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Glossary » Beams » Simply Supported » Uniformly Distributed Load » Three Equal Spans » Wide Flange Steel I Beam » W18 × 50
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 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 = 800 in4) for the W18 × 50 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 × 50 (Wide Flange 18 inch tall × 50 lbf/ft) L = 3.00 ft (lbf/ft) (in) (psi) 50.0 1.95 × 10-6 6.07 60.0 2.34 × 10-6 7.29 70.0 2.73 × 10-6 8.50 80.0 3.12 × 10-6 9.71 90.0 3.52 × 10-6 10.9 100 3.91 × 10-6 12.1 200 7.81 × 10-6 24.3 300 1.17 × 10-5 36.4 400 1.56 × 10-5 48.6 500 1.95 × 10-5 60.7 600 2.34 × 10-5 72.9 700 2.73 × 10-5 85.0 800 3.12 × 10-5 97.1 900 3.52 × 10-5 109 1000 3.91 × 10-5 121 2000 7.81 × 10-5 243 3000 1.17 × 10-4 364 4000 1.56 × 10-4 486 5000 1.95 × 10-4 607 6000 2.34 × 10-4 729 7000 2.73 × 10-4 850 8000 3.12 × 10-4 971 9000 3.52 × 10-4 1090 1.00 × 104 3.91 × 10-4 1210 2.00 × 104 7.81 × 10-4 2430 3.00 × 104 0.00117 3640 4.00 × 104 0.00156 4860 5.00 × 104 0.00195 6070 6.00 × 104 0.00234 7290 7.00 × 104 0.00273 8500 8.00 × 104 0.00312 9710 9.00 × 104 0.00352 1.09 × 104 1.00 × 105 0.00391 1.21 × 104 2.00 × 105 0.00781 2.43 × 104 3.00 × 105 0.0117 3.64 × 104 4.00 × 105 0.0156 4.86 × 104 5.00 × 105 0.0195 6.07 × 104 6.00 × 105 0.0234 7.29 × 104 7.00 × 105 0.0273 8.50 × 104 8.00 × 105 0.0312 9.71 × 104 9.00 × 105 0.0352 1.09 × 105 1.00 × 106 0.0391 1.21 × 105 2.00 × 106 0.0781 2.43 × 105 2.45 × 106 0.0955 2.97 × 105
 Steel I Beam: W18 × 50 (Wide Flange 18 inch tall × 50 lbf/ft) L = 5.00 ft (lbf/ft) (in) (psi) 50.0 1.51 × 10-5 16.9 60.0 1.81 × 10-5 20.2 70.0 2.11 × 10-5 23.6 80.0 2.41 × 10-5 27.0 90.0 2.71 × 10-5 30.4 100 3.01 × 10-5 33.7 200 6.03 × 10-5 67.5 300 9.04 × 10-5 101 400 1.21 × 10-4 135 500 1.51 × 10-4 169 600 1.81 × 10-4 202 700 2.11 × 10-4 236 800 2.41 × 10-4 270 900 2.71 × 10-4 304 1000 3.01 × 10-4 337 2000 6.03 × 10-4 675 3000 9.04 × 10-4 1010 4000 0.00121 1350 5000 0.00151 1690 6000 0.00181 2020 7000 0.00211 2360 8000 0.00241 2700 9000 0.00271 3040 1.00 × 104 0.00301 3370 2.00 × 104 0.00603 6750 3.00 × 104 0.00904 1.01 × 104 4.00 × 104 0.0121 1.35 × 104 5.00 × 104 0.0151 1.69 × 104 6.00 × 104 0.0181 2.02 × 104 7.00 × 104 0.0211 2.36 × 104 8.00 × 104 0.0241 2.70 × 104 9.00 × 104 0.0271 3.04 × 104 1.00 × 105 0.0301 3.37 × 104 2.00 × 105 0.0603 6.75 × 104 3.00 × 105 0.0904 1.01 × 105 4.00 × 105 0.121 1.35 × 105 5.00 × 105 0.151 1.69 × 105 6.00 × 105 0.181 2.02 × 105 7.00 × 105 0.211 2.36 × 105 8.00 × 105 0.241 2.70 × 105 8.81 × 105 0.265 2.97 × 105
