Analisis On-Bottom Stability, Global Buckling, dan Crossing Cable Pipa Bawah Laut (Studi Kasus Tanjung Batu, Kalimantan Timur)

Isnaeni, Adrian Rahmat (2023) Analisis On-Bottom Stability, Global Buckling, dan Crossing Cable Pipa Bawah Laut (Studi Kasus Tanjung Batu, Kalimantan Timur). Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Jalur pipa merupakan salah satu sarana transportasi yang banyak digunakan dalam industri minyak dan gas. Dalam perencanaan jalur pipa yang akan dibangun perlu dilakukan survei terkait keadaan lingkungan dan keberadaan objek eksisting di sepanjang jalur yang akan dilewati pipa. Pipa harus didesain dalam berbagai tahapan untuk memastikan keamanan sehingga pipa dapat beroperasi dengan optimal. Tahapan-tahapan tersebut meliputi perhitungan stabilitas pipa di dasar laut, kerentanan pipa terhadap buckling, alat penunjang pipa ketika terdapat persilangan antara jalur pipa dengan obje eksisting, hingga tegangan pada bentangan bebas yang terjadi pada pipa. Dalam setiap tahapan perlu mengacu dan memenuhi kriteria yang telah diberikan oleh standar maupun code internasional yang berlaku seperti yang diterbitkan oleh Det Norske Veritas-German Lloyd (DNVGL) dan American Society of Mechanical Engineering (ASME). Analisis stabilitas pipa di dasar laut dengan acuan code DNVGL RP F109 memberikan kriteria dimana pipa dapat stabil secara vertikal maupun lateral. Dalam tugas akhir ini desain pipa yang dianalisis telah memenuhi kriteria stabilitas absolut dengan ketebalan lapisan beton 35 mm. pada analisis struktur penopang pipa pada saat persilangan dengan kabel bawah laut diketahui bahwa support pipa telah memenuhi kriteria stabilitas dan menopang pipa dengan jarak clearance dengan dasar laut sebesar 0.3 m dengan penurunan total sebesar 78.47 mm. kemudian pada analisi kerentanan pipa terhadap upheaval buckling, pipa dan struktur penopang dapat melawan gaya ke bawah yang diperlukan agar pipa tidak terjadi upheaval buckling. Pada analisis bentangan yang terjadi pada saat pipa mengalami bentang bebas sepanjang 7 m, pipa tidak mengalami VIV dan tegangan ekuivalen yang terjadi pada pipa sebesar 123.12 MPa. Perhitungan secara analitik terhadap upheaval buckling divalidasi melalui aplikasi AutoPIPE dan tegangan ekuivalen divalidasi melalui pemodelan komputasi dengan aplikasi AutoPIPE dan ANSYS dimana untuk upheaval buckling diketahui bahwa pipa tidak rentan terhadap upheaval buckling dan untuk tegangan ekuivalen pada AutoPIPE didapati sebesar 126.54 MPa dan pada ANSYS didapati sebesar 118.15 MPa. Sehingga masing-masing memiliki nilai eror sebesar 2.78% dan 4.03% terhadap perhitungan analitik.
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Pipeline is one of the transportation facilities widely used in the oil and gas industry. In the planning of a pipeline to be constructed, surveys need to be conducted regarding the environmental conditions and the presence of existing objects along the pipeline route. The pipeline must be designed in various stages to ensure safety so that it can operate optimally. These stages include calculations of pipeline stability on the seabed, pipeline vulnerability to buckling, supporting tools for pipelines when there are intersections between the pipeline route and existing objects, and the stress on the free spans of the pipeline. In each stage, it is necessary to refer to and meet the criteria provided by applicable international standards and codes, such as those published by Det Norske Veritas-German Lloyd (DNVGL) and the American Society of Mechanical Engineering (ASME). The analysis of pipeline stability on the seabed using the DNVGL RP F109 code provides criteria where the pipeline can be stable both vertically and laterally. In this final project, the analyzed pipeline design has met the absolute stability criteria with a concrete layer thickness of 35 mm. In the analysis of the pipeline support structure during the crossing with an underwater cable, it is known that the pipeline support meets the stability criteria and supports the pipeline with a clearance distance from the seabed of 0.3 m, with a total deflection of 136.4 mm. Furthermore, in the analysis of pipeline vulnerability to upheaval buckling, it is determined that the pipeline and supporting structure can withstand the required downward force to prevent upheaval buckling. In the analysis of the span that occurs when the pipeline undergoes a free span of 7 m, the pipeline does not experience Vortex-Induced Vibration (VIV), and the equivalent stress on the pipeline is 123.12 MPa. Analytical calculations for upheaval buckling are validated using the AutoPIPE application, and the equivalent stress is validated through computational modeling using AutoPIPE and ANSYS applications. It is found that for upheaval buckling, the pipeline is not susceptible, and for the equivalent stress, AutoPIPE yields a value of 126.54 MPa, while ANSYS yields a value of 118.15 MPa. Each of these values has an error of 2.78% and 4.03% compared to the analytical calculations.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Stabilitas Pipa, Upheaval Buckling, Tegangan Ekuivalen, support,On-Bottom Stability, Upheaval Buckling, Equivalent Stress, support.
Subjects:	T Technology > TJ Mechanical engineering and machinery > TJ930 Pipelines (General). Underwater pipelines.
Divisions:	Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38201-(S1) Undergraduate Thesis
Depositing User:	Adrian Rahmat Isnaeni
Date Deposited:	22 Jul 2023 07:56
Last Modified:	22 Jul 2023 07:56
URI:	http://repository.its.ac.id/id/eprint/98831

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