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Wide Flange Steel I Beam: W18 × 40
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Glossary » Beams » Simply Supported » Uniformly Distributed Load » Single Span » Wide Flange Steel I Beam » W18 × 40
Wide Flange Steel I Beam | Single Span | Two Equal Spans | Three Equal Spans | Four Equal Spans

For a simply supported beam in a single span, the maximum displacement w_max and the maximum normal stress stress_max occur at the center of the beam.
The tabulated data listed in this page are calculated based on the area moment of inertia (Ixx = 612 in4) for the W18 × 40 Wide Flange Steel I Beam and the typical Young's modulus (E = 3.046 × 107 psi) of steels. Note that the typical yielding stress Yield of steels can range from 1.015 × 104 to 2.970 × 105 psi. The purpose of this page is to give a rough estimation of the load-bearing capacity of this particular beam, rather than a guideline for designing actual building structures. Please check your local building codes for regulatory requirements.

Note: The weight of the beam itself is not included in the calculation.
L = 3 ft
L = 5 ft
L = 10 ft
L = 15 ft
L = 20 ft
L = 25 ft
L = 30 ft
L = 40 ft
L = 50 ft
L = 60 ft
L = 70 ft
L = 80 ft
L = 90 ft
L = 100 ft
L = 125 ft
   
Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft)
L = 3.00 ft
P (lbf/ft) w_max (in) stress_max (psi)
40.0 3.91 × 10-6 7.90
50.0 4.89 × 10-6 9.87
60.0 5.87 × 10-6 11.8
70.0 6.84 × 10-6 13.8
80.0 7.82 × 10-6 15.8
90.0 8.80 × 10-6 17.8
100 9.78 × 10-6 19.7
200 1.96 × 10-5 39.5
300 2.93 × 10-5 59.2
400 3.91 × 10-5 79.0
500 4.89 × 10-5 98.7
600 5.87 × 10-5 118
700 6.84 × 10-5 138
800 7.82 × 10-5 158
900 8.80 × 10-5 178
1000 9.78 × 10-5 197
2000 1.96 × 10-4 395
3000 2.93 × 10-4 592
4000 3.91 × 10-4 790
5000 4.89 × 10-4 987
6000 5.87 × 10-4 1180
7000 6.84 × 10-4 1380
8000 7.82 × 10-4 1580
9000 8.80 × 10-4 1780
1.00 × 104 9.78 × 10-4 1970
2.00 × 104 0.00196 3950
3.00 × 104 0.00293 5920
4.00 × 104 0.00391 7900
5.00 × 104 0.00489 9870
6.00 × 104 0.00587 1.18 × 104
7.00 × 104 0.00684 1.38 × 104
8.00 × 104 0.00782 1.58 × 104
9.00 × 104 0.00880 1.78 × 104
1.00 × 105 0.00978 1.97 × 104
2.00 × 105 0.0196 3.95 × 104
3.00 × 105 0.0293 5.92 × 104
4.00 × 105 0.0391 7.90 × 104
5.00 × 105 0.0489 9.87 × 104
6.00 × 105 0.0587 1.18 × 105
7.00 × 105 0.0684 1.38 × 105
8.00 × 105 0.0782 1.58 × 105
9.00 × 105 0.0880 1.78 × 105
1.00 × 106 0.0978 1.97 × 105
1.50 × 106 0.147 2.97 × 105
Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft)
L = 5.00 ft
P (lbf/ft) w_max (in) stress_max (psi)
40.0 3.02 × 10-5 21.9
50.0 3.77 × 10-5 27.4
60.0 4.53 × 10-5 32.9
70.0 5.28 × 10-5 38.4
80.0 6.04 × 10-5 43.9
90.0 6.79 × 10-5 49.4
100 7.54 × 10-5 54.8
200 1.51 × 10-4 110
300 2.26 × 10-4 165
400 3.02 × 10-4 219
500 3.77 × 10-4 274
600 4.53 × 10-4 329
700 5.28 × 10-4 384
800 6.04 × 10-4 439
900 6.79 × 10-4 494
1000 7.54 × 10-4 548
2000 0.00151 1100
3000 0.00226 1650
4000 0.00302 2190
5000 0.00377 2740
6000 0.00453 3290
7000 0.00528 3840
8000 0.00604 4390
9000 0.00679 4940
1.00 × 104 0.00754 5480
2.00 × 104 0.0151 1.10 × 104
3.00 × 104 0.0226 1.65 × 104
4.00 × 104 0.0302 2.19 × 104
5.00 × 104 0.0377 2.74 × 104
6.00 × 104 0.0453 3.29 × 104
7.00 × 104 0.0528 3.84 × 104
8.00 × 104 0.0604 4.39 × 104
