W36×135 Steel Beam
A W36×135 is a wide flange steel beam 35.6 inches deep with 12-inch flanges, weighing 135 pounds per foot. In ASTM A992 steel (Fy = 50 ksi) it has a design bending strength of 1,909 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 577 kips.
Design a W36×135 beam Opens a 54 ft span in the free beam designer.
W36×135 dimensions
| Dimension | Value |
|---|---|
| Depth, d | 35.6 in |
| Flange width, bf | 12.0 in |
| Flange thickness, tf | 0.790 in |
| Web thickness, tw | 0.600 in |
| Distance to web toe of fillet, kdes | 1.54 in |
| Distance between flange centroids, ho | 34.81 in |
| Cross-sectional area, A | 39.7 in2 |
| Weight | 135 lb/ft |
Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.
W36×135 section properties
| Property | Strong axis (x) | Weak axis (y) |
|---|---|---|
| Moment of inertia, I | 7800 in4 | 225 in4 |
| Elastic section modulus, S | 439 in3 | 37.7 in3 |
| Plastic section modulus, Z | 509 in3 | 59.7 in3 |
| Radius of gyration, r | 14.0 in | 2.38 in |
| Torsion and slenderness | Value |
|---|---|
| Torsional constant, J | 7.00 in4 |
| Warping constant, Cw | 68100 in6 |
| Effective radius of gyration, rts | 2.99 in |
| Flange slenderness, bf/2tf | 7.56 |
| Web slenderness, h/tw | 54.1 |
W36×135 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 = 1,909 kip-ft | Mn/Ω = 1,270 kip-ft |
| Shear | φVn = 577 kips | Vn/Ω = 384 kips |
If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to Lp = 8.4 ft between braces it keeps its full strength; past Lr = 24.2 ft it buckles elastically. With uniform moment between braces (Cb = 1.0):
| Unbraced length, Lb | φMn (LRFD) | Mn/Ω (ASD) |
|---|---|---|
| Braced | 1,909 kip-ft | 1,270 kip-ft |
| 5 ft | 1,909 kip-ft | 1,270 kip-ft |
| 8.4 ft (Lp) | 1,909 kip-ft | 1,270 kip-ft |
| 10 ft | 1,833 kip-ft | 1,219 kip-ft |
| 15 ft | 1,593 kip-ft | 1,060 kip-ft |
| 20 ft | 1,354 kip-ft | 901 kip-ft |
| 24.2 ft (Lr) | 1,152 kip-ft | 767 kip-ft |
| 25 ft | 1,089 kip-ft | 725 kip-ft |
| 30 ft | 799 kip-ft | 532 kip-ft |
| 35 ft | 622 kip-ft | 414 kip-ft |
| 40 ft | 506 kip-ft | 337 kip-ft |
| 45 ft | 424 kip-ft | 282 kip-ft |
| 50 ft | 365 kip-ft | 243 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.
W36×135 load table by span
The largest uniform load a simply supported W36×135 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 0.135 kips per foot.
| Span | Factored load (LRFD) | Allowable load (ASD) | Load at span/360 | Load at span/240 |
|---|---|---|---|---|
| 18 ft | 47.1 | 31.4 | 57.5 | 86.2 |
| 20 ft | 38.2 | 25.4 | 41.9 | 62.8 |
| 22 ft | 31.5 | 21.0 | 31.5 | 47.2 |
| 24 ft | 26.5 | 17.6 | 24.2 | 36.4 |
| 26 ft | 22.6 | 15.0 | 19.1 | 28.6 |
| 28 ft | 19.5 | 13.0 | 15.3 | 22.9 |
| 30 ft | 17.0 | 11.3 | 12.4 | 18.6 |
| 32 ft | 14.9 | 9.92 | 10.2 | 15.3 |
| 34 ft | 13.2 | 8.79 | 8.53 | 12.8 |
| 36 ft | 11.8 | 7.84 | 7.18 | 10.8 |
| 38 ft | 10.6 | 7.04 | 6.11 | 9.16 |
| 40 ft | 9.54 | 6.35 | 5.24 | 7.85 |
| 42 ft | 8.66 | 5.76 | 4.52 | 6.78 |
| 44 ft | 7.89 | 5.25 | 3.93 | 5.90 |
| 46 ft | 7.22 | 4.80 | 3.44 | 5.16 |
| 48 ft | 6.63 | 4.41 | 3.03 | 4.55 |
| 50 ft | 6.11 | 4.06 | 2.68 | 4.02 |
| 52 ft | 5.65 | 3.76 | 2.38 | 3.57 |
| 54 ft | 5.24 | 3.48 | 2.13 | 3.19 |
| 56 ft | 4.87 | 3.24 | 1.91 | 2.86 |
| 58 ft | 4.54 | 3.02 | 1.72 | 2.58 |
| 60 ft | 4.24 | 2.82 | 1.55 | 2.33 |
| 62 ft | 3.97 | 2.64 | 1.41 | 2.11 |
| 64 ft | 3.73 | 2.48 | 1.28 | 1.92 |
| 66 ft | 3.51 | 2.33 | 1.17 | 1.75 |
| 68 ft | 3.30 | 2.20 | 1.07 | 1.60 |
| 70 ft | 3.12 | 2.07 | 0.98 | 1.47 |
| 72 ft | 2.95 | 1.96 | 0.90 | 1.35 |
| 74 ft | 2.79 | 1.86 | 0.83 | 1.24 |
| 76 ft | 2.64 | 1.76 | 0.76 | 1.15 |
| 78 ft | 2.51 | 1.67 | 0.71 | 1.06 |
| 80 ft | 2.39 | 1.59 | 0.65 | 0.98 |
| 82 ft | 2.27 | 1.51 | 0.61 | 0.91 |
| 84 ft | 2.16 | 1.44 | 0.57 | 0.85 |
| 86 ft | 2.06 | 1.37 | 0.53 | 0.79 |
| 88 ft | 1.97 | 1.31 | 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 54 ft span, a W36×135 carries a factored load of 5.24 kips per foot (LRFD) or an allowable load of 3.48 kips per foot (ASD). A live load of 2.13 kips per foot would deflect it span/360, which is 1.80 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.
W36×135 questions
What does W36×135 mean?
W means a wide flange shape. 36 is its nominal depth in inches (the actual depth is 35.6 in) and 135 is its weight in pounds per foot.
How much does a W36×135 weigh?
135 pounds per foot, so a 20 ft W36×135 weighs about 2,700 pounds.
How far can a W36×135 span?
It depends on the load. Braced along its length, it carries 47.1 kips per foot of factored load at 18 ft and 1.97 kips per foot at 88 ft; the load table has the spans in between. Floor beams are often 53 to 71 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.
Is a W36×135 a compact section?
Yes. Its flanges (bf/2tf = 7.56) and web (h/tw = 54.1) are both compact for bending in 50 ksi steel.