Parametric Study on Incremental Wave Analysis for Jacket Platform in Malaysian Waters

Offshore structures are often subjected to various environmental factors that can affect
the integrity of the structure. Global overload due to wave-in-deck (WID) load is one
of the factors that can plays a role in the reserve strength ratio of the platform. WID
happens when there is insufficient wave crest to deck air gap causing sea water to enter
the deck. Subsequently, the deck will experience excessive loadings. In this paper,
incremental wave analysis (IWA) is used to analyse the trend of the structure responses
when the waves are higher than the design waves. A software simulation using SACS
had been performed by analysing the structure response subjected to wave with an
incremental of 10%. It was found that the base shear for both 100-year design period
and at structure collapse increases and directly influences the reserve strength ratio of
the structure. Moreover, it was also found that the location of critical joints varies
depending on the wave increment. Lastly, the trend for local displacement in the 45˚
direction is identified. The findings of this study can be use as quick check to identify
critical joint when wave overtopping occur.