W14×342 Steel Beam
A W14×342 is a wide flange steel beam 17.5 inches deep with 16.4-inch flanges, weighing 342 pounds per foot. In ASTM A992 steel (Fy = 50 ksi) it has a design bending strength of 2,520 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 809 kips.
Design a W14×342 beam Opens a 27 ft span in the free beam designer.
W14×342 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 17.5 in |
| Flange width, bf | 16.4 in |
| Flange thickness, tf | 2.47 in |
| Web thickness, tw | 1.54 in |
| Distance to web toe of fillet, kdes | 3.07 in |
| Distance between flange centroids, ho | 15.03 in |
| Cross-sectional area, A | 101 in2 |
| Weight | 342 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W14×342 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 4900 in4 | 1810 in4 |
| Elastic section modulus, S | 558 in3 | 221 in3 |
| Plastic section modulus, Z | 672 in3 | 338 in3 |
| Radius of gyration, r | 6.98 in | 4.24 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 178 in4 |
| Warping constant, Cw | 103000 in6 |
| Effective radius of gyration, rts | 4.95 in |
| Flange slenderness, bf/2tf | 3.31 |
| Web slenderness, h/tw | 7.41 |
W14×342 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 = 2,520 kip-ft | Mn/Ω = 1,677 kip-ft |
| Shear | φVn = 809 kips | Vn/Ω = 539 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 15.0 ft between braces it keeps its full strength; past Lr = 137.6 ft it buckles elastically. With uniform moment between braces (Cb = 1.0):
| Unbraced length, Lb | φMn (LRFD) | Mn/Ω (ASD) |
|---|---|---|
| Braced | 2,520 kip-ft | 1,677 kip-ft |
| 10 ft | 2,520 kip-ft | 1,677 kip-ft |
| 15.0 ft (Lp) | 2,520 kip-ft | 1,677 kip-ft |
| 20 ft | 2,477 kip-ft | 1,648 kip-ft |
| 30 ft | 2,391 kip-ft | 1,591 kip-ft |
| 40 ft | 2,305 kip-ft | 1,533 kip-ft |
| 50 ft | 2,219 kip-ft | 1,476 kip-ft |
| 60 ft | 2,133 kip-ft | 1,419 kip-ft |
| 70 ft | 2,046 kip-ft | 1,362 kip-ft |
| 80 ft | 1,960 kip-ft | 1,304 kip-ft |
| 90 ft | 1,874 kip-ft | 1,247 kip-ft |
| 100 ft | 1,788 kip-ft | 1,190 kip-ft |
| 110 ft | 1,702 kip-ft | 1,133 kip-ft |
| 137.6 ft (Lr) | 1,465 kip-ft | 975 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.
W14×342 load table by span
The largest uniform load a simply supported W14×342 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 0.342 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 9 ft | 179.7* | 119.8* | 288.8 | 433.2 |
| 11 ft | 147.0* | 98.0* | 158.2 | 237.2 |
| 13 ft | 119.3 | 79.4 | 95.8 | 143.7 |
| 15 ft | 89.6 | 59.6 | 62.4 | 93.6 |
| 17 ft | 69.8 | 46.4 | 42.8 | 64.3 |
| 19 ft | 55.8 | 37.2 | 30.7 | 46.0 |
| 21 ft | 45.7 | 30.4 | 22.7 | 34.1 |
| 23 ft | 38.1 | 25.4 | 17.3 | 26.0 |
| 25 ft | 32.3 | 21.5 | 13.5 | 20.2 |
| 27 ft | 27.7 | 18.4 | 10.7 | 16.0 |
| 29 ft | 24.0 | 15.9 | 8.63 | 12.9 |
| 31 ft | 21.0 | 14.0 | 7.07 | 10.6 |
| 33 ft | 18.5 | 12.3 | 5.86 | 8.79 |
| 35 ft | 16.5 | 10.9 | 4.91 | 7.37 |
| 37 ft | 14.7 | 9.80 | 4.16 | 6.23 |
| 39 ft | 13.3 | 8.82 | 3.55 | 5.32 |
| 41 ft | 12.0 | 7.98 | 3.05 | 4.58 |
| 43 ft | 10.9 | 7.25 | 2.65 | 3.97 |
- 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 27 ft span, a W14×342 carries a factored load of 27.7 kips per foot (LRFD) or an allowable load of 18.4 kips per foot (ASD). A live load of 10.7 kips per foot would deflect it span/360, which is 0.90 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.
W14×342 questions
What does W14×342 mean?
W means a wide flange shape. 14 is its nominal depth in inches (the actual depth is 17.5 in) and 342 is its weight in pounds per foot.
How much does a W14×342 weigh?
342 pounds per foot, so a 20 ft W14×342 weighs about 6,840 pounds.
How far can a W14×342 span?
It depends on the load. Braced along its length, it carries 179.7 kips per foot of factored load at 9 ft and 10.9 kips per foot at 43 ft; the load table has the spans in between. Floor beams are often 26 to 35 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W14×342 a compact section?
Yes. Its flanges (bf/2tf = 3.31) and web (h/tw = 7.41) are both compact for bending in 50 ksi steel.