Studies on Jacket Effective Stiffness Estimation for Float-over Mating Analysis

The impact loads on the jacket leg tops is one of the most important design criteria for the float-over installation design which is very sensitive to the jacket stiffness utilized. The deflection at the top of a jacket leg will be influenced by the loads on the other jacket legs with the extent of influence varying for different jacket structures. The phenomenon of the interactive influences between the jacket leg tops is called the group effect. This paper presents an engineering method to investigate the impact loads in the float-over mating analysis based on the effective stiffness which considers the group effect. The group effect results are compared to the typical float-over analysis results and the model test and it shows the best agreement with the model test and considerable reduction on the analyses results.