The pilot reported that he was landing the airplane on a grass runway when the accident occurred. He stated that he had touched down and had lowered the tail when the airplane reached the intersecting paved taxiway for the perpendicular runway. He stated that the airplane "bounced" when it contacted the paved taxiway and began to veer to the right. He attempted to correct and the airplane ground-looped on the paved intersecting runway/taxiway. The damage to the airplane included a bent right wing spar, twisting of the fuselage structure, and damage to the landing gear attach structure within the fuselage.