 | 19.4 | 29.2 |
| 22 ft | 18.9 | 12.6 | 14.6 | 21.9 |
| 24 ft | 15.9 | 10.6 | 11.3 | 16.9 |
| 26 ft | 13.5 | 9.01 | 8.85 | 13.3 |
| 28 ft | 11.7 | 7.77 | 7.08 | 10.6 |
| 30 ft | 10.2 | 6.76 | 5.76 | 8.64 |
| 32 ft | 8.94 | 5.95 | 4.75 | 7.12 |
| 34 ft | 7.92 | 5.27 | 3.96 | 5.94 |
| 36 ft | 7.06 | 4.70 | 3.33 | 5.00 |
| 38 ft | 6.34 | 4.22 | 2.83 | 4.25 |
| 40 ft | 5.72 | 3.80 | 2.43 | 3.65 |
| 42 ft | 5.19 | 3.45 | 2.10 | 3.15 |
| 44 ft | 4.73 | 3.14 | 1.83 | 2.74 |
| 46 ft | 4.32 | 2.88 | 1.60 | 2.40 |
| 48 ft | 3.97 | 2.64 | 1.41 | 2.11 |
| 50 ft | 3.66 | 2.44 | 1.24 | 1.87 |
| 52 ft | 3.38 | 2.25 | 1.11 | 1.66 |
| 54 ft | 3.14 | 2.09 | 0.99 | 1.48 |
| 56 ft | 2.92 | 1.94 | 0.89 | 1.33 |
| 58 ft | 2.72 | 1.81 | 0.80 | 1.20 |
| 60 ft | 2.54 | 1.69 | 0.72 | 1.08 |
| 62 ft | 2.38 | 1.58 | 0.65 | 0.98 |
| 64 ft | 2.23 | 1.49 | 0.59 | 0.89 |
| 66 ft | 2.10 | 1.40 | 0.54 | 0.81 |
| 68 ft | 1.98 | 1.32 | 0.49 | 0.74 |
- 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 W27×102 carries a factored load of 5.19 kips per foot (LRFD) or an allowable load of 3.45 kips per foot (ASD). A live load of 2.10 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.
W27×102 questions
What does W27×102 mean?
W means a wide flange shape. 27 is its nominal depth in inches (the actual depth is 27.1 in) and 102 is its weight in pounds per foot.
How much does a W27×102 weigh?
102 pounds per foot, so a 20 ft W27×102 weighs about 2,040 pounds.
How far can a W27×102 span?
It depends on the load. Braced along its length, it carries 46.7 kips per foot of factored load at 14 ft and 1.98 kips per foot at 68 ft; the load table has the spans in between. Floor beams are often 41 to 54 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W27×102 a compact section?
Yes. Its flanges (bf/2tf = 6.03) and web (h/tw = 47.1) are both compact for bending in 50 ksi steel.