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Glossary » Beams » Simply Supported » Uniformly Distributed Load » Three Equal Spans » S Section Steel I Beam » S20 × 66
S Section Steel I Beam | Single Span | Two Equal Spans | Three Equal Spans | Four Equal Spans

For a simply supported beam in three equal spans, we compute the displacement at the middle of the first and the third spans, and the maximum normal stress stress_max occuring at the second and third supports of the beam.
The tabulated data listed in this page are calculated based on the area moment of inertia (Ixx = 1190 in4) for the S20 × 66 S Section 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: S20 × 66 (S20 inch tall × 66 lbf/ft)
L = 3.00 ft
P (lbf/ft) w_max (in) stress_max (psi)
66.0 1.73 × 10-6 5.99
70.0 1.84 × 10-6 6.35
80.0 2.10 × 10-6 7.26
90.0 2.36 × 10-6 8.17
100 2.63 × 10-6 9.08
200 5.25 × 10-6 18.2
300 7.88 × 10-6 27.2
400 1.05 × 10-5 36.3
500 1.31 × 10-5 45.4
600 1.58 × 10-5 54.5
700 1.84 × 10-5 63.5
800 2.10 × 10-5 72.6
900 2.36 × 10-5 81.7
1000 2.63 × 10-5 90.8
2000 5.25 × 10-5 182
3000 7.88 × 10-5 272
4000 1.05 × 10-4 363
5000 1.31 × 10-4 454
6000 1.58 × 10-4 545
7000 1.84 × 10-4 635
8000 2.10 × 10-4 726
9000 2.36 × 10-4 817
1.00 × 104 2.63 × 10-4 908
2.00 × 104 5.25 × 10-4 1820
3.00 × 104 7.88 × 10-4 2720
4.00 × 104 0.00105 3630
5.00 × 104 0.00131 4540
6.00 × 104 0.00158 5450
7.00 × 104 0.00184 6350
8.00 × 104 0.00210 7260
9.00 × 104 0.00236 8170
1.00 × 105 0.00263 9080
2.00 × 105 0.00525 1.82 × 104
3.00 × 105 0.00788 2.72 × 104
4.00 × 105 0.0105 3.63 × 104
5.00 × 105 0.0131 4.54 × 104
6.00 × 105 0.0158 5.45 × 104
7.00 × 105 0.0184 6.35 × 104
8.00 × 105 0.0210 7.26 × 104
9.00 × 105 0.0236 8.17 × 104
1.00 × 106 0.0263 9.08 × 104
2.00 × 106 0.0525 1.82 × 105
3.00 × 106 0.0788 2.72 × 105
3.27 × 106 0.0859 2.97 × 105
Steel I Beam: S20 × 66 (S20 inch tall × 66 lbf/ft)
L = 5.00 ft
P (lbf/ft) w_max (in) stress_max (psi)
66.0 1.34 × 10-5 16.6
70.0 1.42 × 10-5 17.6
80.0 1.62 × 10-5 20.2
90.0 1.82 × 10-5 22.7
100 2.03 × 10-5 25.2
200 4.05 × 10-5 50.4
300 6.08 × 10-5 75.6
400 8.10 × 10-5 101
500 1.01 × 10-4 126
600 1.22 × 10-4 151
700 1.42 × 10-4 176
800 1.62 × 10-4 202
900 1.82 × 10-4 227
1000 2.03 × 10-4 252
2000 4.05 × 10-4 504
3000 6.08 × 10-4 756
4000 8.10 × 10-4 1010
5000 0.00101 1260
6000 0.00122 1510
7000 0.00142 1760
8000 0.00162 2020
9000 0.00182 2270
1.00 × 104 0.00203 2520
2.00 × 104 0.00405 5040
3.00 × 104 0.00608 7560
4.00 × 104 0.00810 1.01 × 104
5.00 × 104 0.0101 1.26 × 104
6.00 × 104 0.0122 1.51 × 104
7.00 × 104 0.0142 1.76 × 104
8.00 × 104 0.0162 2.02 × 104
9.00 × 104 0.0182 2.27 × 104
