Experimental study on dynamic response of pile-supported wharf under wave and ship berthing collision

Pile-supported wharf is widely used in deep-water port engineering, which is inevitably subject to joint action of wave and ship berthing collision in marine environment. The evaluation of dynamic response of pile-supported wharf under wave and berthing collision is particularly essential for the design of deep-water port in-frastructures. In this study, a wave flume experiment was carried out to investigate the dynamic response of pile-supported wharf embedded in a saturated sand stratum under a given wave and a three-stage pendulum steel ball collision. The pendulum collision was applied at the corner and edge midpoint of the wharf deck, respectively. A variety of representative responses are explored, including time histories of acceleration, displacement, hydro-dynamic pressure, pore water pressure, and strain, which characterize the important aspects of dynamic behavior of pile-supported wharf-ground system. Acceleration and displacement of deck as well as acceleration of sand stratum are dominated by the berthing collision; hydrodynamic pressure on piles and pore water pressure of sand stratum are controlled by the wave action; and strain and bending moment on piles are depended on the joint action of wave and collision. It should be noted that dynamic response characteristics of pile-supported wharf will change significantly due to the decreasing of pile effective buried depth near berths induced by the berthing collision energy accumulation. Furthermore, pile group effects including wave scour around piles, collision energy propagation in a sand stratum, and peak bending moment on piles are explored. For comparison, dynamic response of a single pile-ground system and free field are also discussed. Dynamic response of sand stratum around single pile induced by berthing collision on wharf deck is greater than that of free field at the same distance. Experiment techniques and insights from this study may be of significance to the design and mainte-nance of pile-supported wharves.