Concentrated Plasticity Model, P-M interaction

[kcorproro]

hi, I use to beam and column a Concentrated Plasticity Model(rotational spring in the end of the elastic beams and columns ),the rotational springs capture the nonlinear behavior of the frame, but is it validate consider the column with only flexural behaviour without axial- moment interaction to column?
what hypothesis should I assume to validate the model? or change elastic beam column element to "dispBeamColumn" or "forceBeamColumn" element. thanks.

[fmk]

that is the drawback of using hinges .. whether or not it effects the results depends on the structure being modeled and whether axial forces are changing and the if the axial force moment interaction is important in the response .. columns usually more important than beams .. you could of course model both and compare the results.