1.00 × 105 0.0203 2.52 × 104
2.00 × 105 0.0405 5.04 × 104
3.00 × 105 0.0608 7.56 × 104
4.00 × 105 0.0810 1.01 × 105
5.00 × 105 0.101 1.26 × 105
6.00 × 105 0.122 1.51 × 105
7.00 × 105 0.142 1.76 × 105
8.00 × 105 0.162 2.02 × 105
9.00 × 105 0.182 2.27 × 105
1.00 × 106 0.203 2.52 × 105
1.18 × 106 0.239 2.97 × 105
Steel I Beam: S20 × 66 (S20 inch tall × 66 lbf/ft)
L = 10.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
66.0 2.14 × 10-4 66.6
70.0 2.27 × 10-4 70.6
80.0 2.59 × 10-4 80.7
90.0 2.92 × 10-4 90.8
100 3.24 × 10-4 101
200 6.48 × 10-4 202
300 9.73 × 10-4 303
400 0.00130 403
500 0.00162 504
600 0.00195 605
700 0.00227 706
800 0.00259 807
900 0.00292 908
1000 0.00324 1010
2000 0.00648 2020
3000 0.00973 3030
4000 0.0130 4030
5000 0.0162 5040
6000 0.0195 6050
7000 0.0227 7060
8000 0.0259 8070
9000 0.0292 9080
1.00 × 104 0.0324 1.01 × 104
2.00 × 104 0.0648 2.02 × 104
3.00 × 104 0.0973 3.03 × 104
4.00 × 104 0.130 4.03 × 104
5.00 × 104 0.162 5.04 × 104
6.00 × 104 0.195 6.05 × 104
7.00 × 104 0.227 7.06 × 104
8.00 × 104 0.259 8.07 × 104
9.00 × 104 0.292 9.08 × 104
1.00 × 105 0.324 1.01 × 105
2.00 × 105 0.648 2.02 × 105
2.95 × 105 0.955 2.97 × 105
Steel I Beam: S20 × 66 (S20 inch tall × 66 lbf/ft)
L = 15.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
66.0 0.00108 150
70.0 0.00115 159
80.0 0.00131 182
90.0 0.00148 204
100 0.00164 227
200 0.00328 454
300 0.00492 681
400 0.00656 908
500 0.00821 1130
600 0.00985 1360
700 0.0115 1590
800 0.0131 1820
900 0.0148 2040
1000 0.0164 2270
2000 0.0328 4540
3000 0.0492 6810
4000 0.0656 9080
5000 0.0821 1.13 × 104
6000 0.0985 1.36 × 104
7000 0.115 1.59 × 104
8000 0.131 1.82 × 104
9000 0.148 2.04 × 104
1.00 × 104 0.164 2.27 × 104
2.00 × 104 0.328 4.54 × 104
3.00 × 104 0.492 6.81 × 104
4.00 × 104 0.656 9.08 × 104
5.00 × 104 0.821 1.13 × 105
6.00 × 104 0.985 1.36 × 105
7.00 × 104 1.15 1.59 × 105
8.00 × 104 1.31 1.82 × 105
9.00 × 104 1.48 2.04 × 105
1.00 × 105 1.64 2.27 × 105
1.31 × 105 2.15 2.97 × 105
Steel I Beam: S20 × 66 (S20 inch tall × 66 lbf/ft)
L = 20.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
66.0 0.00342 266
70.0 0.00363 282
80.0 0.00415 323
90.0 0.00467 363
100 0.00519 403
200 0.0104 807
300 0.0156 1210
400 0.0207 1610
500 0.0259 2020
600 0.0311 2420
700 0.0363 2820
800 0.0415 3230
900 0.0467 3630
1000 0.0519 4030
2000 0.104 8070
3000 0.156 1.21 × 104
4000 0.207 1.61 × 104
5000 0.259 2.02 × 104
6000 0.311 2.42 × 104
7000 0.363 2.82 × 104
8000 0.415 3.23 × 104
9000 0.467 3.63 × 104
1.00 × 104 0.519 4.03 × 104
2.00 × 104 1.04 8.07 × 104
3.00 × 104 1.56 1.21 × 105
4.00 × 104 2.07 1.61 × 105
5.00 × 104 2.59 2.02 × 105