9.00 × 104 0.0679 4.94 × 104
1.00 × 105 0.0754 5.48 × 104
2.00 × 105 0.151 1.10 × 105
3.00 × 105 0.226 1.65 × 105
4.00 × 105 0.302 2.19 × 105
5.00 × 105 0.377 2.74 × 105
5.42 × 105 0.409 2.97 × 105
Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft)
L = 10.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
40.0 4.83 × 10-4 87.7
50.0 6.04 × 10-4 110
60.0 7.24 × 10-4 132
70.0 8.45 × 10-4 154
80.0 9.66 × 10-4 175
90.0 0.00109 197
100 0.00121 219
200 0.00241 439
300 0.00362 658
400 0.00483 877
500 0.00604 1100
600 0.00724 1320
700 0.00845 1540
800 0.00966 1750
900 0.0109 1970
1000 0.0121 2190
2000 0.0241 4390
3000 0.0362 6580
4000 0.0483 8770
5000 0.0604 1.10 × 104
6000 0.0724 1.32 × 104
7000 0.0845 1.54 × 104
8000 0.0966 1.75 × 104
9000 0.109 1.97 × 104
1.00 × 104 0.121 2.19 × 104
2.00 × 104 0.241 4.39 × 104
3.00 × 104 0.362 6.58 × 104
4.00 × 104 0.483 8.77 × 104
5.00 × 104 0.604 1.10 × 105
6.00 × 104 0.724 1.32 × 105
7.00 × 104 0.845 1.54 × 105
8.00 × 104 0.966 1.75 × 105
9.00 × 104 1.09 1.97 × 105
1.00 × 105 1.21 2.19 × 105
1.35 × 105 1.63 2.97 × 105
Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft)
L = 15.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
40.0 0.00244 197
50.0 0.00306 247
60.0 0.00367 296
70.0 0.00428 345
80.0 0.00489 395
90.0 0.00550 444
100 0.00611 494
200 0.0122 987
300 0.0183 1480
400 0.0244 1970
500 0.0306 2470
600 0.0367 2960
700 0.0428 3450
800 0.0489 3950
900 0.0550 4440
1000 0.0611 4940
2000 0.122 9870
3000 0.183 1.48 × 104
4000 0.244 1.97 × 104
5000 0.306 2.47 × 104
6000 0.367 2.96 × 104
7000 0.428 3.45 × 104
8000 0.489 3.95 × 104
9000 0.550 4.44 × 104
1.00 × 104 0.611 4.94 × 104
2.00 × 104 1.22 9.87 × 104
3.00 × 104 1.83 1.48 × 105
4.00 × 104 2.44 1.97 × 105
5.00 × 104 3.06 2.47 × 105
6.00 × 104 3.67 2.96 × 105
6.02 × 104 3.68 2.97 × 105
Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft)
L = 20.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
40.0 0.00773 351
50.0 0.00966 439
60.0 0.0116 526
70.0 0.0135 614
80.0 0.0155 702
90.0 0.0174 790
100 0.0193 877
200 0.0386 1750
300 0.0579 2630
400 0.0773 3510
500 0.0966 4390
600 0.116 5260
700 0.135 6140
800 0.155 7020
900 0.174 7900
1000 0.193 8770
2000 0.386 1.75 × 104
3000 0.579 2.63 × 104
4000 0.773 3.51 × 104
5000 0.966 4.39 × 104
6000 1.16 5.26 × 104
7000 1.35 6.14 × 104
8000 1.55 7.02 × 104
9000 1.74 7.90 × 104
1.00 × 104 1.93 8.77 × 104
2.00 × 104 3.86 1.75 × 105
3.00 × 104 5.79 2.63 × 105
3.39 × 104 6.54 2.97 × 105
Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft)
L = 25.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
40.0 0.0189 548
50.0 0.0236 686
60.0 0.0283 823
70.0 0.0330 960
80.0 0.0377 1100
90.0 0.0424 1230
100 0.0472 1370
200 0.0943 2740
300 0.141 4110
400 0.189 5480
500 0.236 6860
600 0.283 8230
700 0.330 9600
800 0.377 1.10 × 104
900 0.424 1.23 × 104
1000 0.472 1.37 × 104
2000 0.943 2.74 × 104
3000 1.41 4.11 × 104
4000 1.89 5.48 × 104
5000 2.36 6.86 × 104
6000 2.83 8.23 × 104
7000 3.30 9.60 × 104
8000 3.77 1.10 × 105
9000 4.24 1.23 × 105
1.00 × 104 4.72 1.37 × 105
2.00 × 104 9.43 2.74 × 105
2.17 × 104 10.2 2.97 × 105
Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft)
L = 30.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
40.0 0.0391 790
50.0 0.0489 987
60.0 0.0587 1180
70.0 0.0684 1380
