Analisis On-Bottom Stability dan Mekanisme Lateral Buckling Pada Pipa Bawah Laut Penyalur Gas Studi Kasus Platform KLD Wellhead Menuju Platform KLB

Qur'ani, Amalia Puji (2021) Analisis On-Bottom Stability dan Mekanisme Lateral Buckling Pada Pipa Bawah Laut Penyalur Gas Studi Kasus Platform KLD Wellhead Menuju Platform KLB. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Pipa bawah laut yang di instalasi di dasar laut harus mampu menahan beban lingkungan terutama gelombang dan arus sehingga pipa tetap meletak pada seabed. Disamping interaksi antara beban hidrodinamis, seabed dan pipa itu sendiri terdapat permasalahan lain selama masa operasi pipa. Pada kondisi ini pipa akan menerima beban dari peningkatan suhu yang drastis hasil dari aliran fluida di dalamnya dalam kurun waktu yang lama. Pada pipa yang hanya meletak pada seabed dan beroperasi dalam kondisi temperature dan pressure yang tinggi akan berpotensi untuk mengalami buckling atau deformasi plastis. Dalam Tugas Akhir ini dilakukan analisa terhadap stabilitas dan mekanisme lateral buckling pada pipa gas bawah laut pada platform KLD Welhead menuju platform KLB. Pada penelitian ini dilakukan analisis on-bottom stability meliputi analisis vertical dan lateral dengan menggunakan metode absolute static stability dimana pipa tidak diijinkan bergerak bebas. Berdasarkan DNVGL RP-F109 yang digunakan, pipa bawah laut dapat dikatakan stabil apabila memiliki nilai design criteria kurang dari atau sama dengan satu baik secara vertikal maupun lateral. Melalui penelitian yang dilakukan, didapatkan nilai design criteria stabilitas vertikal sebesar 0,631. Sedangkan nilai design criteria stabilitas lateral pada kilometer point 0.0 adalah sebesar 0,721 dan pada kilometer point 3.5 bernilai 0,673 yang mana nilai-nilai tersebut kurang dari satu sehingga pipa dapat dikatakan memenuhi kriteria stabilitas. Sementara pada masa operasionalnya, potensi pipa terhadap terjadinya lateral buckling dianalisis dengan menggunakan metode Hobbs yang mengasumsikan seabed berbentuk datar. Berdasarkan metode Hobbs yang digunakan, pipa tidak terindikasi akan kegagalan karena pada hasil analisis actual stress yang terjadi tidak melebihi hasil allowable stress yang merupakan syarat terjadinya lateral buckling. Pada penelitian ini gaya aksial efektif yang bekerja pada pipa lebih kecil dari pada gaya critical buckling nya. Dimana besarya gaya critical sebesar 309000 N sedangkan gaya aksial efektif terbesar yaitu 282445,74 N. Pada penelitian dapat dikatakan bahwa pipa stabil di dasar laut dan aman terhadap pengaruh lateral buckling pada saat beroperasi.
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Submarine pipes installed on the seabed must be able to withstand environmental loads, especially waves and currents so that the pipes remain on the seabed. Besides the interaction between the hydrodynamic load, the seabed and the pipe itself, there are other problems during the operation of the pipe. In this condition the pipe will receive the load from a drastic increase in temperature resulting from the flow of fluid in it for a long time. Pipes that are only placed on the seabed and operate under conditions of high temperature and pressure will have the potential to experience buckling or plastic deformation. In this final project, an analysis of the stability and lateral buckling mechanism of the subsea gas pipeline on the KLD Welhead platform is carried out to the KLB platform. In this research, an analysis of on-bottom stability includes vertical and lateral analysis using the absolute static stability method where the pipe is not allowed to move freely. Based on the DNVGL RP-F109 used, the subsea pipeline can be said to be stable if it has a design criterion value of less than or equal to one both vertically and laterally. Through the research conducted, the value of the design criteria for vertical stability was 0.631. While the value of the design criteria for lateral stability at kilometer point 0.0 is 0.721 and at kilometer point 3.5 it is worth 0.673, where these values are less than one so that the pipe can be said to meet the stability criteria. Meanwhile, during its operational period, the potential of the pipe to the occurrence of lateral buckling was analyzed using the Hobbs method which assumes a flat seabed. Based on the Hobbs method used, the pipe does not indicate failure because the results of the analysis of the actual stress that occur do not exceed the results of the allowable stress which is a requirement for lateral buckling. In this study, the effective axial force acting on the pipe is smaller than the critical buckling force. Where the magnitude of the critical force is 309000 N while the largest effective axial force is 282445.74 N. In this study, it can be said that the pipe is stable on the seabed and is safe against the effects of lateral buckling during operation.

Item Type:	Thesis (Undergraduate)
Uncontrolled Keywords:	On-Bottom Stability, Lateral Buckling, Pipa Bawah Laut, Submarine Pipeline
Subjects:	T Technology > TJ Mechanical engineering and machinery > TJ930 Pipelines (General). Underwater pipelines. T Technology > TN Mining engineering. Metallurgy > TN880.5 Natural gas pipelines
Divisions:	Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38201-(S1) Undergraduate Thesis
Depositing User:	Amalia puji qurani
Date Deposited:	24 Aug 2021 04:46
Last Modified:	24 Aug 2021 04:46
URI:	http://repository.its.ac.id/id/eprint/89055

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