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I have developed a 2D planar model where I performed a modal analysis and an analysis under gravitational loads. When evaluating the results, I noticed that the deformation due to vertical loads is adequate; however, the direction of the moments is incorrect. This issue prevents the plastic hinges I have defined from forming as expected.

I would greatly appreciate your help in identifying the problem. I have attached the model for reference.

Thank you very much in advance!

Kind regards,
EMNV

When evaluating the results, I noticed that the deformation due to vertical loads is adequate; however, the direction of the moments is incorrect.

This is true, but it's only a visualization issue. In a 2D analysis, OpenSees does not happen y or z to the "M" output. So STKO doesn't know if it's My or Mz. In a 3D model this issue does not happen.

This issue prevents the plastic hinges I have defined from forming as expected.

This happens for another reason. You defined a 3D zero length material (with all 6 DOFs switched on), later you moved to 2D (keeping those options switched on).
We spot a bug where STKO writes the full 6 springs if active (even if you moved to 2D analysis).
So you have 2 options:

• Use this model (where I manually switched off the 4,5, and 6th DOFs of the zeroLength materials)

  ID1010_2D_v01.zip

  (169 KiB) Downloaded 89 times

• Or replace this file (which contains the bugfix) in C:\Program Files\STKO\external_solvers\opensees\element_properties\zero_length_elements , replacing the existing one (unzip it first)

  zeroLength.zip

  (3.48 KiB) Downloaded 73 times