PILE FOUNDATION

PROBLEM TO BE SOLVED: To provide a pile foundation that supports one unit with a plurality of piles, the pile foundation allowing economically efficient design of a footing that connects pile heads, and keeping resisting force, rigidity, and pile head fixation degree to withstand horizontal force constant in all directions.SOLUTION: A pile foundation supports, with a plurality of piles, a vertical load of one column of a base-isolated structure or an aseismic structure or one unit of seismic isolator. A distance has been secured between a tip part of adjacent piles, in a bearing layer of a ground around the piles, that equals to or is greater than a necessary separation distance determined in accordance with a pile diameter or a pile tip part diameter. A pile head is disposed in a range that satisfies an equation 1.0Do