 Steel I Beam: W18 × 50 (Wide Flange 18 inch tall × 50 lbf/ft) L = 10.0 ft (lbf/ft) (in) (psi) 50.0 2.41 × 10-4 67.5 60.0 2.89 × 10-4 81.0 70.0 3.38 × 10-4 94.4 80.0 3.86 × 10-4 108 90.0 4.34 × 10-4 121 100 4.82 × 10-4 135 200 9.64 × 10-4 270 300 0.00145 405 400 0.00193 540 500 0.00241 675 600 0.00289 810 700 0.00338 944 800 0.00386 1080 900 0.00434 1210 1000 0.00482 1350 2000 0.00964 2700 3000 0.0145 4050 4000 0.0193 5400 5000 0.0241 6750 6000 0.0289 8100 7000 0.0338 9440 8000 0.0386 1.08 × 104 9000 0.0434 1.21 × 104 1.00 × 104 0.0482 1.35 × 104 2.00 × 104 0.0964 2.70 × 104 3.00 × 104 0.145 4.05 × 104 4.00 × 104 0.193 5.40 × 104 5.00 × 104 0.241 6.75 × 104 6.00 × 104 0.289 8.10 × 104 7.00 × 104 0.338 9.44 × 104 8.00 × 104 0.386 1.08 × 105 9.00 × 104 0.434 1.21 × 105 1.00 × 105 0.482 1.35 × 105 2.00 × 105 0.964 2.70 × 105 2.20 × 105 1.06 2.97 × 105
 Steel I Beam: W18 × 50 (Wide Flange 18 inch tall × 50 lbf/ft) L = 15.0 ft (lbf/ft) (in) (psi) 50.0 0.00122 152 60.0 0.00146 182 70.0 0.00171 213 80.0 0.00195 243 90.0 0.00220 273 100 0.00244 304 200 0.00488 607 300 0.00732 911 400 0.00977 1210 500 0.0122 1520 600 0.0146 1820 700 0.0171 2130 800 0.0195 2430 900 0.0220 2730 1000 0.0244 3040 2000 0.0488 6070 3000 0.0732 9110 4000 0.0977 1.21 × 104 5000 0.122 1.52 × 104 6000 0.146 1.82 × 104 7000 0.171 2.13 × 104 8000 0.195 2.43 × 104 9000 0.220 2.73 × 104 1.00 × 104 0.244 3.04 × 104 2.00 × 104 0.488 6.07 × 104 3.00 × 104 0.732 9.11 × 104 4.00 × 104 0.977 1.21 × 105 5.00 × 104 1.22 1.52 × 105 6.00 × 104 1.46 1.82 × 105 7.00 × 104 1.71 2.13 × 105 8.00 × 104 1.95 2.43 × 105 9.00 × 104 2.20 2.73 × 105 9.78 × 104 2.39 2.97 × 105
 Steel I Beam: W18 × 50 (Wide Flange 18 inch tall × 50 lbf/ft) L = 20.0 ft (lbf/ft) (in) (psi) 50.0 0.00386 270 60.0 0.00463 324 70.0 0.00540 378 80.0 0.00617 432 90.0 0.00694 486 100 0.00772 540 200 0.0154 1080 300 0.0231 1620 400 0.0309 2160 500 0.0386 2700 600 0.0463 3240 700 0.0540 3780 800 0.0617 4320 900 0.0694 4860 1000 0.0772 5400 2000 0.154 1.08 × 104 3000 0.231 1.62 × 104 4000 0.309 2.16 × 104 5000 0.386 2.70 × 104 6000 0.463 3.24 × 104 7000 0.540 3.78 × 104 8000 0.617 4.32 × 104 9000 0.694 4.86 × 104 1.00 × 104 0.772 5.40 × 104 2.00 × 104 1.54 1.08 × 105 3.00 × 104 2.31 1.62 × 105 4.00 × 104 3.09 2.16 × 105 5.00 × 104 3.86 2.70 × 105 5.50 × 104 4.25 2.97 × 105
