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Glossary » Beams » Simply Supported » Uniformly Distributed Load » Four Equal Spans » Wide Flange Steel I Beam » W8 × 13
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 = 39.6 in4) for the W8 × 13 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
   
Steel I Beam: W8 × 13 (Wide Flange 8 inch tall × 13 lbf/ft)
L = 3.00 ft
P (lbf/ft) w_max (in) stress_max (psi)
13.0 9.50 × 10-6 15.2
20.0 1.46 × 10-5 23.3
30.0 2.19 × 10-5 35.0
40.0 2.92 × 10-5 46.7
50.0 3.66 × 10-5 58.3
60.0 4.39 × 10-5 70.0
70.0 5.12 × 10-5 81.7
80.0 5.85 × 10-5 93.4
90.0 6.58 × 10-5 105
100 7.31 × 10-5 117
200 1.46 × 10-4 233
300 2.19 × 10-4 350
400 2.92 × 10-4 467
500 3.66 × 10-4 583
600 4.39 × 10-4 700
700 5.12 × 10-4 817
800 5.85 × 10-4 934
900 6.58 × 10-4 1050
1000 7.31 × 10-4 1170
2000 0.00146 2330
3000 0.00219 3500
4000 0.00292 4670
5000 0.00366 5830
6000 0.00439 7000
7000 0.00512 8170
8000 0.00585 9340
9000 0.00658 1.05 × 104
1.00 × 104 0.00731 1.17 × 104
2.00 × 104 0.0146 2.33 × 104
3.00 × 104 0.0219 3.50 × 104
4.00 × 104 0.0292 4.67 × 104
5.00 × 104 0.0366 5.83 × 104
6.00 × 104 0.0439 7.00 × 104
7.00 × 104 0.0512 8.17 × 104
8.00 × 104 0.0585 9.34 × 104
9.00 × 104 0.0658 1.05 × 105
1.00 × 105 0.0731 1.17 × 105
2.00 × 105 0.146 2.33 × 105
2.55 × 105 0.186 2.97 × 105
Steel I Beam: W8 × 13 (Wide Flange 8 inch tall × 13 lbf/ft)
L = 5.00 ft
P (lbf/ft) w_max (in) stress_max (psi)
13.0 7.33 × 10-5 42.1
20.0 1.13 × 10-4 64.8
30.0 1.69 × 10-4 97.2
40.0 2.26 × 10-4 130
50.0 2.82 × 10-4 162
60.0 3.38 × 10-4 194
70.0 3.95 × 10-4 227
80.0 4.51 × 10-4 259
90.0 5.08 × 10-4 292
100 5.64 × 10-4 324
200 0.00113 648
300 0.00169 972
400 0.00226 1300
500 0.00282 1620
600 0.00338 1940
700 0.00395 2270
800 0.00451 2590
900 0.00508 2920
1000 0.00564 3240
2000 0.0113 6480
3000 0.0169 9720
4000 0.0226 1.30 × 104
5000 0.0282 1.62 × 104
6000 0.0338 1.94 × 104
7000 0.0395 2.27 × 104
8000 0.0451 2.59 × 104
9000 0.0508 2.92 × 104
1.00 × 104 0.0564 3.24 × 104
2.00 × 104 0.113 6.48 × 104
3.00 × 104 0.169 9.72 × 104
4.00 × 104 0.226 1.30 × 105
5.00 × 104 0.282 1.62 × 105
6.00 × 104 0.338 1.94 × 105
7.00 × 104 0.395 2.27 × 105
8.00 × 104 0.451 2.59 × 105
9.00 × 104 0.508 2.92 × 105
9.16 × 104 0.517 2.97 × 105
Steel I Beam: W8 × 13 (Wide Flange 8 inch tall × 13 lbf/ft)
L = 10.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
13.0 0.00117 169
20.0 0.00181 259
30.0 0.00271 389
40.0 0.00361 519
50.0 0.00451 648
60.0 0.00542 778
70.0 0.00632 908
80.0 0.00722 1040
90.0 0.00812 1170
100 0.00903 1300
200 0.0181 2590
300 0.0271 3890
400 0.0361 5190
500 0.0451 6480
600 0.0542 7780
700 0.0632 9080
800 0.0722 1.04 × 104
900 0.0812 1.17 × 104
1000 0.0903 1.30 × 104
2000 0.181 2.59 × 104
3000 0.271 3.89 × 104
4000 0.361 5.19 × 104
5000 0.451 6.48 × 104
6000 0.542 7.78 × 104
7000 0.632 9.08 × 104
8000 0.722 1.04 × 105
9000 0.812 1.17 × 105
1.00 × 104 0.903 1.30 × 105
2.00 × 104 1.81 2.59 × 105
2.29 × 104 2.07 2.97 × 105
Steel I Beam: W8 × 13 (Wide Flange 8 inch tall × 13 lbf/ft)
L = 15.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
13.0 0.00594 379
20.0 0.00914 583
30.0 0.0137 875
40.0 0.0183 1170
50.0 0.0228 1460
60.0 0.0274 1750
70.0 0.0320 2040
80.0 0.0366 2330
90.0 0.0411 2630
100 0.0457 2920
200 0.0914 5830
300 0.137 8750
400 0.183 1.17 × 104
500 0.228 1.46 × 104
600 0.274 1.75 × 104
700 0.320 2.04 × 104
800 0.366 2.33 × 104
900 0.411 2.63 × 104
1000 0.457 2.92 × 104
2000 0.914 5.83 × 104
3000 1.37 8.75 × 104
4000 1.83 1.17 × 105
5000 2.28 1.46 × 105
6000 2.74 1.75 × 105
7000 3.20 2.04 × 105
8000 3.66 2.33 × 105
9000 4.11 2.63 × 105
1.00 × 104 4.57 2.92 × 105
1.02 × 104 4.65 2.97 × 105
