Investigation of dynamic responses of various bent structures in offshore high-pile wharfs subjected to impact loading

High-pile wharf structures are subjected to significant safety challenges under repeated horizontal impacts. The dynamic behavior of complete bent systems subjected to graded impact loading remains insufficiently investigated, and the resistance mechanisms associated with inclined pile configurations have yet to be fully clarified. This study combines scaled model testing with numerical simulations to examine the staged damage evolution and dynamic response of a representative high-pile wharf structure under sequential horizontal impacts. The results show that after 26 graded impact events, the double-inclined pile configuration exhibited markedly improved displacement control, reducing cumulative pile-head displacement by approximately 66 % compared to the vertical pile configuration. The inclined arrangement effectively redistributed impact forces, mitigated stiffness degradation, and enhanced structural resilience under graded loading. In contrast, single-sided inclined configurations exhibited pronounced eccentric effects and localized damage under high-energy impacts, indicating strong directional sensitivity. Moreover, a comprehensive evaluation based on plastic energy absorption ratio, equivalent plastic strain, damage volume ratio, and horizontal displacement enabled an in-depth assessment of energy dissipation and damage evolution in pile-supported frames. These findings offer theoretical insight and practical guidance for improving impact resistance and resilience in offshore high-pile wharf design.