FOUNDATION STRUCTURE

PROBLEM TO BE SOLVED: To improve the safety during earthquake and reduce cost for foundation slab and pile, and to cope with a pull-out force and buoyancy by ground water during earthquake. SOLUTION: Two kinds of piles are used together; that is, head pin-coupled pile 3a, with which the pile head portion is pin-coupled to a foundation slab arranged at the top side of the pile head portion, thereby transmitting the axial force and shearing force; while allowing relative rotation, and a head portion rigid coupling pile 3b, with which the pile head portion is rigidly connected to the foundation slab 4 arranged at the top of the pile head portion where the turning moment, axial force and shearing force can be transmitted. The head portion rigid coupling pile 3b is arranged, at a place where the pull-out force acts during earthquake, that is, a position below the outer peripheral column 1a of a building, and the head pin-coupled piles 3a are arranged at other different places.