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Glossary » Beams » Simply Supported » Uniformly Distributed Load » Four Equal Spans » Wide Flange Steel I Beam » W8 × 18
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 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 = 61.9 in4) for the W8 × 18 Wide Flange 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: W8 × 18 (Wide Flange 8 inch tall × 18 lbf/ft) L = 3.00 ft (lbf/ft) (in) (psi) 18.0 8.42 × 10-6 13.7 20.0 9.35 × 10-6 15.2 30.0 1.40 × 10-5 22.8 40.0 1.87 × 10-5 30.4 50.0 2.34 × 10-5 38.0 60.0 2.81 × 10-5 45.6 70.0 3.27 × 10-5 53.2 80.0 3.74 × 10-5 60.8 90.0 4.21 × 10-5 68.4 100 4.68 × 10-5 76.1 200 9.35 × 10-5 152 300 1.40 × 10-4 228 400 1.87 × 10-4 304 500 2.34 × 10-4 380 600 2.81 × 10-4 456 700 3.27 × 10-4 532 800 3.74 × 10-4 608 900 4.21 × 10-4 684 1000 4.68 × 10-4 761 2000 9.35 × 10-4 1520 3000 0.00140 2280 4000 0.00187 3040 5000 0.00234 3800 6000 0.00281 4560 7000 0.00327 5320 8000 0.00374 6080 9000 0.00421 6840 1.00 × 104 0.00468 7610 2.00 × 104 0.00935 1.52 × 104 3.00 × 104 0.0140 2.28 × 104 4.00 × 104 0.0187 3.04 × 104 5.00 × 104 0.0234 3.80 × 104 6.00 × 104 0.0281 4.56 × 104 7.00 × 104 0.0327 5.32 × 104 8.00 × 104 0.0374 6.08 × 104 9.00 × 104 0.0421 6.84 × 104 1.00 × 105 0.0468 7.61 × 104 2.00 × 105 0.0935 1.52 × 105 3.00 × 105 0.140 2.28 × 105 3.91 × 105 0.183 2.97 × 105
 Steel I Beam: W8 × 18 (Wide Flange 8 inch tall × 18 lbf/ft) L = 5.00 ft (lbf/ft) (in) (psi) 18.0 6.50 × 10-5 38.0 20.0 7.22 × 10-5 42.3 30.0 1.08 × 10-4 63.4 40.0 1.44 × 10-4 84.5 50.0 1.80 × 10-4 106 60.0 2.17 × 10-4 127 70.0 2.53 × 10-4 148 80.0 2.89 × 10-4 169 90.0 3.25 × 10-4 190 100 3.61 × 10-4 211 200 7.22 × 10-4 423 300 0.00108 634 400 0.00144 845 500 0.00180 1060 600 0.00217 1270 700 0.00253 1480 800 0.00289 1690 900 0.00325 1900 1000 0.00361 2110 2000 0.00722 4230 3000 0.0108 6340 4000 0.0144 8450 5000 0.0180 1.06 × 104 6000 0.0217 1.27 × 104 7000 0.0253 1.48 × 104 8000 0.0289 1.69 × 104 9000 0.0325 1.90 × 104 1.00 × 104 0.0361 2.11 × 104 2.00 × 104 0.0722 4.23 × 104 3.00 × 104 0.108 6.34 × 104 4.00 × 104 0.144 8.45 × 104 5.00 × 104 0.180 1.06 × 105 6.00 × 104 0.217 1.27 × 105 7.00 × 104 0.253 1.48 × 105 8.00 × 104 0.289 1.69 × 105 9.00 × 104 0.325 1.90 × 105 1.00 × 105 0.361 2.11 × 105 1.41 × 105 0.507 2.97 × 105
 Steel I Beam: W8 × 18 (Wide Flange 8 inch tall × 18 lbf/ft) L = 10.0 ft (lbf/ft) (in) (psi) 18.0 0.00104 152 20.0 0.00115 169 30.0 0.00173 254 40.0 0.00231 338 50.0 0.00289 423 60.0 0.00346 507 70.0 0.00404 592 80.0 0.00462 676 90.0 0.00520 761 100 0.00577 845 200 0.0115 1690 300 0.0173 2540 400 0.0231 3380 500 0.0289 4230 600 0.0346 5070 700 0.0404 5920 800 0.0462 6760 900 0.0520 7610 1000 0.0577 8450 2000 0.115 1.69 × 104 3000 0.173 2.54 × 104 4000 0.231 3.38 × 104 5000 0.289 4.23 × 104 6000 0.346 5.07 × 104 7000 0.404 5.92 × 104 8000 0.462 6.76 × 104 9000 0.520 7.61 × 104 1.00 × 104 0.577 8.45 × 104 2.00 × 104 1.15 1.69 × 105 3.00 × 104 1.73 2.54 × 105 3.52 × 104 2.03 2.97 × 105
 Steel I Beam: W8 × 18 (Wide Flange 8 inch tall × 18 lbf/ft) L = 15.0 ft (lbf/ft) (in) (psi) 18.0 0.00526 342 20.0 0.00585 380 30.0 0.00877 570 40.0 0.0117 761 50.0 0.0146 951 60.0 0.0175 1140 70.0 0.0205 1330 80.0 0.0234 1520 90.0 0.0263 1710 100 0.0292 1900 200 0.0585 3800 300 0.0877 5700 400 0.117 7610 500 0.146 9510 600 0.175 1.14 × 104 700 0.205 1.33 × 104 800 0.234 1.52 × 104 900 0.263 1.71 × 104 1000 0.292 1.90 × 104 2000 0.585 3.80 × 104 3000 0.877 5.70 × 104 4000 1.17 7.61 × 104 5000 1.46 9.51 × 104 6000 1.75 1.14 × 105 7000 2.05 1.33 × 105 8000 2.34 1.52 × 105 9000 2.63 1.71 × 105 1.00 × 104 2.92 1.90 × 105 1.56 × 104 4.57 2.97 × 105