 Steel I Beam: W18 × 50 (Wide Flange 18 inch tall × 50 lbf/ft) L = 25.0 ft (lbf/ft) (in) (psi) 50.0 0.00942 422 60.0 0.0113 506 70.0 0.0132 590 80.0 0.0151 675 90.0 0.0170 759 100 0.0188 843 200 0.0377 1690 300 0.0565 2530 400 0.0753 3370 500 0.0942 4220 600 0.113 5060 700 0.132 5900 800 0.151 6750 900 0.170 7590 1000 0.188 8430 2000 0.377 1.69 × 104 3000 0.565 2.53 × 104 4000 0.753 3.37 × 104 5000 0.942 4.22 × 104 6000 1.13 5.06 × 104 7000 1.32 5.90 × 104 8000 1.51 6.75 × 104 9000 1.70 7.59 × 104 1.00 × 104 1.88 8.43 × 104 2.00 × 104 3.77 1.69 × 105 3.00 × 104 5.65 2.53 × 105 3.52 × 104 6.64 2.97 × 105
 Steel I Beam: W18 × 50 (Wide Flange 18 inch tall × 50 lbf/ft) L = 30.0 ft (lbf/ft) (in) (psi) 50.0 0.0195 607 60.0 0.0234 729 70.0 0.0273 850 80.0 0.0312 971 90.0 0.0352 1090 100 0.0391 1210 200 0.0781 2430 300 0.117 3640 400 0.156 4860 500 0.195 6070 600 0.234 7290 700 0.273 8500 800 0.312 9710 900 0.352 1.09 × 104 1000 0.391 1.21 × 104 2000 0.781 2.43 × 104 3000 1.17 3.64 × 104 4000 1.56 4.86 × 104 5000 1.95 6.07 × 104 6000 2.34 7.29 × 104 7000 2.73 8.50 × 104 8000 3.12 9.71 × 104 9000 3.52 1.09 × 105 1.00 × 104 3.91 1.21 × 105 2.00 × 104 7.81 2.43 × 105 2.45 × 104 9.55 2.97 × 105
 Steel I Beam: W18 × 50 (Wide Flange 18 inch tall × 50 lbf/ft) L = 40.0 ft (lbf/ft) (in) (psi) 50.0 0.0617 1080 60.0 0.0741 1300 70.0 0.0864 1510 80.0 0.0988 1730 90.0 0.111 1940 100 0.123 2160 200 0.247 4320 300 0.370 6480 400 0.494 8640 500 0.617 1.08 × 104 600 0.741 1.30 × 104 700 0.864 1.51 × 104 800 0.988 1.73 × 104 900 1.11 1.94 × 104 1000 1.23 2.16 × 104 2000 2.47 4.32 × 104 3000 3.70 6.48 × 104 4000 4.94 8.64 × 104 5000 6.17 1.08 × 105 6000 7.41 1.30 × 105 7000 8.64 1.51 × 105 8000 9.88 1.73 × 105 9000 11.1 1.94 × 105 1.00 × 104 12.3 2.16 × 105 1.38 × 104 17.0 2.97 × 105
 Steel I Beam: W18 × 50 (Wide Flange 18 inch tall × 50 lbf/ft) L = 50.0 ft (lbf/ft) (in) (psi) 50.0 0.151 1690 60.0 0.181 2020 70.0 0.211 2360 80.0 0.241 2700 90.0 0.271 3040 100 0.301 3370 200 0.603 6750 300 0.904 1.01 × 104 400 1.21 1.35 × 104 500 1.51 1.69 × 104 600 1.81 2.02 × 104 700 2.11 2.36 × 104 800 2.41 2.70 × 104 900 2.71 3.04 × 104 1000 3.01 3.37 × 104 2000 6.03 6.75 × 104 3000 9.04 1.01 × 105 4000 12.1 1.35 × 105 5000 15.1 1.69 × 105 5970 18.0 2.01 × 105
