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Glossary » Beams » Simply Supported » Uniformly Distributed Load » Four Equal Spans » Wide Flange Steel I Beam » W18 × 35
Wide Flange Steel I Beam | Single Span | Two Equal Spans | Three Equal Spans | Four Equal Spans

For a simply supported beam in four equal spans, we compute the displacement at the middle of the first and fourth spans, and the maximum normal stress stress_max occuring at the second and fourth supports of the beam.
The tabulated data listed in this page are calculated based on the area moment of inertia (Ixx = 510 in4) for the W18 × 35 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
L = 150 ft
  
Steel I Beam: W18 × 35 (Wide Flange 18 inch tall × 35 lbf/ft)
L = 3.00 ft
P (lbf/ft) w_max (in) stress_max (psi)
35.0 1.99 × 10-6 7.03
40.0 2.27 × 10-6 8.03
50.0 2.84 × 10-6 10.0
60.0 3.41 × 10-6 12.0
70.0 3.97 × 10-6 14.1
80.0 4.54 × 10-6 16.1
90.0 5.11 × 10-6 18.1
100 5.68 × 10-6 20.1
200 1.14 × 10-5 40.1
300 1.70 × 10-5 60.2
400 2.27 × 10-5 80.3
500 2.84 × 10-5 100
600 3.41 × 10-5 120
700 3.97 × 10-5 141
800 4.54 × 10-5 161
900 5.11 × 10-5 181
1000 5.68 × 10-5 201
2000 1.14 × 10-4 401
3000 1.70 × 10-4 602
4000 2.27 × 10-4 803
5000 2.84 × 10-4 1000
6000 3.41 × 10-4 1200
7000 3.97 × 10-4 1410
8000 4.54 × 10-4 1610
9000 5.11 × 10-4 1810
1.00 × 104 5.68 × 10-4 2010
2.00 × 104 0.00114 4010
3.00 × 104 0.00170 6020
4.00 × 104 0.00227 8030
5.00 × 104 0.00284 1.00 × 104
6.00 × 104 0.00341 1.20 × 104
7.00 × 104 0.00397 1.41 × 104
8.00 × 104 0.00454 1.61 × 104
9.00 × 104 0.00511 1.81 × 104
1.00 × 105 0.00568 2.01 × 104
2.00 × 105 0.0114 4.01 × 104
3.00 × 105 0.0170 6.02 × 104
4.00 × 105 0.0227 8.03 × 104
5.00 × 105 0.0284 1.00 × 105
6.00 × 105 0.0341 1.20 × 105
7.00 × 105 0.0397 1.41 × 105
8.00 × 105 0.0454 1.61 × 105
9.00 × 105 0.0511 1.81 × 105
1.00 × 106 0.0568 2.01 × 105
1.48 × 106 0.0840 2.97 × 105
Steel I Beam: W18 × 35 (Wide Flange 18 inch tall × 35 lbf/ft)
L = 5.00 ft
P (lbf/ft) w_max (in) stress_max (psi)
35.0 1.53 × 10-5 19.5
40.0 1.75 × 10-5 22.3
50.0 2.19 × 10-5 27.9
60.0 2.63 × 10-5 33.5
70.0 3.07 × 10-5 39.0
80.0 3.50 × 10-5 44.6
90.0 3.94 × 10-5 50.2
100 4.38 × 10-5 55.8
200 8.76 × 10-5 112
300 1.31 × 10-4 167
400 1.75 × 10-4 223
500 2.19 × 10-4 279
600 2.63 × 10-4 335
700 3.07 × 10-4 390
800 3.50 × 10-4 446
900 3.94 × 10-4 502
1000 4.38 × 10-4 558
2000 8.76 × 10-4 1120
3000 0.00131 1670
4000 0.00175 2230
5000 0.00219 2790
6000 0.00263 3350
7000 0.00307 3900
8000 0.00350 4460
9000 0.00394 5020
1.00 × 104 0.00438 5580
