This paper proposes an improved simplified method which connects a pile head and a pile cap. The improved simplified connection method consists of a pile head embedded in the pile cap up to about 100mm depth and a tapered clearance around the pile head. To investigate mechanical characteristics of the proposed connection method, full-scale structural tests under various axial load conditions are conducted. From the test results, it is revealed that the maximum bending moment of the proposed pile head joint does not reach the ultimate bending moment of the pile, and that the relationship between bending moment and rotation angle of the pile head can be explained well by hyperbolic curves under various axial load conditions. Therefore the proposed connection method is very useful to reduce the bending moment of the pile head. It is reasonable to use hyperbolic function for seismic design of the proposed connection method.
