W14×109 Steel Beam
A W14×109 is a wide flange steel beam 14.3 inches deep with 14.6-inch flanges, weighing 109 pounds per foot. In ASTM A992 steel (Fy = 50 ksi) it has a design bending strength of 720 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 225 kips.
Design a W14×109 beam Opens a 21 ft span in the free beam designer.
W14×109 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 14.3 in |
| Flange width, bf | 14.6 in |
| Flange thickness, tf | 0.860 in |
| Web thickness, tw | 0.525 in |
| Distance to web toe of fillet, kdes | 1.46 in |
| Distance between flange centroids, ho | 13.44 in |
| Cross-sectional area, A | 32.0 in2 |
| Weight | 109 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W14×109 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 1240 in4 | 447 in4 |
| Elastic section modulus, S | 173 in3 | 61.2 in3 |
| Plastic section modulus, Z | 192 in3 | 92.7 in3 |
| Radius of gyration, r | 6.22 in | 3.73 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 7.12 in4 |
| Warping constant, Cw | 20200 in6 |
| Effective radius of gyration, rts | 4.17 in |
| Flange slenderness, bf/2tf | 8.49 |
| Web slenderness, h/tw | 21.7 |
W14×109 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 = 720 kip-ft | Mn/Ω = 479 kip-ft |
| Shear | φVn = 225 kips | Vn/Ω = 150 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 13.2 ft between braces it keeps its full strength; past Lr = 48.4 ft it buckles elastically. With uniform moment between braces (Cb = 1.0):
| Unbraced length, Lb | φMn (LRFD) | Mn/Ω (ASD) |
|---|---|---|
| Braced | 720 kip-ft | 479 kip-ft |
| 10 ft | 720 kip-ft | 479 kip-ft |
| 13.2 ft (Lp) | 720 kip-ft | 479 kip-ft |
| 20 ft | 669 kip-ft | 445 kip-ft |
| 30 ft | 593 kip-ft | 395 kip-ft |
| 40 ft | 518 kip-ft | 344 kip-ft |
| 48.4 ft (Lr) | 454 kip-ft | 302 kip-ft |
| 50 ft | 437 kip-ft | 291 kip-ft |
| 60 ft | 355 kip-ft | 236 kip-ft |
| 70 ft | 299 kip-ft | 199 kip-ft |
| 80 ft | 259 kip-ft | 172 kip-ft |
| 90 ft | 228 kip-ft | 152 kip-ft |
| 100 ft | 204 kip-ft | 136 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.
W14×109 load table by span
The largest uniform load a simply supported W14×109 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 0.109 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 7 ft | 64.4* | 42.9* | 155.3 | 233.0 |
| 9 ft | 50.1* | 33.4* | 73.1 | 109.6 |
| 11 ft | 41.0* | 27.3* | 40.0 | 60.0 |
| 13 ft | 34.1 | 22.7 | 24.2 | 36.4 |
| 15 ft | 25.6 | 17.0 | 15.8 | 23.7 |
| 17 ft | 19.9 | 13.3 | 10.8 | 16.3 |
| 19 ft | 16.0 | 10.6 | 7.77 | 11.7 |
| 21 ft | 13.1 | 8.69 | 5.75 | 8.63 |
| 23 ft | 10.9 | 7.24 | 4.38 | 6.57 |
| 25 ft | 9.22 | 6.13 | 3.41 | 5.11 |
| 27 ft | 7.90 | 5.26 | 2.71 | 4.06 |
| 29 ft | 6.85 | 4.56 | 2.18 | 3.28 |
| 31 ft | 5.99 | 3.99 | 1.79 | 2.68 |
| 33 ft | 5.29 | 3.52 | 1.48 | 2.22 |
| 35 ft | 4.70 | 3.13 | 1.24 | 1.86 |
- 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 21 ft span, a W14×109 carries a factored load of 13.1 kips per foot (LRFD) or an allowable load of 8.69 kips per foot (ASD). A live load of 5.75 kips per foot would deflect it span/360, which is 0.70 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.
W14×109 questions
What does W14×109 mean?
W means a wide flange shape. 14 is its nominal depth in inches (the actual depth is 14.3 in) and 109 is its weight in pounds per foot.
How much does a W14×109 weigh?
109 pounds per foot, so a 20 ft W14×109 weighs about 2,180 pounds.
How far can a W14×109 span?
It depends on the load. Braced along its length, it carries 64.4 kips per foot of factored load at 7 ft and 4.70 kips per foot at 35 ft; the load table has the spans in between. Floor beams are often 21 to 29 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W14×109 a compact section?
Yes. Its flanges (bf/2tf = 8.49) and web (h/tw = 21.7) are both compact for bending in 50 ksi steel.