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Glossary » Beams » Simply Supported » Uniformly Distributed Load » Three Equal Spans » S Section Steel I Beam » S18 × 70
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 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 = 926 in4) for the S18 × 70 S Section Steel I Beam and the typical Young's modulus (E = 3.046 × 107 psi) of steels. Note that the typical yielding stress 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.

 Steel I Beam: S18 × 70 (S18 inch tall × 70 lbf/ft) L = 3.00 ft (lbf/ft) (in) (psi) 70.0 2.36 × 10-6 7.35 80.0 2.70 × 10-6 8.40 90.0 3.04 × 10-6 9.45 100 3.37 × 10-6 10.5 200 6.75 × 10-6 21.0 300 1.01 × 10-5 31.5 400 1.35 × 10-5 42.0 500 1.69 × 10-5 52.5 600 2.02 × 10-5 63.0 700 2.36 × 10-5 73.5 800 2.70 × 10-5 84.0 900 3.04 × 10-5 94.5 1000 3.37 × 10-5 105 2000 6.75 × 10-5 210 3000 1.01 × 10-4 315 4000 1.35 × 10-4 420 5000 1.69 × 10-4 525 6000 2.02 × 10-4 630 7000 2.36 × 10-4 735 8000 2.70 × 10-4 840 9000 3.04 × 10-4 945 1.00 × 104 3.37 × 10-4 1050 2.00 × 104 6.75 × 10-4 2100 3.00 × 104 0.00101 3150 4.00 × 104 0.00135 4200 5.00 × 104 0.00169 5250 6.00 × 104 0.00202 6300 7.00 × 104 0.00236 7350 8.00 × 104 0.00270 8400 9.00 × 104 0.00304 9450 1.00 × 105 0.00337 1.05 × 104 2.00 × 105 0.00675 2.10 × 104 3.00 × 105 0.0101 3.15 × 104 4.00 × 105 0.0135 4.20 × 104 5.00 × 105 0.0169 5.25 × 104 6.00 × 105 0.0202 6.30 × 104 7.00 × 105 0.0236 7.35 × 104 8.00 × 105 0.0270 8.40 × 104 9.00 × 105 0.0304 9.45 × 104 1.00 × 106 0.0337 1.05 × 105 2.00 × 106 0.0675 2.10 × 105 2.83 × 106 0.0955 2.97 × 105
 Steel I Beam: S18 × 70 (S18 inch tall × 70 lbf/ft) L = 5.00 ft (lbf/ft) (in) (psi) 70.0 1.82 × 10-5 20.4 80.0 2.08 × 10-5 23.3 90.0 2.34 × 10-5 26.2 100 2.60 × 10-5 29.2 200 5.21 × 10-5 58.3 300 7.81 × 10-5 87.5 400 1.04 × 10-4 117 500 1.30 × 10-4 146 600 1.56 × 10-4 175 700 1.82 × 10-4 204 800 2.08 × 10-4 233 900 2.34 × 10-4 262 1000 2.60 × 10-4 292 2000 5.21 × 10-4 583 3000 7.81 × 10-4 875 4000 0.00104 1170 5000 0.00130 1460 6000 0.00156 1750 7000 0.00182 2040 8000 0.00208 2330 9000 0.00234 2620 1.00 × 104 0.00260 2920 2.00 × 104 0.00521 5830 3.00 × 104 0.00781 8750 4.00 × 104 0.0104 1.17 × 104 5.00 × 104 0.0130 1.46 × 104 6.00 × 104 0.0156 1.75 × 104 7.00 × 104 0.0182 2.04 × 104 8.00 × 104 0.0208 2.33 × 104 9.00 × 104 0.0234 2.62 × 104 1.00 × 105 0.0260 2.92 × 104 2.00 × 105 0.0521 5.83 × 104 3.00 × 105 0.0781 8.75 × 104 4.00 × 105 0.104 1.17 × 105 5.00 × 105 0.130 1.46 × 105 6.00 × 105 0.156 1.75 × 105 7.00 × 105 0.182 2.04 × 105 8.00 × 105 0.208 2.33 × 105 9.00 × 105 0.234 2.62 × 105 1.00 × 106 0.260 2.92 × 105 1.02 × 106 0.265 2.97 × 105
