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Can I elevate a bed by 4 inches with PVC and sleep on it?

  1. Aug 22, 2015 #1
    Hi everyone, it's my first post!

    I need to elevate a bed by 4 inches for a while. I did some work on this problem already. Here's all the information I used to reach my conclusion:

    expected total weight with mattress and occupants = 220.92200 kilograms
    bed weight = 54 kg = 54,000 grams = 119.05 lb
    bed dimmensions = 199.4 x 106.7 x 149.9 cm

    cross section of the legs = 6.205 cm
    radias of the legs = 3.10125 cm
    area of the legs = 30.22 cm2
    circumference of leg = 19.5 cm (Does not reflect the actual around of metal contacting floor)

    Bed image = https://www.amazon.com/Twin-Over-Bu...280771&sr=8-1-fkmr1&keywords=2256w+coaster+co

    My original plan was to get PVC and just put the PVC around the legs of the bed. I looked it up and PVC's compression strength and modulus are about =

    Clear PVC pipe Physical properties
    Compressive Strength psi @75°F 8,300
    Compressive Modulus psi @ 75°F 307,000
    http://plascowelding.com/pdf2007/PV...Pipe&Fittings/PVC(SCH.40&SCH.80)ClearPipe.PDF

    PSI to Pa conversion
    8,300 PSI * 6,894.76 Pa/PSI = 57,226,508 Pa
    307,000 PSI * 6,894.76 Pa/PSI = 2,116,691,320 Pa

    I ran the numbers assuming that I could use the pressure the legs exert as a decent yardstick to approximate how much stress the PVC would have to endure:

    220.9220 kg * 9.8 m/s^2 = 2 165.0356 newtons

    2 165.0356 newtons / 8.96 centimeters^2 = 2,416,334.38 pascals

    Now the 8.96 cm^2 figure is based on the thickness of the beds legs which are hollow.

    2,416,33.38 Pa < 57,226,508 Pa & 2,116,691,320 Pa

    But... I feel like I'm missing something with this. I want to verify my conclusion before going ahead with this.

    If my stuff is completely bogus then by all means suggest an alternate method.
     
    Last edited by a moderator: May 7, 2017
  2. jcsd
  3. Aug 22, 2015 #2
    We used to prop the box spring up on milk crates.
     
  4. Aug 22, 2015 #3

    rbelli1

    User Avatar
    Gold Member

    Also you could just try it. If you have total structural failure you will be falling 4 inches. On a mattress.

    Try to get tubing that rests flat on bottom of the main frame. Avoid having any lateral or point stress from braces, welds, bolts, etc.

    Bricks or wood blocks work as well.

    BoB
     
  5. Aug 23, 2015 #4

    Baluncore

    User Avatar
    Science Advisor

    You have only considered the static loads, the dynamic loads may exceed those significantly. You need to consider young ones using the bed as a trampoline.
     
  6. Aug 24, 2015 #5
    I think there are better ways to get where you want to go.
    http://www.target.com/p/honey-can-d...pid=15743595&gclid=CODIuNiYwscCFY6EaQod5agJMA
    In addition, depending of the size of the PVC, movement on the bed might impart a moment
    where the metal leg contacts the PVC and split it open.
     
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