Wide Flange Steel I Beam: W8 × 21

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Glossary » Beams » Simply Supported » Uniformly Distributed Load » Three 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 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 = 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 8.71 × 10-6 12.5 30.0 1.24 × 10-5 17.8 40.0 1.66 × 10-5 23.8 50.0 2.07 × 10-5 29.7 60.0 2.49 × 10-5 35.6 70.0 2.90 × 10-5 41.6 80.0 3.32 × 10-5 47.5 90.0 3.73 × 10-5 53.4 100 4.15 × 10-5 59.4 200 8.30 × 10-5 119 300 1.24 × 10-4 178 400 1.66 × 10-4 238 500 2.07 × 10-4 297 600 2.49 × 10-4 356 700 2.90 × 10-4 416 800 3.32 × 10-4 475 900 3.73 × 10-4 534 1000 4.15 × 10-4 594 2000 8.30 × 10-4 1190 3000 0.00124 1780 4000 0.00166 2380 5000 0.00207 2970 6000 0.00249 3560 7000 0.00290 4160 8000 0.00332 4750 9000 0.00373 5340 1.00 × 104 0.00415 5940 2.00 × 104 0.00830 1.19 × 104 3.00 × 104 0.0124 1.78 × 104 4.00 × 104 0.0166 2.38 × 104 5.00 × 104 0.0207 2.97 × 104 6.00 × 104 0.0249 3.56 × 104 7.00 × 104 0.0290 4.16 × 104 8.00 × 104 0.0332 4.75 × 104 9.00 × 104 0.0373 5.34 × 104 1.00 × 105 0.0415 5.94 × 104 2.00 × 105 0.0830 1.19 × 105 3.00 × 105 0.124 1.78 × 105 4.00 × 105 0.166 2.38 × 105 5.00 × 105 0.207 2.97 × 105 5.00 × 105 0.208 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 6.72 × 10-5 34.6 30.0 9.61 × 10-5 49.5 40.0 1.28 × 10-4 66.0 50.0 1.60 × 10-4 82.5 60.0 1.92 × 10-4 99.0 70.0 2.24 × 10-4 115 80.0 2.56 × 10-4 132 90.0 2.88 × 10-4 148 100 3.20 × 10-4 165 200 6.40 × 10-4 330 300 9.61 × 10-4 495 400 0.00128 660 500 0.00160 825 600 0.00192 990 700 0.00224 1150 800 0.00256 1320 900 0.00288 1480 1000 0.00320 1650 2000 0.00640 3300 3000 0.00961 4950 4000 0.0128 6600 5000 0.0160 8250 6000 0.0192 9900 7000 0.0224 1.15 × 104 8000 0.0256 1.32 × 104 9000 0.0288 1.48 × 104 1.00 × 104 0.0320 1.65 × 104 2.00 × 104 0.0640 3.30 × 104 3.00 × 104 0.0961 4.95 × 104 4.00 × 104 0.128 6.60 × 104 5.00 × 104 0.160 8.25 × 104 6.00 × 104 0.192 9.90 × 104 7.00 × 104 0.224 1.15 × 105 8.00 × 104 0.256 1.32 × 105 9.00 × 104 0.288 1.48 × 105 1.00 × 105 0.320 1.65 × 105 1.80 × 105 0.577 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 0.00108 139 30.0 0.00154 198 40.0 0.00205 264 50.0 0.00256 330 60.0 0.00307 396 70.0 0.00359 462 80.0 0.00410 528 90.0 0.00461 594 100 0.00512 660 200 0.0102 1320 300 0.0154 1980 400 0.0205 2640 500 0.0256 3300 600 0.0307 3960 700 0.0359 4620 800 0.0410 5280 900 0.0461 5940 1000 0.0512 6600 2000 0.102 1.32 × 104 3000 0.154 1.98 × 104 4000 0.205 2.64 × 104 5000 0.256 3.30 × 104 6000 0.307 3.96 × 104 7000 0.359 4.62 × 104 8000 0.410 5.28 × 104 9000 0.461 5.94 × 104 1.00 × 104 0.512 6.60 × 104 2.00 × 104 1.02 1.32 × 105 3.00 × 104 1.54 1.98 × 105 4.00 × 104 2.05 2.64 × 105 4.50 × 104 2.31 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 0.00545 312 30.0 0.00778 445 40.0 0.0104 594 50.0 0.0130 742 60.0 0.0156 891 70.0 0.0182 1040 80.0 0.0207 1190 90.0 0.0233 1340 100 0.0259 1480 200 0.0519 2970 300 0.0778 4450 400 0.104 5940 500 0.130 7420 600 0.156 8910 700 0.182 1.04 × 104 800 0.207 1.19 × 104 900 0.233 1.34 × 104 1000 0.259 1.48 × 104 2000 0.519 