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Glossary » Beams » Simply Supported » Uniformly Distributed Load » Three Equal Spans » Wide Flange Steel I Beam » W12 × 120
Wide Flange 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 = 1070 in4) for the W12 × 120 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: W12 × 120 (Wide Flange 12 inch tall × 120 lbf/ft)
L = 3.00 ft
P (lbf/ft) w_max (in) stress_max (psi)
120 3.50 × 10-6 7.95
200 5.84 × 10-6 13.2
300 8.76 × 10-6 19.9
400 1.17 × 10-5 26.5
500 1.46 × 10-5 33.1
600 1.75 × 10-5 39.7
700 2.04 × 10-5 46.3
800 2.34 × 10-5 53.0
900 2.63 × 10-5 59.6
1000 2.92 × 10-5 66.2
2000 5.84 × 10-5 132
3000 8.76 × 10-5 199
4000 1.17 × 10-4 265
5000 1.46 × 10-4 331
6000 1.75 × 10-4 397
7000 2.04 × 10-4 463
8000 2.34 × 10-4 530
9000 2.63 × 10-4 596
1.00 × 104 2.92 × 10-4 662
2.00 × 104 5.84 × 10-4 1320
3.00 × 104 8.76 × 10-4 1990
4.00 × 104 0.00117 2650
5.00 × 104 0.00146 3310
6.00 × 104 0.00175 3970
7.00 × 104 0.00204 4630
8.00 × 104 0.00234 5300
9.00 × 104 0.00263 5960
1.00 × 105 0.00292 6620
2.00 × 105 0.00584 1.32 × 104
3.00 × 105 0.00876 1.99 × 104
4.00 × 105 0.0117 2.65 × 104
5.00 × 105 0.0146 3.31 × 104
6.00 × 105 0.0175 3.97 × 104
7.00 × 105 0.0204 4.63 × 104
8.00 × 105 0.0234 5.30 × 104
9.00 × 105 0.0263 5.96 × 104
1.00 × 106 0.0292 6.62 × 104
2.00 × 106 0.0584 1.32 × 105
3.00 × 106 0.0876 1.99 × 105
4.00 × 106 0.117 2.65 × 105
4.49 × 106 0.131 2.97 × 105
Steel I Beam: W12 × 120 (Wide Flange 12 inch tall × 120 lbf/ft)
L = 5.00 ft
P (lbf/ft) w_max (in) stress_max (psi)
120 2.70 × 10-5 22.1
200 4.51 × 10-5 36.8
300 6.76 × 10-5 55.2
400 9.01 × 10-5 73.6
500 1.13 × 10-4 92.0
600 1.35 × 10-4 110
700 1.58 × 10-4 129
800 1.80 × 10-4 147
900 2.03 × 10-4 166
1000 2.25 × 10-4 184
2000 4.51 × 10-4 368
3000 6.76 × 10-4 552
4000 9.01 × 10-4 736
5000 0.00113 920
6000 0.00135 1100
7000 0.00158 1290
8000 0.00180 1470
9000 0.00203 1660
1.00 × 104 0.00225 1840
2.00 × 104 0.00451 3680
3.00 × 104 0.00676 5520
4.00 × 104 0.00901 7360
5.00 × 104 0.0113 9200
6.00 × 104 0.0135 1.10 × 104
7.00 × 104 0.0158 1.29 × 104
8.00 × 104 0.0180 1.47 × 104
9.00 × 104 0.0203 1.66 × 104
1.00 × 105 0.0225 1.84 × 104
2.00 × 105 0.0451 3.68 × 104
3.00 × 105 0.0676 5.52 × 104
4.00 × 105 0.0901 7.36 × 104
5.00 × 105 0.113 9.20 × 104
6.00 × 105 0.135 1.10 × 105
7.00 × 105 0.158 1.29 × 105
8.00 × 105 0.180 1.47 × 105
9.00 × 105 0.203 1.66 × 105
1.00 × 106 0.225 1.84 × 105
1.61 × 106 0.364 2.97 × 105
Steel I Beam: W12 × 120 (Wide Flange 12 inch tall × 120 lbf/ft)
L = 10.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
120 4.33 × 10-4 88.3
200 7.21 × 10-4 147
300 0.00108 221
400 0.00144 294
500 0.00180 368
600 0.00216 441
700 0.00252 515
800 0.00288 589
900 0.00324 662
1000 0.00361 736
2000 0.00721 1470
3000 0.0108 2210
4000 0.0144 2940
5000 0.0180 3680
6000 0.0216 4410