 Steel I Beam: W8 × 18 (Wide Flange 8 inch tall × 18 lbf/ft) L = 20.0 ft (lbf/ft) (in) (psi) 18.0 0.0166 608 20.0 0.0185 676 30.0 0.0277 1010 40.0 0.0370 1350 50.0 0.0462 1690 60.0 0.0554 2030 70.0 0.0647 2370 80.0 0.0739 2700 90.0 0.0831 3040 100 0.0924 3380 200 0.185 6760 300 0.277 1.01 × 104 400 0.370 1.35 × 104 500 0.462 1.69 × 104 600 0.554 2.03 × 104 700 0.647 2.37 × 104 800 0.739 2.70 × 104 900 0.831 3.04 × 104 1000 0.924 3.38 × 104 2000 1.85 6.76 × 104 3000 2.77 1.01 × 105 4000 3.70 1.35 × 105 5000 4.62 1.69 × 105 6000 5.54 2.03 × 105 7000 6.47 2.37 × 105 8000 7.39 2.70 × 105 8790 8.12 2.97 × 105
 Steel I Beam: W8 × 18 (Wide Flange 8 inch tall × 18 lbf/ft) L = 25.0 ft (lbf/ft) (in) (psi) 18.0 0.0406 951 20.0 0.0451 1060 30.0 0.0677 1580 40.0 0.0902 2110 50.0 0.113 2640 60.0 0.135 3170 70.0 0.158 3700 80.0 0.180 4230 90.0 0.203 4750 100 0.226 5280 200 0.451 1.06 × 104 300 0.677 1.58 × 104 400 0.902 2.11 × 104 500 1.13 2.64 × 104 600 1.35 3.17 × 104 700 1.58 3.70 × 104 800 1.80 4.23 × 104 900 2.03 4.75 × 104 1000 2.26 5.28 × 104 2000 4.51 1.06 × 105 3000 6.77 1.58 × 105 3610 8.14 1.91 × 105
 Steel I Beam: W8 × 18 (Wide Flange 8 inch tall × 18 lbf/ft) L = 30.0 ft (lbf/ft) (in) (psi) 18.0 0.0842 1370 20.0 0.0935 1520 30.0 0.140 2280 40.0 0.187 3040 50.0 0.234 3800 60.0 0.281 4560 70.0 0.327 5320 80.0 0.374 6080 90.0 0.421 6840 100 0.468 7610 200 0.935 1.52 × 104 300 1.40 2.28 × 104 400 1.87 3.04 × 104 500 2.34 3.80 × 104 600 2.81 4.56 × 104 700 3.27 5.32 × 104 800 3.74 6.08 × 104 900 4.21 6.84 × 104 1000 4.68 7.61 × 104 1740 8.14 1.32 × 105
 Steel I Beam: W8 × 18 (Wide Flange 8 inch tall × 18 lbf/ft) L = 40.0 ft (lbf/ft) (in) (psi) 18.0 0.266 2430 20.0 0.296 2700 30.0 0.443 4060 40.0 0.591 5410 50.0 0.739 6760 60.0 0.887 8110 70.0 1.03 9460 80.0 1.18 1.08 × 104 90.0 1.33 1.22 × 104 100 1.48 1.35 × 104 200 2.96 2.70 × 104 300 4.43 4.06 × 104 400 5.91 5.41 × 104 500 7.39 6.76 × 104 551 8.14 7.45 × 104
 Steel I Beam: W8 × 18 (Wide Flange 8 inch tall × 18 lbf/ft) L = 50.0 ft (lbf/ft) (in) (psi) 18.0 0.650 3800 20.0 0.722 4230 30.0 1.08 6340 40.0 1.44 8450 50.0 1.80 1.06 × 104 60.0 2.17 1.27 × 104 70.0 2.53 1.48 × 104 80.0 2.89 1.69 × 104 90.0 3.25 1.90 × 104 100 3.61 2.11 × 104 200 7.22 4.23 × 104 226 8.14 4.77 × 104
 Steel I Beam: W8 × 18 (Wide Flange 8 inch tall × 18 lbf/ft) L = 60.0 ft (lbf/ft) (in) (psi) 18.0 1.35 5480 20.0 1.50 6080 30.0 2.25 9130 40.0 2.99 1.22 × 104 50.0 3.74 1.52 × 104 60.0 4.49 1.83 × 104 70.0 5.24 2.13 × 104 80.0 5.99 2.43 × 104 90.0 6.74 2.74 × 104 100 7.48 3.04 × 104 109 8.14 3.31 × 104
 Steel I Beam: W8 × 18 (Wide Flange 8 inch tall × 18 lbf/ft) L = 70.0 ft (lbf/ft) (in) (psi) 18.0 2.50 7450 20.0 2.77 8280 30.0 4.16 1.24 × 104 40.0 5.55 1.66 × 104 50.0 6.93 2.07 × 104 58.7 8.14 2.43 × 104
 Steel I Beam: W8 × 18 (Wide Flange 8 inch tall × 18 lbf/ft) L = 80.0 ft (lbf/ft) (in) (psi) 18.0 4.26 9730 20.0 4.73 1.08 × 104 30.0 7.10 1.62 × 104 34.4 8.14 1.86 × 104
 Steel I Beam: W8 × 18 (Wide Flange 8 inch tall × 18 lbf/ft) L = 90.0 ft (lbf/ft) (in) (psi) 18.0 6.82 1.23 × 104 20.0 7.58 1.37 × 104 21.5 8.14 1.47 × 104