Condo building structure damaging unit. Who pays for repairs?

I am in Illinois. We own a condo. The condo is on a crawl space. The steel support column is sitting on a piece of rotted wood (which has collapsed) and therefore, now sitting on gravel, which is over dirt. This should be sitting on a concrete pad, not dirt. The steel support columns have both given way and the condo unit is now sinking about 2 inches. This has done substantial damage to the interior of our unit. The condo association says that the damage on my unit is my responsibility. Is that true? I can not imagine that a common element that has given way and caused damage to my unit would be my responsibility. None of this is an insurance claim. I don't see in the IL Condominium Act where damage to unit from common element is addressed.