This paper selects a structural segment of a pile wharf as the research object and builds a spatial finite element model
and the response of such a structure under horizontal earthquake effect is studied with the vibration mode decomposition response
spectrum. The change of internal force in piled foundations under the effect of different direction of earthquake is studied.
The computed results show that the bending moment of fork pile top under the longitudinal earthquake effect is bigger obviously
than that under the lateral earthquake effect. When the arrangement of pile foundation on the vertical axis is asymmetry，the
pile torque under the longitudinal earthquake effect is bigger. Under the lateral earthquake effect, the axial force of the later fork
pile is bigger. The research results in the paper can provide references for the aseismatic design of pile wharfs.