Seismic response and damage limit of concrete filled steel tube frame

Seismic response and damage of Concrete Filled steel Tube frame (CFT frame) under strong ground motion are calculated. The damage ratios of cracking and local buckling of CFT column and H-section beam, which are closely related to the collapse of CFT frame, are obtained in relation with the column-over-design factor and the strength ratio of CFT column. On the basis of the calculated results, the damage limits of CFT frame are investigated to prevent the local buckling and steel tube cracking of CFT column in relation with the ultimate state design conditions which are the column-over-design factor of CFT frame, the strength ratio of CFT column and the maximum velocity of input ground motion.