 Steel I Beam: S18 × 70 (S18 inch tall × 70 lbf/ft) L = 10.0 ft (lbf/ft) (in) (psi) 70.0 2.92 × 10-4 81.6 80.0 3.33 × 10-4 93.3 90.0 3.75 × 10-4 105 100 4.17 × 10-4 117 200 8.33 × 10-4 233 300 0.00125 350 400 0.00167 467 500 0.00208 583 600 0.00250 700 700 0.00292 816 800 0.00333 933 900 0.00375 1050 1000 0.00417 1170 2000 0.00833 2330 3000 0.0125 3500 4000 0.0167 4670 5000 0.0208 5830 6000 0.0250 7000 7000 0.0292 8160 8000 0.0333 9330 9000 0.0375 1.05 × 104 1.00 × 104 0.0417 1.17 × 104 2.00 × 104 0.0833 2.33 × 104 3.00 × 104 0.125 3.50 × 104 4.00 × 104 0.167 4.67 × 104 5.00 × 104 0.208 5.83 × 104 6.00 × 104 0.250 7.00 × 104 7.00 × 104 0.292 8.16 × 104 8.00 × 104 0.333 9.33 × 104 9.00 × 104 0.375 1.05 × 105 1.00 × 105 0.417 1.17 × 105 2.00 × 105 0.833 2.33 × 105 2.55 × 105 1.06 2.97 × 105
 Steel I Beam: S18 × 70 (S18 inch tall × 70 lbf/ft) L = 15.0 ft (lbf/ft) (in) (psi) 70.0 0.00148 184 80.0 0.00169 210 90.0 0.00190 236 100 0.00211 262 200 0.00422 525 300 0.00633 787 400 0.00844 1050 500 0.0105 1310 600 0.0127 1570 700 0.0148 1840 800 0.0169 2100 900 0.0190 2360 1000 0.0211 2620 2000 0.0422 5250 3000 0.0633 7870 4000 0.0844 1.05 × 104 5000 0.105 1.31 × 104 6000 0.127 1.57 × 104 7000 0.148 1.84 × 104 8000 0.169 2.10 × 104 9000 0.190 2.36 × 104 1.00 × 104 0.211 2.62 × 104 2.00 × 104 0.422 5.25 × 104 3.00 × 104 0.633 7.87 × 104 4.00 × 104 0.844 1.05 × 105 5.00 × 104 1.05 1.31 × 105 6.00 × 104 1.27 1.57 × 105 7.00 × 104 1.48 1.84 × 105 8.00 × 104 1.69 2.10 × 105 9.00 × 104 1.90 2.36 × 105 1.00 × 105 2.11 2.62 × 105 1.13 × 105 2.39 2.97 × 105
 Steel I Beam: S18 × 70 (S18 inch tall × 70 lbf/ft) L = 20.0 ft (lbf/ft) (in) (psi) 70.0 0.00467 327 80.0 0.00533 373 90.0 0.00600 420 100 0.00667 467 200 0.0133 933 300 0.0200 1400 400 0.0267 1870 500 0.0333 2330 600 0.0400 2800 700 0.0467 3270 800 0.0533 3730 900 0.0600 4200 1000 0.0667 4670 2000 0.133 9330 3000 0.200 1.40 × 104 4000 0.267 1.87 × 104 5000 0.333 2.33 × 104 6000 0.400 2.80 × 104 7000 0.467 3.27 × 104 8000 0.533 3.73 × 104 9000 0.600 4.20 × 104 1.00 × 104 0.667 4.67 × 104 2.00 × 104 1.33 9.33 × 104 3.00 × 104 2.00 1.40 × 105 4.00 × 104 2.67 1.87 × 105 5.00 × 104 3.33 2.33 × 105 6.00 × 104 4.00 2.80 × 105 6.37 × 104 4.24 2.97 × 105
 Steel I Beam: S18 × 70 (S18 inch tall × 70 lbf/ft) L = 25.0 ft (lbf/ft) (in) (psi) 70.0 0.0114 510 80.0 0.0130 583 90.0 0.0146 656 100 0.0163 729 200 0.0325 1460 300 0.0488 2190 400 0.0651 2920 500 0.0814 3640 600 0.0976 4370 700 0.114 5100 800 0.130 5830 900 0.146 6560 1000 0.163 7290 2000 0.325 1.46 × 104 3000 0.488 2.19 × 104 4000 0.651 2.92 × 104 5000 0.814 3.64 × 104 6000 0.976 4.37 × 104 7000 1.14 5.10 × 104 8000 1.30 5.83 × 104 9000 1.46 6.56 × 104 1.00 × 104 1.63 7.29 × 104 2.00 × 104 3.25 1.46 × 105 3.00 × 104 4.88 2.19 × 105 4.00 × 104 6.51 2.92 × 105 4.07 × 104 6.63 2.97 × 105
 Steel I Beam: S18 × 70 (S18 inch tall × 70 lbf/ft) L = 30.0 ft (lbf/ft) (in) (psi) 70.0 0.0236 735 80.0 0.0270 840 90.0 0.0304 945 100 0.0337 1050 200 0.0675 2100 300 0.101 3150 400 0.135 4200 500 0.169 5250 600 0.202 6300 700 0.236 7350 800 0.270 8400 900 0.304 9450 1000 0.337 1.05 × 104 2000 0.675 2.10 × 104 3000 1.01 3.15 × 104 4000 1.35 4.20 × 104 5000 1.69 5.25 × 104 6000 2.02 6.30 × 104 7000 2.36 7.35 × 104 8000 2.70 8.40 × 104 9000 3.04 9.45 × 104 1.00 × 104 3.37 1.05 × 105 2.00 × 104 6.75 2.10 × 105 2.83 × 104 9.55 2.97 × 105
