RELIABILITY EVALUATIONS OF AN OFFSHORE PLATFORM WITH PARTIAL POROUS CYLINDERS DUE TO WAVE AND SEISMIC FORCES

摘要

In the present study, the partial porous cylinder, which is composed of a porous part located near free surface and a rigid part bounded top and bottom by impermeable end caps, is suggested to reduce the effect of wave forces. In order to calculate the wave force acting on the partial porous cylinder the fluid domain is divided into three regions, and the scattering wave in each fluid region is expressed by an Eigen-function expansion method. Applying Darcy's law to the porous boundary condition, the effect of porosity can be simplified. Using the wave and the seismic forces, the dynamic response evaluations of the offshore platform with partial porous cylinders are carried out through the modal analysis and the substructure method based on the effect of soil-structure interaction. The displacement and the bending stress at critical structure members are computed using the Monte Carlo Simulation (MCS). Using the reliability index based on the results from MCS, the reliability evaluations of the offshore platform with partial porous cylinders are examined.