2.97 × 104 3000 0.778 4.45 × 104 4000 1.04 5.94 × 104 5000 1.30 7.42 × 104 6000 1.56 8.91 × 104 7000 1.82 1.04 × 105 8000 2.07 1.19 × 105 9000 2.33 1.34 × 105 1.00 × 104 2.59 1.48 × 105 2.00 × 104 5.19 2.97 × 105 2.00 × 104 5.19 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 0.0172 554 30.0 0.0246 792 40.0 0.0328 1060 50.0 0.0410 1320 60.0 0.0492 1580 70.0 0.0574 1850 80.0 0.0656 2110 90.0 0.0738 2380 100 0.0820 2640 200 0.164 5280 300 0.246 7920 400 0.328 1.06 × 104 500 0.410 1.32 × 104 600 0.492 1.58 × 104 700 0.574 1.85 × 104 800 0.656 2.11 × 104 900 0.738 2.38 × 104 1000 0.820 2.64 × 104 2000 1.64 5.28 × 104 3000 2.46 7.92 × 104 4000 3.28 1.06 × 105 5000 4.10 1.32 × 105 6000 4.92 1.58 × 105 7000 5.74 1.85 × 105 8000 6.56 2.11 × 105 9000 7.38 2.38 × 105 1.00 × 104 8.20 2.64 × 105 1.13 × 104 9.23 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 0.0420 866 30.0 0.0600 1240 40.0 0.0801 1650 50.0 0.100 2060 60.0 0.120 2470 70.0 0.140 2890 80.0 0.160 3300 90.0 0.180 3710 100 0.200 4120 200 0.400 8250 300 0.600 1.24 × 104 400 0.801 1.65 × 104 500 1.00 2.06 × 104 600 1.20 2.47 × 104 700 1.40 2.89 × 104 800 1.60 3.30 × 104 900 1.80 3.71 × 104 1000 2.00 4.12 × 104 2000 4.00 8.25 × 104 3000 6.00 1.24 × 105 4000 8.01 1.65 × 105 4140 8.28 1.71 × 105
 Steel I Beam: W8 × 21 (Wide Flange 8 inch tall × 21 lbf/ft) L = 30.0 ft (lbf/ft) (in) (psi) 21.0 0.0871 1250 30.0 0.124 1780 40.0 0.166 2380 50.0 0.207 2970 60.0 0.249 3560 70.0 0.290 4160 80.0 0.332 4750 90.0 0.373 5340 100 0.415 5940 200 0.830 1.19 × 104 300 1.24 1.78 × 104 400 1.66 2.38 × 104 500 2.07 2.97 × 104 600 2.49 3.56 × 104 700 2.90 4.16 × 104 800 3.32 4.75 × 104 900 3.73 5.34 × 104 1000 4.15 5.94 × 104 2000 8.28 1.18 × 105
 Steel I Beam: W8 × 21 (Wide Flange 8 inch tall × 21 lbf/ft) L = 40.0 ft (lbf/ft) (in) (psi) 21.0 0.275 2220 30.0 0.393 3170 40.0 0.525 4220 50.0 0.656 5280 60.0 0.787 6330 70.0 0.918 7390 80.0 1.05 8440 90.0 1.18 9500 100 1.31 1.06 × 104 200 2.62 2.11 × 104 300 3.93 3.17 × 104 400 5.25 4.22 × 104 500 6.56 5.28 × 104 600 7.87 6.33 × 104 631 8.28 6.66 × 104
 Steel I Beam: W8 × 21 (Wide Flange 8 inch tall × 21 lbf/ft) L = 50.0 ft (lbf/ft) (in) (psi) 21.0 0.672 3460 30.0 0.961 4950 40.0 1.28 6600 50.0 1.60 8250 60.0 1.92 9900 70.0 2.24 1.15 × 104 80.0 2.56 1.32 × 104 90.0 2.88 1.48 × 104 100 3.20 1.65 × 104 200 6.40 3.30 × 104 259 8.28 4.27 × 104
 Steel I Beam: W8 × 21 (Wide Flange 8 inch tall × 21 lbf/ft) L = 60.0 ft (lbf/ft) (in) (psi) 21.0 1.39 4990 30.0 1.99 7130 40.0 2.66 9500 50.0 3.32 1.19 × 104 60.0 3.98 1.43 × 104 70.0 4.65 1.66 × 104 80.0 5.31 1.90 × 104 90.0 5.98 2.14 × 104 100 6.64 2.38 × 104 125 8.28 2.96 × 104
 Steel I Beam: W8 × 21 (Wide Flange 8 inch tall × 21 lbf/ft) L = 70.0 ft (lbf/ft) (in) (psi) 21.0 2.58 6790 30.0 3.69 9700 40.0 4.92 1.29 × 104 50.0 6.15 1.62 × 104 60.0 7.38 1.94 × 104 67.3 8.28 2.18 × 104
 Steel I Beam: W8 × 21 (Wide Flange 8 inch tall × 21 lbf/ft) L = 80.0 ft (lbf/ft) (in) (psi) 21.0 4.41 8870 30.0 6.30 1.27 × 104 39.5 8.28 1.67 × 104
 Steel I Beam: W8 × 21 (Wide Flange 8 inch tall × 21 lbf/ft) L = 90.0 ft (lbf/ft) (in) (psi) 21.0 7.06 1.12 × 104 24.6 8.28 1.32 × 104