7000 0.0252 5150
8000 0.0288 5890
9000 0.0324 6620
1.00 × 104 0.0361 7360
2.00 × 104 0.0721 1.47 × 104
3.00 × 104 0.108 2.21 × 104
4.00 × 104 0.144 2.94 × 104
5.00 × 104 0.180 3.68 × 104
6.00 × 104 0.216 4.41 × 104
7.00 × 104 0.252 5.15 × 104
8.00 × 104 0.288 5.89 × 104
9.00 × 104 0.324 6.62 × 104
1.00 × 105 0.361 7.36 × 104
2.00 × 105 0.721 1.47 × 105
3.00 × 105 1.08 2.21 × 105
4.00 × 105 1.44 2.94 × 105
4.04 × 105 1.46 2.97 × 105
Steel I Beam: W12 × 120 (Wide Flange 12 inch tall × 120 lbf/ft)
L = 15.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
120 0.00219 199
200 0.00365 331
300 0.00548 497
400 0.00730 662
500 0.00913 828
600 0.0110 993
700 0.0128 1160
800 0.0146 1320
900 0.0164 1490
1000 0.0183 1660
2000 0.0365 3310
3000 0.0548 4970
4000 0.0730 6620
5000 0.0913 8280
6000 0.110 9930
7000 0.128 1.16 × 104
8000 0.146 1.32 × 104
9000 0.164 1.49 × 104
1.00 × 104 0.183 1.66 × 104
2.00 × 104 0.365 3.31 × 104
3.00 × 104 0.548 4.97 × 104
4.00 × 104 0.730 6.62 × 104
5.00 × 104 0.913 8.28 × 104
6.00 × 104 1.10 9.93 × 104
7.00 × 104 1.28 1.16 × 105
8.00 × 104 1.46 1.32 × 105
9.00 × 104 1.64 1.49 × 105
1.00 × 105 1.83 1.66 × 105
1.79 × 105 3.28 2.97 × 105
Steel I Beam: W12 × 120 (Wide Flange 12 inch tall × 120 lbf/ft)
L = 20.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
120 0.00692 353
200 0.0115 589
300 0.0173 883
400 0.0231 1180
500 0.0288 1470
600 0.0346 1770
700 0.0404 2060
800 0.0462 2350
900 0.0519 2650
1000 0.0577 2940
2000 0.115 5890
3000 0.173 8830
4000 0.231 1.18 × 104
5000 0.288 1.47 × 104
6000 0.346 1.77 × 104
7000 0.404 2.06 × 104
8000 0.462 2.35 × 104
9000 0.519 2.65 × 104
1.00 × 104 0.577 2.94 × 104
2.00 × 104 1.15 5.89 × 104
3.00 × 104 1.73 8.83 × 104
4.00 × 104 2.31 1.18 × 105
5.00 × 104 2.88 1.47 × 105
6.00 × 104 3.46 1.77 × 105
7.00 × 104 4.04 2.06 × 105
8.00 × 104 4.62 2.35 × 105
9.00 × 104 5.19 2.65 × 105
1.00 × 105 5.77 2.94 × 105
1.01 × 105 5.82 2.97 × 105
Steel I Beam: W12 × 120 (Wide Flange 12 inch tall × 120 lbf/ft)
L = 25.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
120 0.0169 552
200 0.0282 920
300 0.0423 1380
400 0.0563 1840
500 0.0704 2300
600 0.0845 2760
700 0.0986 3220
800 0.113 3680
900 0.127 4140
1000 0.141 4600
2000 0.282 9200
3000 0.423 1.38 × 104
4000 0.563 1.84 × 104
5000 0.704 2.30 × 104
6000 0.845 2.76 × 104
7000 0.986 3.22 × 104
8000 1.13 3.68 × 104
9000 1.27 4.14 × 104
1.00 × 104 1.41 4.60 × 104
2.00 × 104 2.82 9.20 × 104
3.00 × 104 4.23 1.38 × 105
4.00 × 104 5.63 1.84 × 105
5.00 × 104 7.04 2.30 × 105
6.00 × 104 8.45 2.76 × 105
6.46 × 104 9.10 2.97 × 105
Steel I Beam: W12 × 120 (Wide Flange 12 inch tall × 120 lbf/ft)
L = 30.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
120 0.0350 795
200 0.0584 1320
300 0.0876 1990
400 0.117 2650
500 0.146 3310
600 0.175 3970
700 0.204 4630
800 0.234 5300
900 0.263 5960
1000 0.292 6620
2000 0.584 1.32 × 104
