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I want to use rotSpring2DModIKModel for a one-story, one-bay 3D structure in which there are two parallel moment frames in X direction and two simple pinned frames in Y direction. Can I do the following changes in rotSpring2DModIKModel.tcl for defining springs of columns in the X moment frames? 1- C...

How can i model a sdof system for specific ductility?
For example i want to model a sdof system with mu(ductility)=3, but i don't know what material or element i should use ?

I tested this problem (Example: 2-Story Steel Moment Frame with Concentrated Plasticity). When I defined zero mass for the leaning column, opensees couldn't calculate the eigenvalue. But if these zero masses are removed, the periods will be calculated correctly. version with zero mass in leaning col...

Thanks from both of you. By a little chance I found the problem. it happens when I was trying to use leaning column in my model, if I give zero mass to nodes which are correspond to the leaning column the period is wrong (6.2) but when I delete this zero masses, it works correct and gives 0.7, I thi...

I have a problem in calculating period by opensees.
why when I define mass at the end of nodes in the format of (node 32 45.75 9.45 -mass 13459.4 1e-9 1e-9 ), I've got the 1st period 0.7,
but surprisingly when I define it separately, (mass 32 13459.4 1e-9 1e-9 ), the 1st period will be 6.2 ?!