Dynamic Response of the Ship Lock Head Under Long-Period Ground Motions Considering Fluid-Structure Interaction

The seismic performance of large ship lock head structures under long-period ground motions is critically understudied. This research develops a validated three-dimensional finite element model incorporating fluid-structure interaction and foundation effects. Comparative analysis demonstrates that long-period ground motions cause substantially larger structural displacements and principal stresses, shift spectral peaks toward lower frequencies, and generate greater sloshing wave heights and dynamic water pressures than ordinary seismic excitations. These findings confirm the heightened threat posed by long-period ground motions to ship lock safety, requiring specialized seismic design considerations foundation effects and FSI. The results indicate that long-period ground motions significantly amplify the structural displacement response and spectral amplitudes, with dominant spectral peaks shifting toward lower frequencies as peak displacements increase. Compared with ordinary ground motions, the principal stresses, sloshing wave heights, and dynamic water pressures are significantly increased. Under high water level conditions, the average peak dynamic water pressure reaches 87.31 kPa under long-period ground motions, exceeding the 82.08 kPa induced by ordinary ground motions.