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Glossary » Beams » Simply Supported » Uniformly Distributed Load » Three Equal Spans » S Section Steel I Beam » S6 × 12.5
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 = 22.1 in4) for the S6 × 12.5 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
   
Steel I Beam: S6 × 12.5 (S6 inch tall × 12.5 lbf/ft)
L = 3.00 ft
P (lbf/ft) w_max (in) stress_max (psi)
12.5 1.77 × 10-5 18.3
20.0 2.83 × 10-5 29.3
30.0 4.24 × 10-5 44.0
40.0 5.66 × 10-5 58.6
50.0 7.07 × 10-5 73.3
60.0 8.48 × 10-5 88.0
70.0 9.90 × 10-5 103
80.0 1.13 × 10-4 117
90.0 1.27 × 10-4 132
100 1.41 × 10-4 147
200 2.83 × 10-4 293
300 4.24 × 10-4 440
400 5.66 × 10-4 586
500 7.07 × 10-4 733
600 8.48 × 10-4 880
700 9.90 × 10-4 1030
800 0.00113 1170
900 0.00127 1320
1000 0.00141 1470
2000 0.00283 2930
3000 0.00424 4400
4000 0.00566 5860
5000 0.00707 7330
6000 0.00848 8800
7000 0.00990 1.03 × 104
8000 0.0113 1.17 × 104
9000 0.0127 1.32 × 104
1.00 × 104 0.0141 1.47 × 104
2.00 × 104 0.0283 2.93 × 104
3.00 × 104 0.0424 4.40 × 104
4.00 × 104 0.0566 5.86 × 104
5.00 × 104 0.0707 7.33 × 104
6.00 × 104 0.0848 8.80 × 104
7.00 × 104 0.0990 1.03 × 105
8.00 × 104 0.113 1.17 × 105
9.00 × 104 0.127 1.32 × 105
1.00 × 105 0.141 1.47 × 105
2.00 × 105 0.283 2.93 × 105
2.03 × 105 0.286 2.97 × 105
Steel I Beam: S6 × 12.5 (S6 inch tall × 12.5 lbf/ft)
L = 5.00 ft
P (lbf/ft) w_max (in) stress_max (psi)
12.5 1.36 × 10-4 50.9
20.0 2.18 × 10-4 81.4
30.0 3.27 × 10-4 122
40.0 4.36 × 10-4 163
50.0 5.46 × 10-4 204
60.0 6.55 × 10-4 244
70.0 7.64 × 10-4 285
80.0 8.73 × 10-4 326
90.0 9.82 × 10-4 367
100 0.00109 407
200 0.00218 814
300 0.00327 1220
400 0.00436 1630
500 0.00546 2040
600 0.00655 2440
700 0.00764 2850
800 0.00873 3260
900 0.00982 3670
1000 0.0109 4070
2000 0.0218 8140
3000 0.0327 1.22 × 104
4000 0.0436 1.63 × 104
5000 0.0546 2.04 × 104
6000 0.0655 2.44 × 104
7000 0.0764 2.85 × 104
8000 0.0873 3.26 × 104
9000 0.0982 3.67 × 104
1.00 × 104 0.109 4.07 × 104
2.00 × 104 0.218 8.14 × 104
3.00 × 104 0.327 1.22 × 105
4.00 × 104 0.436 1.63 × 105
5.00 × 104 0.546 2.04 × 105
6.00 × 104 0.655 2.44 × 105
7.00 × 104 0.764 2.85 × 105
7.29 × 104 0.796 2.97 × 105
Steel I Beam: S6 × 12.5 (S6 inch tall × 12.5 lbf/ft)
L = 10.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
12.5 0.00218 204
20.0 0.00349 326
30.0 0.00524 489
40.0 0.00698 652
50.0 0.00873 814
60.0 0.0105 977
70.0 0.0122 1140
80.0 0.0140 1300
90.0 0.0157 1470
100 0.0175 1630
200 0.0349 3260
300 0.0524 4890
400 0.0698 6520
500 0.0873 8140
600 0.105 9770
700 0.122 1.14 × 104
800 0.140 1.30 × 104
900 0.157 1.47 × 104
1000 0.175 1.63 × 104
2000 0.349 3.26 × 104
3000 0.524 4.89 × 104
4000 0.698 6.52 × 104
5000 0.873 8.14 × 104
6000 1.05 9.77 × 104
7000 1.22 1.14 × 105
8000 1.40 1.30 × 105
9000 1.57 1.47 × 105
1.00 × 104 1.75 1.63 × 105
1.82 × 104 3.18 2.97 × 105
Steel I Beam: S6 × 12.5 (S6 inch tall × 12.5 lbf/ft)
L = 15.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
12.5 0.0110 458
20.0 0.0177 733
30.0 0.0265 1100
40.0 0.0353 1470
50.0 0.0442 1830
60.0 0.0530 2200
