Wide Flange Steel I Beam: W8 × 21

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Glossary » Beams » Simply Supported » Uniformly Distributed Load » Four Equal Spans » Wide Flange Steel I Beam » W8 × 21
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 = 75.3 in4) for the W8 × 21 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 × 21 (Wide Flange 8 inch tall × 21 lbf/ft) L = 3.00 ft (lbf/ft) (in) (psi) 21.0 8.07 × 10-6 13.4 30.0 1.15 × 10-5 19.1 40.0 1.54 × 10-5 25.4 50.0 1.92 × 10-5 31.8 60.0 2.31 × 10-5 38.2 70.0 2.69 × 10-5 44.5 80.0 3.08 × 10-5 50.9 90.0 3.46 × 10-5 57.2 100 3.84 × 10-5 63.6 200 7.69 × 10-5 127 300 1.15 × 10-4 191 400 1.54 × 10-4 254 500 1.92 × 10-4 318 600 2.31 × 10-4 382 700 2.69 × 10-4 445 800 3.08 × 10-4 509 900 3.46 × 10-4 572 1000 3.84 × 10-4 636 2000 7.69 × 10-4 1270 3000 0.00115 1910 4000 0.00154 2540 5000 0.00192 3180 6000 0.00231 3820 7000 0.00269 4450 8000 0.00308 5090 9000 0.00346 5720 1.00 × 104 0.00384 6360 2.00 × 104 0.00769 1.27 × 104 3.00 × 104 0.0115 1.91 × 104 4.00 × 104 0.0154 2.54 × 104 5.00 × 104 0.0192 3.18 × 104 6.00 × 104 0.0231 3.82 × 104 7.00 × 104 0.0269 4.45 × 104 8.00 × 104 0.0308 5.09 × 104 9.00 × 104 0.0346 5.72 × 104 1.00 × 105 0.0384 6.36 × 104 2.00 × 105 0.0769 1.27 × 105 3.00 × 105 0.115 1.91 × 105 4.00 × 105 0.154 2.54 × 105 4.67 × 105 0.180 2.97 × 105
 Steel I Beam: W8 × 21 (Wide Flange 8 inch tall × 21 lbf/ft) L = 5.00 ft (lbf/ft) (in) (psi) 21.0 6.23 × 10-5 37.1 30.0 8.90 × 10-5 53.0 40.0 1.19 × 10-4 70.7 50.0 1.48 × 10-4 88.3 60.0 1.78 × 10-4 106 70.0 2.08 × 10-4 124 80.0 2.37 × 10-4 141 90.0 2.67 × 10-4 159 100 2.97 × 10-4 177 200 5.93 × 10-4 353 300 8.90 × 10-4 530 400 0.00119 707 500 0.00148 883 600 0.00178 1060 700 0.00208 1240 800 0.00237 1410 900 0.00267 1590 1000 0.00297 1770 2000 0.00593 3530 3000 0.00890 5300 4000 0.0119 7070 5000 0.0148 8830 6000 0.0178 1.06 × 104 7000 0.0208 1.24 × 104 8000 0.0237 1.41 × 104 9000 0.0267 1.59 × 104 1.00 × 104 0.0297 1.77 × 104 2.00 × 104 0.0593 3.53 × 104 3.00 × 104 0.0890 5.30 × 104 4.00 × 104 0.119 7.07 × 104 5.00 × 104 0.148 8.83 × 104 6.00 × 104 0.178 1.06 × 105 7.00 × 104 0.208 1.24 × 105 8.00 × 104 0.237 1.41 × 105 9.00 × 104 0.267 1.59 × 105 1.00 × 105 0.297 1.77 × 105 1.68 × 105 0.499 2.97 × 105
 Steel I Beam: W8 × 21 (Wide Flange 8 inch tall × 21 lbf/ft) L = 10.0 ft (lbf/ft) (in) (psi) 21.0 9.97 × 10-4 148 30.0 0.00142 212 40.0 0.00190 283 50.0 0.00237 353 60.0 0.00285 424 70.0 0.00332 495 80.0 0.00380 565 90.0 0.00427 636 100 0.00475 707 200 0.00949 1410 300 0.0142 2120 400 0.0190 2830 500 0.0237 3530 600 0.0285 4240 700 0.0332 4950 800 0.0380 5650 900 0.0427 6360 1000 0.0475 7070 2000 0.0949 1.41 × 104 3000 0.142 2.12 × 104 4000 0.190 2.83 × 104 5000 0.237 3.53 × 104 6000 0.285 4.24 × 104 7000 0.332 4.95 × 104 8000 0.380 5.65 × 104 9000 0.427 6.36 × 104 1.00 × 104 0.475 7.07 × 104 2.00 × 104 0.949 1.41 × 105 3.00 × 104 1.42 2.12 × 105 4.00 × 104 1.90 2.83 × 105 4.20 × 104 2.00 2.97 × 105
 Steel I Beam: W8 × 21 (Wide Flange 8 inch tall × 21 lbf/ft) L = 15.0 ft (lbf/ft) (in) (psi) 21.0 0.00505 334 30.0 0.00721 477 40.0 0.00961 636 50.0 0.0120 795 60.0 0.0144 954 70.0 0.0168 1110 80.0 0.0192 1270 90.0 0.0216 1430 100 0.0240 1590 200 0.0481 3180 300 0.0721 4770 400 0.0961 6360 500 0.120 7950 600 0.144 9540 700 0.168 1.11 × 104 800 0.192 1.27 × 104 900 0.216 1.43 × 104 1000 0.240 1.59 × 104 2000 0.481 3.18 × 104 3000 0.721 4.77 × 104 4000 0.961 6.36 × 104 5000 1.20 7.95 × 104 6000 1.44 9.54 × 104 7000 1.68 1.11 × 105 8000 1.92 1.27 × 105 9000 2.16 1.43 × 105 1.00 × 104 2.40 1.59 × 105 1.87 × 104 4.49 2.97 × 105
