Numerical simulation in dynamic analysis of deepwater group pile foundation of bridges

The influence of fluid-structure interaction on the dynamic characteristics of deepwater group pile foundation is investigated. For this purpose, a three-dimensional solid finite element model simulating the structure and a three-dimensional potential fluid model representing the water were developed using the software ADINA. Four parameters including the water depth, the width of pile cap, the height of pile cap and the superstructure mass were considered to investigate their effects on the fluid-structure interaction. Then possible improvement to the interaction influence by the change to the pile layout and number was examined. It is found that while the fluid-structure interaction due to water depth has significant influence on the dynamic characteristics of group pile foundation, effects due to the structural dimensions should also be included. In addition, the provision of raking piles can reduce the impact that water has on the foundation, but a larger pile cap with additional vertical piles can also produce this effect.