6.00 × 104 3.11 2.42 × 105
7.00 × 104 3.63 2.82 × 105
7.36 × 104 3.82 2.97 × 105
Steel I Beam: S20 × 66 (S20 inch tall × 66 lbf/ft)
L = 25.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
66.0 0.00836 416
70.0 0.00886 441
80.0 0.0101 504
90.0 0.0114 567
100 0.0127 630
200 0.0253 1260
300 0.0380 1890
400 0.0507 2520
500 0.0633 3150
600 0.0760 3780
700 0.0886 4410
800 0.101 5040
900 0.114 5670
1000 0.127 6300
2000 0.253 1.26 × 104
3000 0.380 1.89 × 104
4000 0.507 2.52 × 104
5000 0.633 3.15 × 104
6000 0.760 3.78 × 104
7000 0.886 4.41 × 104
8000 1.01 5.04 × 104
9000 1.14 5.67 × 104
1.00 × 104 1.27 6.30 × 104
2.00 × 104 2.53 1.26 × 105
3.00 × 104 3.80 1.89 × 105
4.00 × 104 5.07 2.52 × 105
4.71 × 104 5.97 2.97 × 105
Steel I Beam: S20 × 66 (S20 inch tall × 66 lbf/ft)
L = 30.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
66.0 0.0173 599
70.0 0.0184 635
80.0 0.0210 726
90.0 0.0236 817
100 0.0263 908
200 0.0525 1820
300 0.0788 2720
400 0.105 3630
500 0.131 4540
600 0.158 5450
700 0.184 6350
800 0.210 7260
900 0.236 8170
1000 0.263 9080
2000 0.525 1.82 × 104
3000 0.788 2.72 × 104
4000 1.05 3.63 × 104
5000 1.31 4.54 × 104
6000 1.58 5.45 × 104
7000 1.84 6.35 × 104
8000 2.10 7.26 × 104
9000 2.36 8.17 × 104
1.00 × 104 2.63 9.08 × 104
2.00 × 104 5.25 1.82 × 105
3.00 × 104 7.88 2.72 × 105
3.27 × 104 8.59 2.97 × 105
Steel I Beam: S20 × 66 (S20 inch tall × 66 lbf/ft)
L = 40.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
66.0 0.0548 1060
70.0 0.0581 1130
80.0 0.0664 1290
90.0 0.0747 1450
100 0.0830 1610
200 0.166 3230
300 0.249 4840
400 0.332 6450
500 0.415 8070
600 0.498 9680
700 0.581 1.13 × 104
800 0.664 1.29 × 104
900 0.747 1.45 × 104
1000 0.830 1.61 × 104
2000 1.66 3.23 × 104
3000 2.49 4.84 × 104
4000 3.32 6.45 × 104
5000 4.15 8.07 × 104
6000 4.98 9.68 × 104
7000 5.81 1.13 × 105
8000 6.64 1.29 × 105
9000 7.47 1.45 × 105
1.00 × 104 8.30 1.61 × 105
1.84 × 104 15.3 2.97 × 105
Steel I Beam: S20 × 66 (S20 inch tall × 66 lbf/ft)
L = 50.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
66.0 0.134 1660
70.0 0.142 1760
80.0 0.162 2020
90.0 0.182 2270
100 0.203 2520
200 0.405 5040
300 0.608 7560
400 0.810 1.01 × 104
500 1.01 1.26 × 104
600 1.22 1.51 × 104
700 1.42 1.76 × 104
800 1.62 2.02 × 104
900 1.82 2.27 × 104
1000 2.03 2.52 × 104
2000 4.05 5.04 × 104
3000 6.08 7.56 × 104
4000 8.10 1.01 × 105
5000 10.1 1.26 × 105
6000 12.2 1.51 × 105
7000 14.2 1.76 × 105
8000 16.2 2.02 × 105
9000 18.2 2.27 × 105
9870 20.0 2.49 × 105
Steel I Beam: S20 × 66 (S20 inch tall × 66 lbf/ft)
L = 60.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
66.0 0.277 2400
70.0 0.294 2540
80.0 0.336 2900