 Steel I Beam: S18 × 70 (S18 inch tall × 70 lbf/ft) L = 40.0 ft (lbf/ft) (in) (psi) 70.0 0.0747 1310 80.0 0.0853 1490 90.0 0.0960 1680 100 0.107 1870 200 0.213 3730 300 0.320 5600 400 0.427 7460 500 0.533 9330 600 0.640 1.12 × 104 700 0.747 1.31 × 104 800 0.853 1.49 × 104 900 0.960 1.68 × 104 1000 1.07 1.87 × 104 2000 2.13 3.73 × 104 3000 3.20 5.60 × 104 4000 4.27 7.46 × 104 5000 5.33 9.33 × 104 6000 6.40 1.12 × 105 7000 7.47 1.31 × 105 8000 8.53 1.49 × 105 9000 9.60 1.68 × 105 1.00 × 104 10.7 1.87 × 105 1.59 × 104 17.0 2.97 × 105
 Steel I Beam: S18 × 70 (S18 inch tall × 70 lbf/ft) L = 50.0 ft (lbf/ft) (in) (psi) 70.0 0.182 2040 80.0 0.208 2330 90.0 0.234 2620 100 0.260 2920 200 0.521 5830 300 0.781 8750 400 1.04 1.17 × 104 500 1.30 1.46 × 104 600 1.56 1.75 × 104 700 1.82 2.04 × 104 800 2.08 2.33 × 104 900 2.34 2.62 × 104 1000 2.60 2.92 × 104 2000 5.21 5.83 × 104 3000 7.81 8.75 × 104 4000 10.4 1.17 × 105 5000 13.0 1.46 × 105 6000 15.6 1.75 × 105 6910 18.0 2.02 × 105
 Steel I Beam: S18 × 70 (S18 inch tall × 70 lbf/ft) L = 60.0 ft (lbf/ft) (in) (psi) 70.0 0.378 2940 80.0 0.432 3360 90.0 0.486 3780 100 0.540 4200 200 1.08 8400 300 1.62 1.26 × 104 400 2.16 1.68 × 104 500 2.70 2.10 × 104 600 3.24 2.52 × 104 700 3.78 2.94 × 104 800 4.32 3.36 × 104 900 4.86 3.78 × 104 1000 5.40 4.20 × 104 2000 10.8 8.40 × 104 3000 16.2 1.26 × 105 3330 18.0 1.40 × 105
 Steel I Beam: S18 × 70 (S18 inch tall × 70 lbf/ft) L = 70.0 ft (lbf/ft) (in) (psi) 70.0 0.700 4000 80.0 0.800 4570 90.0 0.900 5140 100 1.00 5710 200 2.00 1.14 × 104 300 3.00 1.71 × 104 400 4.00 2.29 × 104 500 5.00 2.86 × 104 600 6.00 3.43 × 104 700 7.00 4.00 × 104 800 8.00 4.57 × 104 900 9.00 5.14 × 104 1000 10.0 5.71 × 104 1800 18.0 1.03 × 105
 Steel I Beam: S18 × 70 (S18 inch tall × 70 lbf/ft) L = 80.0 ft (lbf/ft) (in) (psi) 70.0 1.19 5230 80.0 1.37 5970 90.0 1.54 6720 100 1.71 7460 200 3.41 1.49 × 104 300 5.12 2.24 × 104 400 6.83 2.99 × 104 500 8.53 3.73 × 104 600 10.2 4.48 × 104 700 11.9 5.23 × 104 800 13.7 5.97 × 104 900 15.4 6.72 × 104 1000 17.1 7.46 × 104 1050 18.0 7.87 × 104
 Steel I Beam: S18 × 70 (S18 inch tall × 70 lbf/ft) L = 90.0 ft (lbf/ft) (in) (psi) 70.0 1.91 6610 80.0 2.19 7560 90.0 2.46 8500 100 2.73 9450 200 5.47 1.89 × 104 300 8.20 2.83 × 104 400 10.9 3.78 × 104 500 13.7 4.72 × 104 600 16.4 5.67 × 104 659 18.0 6.22 × 104
 Steel I Beam: S18 × 70 (S18 inch tall × 70 lbf/ft) L = 100 ft (lbf/ft) (in) (psi) 70.0 2.92 8160 80.0 3.33 9330 90.0 3.75 1.05 × 104 100 4.17 1.17 × 104 200 8.33 2.33 × 104 300 12.5 3.50 × 104 400 16.7 4.67 × 104 432 18.0 5.04 × 104
 Steel I Beam: S18 × 70 (S18 inch tall × 70 lbf/ft) L = 125 ft (lbf/ft) (in) (psi) 70.0 7.12 1.28 × 104 80.0 8.14 1.46 × 104 90.0 9.15 1.64 × 104 100 10.2 1.82 × 104 177 18.0 3.22 × 104
 Steel I Beam: S18 × 70 (S18 inch tall × 70 lbf/ft) L = 150 ft (lbf/ft) (in) (psi) 70.0 14.8 1.84 × 104 80.0 16.9 2.10 × 104 85.3 18.0 2.24 × 104