80.0 0.0782 1580
90.0 0.0880 1780
100 0.0978 1970
200 0.196 3950
300 0.293 5920
400 0.391 7900
500 0.489 9870
600 0.587 1.18 × 104
700 0.684 1.38 × 104
800 0.782 1.58 × 104
900 0.880 1.78 × 104
1000 0.978 1.97 × 104
2000 1.96 3.95 × 104
3000 2.93 5.92 × 104
4000 3.91 7.90 × 104
5000 4.89 9.87 × 104
6000 5.87 1.18 × 105
7000 6.84 1.38 × 105
8000 7.82 1.58 × 105
9000 8.80 1.78 × 105
1.00 × 104 9.78 1.97 × 105
1.50 × 104 14.7 2.97 × 105
Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft)
L = 40.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
40.0 0.124 1400
50.0 0.155 1750
60.0 0.185 2110
70.0 0.216 2460
80.0 0.247 2810
90.0 0.278 3160
100 0.309 3510
200 0.618 7020
300 0.927 1.05 × 104
400 1.24 1.40 × 104
500 1.55 1.75 × 104
600 1.85 2.11 × 104
700 2.16 2.46 × 104
800 2.47 2.81 × 104
900 2.78 3.16 × 104
1000 3.09 3.51 × 104
2000 6.18 7.02 × 104
3000 9.27 1.05 × 105
4000 12.4 1.40 × 105
5000 15.5 1.75 × 105
5790 17.9 2.03 × 105
Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft)
L = 50.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
40.0 0.302 2190
50.0 0.377 2740
60.0 0.453 3290
70.0 0.528 3840
80.0 0.604 4390
90.0 0.679 4940
100 0.754 5480
200 1.51 1.10 × 104
300 2.26 1.65 × 104
400 3.02 2.19 × 104
500 3.77 2.74 × 104
600 4.53 3.29 × 104
700 5.28 3.84 × 104
800 6.04 4.39 × 104
900 6.79 4.94 × 104
1000 7.54 5.48 × 104
2000 15.1 1.10 × 105
2370 17.9 1.30 × 105
Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft)
L = 60.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
40.0 0.626 3160
50.0 0.782 3950
60.0 0.939 4740
70.0 1.10 5530
80.0 1.25 6320
90.0 1.41 7110
100 1.56 7900
200 3.13 1.58 × 104
300 4.69 2.37 × 104
400 6.26 3.16 × 104
500 7.82 3.95 × 104
600 9.39 4.74 × 104
700 11.0 5.53 × 104
800 12.5 6.32 × 104
900 14.1 7.11 × 104
1000 15.6 7.90 × 104
1140 17.9 9.04 × 104
Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft)
L = 70.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
40.0 1.16 4300
50.0 1.45 5370
60.0 1.74 6450
70.0 2.03 7520
80.0 2.32 8600
90.0 2.61 9670
100 2.90 1.07 × 104
200 5.80 2.15 × 104
300 8.69 3.22 × 104
400 11.6 4.30 × 104
500 14.5 5.37 × 104
600 17.4 6.45 × 104
618 17.9 6.64 × 104
Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft)
L = 80.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
40.0 1.98 5620
50.0 2.47 7020
60.0 2.97 8420
70.0 3.46 9830
80.0 3.96 1.12 × 104
90.0 4.45 1.26 × 104
100 4.94 1.40 × 104
200 9.89 2.81 × 104
300 14.8 4.21 × 104
362 17.9 5.08 × 104
Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft)
L = 90.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
40.0 3.17 7110
50.0 3.96 8880
60.0 4.75 1.07 × 104
70.0 5.54 1.24 × 104
80.0 6.34 1.42 × 104
90.0 7.13 1.60 × 104
100 7.92 1.78 × 104
200 15.8 3.55 × 104
226 17.9 4.02 × 104
Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft)
L = 100 ft
P (lbf/ft) w_max (in) stress_max (psi)
40.0 4.83 8770
50.0 6.04 1.10 × 104
60.0 7.24 1.32 × 104
70.0 8.45 1.54 × 104
80.0 9.66 1.75 × 104
90.0 10.9 1.97 × 104
100 12.1 2.19 × 104
148 17.9 3.25 × 104
Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft)
L = 125 ft
P (lbf/ft) w_max (in) stress_max (psi)
40.0 11.8 1.37 × 104
50.0 14.7 1.71 × 104
60.0 17.7 2.06 × 104
60.7 17.9 2.08 × 104
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