 Steel I Beam: W8 × 21 (Wide Flange 8 inch tall × 21 lbf/ft) L = 20.0 ft (lbf/ft) (in) (psi) 21.0 0.0159 594 30.0 0.0228 848 40.0 0.0304 1130 50.0 0.0380 1410 60.0 0.0456 1700 70.0 0.0532 1980 80.0 0.0608 2260 90.0 0.0684 2540 100 0.0759 2830 200 0.152 5650 300 0.228 8480 400 0.304 1.13 × 104 500 0.380 1.41 × 104 600 0.456 1.70 × 104 700 0.532 1.98 × 104 800 0.608 2.26 × 104 900 0.684 2.54 × 104 1000 0.759 2.83 × 104 2000 1.52 5.65 × 104 3000 2.28 8.48 × 104 4000 3.04 1.13 × 105 5000 3.80 1.41 × 105 6000 4.56 1.70 × 105 7000 5.32 1.98 × 105 8000 6.08 2.26 × 105 9000 6.84 2.54 × 105 1.00 × 104 7.59 2.83 × 105 1.05 × 104 7.98 2.97 × 105
 Steel I Beam: W8 × 21 (Wide Flange 8 inch tall × 21 lbf/ft) L = 25.0 ft (lbf/ft) (in) (psi) 21.0 0.0389 927 30.0 0.0556 1320 40.0 0.0742 1770 50.0 0.0927 2210 60.0 0.111 2650 70.0 0.130 3090 80.0 0.148 3530 90.0 0.167 3970 100 0.185 4420 200 0.371 8830 300 0.556 1.32 × 104 400 0.742 1.77 × 104 500 0.927 2.21 × 104 600 1.11 2.65 × 104 700 1.30 3.09 × 104 800 1.48 3.53 × 104 900 1.67 3.97 × 104 1000 1.85 4.42 × 104 2000 3.71 8.83 × 104 3000 5.56 1.32 × 105 4000 7.42 1.77 × 105 4470 8.28 1.97 × 105
 Steel I Beam: W8 × 21 (Wide Flange 8 inch tall × 21 lbf/ft) L = 30.0 ft (lbf/ft) (in) (psi) 21.0 0.0807 1340 30.0 0.115 1910 40.0 0.154 2540 50.0 0.192 3180 60.0 0.231 3820 70.0 0.269 4450 80.0 0.308 5090 90.0 0.346 5720 100 0.384 6360 200 0.769 1.27 × 104 300 1.15 1.91 × 104 400 1.54 2.54 × 104 500 1.92 3.18 × 104 600 2.31 3.82 × 104 700 2.69 4.45 × 104 800 3.08 5.09 × 104 900 3.46 5.72 × 104 1000 3.84 6.36 × 104 2000 7.69 1.27 × 105 2150 8.28 1.37 × 105
 Steel I Beam: W8 × 21 (Wide Flange 8 inch tall × 21 lbf/ft) L = 40.0 ft (lbf/ft) (in) (psi) 21.0 0.255 2370 30.0 0.365 3390 40.0 0.486 4520 50.0 0.608 5650 60.0 0.729 6780 70.0 0.851 7910 80.0 0.972 9040 90.0 1.09 1.02 × 104 100 1.22 1.13 × 104 200 2.43 2.26 × 104 300 3.65 3.39 × 104 400 4.86 4.52 × 104 500 6.08 5.65 × 104 600 7.29 6.78 × 104 681 8.28 7.70 × 104
 Steel I Beam: W8 × 21 (Wide Flange 8 inch tall × 21 lbf/ft) L = 50.0 ft (lbf/ft) (in) (psi) 21.0 0.623 3710 30.0 0.890 5300 40.0 1.19 7070 50.0 1.48 8830 60.0 1.78 1.06 × 104 70.0 2.08 1.24 × 104 80.0 2.37 1.41 × 104 90.0 2.67 1.59 × 104 100 2.97 1.77 × 104 200 5.93 3.53 × 104 279 8.28 4.93 × 104
 Steel I Beam: W8 × 21 (Wide Flange 8 inch tall × 21 lbf/ft) L = 60.0 ft (lbf/ft) (in) (psi) 21.0 1.29 5340 30.0 1.85 7630 40.0 2.46 1.02 × 104 50.0 3.08 1.27 × 104 60.0 3.69 1.53 × 104 70.0 4.31 1.78 × 104 80.0 4.92 2.04 × 104 90.0 5.54 2.29 × 104 100 6.15 2.54 × 104 135 8.28 3.42 × 104
 Steel I Beam: W8 × 21 (Wide Flange 8 inch tall × 21 lbf/ft) L = 70.0 ft (lbf/ft) (in) (psi) 21.0 2.39 7270 30.0 3.42 1.04 × 104 40.0 4.56 1.38 × 104 50.0 5.70 1.73 × 104 60.0 6.84 2.08 × 104 70.0 7.98 2.42 × 104 72.7 8.28 2.52 × 104
 Steel I Beam: W8 × 21 (Wide Flange 8 inch tall × 21 lbf/ft) L = 80.0 ft (lbf/ft) (in) (psi) 21.0 4.08 9500 30.0 5.83 1.36 × 104 40.0 7.78 1.81 × 104 42.6 8.28 1.93 × 104
 Steel I Beam: W8 × 21 (Wide Flange 8 inch tall × 21 lbf/ft) L = 90.0 ft (lbf/ft) (in) (psi) 21.0 6.54 1.20 × 104 26.6 8.28 1.52 × 104