Nonlinear Soil - Pile - Structure Interaction in Dynamic or Seismic Response

The stiffness and damping of pile foundations are proposed, which vary with the ratio of shear modulus Gi / Go to indicate the nonlinear properties of soil. The range of Gi / Go is defined with different vibration intensities for applications, and a computer program DYNAN is available based on the boundary zone model with non-reflective interface. Two engineering cases are studied to illustrate the nonlinear soil-pile-structure interaction. In the first case a piled foundation is examined under dynamic loads. The measurements of vibration were carried out in the field for a revamped project, and the measured data matched with the results calculated by the program. In the second case a piled foundation is examined under seismic loads. The seismic forces and response are calculated using the time history analysis and response spectrum analysis, and compared with those using the method of equivalent static loads.