 Steel I Beam: W18 × 50 (Wide Flange 18 inch tall × 50 lbf/ft) L = 60.0 ft (lbf/ft) (in) (psi) 50.0 0.312 2430 60.0 0.375 2910 70.0 0.437 3400 80.0 0.500 3890 90.0 0.562 4370 100 0.625 4860 200 1.25 9710 300 1.87 1.46 × 104 400 2.50 1.94 × 104 500 3.12 2.43 × 104 600 3.75 2.91 × 104 700 4.37 3.40 × 104 800 5.00 3.89 × 104 900 5.62 4.37 × 104 1000 6.25 4.86 × 104 2000 12.5 9.71 × 104 2880 18.0 1.40 × 105
 Steel I Beam: W18 × 50 (Wide Flange 18 inch tall × 50 lbf/ft) L = 70.0 ft (lbf/ft) (in) (psi) 50.0 0.579 3310 60.0 0.695 3970 70.0 0.810 4630 80.0 0.926 5290 90.0 1.04 5950 100 1.16 6610 200 2.32 1.32 × 104 300 3.47 1.98 × 104 400 4.63 2.64 × 104 500 5.79 3.31 × 104 600 6.95 3.97 × 104 700 8.10 4.63 × 104 800 9.26 5.29 × 104 900 10.4 5.95 × 104 1000 11.6 6.61 × 104 1550 18.0 1.03 × 105
 Steel I Beam: W18 × 50 (Wide Flange 18 inch tall × 50 lbf/ft) L = 80.0 ft (lbf/ft) (in) (psi) 50.0 0.988 4320 60.0 1.19 5180 70.0 1.38 6040 80.0 1.58 6910 90.0 1.78 7770 100 1.98 8640 200 3.95 1.73 × 104 300 5.93 2.59 × 104 400 7.90 3.45 × 104 500 9.88 4.32 × 104 600 11.9 5.18 × 104 700 13.8 6.04 × 104 800 15.8 6.91 × 104 900 17.8 7.77 × 104 911 18.0 7.86 × 104
 Steel I Beam: W18 × 50 (Wide Flange 18 inch tall × 50 lbf/ft) L = 90.0 ft (lbf/ft) (in) (psi) 50.0 1.58 5460 60.0 1.90 6560 70.0 2.21 7650 80.0 2.53 8740 90.0 2.85 9840 100 3.16 1.09 × 104 200 6.33 2.19 × 104 300 9.49 3.28 × 104 400 12.7 4.37 × 104 500 15.8 5.46 × 104 569 18.0 6.21 × 104
 Steel I Beam: W18 × 50 (Wide Flange 18 inch tall × 50 lbf/ft) L = 100 ft (lbf/ft) (in) (psi) 50.0 2.41 6750 60.0 2.89 8100 70.0 3.38 9440 80.0 3.86 1.08 × 104 90.0 4.34 1.21 × 104 100 4.82 1.35 × 104 200 9.64 2.70 × 104 300 14.5 4.05 × 104 373 18.0 5.03 × 104
 Steel I Beam: W18 × 50 (Wide Flange 18 inch tall × 50 lbf/ft) L = 125 ft (lbf/ft) (in) (psi) 50.0 5.89 1.05 × 104 60.0 7.06 1.26 × 104 70.0 8.24 1.48 × 104 80.0 9.42 1.69 × 104 90.0 10.6 1.90 × 104 100 11.8 2.11 × 104 153 18.0 3.22 × 104
 Steel I Beam: W18 × 50 (Wide Flange 18 inch tall × 50 lbf/ft) L = 150 ft (lbf/ft) (in) (psi) 50.0 12.2 1.52 × 104 60.0 14.6 1.82 × 104 70.0 17.1 2.13 × 104 73.7 18.0 2.24 × 104
Related Pages

Learn the best principles to negotiate the salary you deserve!

Essentials of Manufacturing

Information, coverage of important developments and expert commentary in manufacturing.

Injection Molding Design Guide

Guide for high quality and cost-effective plastic injection molding.

Mechanical Engineers Outlook

Guide for those interested in becoming a mechanical engineer. Includes qualifications, pay, and job duties.