To prevent breakage of a pile resulting from horizontal forces or bending moments from the upper structure.

A foundation board 2 is constructed at the head of piles 1 and a specified isolation structure 3 is arranged on the foundation board and an upper structure 4 is put on the isolation structure 3 to vertically support it. Magnets 5 are arranged at the external walls in the underground of the upper structure 4 and coils 7 are arranged at the opposite positions of the side walls in the underground surrounding the upper structure 4. The coils are set in a closed condition of the circuit so that a specified electromotive force is excited by electromagnetic induction when the magnets approach the coils or separate therefrom. Buffer materials 8 made of a rubber or the like are arranged between the side walls 6 in the underground and the foundation board 2.