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Model Bridge Construction

  • 28-09-2014 10:39PM
    #1
    maquel sanchez
    Registered Users, Registered Users 2 Posts: 15 ✭maquel sanchez


    Hello all !

    I am currently attempting to construct a model truss bridge to span a 700mm gap with a point load of 90N as part of an engineering module. No restriction on height or width or choice of material. It has been requested that the bridge fail when the 90N point load is imposed (or as close as possible)

    From initial research online, I intend to make it from popsicle sticks but have concerns about achieving a pinned joint with this material as glue is not preferred by our lecturer. We are also requested to provide our calculations on how we arrived at the chosen design.

    I like to ask if anyone can provide any tips as to how to start this, as our only experience to date has been with some simple truss analysis and I seem to hitting dead-ends with my online research.

    Thank you in advance for reading this and would welcome any advice/suggestions

    Regards
    John.


Comments

  • #2
    Jamari Numerous Stretcher
    Posts: 13,104 ✭✭✭✭ Jamari Numerous Stretcher


    Use balsa.


  • #3
    maquel sanchez
    Registered Users, Registered Users 2 Posts: 15 ✭maquel sanchez


    Thank you for the reply.
    Do you have any suggestion on how to go about this? As this is very new to me, I am fairly lost when it comes to the process to undertake. I been searching for online material to assist with this but most results only seem to some the assembly of the bridge.


  • #4
    oppenheimer1
    Closed Accounts Posts: 5,733 ✭✭✭oppenheimer1


    maquel sanchez wrote: »
    Thank you for the reply.
    Do you have any suggestion on how to go about this? As this is very new to me, I am fairly lost when it comes to the process to undertake. I been searching for online material to assist with this but most results only seem to some the assembly of the bridge.
    Do a simple truss analysis first. Software like CSC Tedds (or whatever analysis software they use in the department) will give you the forces in the members and if you input the material properties it will tell you how much it will deflect.

    Identify the tension and compression members from the analysis. Use piano wire for the tension members and balsa wood for the compression members. Create the joints using piano wire (just push it through the wood).

    You can get balsa in the model making shop in the city center.


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