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Deflection of fixed beam with point load at center

  1. Aug 11, 2014 #1
    i have a 20.5ft c3x5 steel channel with a point load at the exact center and i wanted to determine its maximum deflection.

    the point load is 921.86lbs, and moment of inertia is 1.86in^4.

    modulus of E= 30,000,000psi
  2. jcsd
  3. Aug 15, 2014 #2
    I'm sorry you are not finding help at the moment. Is there any additional information you can share with us?
  4. Aug 16, 2014 #3


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    if the beam is truly fixed against rotation at both ends, max deflection occurs at midpoint and is equal to PL^3/192EI , or near an inch and a half for your load and beam length and size. But, you have to be careful using long channels because stresses may be excessive if the beam is not laterally supported against local flange buckling, and loading not at the shear center causes additional torsional and warping stresses. If the beam is simply supported, stresses double and deflection increases fourfold. Seems like a very flimsy channel to use for this loading. Allowable stress is a great concern.
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