Dynamic Analysis of an Offshore Platform With Excessive Vibration Under Wave Loading

An offshore platform of jacket type in Bohai Bay vibrates excessively under design environmental conditions, which has affected the normal operation of the platform. In order to mitigate the vibration of the platform, it is essential important to explore the cause of the vibration. So the objective of this study is to investigate the cause of the excessive vibration. In this paper, dynamic characteristics of the offshore platform are analyzed by numerical simulation using finite element (FE) modeling. To further verify the numerical results, a model experiment is conducted. Numerical and experimental results demonstrate that there are relative movement and impact between the piles and the jacket, i.e. the piles and the jacket didn’t connect well to an entity. It is this cause that the stiffness of the platform deceases and impact between piles and the jacket legs induce excessive vibration. And also the grouting measure is advised to reduce the vibration of the offshore platform according to the analysis results.