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Homework Help: Dead Load

  1. Jul 13, 2012 #1
    1. The problem statement, all variables and given/known data

    A beam has a solid square cross section of 100mm and is simply supported by two supports 3m apart. Calculate the dead load that can be safely supported when applied to the middle of the beam.

    2. Relevant equations

    Solid square cross section of beam: 100mm
    Material: unknown
    Distance between two beams: 3m
    Assumption: material is reinforced concrete
    weight of material: 24KN/m3

    Area of square = height x width

    volume = area of solid x length

    dead load = volume x unit weight of material

    3. The attempt at a solution

    area of square = 100mm x 100mm = 10,000mm2 (0.0100m2)

    volume = 0.0100m2 x 3m = 0.0300m3

    dead load = 0.0300m3 x 24KN/m3 = 0.72KNVm3

    ∴ dead load = 0.72KNVm3 / m3 = 720N

    Can someone please tell me where I am going wrong with this as I have been advised this is wrong but I dont know where.

    Thanks in advance for your help.
  2. jcsd
  3. Jul 13, 2012 #2


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    Science Advisor
    Homework Helper

    hi sperrya! :smile:
    no, that's not a dead load, that's the weight of the beam

    a "dead" load is an extra load on top of the beam (in this case, at its middle) …

    what are the properties of the material of the beam that determine how much extra load can be supported? :wink:
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