2.00 × 104 0.00876 1.12 × 104
3.00 × 104 0.0131 1.67 × 104
4.00 × 104 0.0175 2.23 × 104
5.00 × 104 0.0219 2.79 × 104
6.00 × 104 0.0263 3.35 × 104
7.00 × 104 0.0307 3.90 × 104
8.00 × 104 0.0350 4.46 × 104
9.00 × 104 0.0394 5.02 × 104
1.00 × 105 0.0438 5.58 × 104
2.00 × 105 0.0876 1.12 × 105
3.00 × 105 0.131 1.67 × 105
4.00 × 105 0.175 2.23 × 105
5.00 × 105 0.219 2.79 × 105
5.33 × 105 0.233 2.97 × 105
Steel I Beam: W18 × 35 (Wide Flange 18 inch tall × 35 lbf/ft)
L = 10.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
35.0 2.45 × 10-4 78.1
40.0 2.80 × 10-4 89.2
50.0 3.50 × 10-4 112
60.0 4.20 × 10-4 134
70.0 4.91 × 10-4 156
80.0 5.61 × 10-4 178
90.0 6.31 × 10-4 201
100 7.01 × 10-4 223
200 0.00140 446
300 0.00210 669
400 0.00280 892
500 0.00350 1120
600 0.00420 1340
700 0.00491 1560
800 0.00561 1780
900 0.00631 2010
1000 0.00701 2230
2000 0.0140 4460
3000 0.0210 6690
4000 0.0280 8920
5000 0.0350 1.12 × 104
6000 0.0420 1.34 × 104
7000 0.0491 1.56 × 104
8000 0.0561 1.78 × 104
9000 0.0631 2.01 × 104
1.00 × 104 0.0701 2.23 × 104
2.00 × 104 0.140 4.46 × 104
3.00 × 104 0.210 6.69 × 104
4.00 × 104 0.280 8.92 × 104
5.00 × 104 0.350 1.12 × 105
6.00 × 104 0.420 1.34 × 105
7.00 × 104 0.491 1.56 × 105
8.00 × 104 0.561 1.78 × 105
9.00 × 104 0.631 2.01 × 105
1.00 × 105 0.701 2.23 × 105
1.33 × 105 0.933 2.97 × 105
Steel I Beam: W18 × 35 (Wide Flange 18 inch tall × 35 lbf/ft)
L = 15.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
35.0 0.00124 176
40.0 0.00142 201
50.0 0.00177 251
60.0 0.00213 301
70.0 0.00248 351
80.0 0.00284 401
90.0 0.00319 452
100 0.00355 502
200 0.00710 1000
300 0.0106 1510
400 0.0142 2010
500 0.0177 2510
600 0.0213 3010
700 0.0248 3510
800 0.0284 4010
900 0.0319 4520
1000 0.0355 5020
2000 0.0710 1.00 × 104
3000 0.106 1.51 × 104
4000 0.142 2.01 × 104
5000 0.177 2.51 × 104
6000 0.213 3.01 × 104
7000 0.248 3.51 × 104
8000 0.284 4.01 × 104
9000 0.319 4.52 × 104
1.00 × 104 0.355 5.02 × 104
2.00 × 104 0.710 1.00 × 105
3.00 × 104 1.06 1.51 × 105
4.00 × 104 1.42 2.01 × 105
5.00 × 104 1.77 2.51 × 105
5.92 × 104 2.10 2.97 × 105
Steel I Beam: W18 × 35 (Wide Flange 18 inch tall × 35 lbf/ft)
L = 20.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
35.0 0.00392 312
40.0 0.00449 357
50.0 0.00561 446
60.0 0.00673 535
70.0 0.00785 624
80.0 0.00897 714
90.0 0.0101 803
100 0.0112 892
200 0.0224 1780
300 0.0336 2680
400 0.0449 3570
500 0.0561 4460
600 0.0673 5350
700 0.0785 6240
800 0.0897 7140
900 0.101 8030
1000 0.112 8920
2000 0.224 1.78 × 104
3000 0.336 2.68 × 104
4000 0.449 3.57 × 104
5000 0.561 4.46 × 104
