Condo unit owner removes interior support walls from the building

This is a real situation; a unit owner in a condominium removed some interior walls and now the unit owners above say their floor is shifting up and down in a disturbing manner. They were pretty timid about bringing their concerns to the attention of of the unit owner as the demolition was being down (when it would have been cheaper to put in support columns if needed), and only recently brought this to the attention of the association at a recent annual meeting. Here is a hint: the Nebraska condominium property act has a clause that any property owner can do alterations as long as they do not reduce the support of the structure and the Master Deed states that load bearing walls are part of the common area. I am not on the association board of administrators but the board of administrators is aware of the problem but expressed some puzzlement as to what they could do.