The influence of the soil-foundation frequency- dependent behavior on the seismic performance of bridges

Bridge structure performance estimation under a seismic hazard can be significantly influenced by the level of modelling detail within the simulation of the soil structure interaction phenomenon. As the computational demands of such estimation greatly restricts the implementation of a detailed truncated FEM simulation of the semiinfinite soil domain, the Kelvin – Voigt Model within the framework of the substructure method along with other frequency independent simplified methods are frequently selected within the past literature as a computationally viable alternative. Due to their limited dynamic properties, the aforementioned simplified methods are prone to an inefficient approximation on the loading scenario of earthquake excitations with rich frequency content. To this end the limitations of the frequency independent simulation approach and subsequently the necessity of the frequency dependent simulation approach are thoroughly investigated in the following paper through the comparison of the seismic response of bridge structure under the use of the conventional Kelvin Voigt Models and the Lumped Parameter (LP) modelling method. Analyses results demonstrate a phenomenon of redistribution of damage among the bridge’s structural components with the significance of error being highly correlated with the predominant frequency of the excitation.