6000 0.673 5.35 × 104
7000 0.785 6.24 × 104
8000 0.897 7.14 × 104
9000 1.01 8.03 × 104
1.00 × 104 1.12 8.92 × 104
2.00 × 104 2.24 1.78 × 105
3.00 × 104 3.36 2.68 × 105
3.33 × 104 3.73 2.97 × 105
Steel I Beam: W18 × 35 (Wide Flange 18 inch tall × 35 lbf/ft)
L = 25.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
35.0 0.00958 488
40.0 0.0110 558
50.0 0.0137 697
60.0 0.0164 836
70.0 0.0192 976
80.0 0.0219 1120
90.0 0.0246 1250
100 0.0274 1390
200 0.0548 2790
300 0.0821 4180
400 0.110 5580
500 0.137 6970
600 0.164 8360
700 0.192 9760
800 0.219 1.12 × 104
900 0.246 1.25 × 104
1000 0.274 1.39 × 104
2000 0.548 2.79 × 104
3000 0.821 4.18 × 104
4000 1.10 5.58 × 104
5000 1.37 6.97 × 104
6000 1.64 8.36 × 104
7000 1.92 9.76 × 104
8000 2.19 1.12 × 105
9000 2.46 1.25 × 105
1.00 × 104 2.74 1.39 × 105
2.00 × 104 5.48 2.79 × 105
2.13 × 104 5.83 2.97 × 105
Steel I Beam: W18 × 35 (Wide Flange 18 inch tall × 35 lbf/ft)
L = 30.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
35.0 0.0199 703
40.0 0.0227 803
50.0 0.0284 1000
60.0 0.0341 1200
70.0 0.0397 1410
80.0 0.0454 1610
90.0 0.0511 1810
100 0.0568 2010
200 0.114 4010
300 0.170 6020
400 0.227 8030
500 0.284 1.00 × 104
600 0.341 1.20 × 104
700 0.397 1.41 × 104
800 0.454 1.61 × 104
900 0.511 1.81 × 104
1000 0.568 2.01 × 104
2000 1.14 4.01 × 104
3000 1.70 6.02 × 104
4000 2.27 8.03 × 104
5000 2.84 1.00 × 105
6000 3.41 1.20 × 105
7000 3.97 1.41 × 105
8000 4.54 1.61 × 105
9000 5.11 1.81 × 105
1.00 × 104 5.68 2.01 × 105
1.48 × 104 8.40 2.97 × 105
Steel I Beam: W18 × 35 (Wide Flange 18 inch tall × 35 lbf/ft)
L = 40.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
35.0 0.0628 1250
40.0 0.0718 1430
50.0 0.0897 1780
60.0 0.108 2140
70.0 0.126 2500
80.0 0.144 2850
90.0 0.161 3210
100 0.179 3570
200 0.359 7140
300 0.538 1.07 × 104
400 0.718 1.43 × 104
500 0.897 1.78 × 104
600 1.08 2.14 × 104
700 1.26 2.50 × 104
800 1.44 2.85 × 104
900 1.61 3.21 × 104
1000 1.79 3.57 × 104
2000 3.59 7.14 × 104
3000 5.38 1.07 × 105
4000 7.18 1.43 × 105
5000 8.97 1.78 × 105
6000 10.8 2.14 × 105
7000 12.6 2.50 × 105
8000 14.4 2.85 × 105
8320 14.9 2.97 × 105
Steel I Beam: W18 × 35 (Wide Flange 18 inch tall × 35 lbf/ft)
L = 50.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
35.0 0.153 1950
40.0 0.175 2230
50.0 0.219 2790
60.0 0.263 3350
70.0 0.307 3900
80.0 0.350 4460
90.0 0.394 5020
100 0.438 5580
200 0.876 1.12 × 104
300 1.31 1.67 × 104
400 1.75 2.23 × 104
500 2.19 2.79 × 104
600 2.63 3.35 × 104
700 3.07 3.90 × 104
800 3.50 4.46 × 104
900 3.94 5.02 × 104
1000 4.38 5.58 × 104
