When steel piles experience the higher axial compression force caused by the superstructure’s overturning moment in the liquefied soil, the pile’s flexural buckling may occur. In previous papers, the steel piles’ collapse mechanism is presented. On the other hand, the CFT piles may fail when they experience the significant earthquake in the soft ground. In this paper, the centrifugal tests of the superstructure, the CFT piles and the liquefied soil system are conducted and the piles’ ultimate mechanism is clarified. Moreover, the pile’s ultimate strength is evaluated using M-N interaction curves, to which the pile’s elasto-plastic buckling strength is applied.
