A hybrid foundation consisting of a mat foundation and a small number of complementary bearing piles was developed based on a completely new concept and applied to a building construction project in order to evaluate its effectiveness and applicability. The new concept is to maintain a constant pile axial force to avoid pile fracturing even if the building settles due to consolidation of the subsoil. Measured items were the axial forces of the piles, the deformation and settlement of the building, and the relative displacement between the piles and the mat. Then the measurements were compared with a numerical analysis. The measurements show that the reaction control device installed at the head of the pile worked effectively and the comparison between analytical and measured values shows that the behavior of the hybrid foundation can be numerically predicted in the design process.