2000 8.76 1.12 × 105
3000 13.1 1.67 × 105
4000 17.5 2.23 × 105
4040 17.7 2.25 × 105
Steel I Beam: W18 × 35 (Wide Flange 18 inch tall × 35 lbf/ft)
L = 60.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
35.0 0.318 2810
40.0 0.363 3210
50.0 0.454 4010
60.0 0.545 4820
70.0 0.636 5620
80.0 0.727 6420
90.0 0.817 7230
100 0.908 8030
200 1.82 1.61 × 104
300 2.72 2.41 × 104
400 3.63 3.21 × 104
500 4.54 4.01 × 104
600 5.45 4.82 × 104
700 6.36 5.62 × 104
800 7.27 6.42 × 104
900 8.17 7.23 × 104
1000 9.08 8.03 × 104
1950 17.7 1.56 × 105
Steel I Beam: W18 × 35 (Wide Flange 18 inch tall × 35 lbf/ft)
L = 70.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
35.0 0.589 3820
40.0 0.673 4370
50.0 0.841 5460
60.0 1.01 6560
70.0 1.18 7650
80.0 1.35 8740
90.0 1.51 9840
100 1.68 1.09 × 104
200 3.37 2.19 × 104
300 5.05 3.28 × 104
400 6.73 4.37 × 104
500 8.41 5.46 × 104
600 10.1 6.56 × 104
700 11.8 7.65 × 104
800 13.5 8.74 × 104
900 15.1 9.84 × 104
1000 16.8 1.09 × 105
1050 17.7 1.15 × 105
Steel I Beam: W18 × 35 (Wide Flange 18 inch tall × 35 lbf/ft)
L = 80.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
35.0 1.00 5000
40.0 1.15 5710
50.0 1.44 7140
60.0 1.72 8560
70.0 2.01 9990
80.0 2.30 1.14 × 104
90.0 2.58 1.28 × 104
100 2.87 1.43 × 104
200 5.74 2.85 × 104
300 8.61 4.28 × 104
400 11.5 5.71 × 104
500 14.4 7.14 × 104
600 17.2 8.56 × 104
617 17.7 8.80 × 104
Steel I Beam: W18 × 35 (Wide Flange 18 inch tall × 35 lbf/ft)
L = 90.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
35.0 1.61 6320
40.0 1.84 7230
50.0 2.30 9030
60.0 2.76 1.08 × 104
70.0 3.22 1.26 × 104
80.0 3.68 1.45 × 104
90.0 4.14 1.63 × 104
100 4.60 1.81 × 104
200 9.20 3.61 × 104
300 13.8 5.42 × 104
385 17.7 6.95 × 104
Steel I Beam: W18 × 35 (Wide Flange 18 inch tall × 35 lbf/ft)
L = 100 ft
P (lbf/ft) w_max (in) stress_max (psi)
35.0 2.45 7810
40.0 2.80 8920
50.0 3.50 1.12 × 104
60.0 4.20 1.34 × 104
70.0 4.91 1.56 × 104
80.0 5.61 1.78 × 104
90.0 6.31 2.01 × 104
100 7.01 2.23 × 104
200 14.0 4.46 × 104
253 17.7 5.63 × 104
Steel I Beam: W18 × 35 (Wide Flange 18 inch tall × 35 lbf/ft)
L = 125 ft
P (lbf/ft) w_max (in) stress_max (psi)
35.0 5.99 1.22 × 104
40.0 6.84 1.39 × 104
50.0 8.56 1.74 × 104
60.0 10.3 2.09 × 104
70.0 12.0 2.44 × 104
80.0 13.7 2.79 × 104
90.0 15.4 3.14 × 104
100 17.1 3.48 × 104
103 17.7 3.60 × 104
Steel I Beam: W18 × 35 (Wide Flange 18 inch tall × 35 lbf/ft)
L = 150 ft
P (lbf/ft) w_max (in) stress_max (psi)
35.0 12.4 1.76 × 104
40.0 14.2 2.01 × 104
49.9 17.7 2.50 × 104
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