On the modeling of frequency- and intensity-dependent impedance functions at the head of horizontally loaded single piles

Abstract

This paper proposes a phenomenological model that represents both the frequency and intensity dependencies of the dynamic force–displacement relationship at the head of horizontally loaded piles. The present model consists of a bilinear spring unit with hysteretic characteristics and a so-called “Gyro-Lumped Parameter Model (GLPM)” unit arranged in series. The former unit represents the static yielding procedure of soil-pile systems, while the latter represents the frequency-dependent characteristics of impedance functions. Firstly, this study validates the general behavior of the proposed model and then verifies it by simulating the experimentally obtained pile head impedance functions of a single pile for small to large amplitudes of loading in a wide range of frequencies. The results show that the proposed model can sufficiently reproduce variations in the frequency-dependent characteristics of impedance functions for a wide range of loading amplitudes.