Steel I Beam: W8 × 13 (Wide Flange 8 inch tall × 13 lbf/ft)
L = 20.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
13.0 0.0188 674
20.0 0.0289 1040
30.0 0.0433 1560
40.0 0.0578 2070
50.0 0.0722 2590
60.0 0.0866 3110
70.0 0.101 3630
80.0 0.116 4150
90.0 0.130 4670
100 0.144 5190
200 0.289 1.04 × 104
300 0.433 1.56 × 104
400 0.578 2.07 × 104
500 0.722 2.59 × 104
600 0.866 3.11 × 104
700 1.01 3.63 × 104
800 1.16 4.15 × 104
900 1.30 4.67 × 104
1000 1.44 5.19 × 104
2000 2.89 1.04 × 105
3000 4.33 1.56 × 105
4000 5.78 2.07 × 105
5000 7.22 2.59 × 105
5730 8.27 2.97 × 105
Steel I Beam: W8 × 13 (Wide Flange 8 inch tall × 13 lbf/ft)
L = 25.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
13.0 0.0458 1050
20.0 0.0705 1620
30.0 0.106 2430
40.0 0.141 3240
50.0 0.176 4050
60.0 0.212 4860
70.0 0.247 5670
80.0 0.282 6480
90.0 0.317 7290
100 0.353 8100
200 0.705 1.62 × 104
300 1.06 2.43 × 104
400 1.41 3.24 × 104
500 1.76 4.05 × 104
600 2.12 4.86 × 104
700 2.47 5.67 × 104
800 2.82 6.48 × 104
900 3.17 7.29 × 104
1000 3.53 8.10 × 104
2000 7.05 1.62 × 105
2270 7.99 1.84 × 105
Steel I Beam: W8 × 13 (Wide Flange 8 inch tall × 13 lbf/ft)
L = 30.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
13.0 0.0950 1520
20.0 0.146 2330
30.0 0.219 3500
40.0 0.292 4670
50.0 0.366 5830
60.0 0.439 7000
70.0 0.512 8170
80.0 0.585 9340
90.0 0.658 1.05 × 104
100 0.731 1.17 × 104
200 1.46 2.33 × 104
300 2.19 3.50 × 104
400 2.92 4.67 × 104
500 3.66 5.83 × 104
600 4.39 7.00 × 104
700 5.12 8.17 × 104
800 5.85 9.34 × 104
900 6.58 1.05 × 105
1000 7.31 1.17 × 105
1090 7.99 1.28 × 105
Steel I Beam: W8 × 13 (Wide Flange 8 inch tall × 13 lbf/ft)
L = 40.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
13.0 0.300 2700
20.0 0.462 4150
30.0 0.693 6220
40.0 0.924 8300
50.0 1.16 1.04 × 104
60.0 1.39 1.24 × 104
70.0 1.62 1.45 × 104
80.0 1.85 1.66 × 104
90.0 2.08 1.87 × 104
100 2.31 2.07 × 104
200 4.62 4.15 × 104
300 6.93 6.22 × 104
346 7.99 7.17 × 104
Steel I Beam: W8 × 13 (Wide Flange 8 inch tall × 13 lbf/ft)
L = 50.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
13.0 0.733 4210
20.0 1.13 6480
30.0 1.69 9720
40.0 2.26 1.30 × 104
50.0 2.82 1.62 × 104
60.0 3.38 1.94 × 104
70.0 3.95 2.27 × 104
80.0 4.51 2.59 × 104
90.0 5.08 2.92 × 104
100 5.64 3.24 × 104
142 7.99 4.59 × 104
Steel I Beam: W8 × 13 (Wide Flange 8 inch tall × 13 lbf/ft)
L = 60.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
13.0 1.52 6070
20.0 2.34 9340
30.0 3.51 1.40 × 104
40.0 4.68 1.87 × 104
50.0 5.85 2.33 × 104
60.0 7.02 2.80 × 104
68.3 7.99 3.19 × 104
Steel I Beam: W8 × 13 (Wide Flange 8 inch tall × 13 lbf/ft)
L = 70.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
13.0 2.82 8260
20.0 4.33 1.27 × 104
30.0 6.50 1.91 × 104
36.9 7.99 2.34 × 104
Steel I Beam: W8 × 13 (Wide Flange 8 inch tall × 13 lbf/ft)
L = 80.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
13.0 4.81 1.08 × 104
20.0 7.39 1.66 × 104
21.6 7.99 1.79 × 104
Steel I Beam: W8 × 13 (Wide Flange 8 inch tall × 13 lbf/ft)
L = 90.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
13.0 7.70 1.37 × 104
13.5 7.99 1.42 × 104
Additional Information
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Optimize your designs, reduce machining time, and lower your costs.

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Wages, employment opportunities, and growth projections for STEM jobs.

Essentials of Manufacturing

Information, coverage of important developments and expert commentary in manufacturing.

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Direct Metal Laser Sintering (DMLS) 3D printing for parts with reduced cost and little waste.

more publications