As far as I see, the propagation of p-waves and s-waves considered through the soil medium is also considered for structural elements in the same way. Therefore, it is assumed that the bending deformations of structural elements do not have any effect on the wave propagation behavior.
Is that correct? If it is not, how the effect of bending deformation of structural elements is incorporated in wave propagation in FLAC3D?

In FLAC3D, the bending deformations of structural elements usually do not have any effect on the wave propagation behavior because the moduli and density of the structure are usually assumed constants. However, if the bending deformation has effect on moduli and/or density via FISH or any other steps, it will have effect on wave propagation as well.

For structural elements, not just density and elastic modulus but also moment of inertia should affect wave propagation. Is that right? In other words, if we have two structural elements having the same density and modulus but the moment of inertia is (I) for the first one and (100I) for the second one. The wave propagation should be different for the two elements, right?

Moreover, when nonlinearity comes into play for structural elements, bending stiffness (EI) equals to 0 because elastic-perfectly-plastic assumption is adopted for plastic hinges. Since constitutive model is chosen as elastic, the wave propagation throughout structural elements is considered based on elastic properties, however, there should be an interruption in wave propagation at plastic hinge region when EI=0. Am I wrong?