I am trying to calculate the internal forces and their nature in this truss, however, I cannot seem to do so as both the method of joint and the method of section do not work. I think this is because there are not enough conditions of equilibrium that can be used. Is there any way to actually calculate the forces in the members even if this is the case?

For example, at joint A, there are 3 unknown members, and all the members acting through it are only concurrent at that specific point, making it impossible for me to use the equilibrium condition of the sum of moments being 0. The diagram of the truss

It would be extremely appreciated if someone could inform me about how to calculate the forces in the members of this truss. Thank you.

  • 1
    $\begingroup$ As stated below you could try FEM or if you want to solve it by hand, you could try direct stiffness method for trusses, however, considering the number of members the matrices may become very large, so you might want to try excel. Otherwise, you can try the force method for internally statically indeterminate trusses. $\endgroup$
    – Amit
    Commented Dec 10, 2019 at 5:02

1 Answer 1


The structure is not statically determinate, unless you remove bar v. The internal forces will depend on the relative stiffness of the members.

The practical way to do the analysis is make a finite element model.


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