In seismic response of a sea-spanning bridge

dynamic pressure of fluid on bridge piers shows clear fluid-structure interaction.Based on the tensor theory

divergence transform relation in time depen-dent domain and spatial conversation principle in differential form are set up.With the arbitrary Lagrange-Euler description

governing equations of fluid motion in time dependent domain are built up from Navier-Stokes equations in Euler description which govern the fluid motion.Structural computing model

contact condition in fluid-structure interface

computing method of coupling field and controlling of fluid domain mesh motion are carefully presented in this paper.Then a sea-spanning bridge is taken as an example for dynamic analysis of its piers.In the analysis

the input ground motion and the initial conditions in fluid domain are explained in detail.Simulation results show that the fluid-structure interaction theory can simu-late the characteristic feature of fluid and structure in seismic response of bridge piers.The proper initial conditions in fluid domain insure the stability of numerical computation and reduce the computational complexity.Shear force on the bottom of bridge piers is dominant under transversal earthquake excitation and displacement of structure is significant under longitudinal earthquake excitation.A structure with the linear elastic model in the fluid-structure system has a clear nonlinear feature in its seismic response.