3000 0.876 1.99 × 104
4000 1.17 2.65 × 104
5000 1.46 3.31 × 104
6000 1.75 3.97 × 104
7000 2.04 4.63 × 104
8000 2.34 5.30 × 104
9000 2.63 5.96 × 104
1.00 × 104 2.92 6.62 × 104
2.00 × 104 5.84 1.32 × 105
3.00 × 104 8.76 1.99 × 105
4.00 × 104 11.7 2.65 × 105
4.49 × 104 13.1 2.97 × 105
Steel I Beam: W12 × 120 (Wide Flange 12 inch tall × 120 lbf/ft)
L = 40.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
120 0.111 1410
200 0.185 2350
300 0.277 3530
400 0.369 4710
500 0.462 5890
600 0.554 7060
700 0.646 8240
800 0.738 9420
900 0.831 1.06 × 104
1000 0.923 1.18 × 104
2000 1.85 2.35 × 104
3000 2.77 3.53 × 104
4000 3.69 4.71 × 104
5000 4.62 5.89 × 104
6000 5.54 7.06 × 104
7000 6.46 8.24 × 104
8000 7.38 9.42 × 104
9000 8.31 1.06 × 105
1.00 × 104 9.23 1.18 × 105
1.42 × 104 13.1 1.67 × 105
Steel I Beam: W12 × 120 (Wide Flange 12 inch tall × 120 lbf/ft)
L = 50.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
120 0.270 2210
200 0.451 3680
300 0.676 5520
400 0.901 7360
500 1.13 9200
600 1.35 1.10 × 104
700 1.58 1.29 × 104
800 1.80 1.47 × 104
900 2.03 1.66 × 104
1000 2.25 1.84 × 104
2000 4.51 3.68 × 104
3000 6.76 5.52 × 104
4000 9.01 7.36 × 104
5000 11.3 9.20 × 104
5820 13.1 1.07 × 105
Steel I Beam: W12 × 120 (Wide Flange 12 inch tall × 120 lbf/ft)
L = 60.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
120 0.561 3180
200 0.935 5300
300 1.40 7950
400 1.87 1.06 × 104
500 2.34 1.32 × 104
600 2.80 1.59 × 104
700 3.27 1.85 × 104
800 3.74 2.12 × 104
900 4.21 2.38 × 104
1000 4.67 2.65 × 104
2000 9.35 5.30 × 104
2810 13.1 7.44 × 104
Steel I Beam: W12 × 120 (Wide Flange 12 inch tall × 120 lbf/ft)
L = 70.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
120 1.04 4330
200 1.73 7210
300 2.60 1.08 × 104
400 3.46 1.44 × 104
500 4.33 1.80 × 104
600 5.19 2.16 × 104
700 6.06 2.52 × 104
800 6.93 2.88 × 104
900 7.79 3.24 × 104
1000 8.66 3.60 × 104
1520 13.1 5.46 × 104
Steel I Beam: W12 × 120 (Wide Flange 12 inch tall × 120 lbf/ft)
L = 80.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
120 1.77 5650
200 2.95 9420
300 4.43 1.41 × 104
400 5.91 1.88 × 104
500 7.38 2.35 × 104
600 8.86 2.83 × 104
700 10.3 3.30 × 104
800 11.8 3.77 × 104
888 13.1 4.18 × 104
Steel I Beam: W12 × 120 (Wide Flange 12 inch tall × 120 lbf/ft)
L = 90.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
120 2.84 7150
200 4.73 1.19 × 104
300 7.10 1.79 × 104
400 9.46 2.38 × 104
500 11.8 2.98 × 104
555 13.1 3.31 × 104
Steel I Beam: W12 × 120 (Wide Flange 12 inch tall × 120 lbf/ft)
L = 100 ft
P (lbf/ft) w_max (in) stress_max (psi)
120 4.33 8830
200 7.21 1.47 × 104
300 10.8 2.21 × 104
364 13.1 2.68 × 104
Steel I Beam: W12 × 120 (Wide Flange 12 inch tall × 120 lbf/ft)
L = 125 ft
P (lbf/ft) w_max (in) stress_max (psi)
120 10.6 1.38 × 104
149 13.1 1.71 × 104
Additional Information
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