Tugas akhir ini bertujuan untuk mengetahui pengaruh beban gelombang pada jacket steel platform dan pengaruh beban slamming pada beam deck setelah subsidence. Beban gelombang dihitung berdasarkan kondisi lingkungan ekstrim gelombang 100 tahunan. Tegangan jacket member terjadi akibat bertambahnya beban lateral gelombang. Wter depth dimodelkan dengan bertambahnya kedalaman subsidence hingga pucak gelombang menjangkau dasar sub cellar deck. Menggunakan SACS diketahui bahwa tegangan pada jacket member 33 kali lebih besar karena subsidence 5 ft dimana UC unity check 033 sebelum subsidence menjadi 107 setelah subsidence 5 ft. Tegangan member yang terjadi bertambah secara konstan setelah subsidence 5 ft hingga menjangkau dasar sub cellar deck. Pemodelan dengan Flow 3D diketahui bahwa pressure pada beam sub celar deck juga meningkat 13 akibat bertambahnya subsidence dari 5 ft ke 10 ft. Tegangan pada beam dapat diketahui telah melewati deformasi plastic akibat slamming pressure. Tegangan beam deck akibat slamming meningkat dari 309 MPa menjadi 407 MPa. Sehingga dapat diambil kesimpulan bahwa beam deck telah mengalami kegagalan pada kondisi deformasi plastic akibat beban slamming dimana disebabkan setelah subsidence.
ABSTRACT
The purpose of the final project is to evaluate the impact of wave force on a jacket steel platform and the slamming force on the deck beam after subsidence. The wave force is calculated based on the 100 years return periode of extreme wave condition . The jacket member stress is analysed due to the increment of the lateral wave force. The water depth is modelled to be increased by the depth of subsidence until wave crest is reached the sub cellar deck floor. Using SACS it is found that jacket stress member is three times higher due to 5 ft subsidence in which UC unity check is found of 033 before subsidence to be 107 after 5 ft subsidence. The member stress is found to be increased constantly after 5 ft subsidence until reached sub cellar deck floor. Due to 3D-Flow modelling it is found that the pressure on the sub cellar deck beam is also increased by 1.1 due to increasing subsidence from 5 ft to 10 ft. The of the beam is found that it could be reached a plastic deformation due to slamming pressure. The deck beam stress due to slamming is increased from 309 MPa to 470 MPa. It could be concluded that the deck beam could be failure in a plastic deformation condition due to slamming force which is caused by the subsidence.
Source Undergraduate Theses, Offshore Engineering, RSKe 627.98 Put a, 2011
Coverage ITS Community
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