90.0 0.378 3270
100 0.420 3630
200 0.840 7260
300 1.26 1.09 × 104
400 1.68 1.45 × 104
500 2.10 1.82 × 104
600 2.52 2.18 × 104
700 2.94 2.54 × 104
800 3.36 2.90 × 104
900 3.78 3.27 × 104
1000 4.20 3.63 × 104
2000 8.40 7.26 × 104
3000 12.6 1.09 × 105
4000 16.8 1.45 × 105
4760 20.0 1.73 × 105
Steel I Beam: S20 × 66 (S20 inch tall × 66 lbf/ft)
L = 70.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
66.0 0.514 3260
70.0 0.545 3460
80.0 0.623 3950
90.0 0.701 4450
100 0.778 4940
200 1.56 9880
300 2.34 1.48 × 104
400 3.11 1.98 × 104
500 3.89 2.47 × 104
600 4.67 2.96 × 104
700 5.45 3.46 × 104
800 6.23 3.95 × 104
900 7.01 4.45 × 104
1000 7.78 4.94 × 104
2000 15.6 9.88 × 104
2570 20.0 1.27 × 105
Steel I Beam: S20 × 66 (S20 inch tall × 66 lbf/ft)
L = 80.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
66.0 0.876 4260
70.0 0.930 4520
80.0 1.06 5160
90.0 1.20 5810
100 1.33 6450
200 2.66 1.29 × 104
300 3.98 1.94 × 104
400 5.31 2.58 × 104
500 6.64 3.23 × 104
600 7.97 3.87 × 104
700 9.30 4.52 × 104
800 10.6 5.16 × 104
900 12.0 5.81 × 104
1000 13.3 6.45 × 104
1510 20.0 9.72 × 104
Steel I Beam: S20 × 66 (S20 inch tall × 66 lbf/ft)
L = 90.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
66.0 1.40 5390
70.0 1.49 5720
80.0 1.70 6530
90.0 1.91 7350
100 2.13 8170
200 4.25 1.63 × 104
300 6.38 2.45 × 104
400 8.51 3.27 × 104
500 10.6 4.08 × 104
600 12.8 4.90 × 104
700 14.9 5.72 × 104
800 17.0 6.53 × 104
900 19.1 7.35 × 104
940 20.0 7.68 × 104
Steel I Beam: S20 × 66 (S20 inch tall × 66 lbf/ft)
L = 100 ft
P (lbf/ft) w_max (in) stress_max (psi)
66.0 2.14 6660
70.0 2.27 7060
80.0 2.59 8070
90.0 2.92 9080
100 3.24 1.01 × 104
200 6.48 2.02 × 104
300 9.73 3.03 × 104
400 13.0 4.03 × 104
500 16.2 5.04 × 104
600 19.5 6.05 × 104
617 20.0 6.22 × 104
Steel I Beam: S20 × 66 (S20 inch tall × 66 lbf/ft)
L = 125 ft
P (lbf/ft) w_max (in) stress_max (psi)
66.0 5.22 1.04 × 104
70.0 5.54 1.10 × 104
80.0 6.33 1.26 × 104
90.0 7.12 1.42 × 104
100 7.91 1.58 × 104
200 15.8 3.15 × 104
253 20.0 3.98 × 104
Steel I Beam: S20 × 66 (S20 inch tall × 66 lbf/ft)
L = 150 ft
P (lbf/ft) w_max (in) stress_max (psi)
66.0 10.8 1.50 × 104
70.0 11.5 1.59 × 104
80.0 13.1 1.82 × 104
90.0 14.8 2.04 × 104
100 16.4 2.27 × 104
122 20.0 2.76 × 104
Additional Information
Related Pages
Mechanical Engineers Outlook

Guide for those interested in becoming a mechanical engineer. Includes qualifications, pay, and job duties.

STEM Career Outlook

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

3D Scanners

A white paper to assist in the evaluation of 3D scanning hardware solutions.

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