W40×593 Steel Beam

A W40×593 is a wide flange steel beam 43 inches deep with 16.7-inch flanges, weighing 593 pounds per foot. In ASTM A992 steel (F_y = 50 ksi) it has a design bending strength of 10,350 kip-ft (LRFD) when its compression flange is braced, and a design shear strength of 2,309 kips.

Weight593 lb/ft

Depth43 in

I_x50400 in⁴

S_x2340 in³

Z_x2760 in³

φM_n10,350 kip-ft

Design a W40×593 beam Opens a 66 ft span in the free beam designer.

W40×593 dimensions

Dimension	Value
Depth, d	43.0 in
Flange width, b_f	16.7 in
Flange thickness, t_f	3.23 in
Web thickness, t_w	1.79 in
Distance to web toe of fillet, k_des	4.41 in
Distance between flange centroids, h_o	39.77 in
Cross-sectional area, A	174 in²
Weight	593 lb/ft

Dimensions are AISC design values. Detailing dimensions are rounded to the nearest 1/16 in.

W40×593 section properties

Property	Strong axis (x)	Weak axis (y)
Moment of inertia, I	50400 in⁴	2520 in⁴
Elastic section modulus, S	2340 in³	302 in³
Plastic section modulus, Z	2760 in³	481 in³
Radius of gyration, r	17.0 in	3.80 in

Torsion and slenderness	Value
Torsional constant, J	445 in⁴
Warping constant, C_w	997000 in⁶
Effective radius of gyration, r_ts	4.63 in
Flange slenderness, b_f/2t_f	2.58
Web slenderness, h/t_w	19.1

W40×593 bending and shear strength

For ASTM A992 steel (F_y = 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	φM_n = 10,350 kip-ft	M_n/Ω = 6,886 kip-ft
Shear	φV_n = 2,309 kips	V_n/Ω = 1,539 kips

If the compression flange isn't braced, the beam can buckle sideways before it yields. Up to L_p = 13.4 ft between braces it keeps its full strength; past L_r = 63.9 ft it buckles elastically. With uniform moment between braces (C_b = 1.0):

Unbraced length, L_b	φM_n (LRFD)	M_n/Ω (ASD)
Braced	10,350 kip-ft	6,886 kip-ft
10 ft	10,350 kip-ft	6,886 kip-ft
13.4 ft (L_p)	10,350 kip-ft	6,886 kip-ft
20 ft	9,801 kip-ft	6,521 kip-ft
30 ft	8,967 kip-ft	5,966 kip-ft
40 ft	8,133 kip-ft	5,411 kip-ft
50 ft	7,299 kip-ft	4,856 kip-ft
60 ft	6,464 kip-ft	4,301 kip-ft
63.9 ft (L_r)	6,139 kip-ft	4,084 kip-ft
70 ft	5,558 kip-ft	3,698 kip-ft
80 ft	4,820 kip-ft	3,207 kip-ft
90 ft	4,258 kip-ft	2,833 kip-ft
100 ft	3,815 kip-ft	2,539 kip-ft
110 ft	3,457 kip-ft	2,300 kip-ft

A beam with a uniform load between braces has C_b above 1.0 (1.14 for a simple span braced only at its ends), so these values are conservative. The beam designer works out C_b for every segment between braces.

W40×593 load table by span

The largest uniform load a simply supported W40×593 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 0.593 kips per foot.

Span	Factored load (LRFD)	Allowable load (ASD)	Load at span/360	Load at span/240
22 ft	171.1	113.8	203.4	305.0
24 ft	143.8	95.6	156.6	235.0
26 ft	122.5	81.5	123.2	184.8
28 ft	105.6	70.3	98.6	148.0
30 ft	92.0	61.2	80.2	120.3
32 ft	80.9	53.8	66.1	99.1
34 ft	71.6	47.7	55.1	82.6
36 ft	63.9	42.5	46.4	69.6
38 ft	57.3	38.2	39.5	59.2
40 ft	51.8	34.4	33.8	50.8
42 ft	46.9	31.2	29.2	43.8
44 ft	42.8	28.5	25.4	38.1
46 ft	39.1	26.0	22.2	33.4
48 ft	35.9	23.9	19.6	29.4
50 ft	33.1	22.0	17.3	26.0
52 ft	30.6	20.4	15.4	23.1
54 ft	28.4	18.9	13.8	20.6
56 ft	26.4	17.6	12.3	18.5
58 ft	24.6	16.4	11.1	16.6
60 ft	23.0	15.3	10.0	15.0
62 ft	21.5	14.3	9.09	13.6
64 ft	20.2	13.4	8.26	12.4
66 ft	19.0	12.6	7.53	11.3
68 ft	17.9	11.9	6.89	10.3
70 ft	16.9	11.2	6.31	9.47
72 ft	16.0	10.6	5.80	8.70
74 ft	15.1	10.1	5.34	8.02
76 ft	14.3	9.54	4.93	7.40
78 ft	13.6	9.05	4.56	6.84
80 ft	12.9	8.61	4.23	6.34
82 ft	12.3	8.19	3.93	5.89
84 ft	11.7	7.81	3.65	5.48
86 ft	11.2	7.45	3.40	5.11
88 ft	10.7	7.11	3.18	4.77
90 ft	10.2	6.80	2.97	4.46
92 ft	9.78	6.51	2.78	4.17
94 ft	9.37	6.23	2.61	3.91
96 ft	8.98	5.98	2.45	3.67
98 ft	8.62	5.74	2.30	3.45
100 ft	8.28	5.51	2.17	3.25
102 ft	7.96	5.30	2.04	3.06
104 ft	7.66	5.09	1.92	2.89
106 ft	7.37	4.90	1.82	2.73
108 ft	7.10	4.72	1.72	2.58

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 66 ft span, a W40×593 carries a factored load of 19.0 kips per foot (LRFD) or an allowable load of 12.6 kips per foot (ASD). A live load of 7.53 kips per foot would deflect it span/360, which is 2.20 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.

W40×593 questions

What does W40×593 mean?

W means a wide flange shape. 40 is its nominal depth in inches (the actual depth is 43.0 in) and 593 is its weight in pounds per foot.

How much does a W40×593 weigh?

593 pounds per foot, so a 20 ft W40×593 weighs about 11,860 pounds.

How far can a W40×593 span?

It depends on the load. Braced along its length, it carries 171.1 kips per foot of factored load at 22 ft and 7.10 kips per foot at 108 ft; the load table has the spans in between. Floor beams are often 65 to 86 ft for this depth (span-to-depth ratios of about 18 to 24), where deflection usually governs.

Is a W40×593 a compact section?

Yes. Its flanges (b_f/2t_f = 2.58) and web (h/t_w = 19.1) are both compact for bending in 50 ksi steel.