Numerical analysis of bridge piers under earthquakes considering pile‒soil interactions and water‒pier interactions

Abstract

Previous investigations have shown that both pile‒soil interactions and water‒pier interactions have a significant effect on the seismic performance of bridge piers. However, there is a lack of systematic research on the influence of pile‒soil and water‒pier interactions simultaneously on the seismic responses of real bridge piers. This study was conducted to narrow this knowledge gap through a series of numerical analysis. A simplified numerical modelling method for the soil-water-structure system was proposed and validated with results of a centrifuge shaking table test, which considered water‒pier interactions by the additional mass method and pile‒soil interactions by a fine finite element model. The verified numerical modelling method was used to analyse a real bridge pier under near-field and far-field earthquakes. The obtained results show that both pile‒soil interaction and water‒pier interaction increase the pier displacements, and internal forces of the pier decrease by pile‒soil interaction and increase by water‒pier interaction. The effect of water‒pier interaction on the seismic responses of the pier is smaller than that of pile‒soil interaction. The water‒pier interaction significantly increases the bending moments of the base pier considering pile‒soil interactions and shear forces of the base pier without considering pile‒soil interactions.