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External Reaction of Truss

  1. Apr 18, 2017 #1
    Hey guys,

    Sorry for this newbie question, I would to ask how to I obtain the reaction of the pinned connection of A, B, and C (See attachment)? Do I really have to use Force-Method? I actually attempted to use Moment at different places and do simultaneously (Idk if it's the right thing to do) but apparently I got Ay = 38.07kN, By = 37.39kN and Cy = 0, which I think it is wrong, can anybody help?


  2. jcsd
  3. Apr 19, 2017 #2


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    The truss is externally statically indeterminate with 6 unknown reaction forces and just 3 equations of equilibrium, so you have to resort to a painstaking indeterminate analysis using a method of your choice.
  4. Apr 19, 2017 #3
    Thanks for the reply, Jay! I've been studying stiffness method to solve for this question. But I have several question that I would like to ask, (see attachment)

    From the truss, I put them into global coordinate, and named the member (in square), but I would like to ask about the arrow for Near and Far (in Cyan), is there ways to determine or is it assumed by ourselves? Thanks!
  5. Apr 20, 2017 #4
    nodal analysis is how one would do it but as said if there are too many unknowns than knowns, computational methods may have to be used. I know sometimes with complicated trusses using matrices can be an adequate tool I believe.
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