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Glossary » Beams » Simply Supported » Uniformly Distributed Load » Four Equal Spans » Wide Flange Steel I Beam » W18 × 40
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 = 612 in4) for the W18 × 40 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: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft) L = 3.00 ft (lbf/ft) (in) (psi) 40.0 1.89 × 10-6 6.77 50.0 2.37 × 10-6 8.46 60.0 2.84 × 10-6 10.1 70.0 3.31 × 10-6 11.8 80.0 3.78 × 10-6 13.5 90.0 4.26 × 10-6 15.2 100 4.73 × 10-6 16.9 200 9.46 × 10-6 33.8 300 1.42 × 10-5 50.7 400 1.89 × 10-5 67.7 500 2.37 × 10-5 84.6 600 2.84 × 10-5 101 700 3.31 × 10-5 118 800 3.78 × 10-5 135 900 4.26 × 10-5 152 1000 4.73 × 10-5 169 2000 9.46 × 10-5 338 3000 1.42 × 10-4 507 4000 1.89 × 10-4 677 5000 2.37 × 10-4 846 6000 2.84 × 10-4 1010 7000 3.31 × 10-4 1180 8000 3.78 × 10-4 1350 9000 4.26 × 10-4 1520 1.00 × 104 4.73 × 10-4 1690 2.00 × 104 9.46 × 10-4 3380 3.00 × 104 0.00142 5070 4.00 × 104 0.00189 6770 5.00 × 104 0.00237 8460 6.00 × 104 0.00284 1.01 × 104 7.00 × 104 0.00331 1.18 × 104 8.00 × 104 0.00378 1.35 × 104 9.00 × 104 0.00426 1.52 × 104 1.00 × 105 0.00473 1.69 × 104 2.00 × 105 0.00946 3.38 × 104 3.00 × 105 0.0142 5.07 × 104 4.00 × 105 0.0189 6.77 × 104 5.00 × 105 0.0237 8.46 × 104 6.00 × 105 0.0284 1.01 × 105 7.00 × 105 0.0331 1.18 × 105 8.00 × 105 0.0378 1.35 × 105 9.00 × 105 0.0426 1.52 × 105 1.00 × 106 0.0473 1.69 × 105 1.76 × 106 0.0831 2.97 × 105
 Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft) L = 5.00 ft (lbf/ft) (in) (psi) 40.0 1.46 × 10-5 18.8 50.0 1.83 × 10-5 23.5 60.0 2.19 × 10-5 28.2 70.0 2.56 × 10-5 32.9 80.0 2.92 × 10-5 37.6 90.0 3.29 × 10-5 42.3 100 3.65 × 10-5 47.0 200 7.30 × 10-5 94.0 300 1.10 × 10-4 141 400 1.46 × 10-4 188 500 1.83 × 10-4 235 600 2.19 × 10-4 282 700 2.56 × 10-4 329 800 2.92 × 10-4 376 900 3.29 × 10-4 423 1000 3.65 × 10-4 470 2000 7.30 × 10-4 940 3000 0.00110 1410 4000 0.00146 1880 5000 0.00183 2350 6000 0.00219 2820 7000 0.00256 3290 8000 0.00292 3760 9000 0.00329 4230 1.00 × 104 0.00365 4700 2.00 × 104 0.00730 9400 3.00 × 104 0.0110 1.41 × 104 4.00 × 104 0.0146 1.88 × 104 5.00 × 104 0.0183 2.35 × 104 6.00 × 104 0.0219 2.82 × 104 7.00 × 104 0.0256 3.29 × 104 8.00 × 104 0.0292 3.76 × 104 9.00 × 104 0.0329 4.23 × 104 1.00 × 105 0.0365 4.70 × 104 2.00 × 105 0.0730 9.40 × 104 3.00 × 105 0.110 1.41 × 105 4.00 × 105 0.146 1.88 × 105 5.00 × 105 0.183 2.35 × 105 6.00 × 105 0.219 2.82 × 105 6.32 × 105 0.231 2.97 × 105
 Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft) L = 10.0 ft (lbf/ft) (in) (psi) 40.0 2.34 × 10-4 75.2 50.0 2.92 × 10-4 94.0 60.0 3.50 × 10-4 113 70.0 4.09 × 10-4 132 80.0 4.67 × 10-4 150 90.0 5.26 × 10-4 169 100 5.84 × 10-4 188 200 0.00117 376 300 0.00175 564 400 0.00234 752 500 0.00292 940 600 0.00350 1130 700 0.00409 1320 800 0.00467 1500 900 0.00526 1690 1000 0.00584 1880 2000 0.0117 3760 3000 0.0175 5640 4000 0.0234 7520 5000 0.0292 9400 6000 0.0350 1.13 × 104 7000 0.0409 1.32 × 104 8000 0.0467 1.50 × 104 9000 0.0526 1.69 × 104 1.00 × 104 0.0584 1.88 × 104 2.00 × 104 0.117 3.76 × 104 3.00 × 104 0.175 5.64 × 104 4.00 × 104 0.234 7.52 × 104 5.00 × 104 0.292 9.40 × 104 6.00 × 104 0.350 1.13 × 105 7.00 × 104 0.409 1.32 × 105 8.00 × 104 0.467 1.50 × 105 9.00 × 104 0.526 1.69 × 105 1.00 × 105 0.584 1.88 × 105 1.58 × 105 0.923 2.97 × 105
 Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft) L = 15.0 ft (lbf/ft) (in) (psi) 40.0 0.00118 169 50.0 0.00148 211 60.0 0.00177 254 70.0 0.00207 296 80.0 0.00237 338 90.0 0.00266 381 100 0.00296 423 200 0.00591 846 300 0.00887 1270 400 0.0118 1690 500 0.0148 2110 600 0.0177 2540 700 0.0207 2960 800 0.0237 3380 900 0.0266 3810 1000 0.0296 4230 2000 0.0591 8460 3000 0.0887 1.27 × 104 4000 0.118 1.69 × 104 5000 0.148 2.11 × 104 6000 0.177 2.54 × 104 7000 0.207 2.96 × 104 8000 0.237 3.38 × 104 9000 0.266 3.81 × 104 1.00 × 104 0.296 4.23 × 104 2.00 × 104 0.591 8.46 × 104 3.00 × 104 0.887 1.27 × 105 4.00 × 104 1.18 1.69 × 105 5.00 × 104 1.48 2.11 × 105 6.00 × 104 1.77 2.54 × 105 7.00 × 104 2.07 2.96 × 105 7.02 × 104 2.08 2.97 × 105
 Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft) L = 20.0 ft (lbf/ft) (in) (psi) 40.0 0.00374 301 50.0 0.00467 376 60.0 0.00561 451 70.0 0.00654 526 80.0 0.00748 601 90.0 0.00841 677 100 0.00934 752 200 0.0187 1500 300 0.0280 2260 400 0.0374 3010 500 0.0467 3760 600 0.0561 4510 700 0.0654 5260 800 0.0748 6010 900 0.0841 6770 1000 0.0934 7520 2000 0.187 1.50 × 104 3000 0.280 2.26 × 104 4000 0.374 3.01 × 104 5000 0.467 3.76 × 104 6000 0.561 4.51 × 104 7000 0.654 5.26 × 104 8000 0.748 6.01 × 104 9000 0.841 6.77 × 104 1.00 × 104 0.934 7.52 × 104 2.00 × 104 1.87 1.50 × 105 3.00 × 104 2.80 2.26 × 105 3.95 × 104 3.69 2.97 × 105
 Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft) L = 25.0 ft (lbf/ft) (in) (psi) 40.0 0.00913 470 50.0 0.0114 587 60.0 0.0137 705 70.0 0.0160 822 80.0 0.0183 940 90.0 0.0205 1060 100 0.0228 1170 200 0.0456 2350 300 0.0684 3520 400 0.0913 4700 500 0.114 5870 600 0.137 7050 700 0.160 8220 800 0.183 9400 900 0.205 1.06 × 104 1000 0.228 1.17 × 104 2000 0.456 2.35 × 104 3000 0.684 3.52 × 104 4000 0.913 4.70 × 104 5000 1.14 5.87 × 104 6000 1.37 7.05 × 104 7000 1.60 8.22 × 104 8000 1.83 9.40 × 104 9000 2.05 1.06 × 105 1.00 × 104 2.28 1.17 × 105 2.00 × 104 4.56 2.35 × 105 2.53 × 104 5.77 2.97 × 105
 Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft) L = 30.0 ft (lbf/ft) (in) (psi) 40.0 0.0189 677 50.0 0.0237 846 60.0 0.0284 1010 70.0 0.0331 1180 80.0 0.0378 1350 90.0 0.0426 1520 100 0.0473 1690 200 0.0946 3380 300 0.142 5070 400 0.189 6770 500 0.237 8460 600 0.284 1.01 × 104 700 0.331 1.18 × 104 800 0.378 1.35 × 104 900 0.426 1.52 × 104 1000 0.473 1.69 × 104 2000 0.946 3.38 × 104 3000 1.42 5.07 × 104 4000 1.89 6.77 × 104 5000 2.37 8.46 × 104 6000 2.84 1.01 × 105 7000 3.31 1.18 × 105 8000 3.78 1.35 × 105 9000 4.26 1.52 × 105 1.00 × 104 4.73 1.69 × 105 1.76 × 104 8.31 2.97 × 105
 Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft) L = 40.0 ft (lbf/ft) (in) (psi) 40.0 0.0598 1200 50.0 0.0748 1500 60.0 0.0897 1800 70.0 0.105 2110 80.0 0.120 2410 90.0 0.135 2710 100 0.150 3010 200 0.299 6010 300 0.449 9020 400 0.598 1.20 × 104 500 0.748 1.50 × 104 600 0.897 1.80 × 104 700 1.05 2.11 × 104 800 1.20 2.41 × 104 900 1.35 2.71 × 104 1000 1.50 3.01 × 104 2000 2.99 6.01 × 104 3000 4.49 9.02 × 104 4000 5.98 1.20 × 105 5000 7.48 1.50 × 105 6000 8.97 1.80 × 105 7000 10.5 2.11 × 105 8000 12.0 2.41 × 105 9000 13.5 2.71 × 105 9880 14.8 2.97 × 105
 Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft) L = 50.0 ft (lbf/ft) (in) (psi) 40.0 0.146 1880 50.0 0.183 2350 60.0 0.219 2820 70.0 0.256 3290 80.0 0.292 3760 90.0 0.329 4230 100 0.365 4700 200 0.730 9400 300 1.10 1.41 × 104 400 1.46 1.88 × 104 500 1.83 2.35 × 104 600 2.19 2.82 × 104 700 2.56 3.29 × 104 800 2.92 3.76 × 104 900 3.29 4.23 × 104 1000 3.65 4.70 × 104 2000 7.30 9.40 × 104 3000 11.0 1.41 × 105 4000 14.6 1.88 × 105 4900 17.9 2.30 × 105
 Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft) L = 60.0 ft (lbf/ft) (in) (psi) 40.0 0.303 2710 50.0 0.378 3380 60.0 0.454 4060 70.0 0.530 4740 80.0 0.606 5410 90.0 0.681 6090 100 0.757 6770 200 1.51 1.35 × 104 300 2.27 2.03 × 104 400 3.03 2.71 × 104 500 3.78 3.38 × 104 600 4.54 4.06 × 104 700 5.30 4.74 × 104 800 6.06 5.41 × 104 900 6.81 6.09 × 104 1000 7.57 6.77 × 104 2000 15.1 1.35 × 105 2360 17.9 1.60 × 105
 Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft) L = 70.0 ft (lbf/ft) (in) (psi) 40.0 0.561 3680 50.0 0.701 4600 60.0 0.841 5530 70.0 0.982 6450 80.0 1.12 7370 90.0 1.26 8290 100 1.40 9210 200 2.80 1.84 × 104 300 4.21 2.76 × 104 400 5.61 3.68 × 104 500 7.01 4.60 × 104 600 8.41 5.53 × 104 700 9.82 6.45 × 104 800 11.2 7.37 × 104 900 12.6 8.29 × 104 1000 14.0 9.21 × 104 1280 17.9 1.18 × 105
 Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft) L = 80.0 ft (lbf/ft) (in) (psi) 40.0 0.957 4810 50.0 1.20 6010 60.0 1.44 7220 70.0 1.67 8420 80.0 1.91 9620 90.0 2.15 1.08 × 104 100 2.39 1.20 × 104 200 4.78 2.41 × 104 300 7.18 3.61 × 104 400 9.57 4.81 × 104 500 12.0 6.01 × 104 600 14.4 7.22 × 104 700 16.7 8.42 × 104 748 17.9 9.00 × 104
 Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft) L = 90.0 ft (lbf/ft) (in) (psi) 40.0 1.53 6090 50.0 1.92 7610 60.0 2.30 9130 70.0 2.68 1.07 × 104 80.0 3.07 1.22 × 104 90.0 3.45 1.37 × 104 100 3.83 1.52 × 104 200 7.66 3.04 × 104 300 11.5 4.57 × 104 400 15.3 6.09 × 104 467 17.9 7.11 × 104
 Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft) L = 100 ft (lbf/ft) (in) (psi) 40.0 2.34 7520 50.0 2.92 9400 60.0 3.50 1.13 × 104 70.0 4.09 1.32 × 104 80.0 4.67 1.50 × 104 90.0 5.26 1.69 × 104 100 5.84 1.88 × 104 200 11.7 3.76 × 104 300 17.5 5.64 × 104 306 17.9 5.76 × 104
 Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft) L = 125 ft (lbf/ft) (in) (psi) 40.0 5.70 1.17 × 104 50.0 7.13 1.47 × 104 60.0 8.56 1.76 × 104 70.0 9.98 2.06 × 104 80.0 11.4 2.35 × 104 90.0 12.8 2.64 × 104 100 14.3 2.94 × 104 126 17.9 3.69 × 104
 Steel I Beam: W18 × 40 (Wide Flange 18 inch tall × 40 lbf/ft) L = 150 ft (lbf/ft) (in) (psi) 40.0 11.8 1.69 × 104 50.0 14.8 2.11 × 104 60.0 17.7 2.54 × 104 60.5 17.9 2.56 × 104