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I have a retangular steel (A36) tube that is 2x6 inches with a 5/16 inch wall and 11 feet long. Can it center lift a 5000 pound weight attached evenly to its endpoints? How much deflection will occur by this 5000 pound weigth? (Converse: A 5000 pound mid-point weight on this beam supported at its ends.) Its a moment of inertia is 18.2 in^2: MI = (2 * 6^3 - 1.375 * 5.375^3) / 12 = 18.21

Deflection of this beam, center lifting a 5000 pound load: Deflection = 132^3 * 5000 / (48 * 29 * 10^6 * 18.21) = 0.454"

Are these calculations correct? What is the maximun weight this bar can support before being permanently deformed?

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  • $\begingroup$ Start here: engineeringtoolbox.com/beam-stress-deflection-d_1312.html $\endgroup$
    – Solar Mike
    Commented Jun 16 at 18:30
  • $\begingroup$ Lifting rigs that are potentially lethal (2.5 tons is potentially lethal) need a factor of safety of 10 in Australia, and are annually checked to 4. Your beam fails both of those tests woefully. Also, how do you stop the beam from toppling over? $\endgroup$
    – Greg Locock
    Commented Jun 17 at 4:23
  • $\begingroup$ The max tensile stress on the beam is M*y/I, which must be less than the yield stress (36ksi) with a safety factor. $\endgroup$
    – r13
    Commented Jun 18 at 17:53

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