70.0 0.0619 2570
80.0 0.0707 2930
90.0 0.0795 3300
100 0.0884 3670
200 0.177 7330
300 0.265 1.10 × 104
400 0.353 1.47 × 104
500 0.442 1.83 × 104
600 0.530 2.20 × 104
700 0.619 2.57 × 104
800 0.707 2.93 × 104
900 0.795 3.30 × 104
1000 0.884 3.67 × 104
2000 1.77 7.33 × 104
3000 2.65 1.10 × 105
4000 3.53 1.47 × 105
5000 4.42 1.83 × 105
6000 5.30 2.20 × 105
6790 6.00 2.49 × 105
Steel I Beam: S6 × 12.5 (S6 inch tall × 12.5 lbf/ft)
L = 20.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
12.5 0.0349 814
20.0 0.0559 1300
30.0 0.0838 1950
40.0 0.112 2610
50.0 0.140 3260
60.0 0.168 3910
70.0 0.196 4560
80.0 0.223 5210
90.0 0.251 5860
100 0.279 6520
200 0.559 1.30 × 104
300 0.838 1.95 × 104
400 1.12 2.61 × 104
500 1.40 3.26 × 104
600 1.68 3.91 × 104
700 1.96 4.56 × 104
800 2.23 5.21 × 104
900 2.51 5.86 × 104
1000 2.79 6.52 × 104
2000 5.59 1.30 × 105
2150 6.00 1.40 × 105
Steel I Beam: S6 × 12.5 (S6 inch tall × 12.5 lbf/ft)
L = 25.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
12.5 0.0852 1270
20.0 0.136 2040
30.0 0.205 3050
40.0 0.273 4070
50.0 0.341 5090
60.0 0.409 6110
70.0 0.477 7130
80.0 0.546 8140
90.0 0.614 9160
100 0.682 1.02 × 104
200 1.36 2.04 × 104
300 2.05 3.05 × 104
400 2.73 4.07 × 104
500 3.41 5.09 × 104
600 4.09 6.11 × 104
700 4.77 7.13 × 104
800 5.46 8.14 × 104
880 6.00 8.96 × 104
Steel I Beam: S6 × 12.5 (S6 inch tall × 12.5 lbf/ft)
L = 30.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
12.5 0.177 1830
20.0 0.283 2930
30.0 0.424 4400
40.0 0.566 5860
50.0 0.707 7330
60.0 0.848 8800
70.0 0.990 1.03 × 104
80.0 1.13 1.17 × 104
90.0 1.27 1.32 × 104
100 1.41 1.47 × 104
200 2.83 2.93 × 104
300 4.24 4.40 × 104
400 5.66 5.86 × 104
424 6.00 6.22 × 104
Steel I Beam: S6 × 12.5 (S6 inch tall × 12.5 lbf/ft)
L = 40.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
12.5 0.559 3260
20.0 0.894 5210
30.0 1.34 7820
40.0 1.79 1.04 × 104
50.0 2.23 1.30 × 104
60.0 2.68 1.56 × 104
70.0 3.13 1.82 × 104
80.0 3.58 2.09 × 104
90.0 4.02 2.35 × 104
100 4.47 2.61 × 104
134 6.00 3.50 × 104
Steel I Beam: S6 × 12.5 (S6 inch tall × 12.5 lbf/ft)
L = 50.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
12.5 1.36 5090
20.0 2.18 8140
30.0 3.27 1.22 × 104
40.0 4.36 1.63 × 104
50.0 5.46 2.04 × 104
55.0 6.00 2.24 × 104
Steel I Beam: S6 × 12.5 (S6 inch tall × 12.5 lbf/ft)
L = 60.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
12.5 2.83 7330
20.0 4.52 1.17 × 104
26.5 6.00 1.56 × 104
Steel I Beam: S6 × 12.5 (S6 inch tall × 12.5 lbf/ft)
L = 70.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
12.5 5.24 9980
14.3 6.00 1.14 × 104
Additional Information
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STEM Career Outlook

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

Selecting the Right 3D Printer

Discover how to choose the right 3D printer for your needs and the key performance attributes to consider.

Negotiate Your Salary

Learn the best principles to negotiate the salary you deserve!

CNC Machining Design Guide

Optimize your designs, reduce machining time, and lower your costs.

more publications