Effect of Pile Scouring on the Structural Behavior of a Fixed Jacket Platform with Consideration of Non-linear Pile Seabed Interaction

In offshore structures, most of failures are caused by the lack of sufficient piles strength. Scour phenomena affects the load transition and the pile strength. The necessity of the consideration of scouring phenomena amplifies when the scour depth becomes remarkable, which can endanger the jacket stability. In this paper, a new method is used to consider the pile scouring using nonlinear pushover analysis with SACS software. A recently-built existing jacket platform namely SPD 19C is selected as a case study. Results show that Reserve Strength Ratio (RSR) of the jacket platform decreases when scour depth increased in the both aged and recently-built cases. RSR decreasing becomes more sensible as scour depth increases. According to API RP2A collapse will be occurred in the range of RSR< 1.6. It is shown at RSR=1.6, collapse will be occurred in the scouring depth of 13.5m and 11m for recently-built and aged platform respectively, which both have approximately 27% lower RSR than their original state. So scour protection methods should be addressed in vulnerable areas as preventive alternatives.