Chapter 11 - Critical Excitation for Earthquake Energy Input in Structure-Pile-Soil System

Abstract

This chapter discusses a new method in the frequency domain for the computation of earthquake input energies both to a structure–pile system and a structure only. In investigating the energy flow in the structure–pile system, many difficulties arise resulting from the dynamic interaction between the pile and the surrounding soil. It can be shown that the formulation of the earthquake input energy in the frequency domain is effective for deriving the earthquake input energy both to a structure–pile system and a structure only. An efficient continuum model consisting of a dynamic Winkler-type soil element and a pile is used to express the dynamic behavior of the structure–pile system accurately. The formulation of the earthquake input energy in the frequency domain is appropriate for introducing the frequency-dependent vibration property of the surface ground. It is demonstrated that the present formulation is effective for various input levels and ground properties. The energy input mechanism in the building structure–pile system can be well described by the newly introduced energy transfer function. The chapter introduces a new concept called the input energy densities at various underground levels, which is used to disclose the energy input mechanism in the building structure–pile system.