Analisis Ultimate Limit State (ULS) pada Pipa Dalam Kondisi Free Span (Studi Kasus: Free Span MGL 14” CPP – ORF yang Dioperasikan oleh PT XYZ)

Putri, Maria Deviyanti Riska (2021) Analisis Ultimate Limit State (ULS) pada Pipa Dalam Kondisi Free Span (Studi Kasus: Free Span MGL 14” CPP – ORF yang Dioperasikan oleh PT XYZ). Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Indonesia merupakan salah satu negara penghasil gas alam dengan cadangan temuan terbesar. Dengan jumlah produksi dan konsumsi gas alam yang terus meningkat, kelancaran dan efisiensi pada sektor midstream sangat penting melalui penggunaan pipa yang handal dalam kondisi operasi. Dalam industri migas, pipa merupakan moda transportasi fluida paling ekonomis dan handal jika dibandingkan dengan moda transportasi laut ke darat lainnya. Bentangan bebas dapat terjadi akibat dasar laut yang tidak merata atau terjadinya penggerusan lokal pada dasar laut. Segmen span pipa juga dapat terekspos oleh bahaya yang tinggi, salah satunya, bahaya rupture akibat bentangan bebas yang mengalami tekukan dan lendutan. Penelitian ini bertujuan untuk melakukan pengecekkan terhadap kekuatan struktur pipa yang terbentang bebas dengan metode analisis Ultimate Limit State (ULS). Hasil analisis tegangan menunjukkan bahwa tegangan yang bekerja pada pipa berada di bawah Allowable Stress dan telah memenuhi konsep Allowable Stress Design berdasarkan ASME B31.8. Adapun besarnya tegangan hoop adalah 78.33 MPa, tegangan longitudinal maksimal adalah 174.12 MPa terjadi pada span 29.31 m, dan tegangan Von Mises maksimal adalah 36.24 MPa terjadi pada span 11 m. Berdasarkan hasil analisis ULS, pipa tidak mengalami tekukan dan mampu menahan tekanan dan keruntuhan sesuai dengan konsep limit state design. Hasil perhitungan panjang bentangan bebas dilakukan pada kondisi statis dan dinamis. Panjang bentangan beban ijin statis adalah 22.51 m, sedangkan panjang bentangan bebas ijin dinamis pada arah in-line adalah 29.28 m dan pada arah cross-flow adalah 36.43 m. ===================================================================================================== Indonesia is one of the natural gas producing countries with the largest proven reserves. With the production and consumption of natural gas increasing, continuous operation and efficiency in midstream sector is essential through the use of reliable pipelines in operating conditions. In the oil and gas industry, pipelines are the most economical and reliable mode of fluid transportation when compared to other modes of sea-to-land transportation. Pipeline spans may occur due to natural seabed irregularities or local scour of seabed. Free span segment can also be exposed to potentially high hazards, such as rupture due to bending and deflection of the free span. This study aims to check the strength of the free spanning pipelines using the Ultimate Limit State (ULS) analysis method. The results of the stress analysis show that the stresses acting on the pipelines are below its Allowable Stress and has complied with the Allowable Stress Design (ASD) concept based on ASME B31.8 standard. The magnitude of hoop stress is 78.33 MPa, the maximum longitudinal stress is 174.12 MPa occurs at a span of 29.31 m, and the maximum Von Mises stress is 236.24 MPa occurs at a span of 11 m. Based on the results of the ULS analysis, the pipeline does not experience buckling and is able to withstand pressure and collapse in accordance with the limit state design concept. The results of the calculation of the allowable span length are carried out in static and dynamic conditions. The allowable span length in static condition is 22.51 m. Meanwhile, allowable span length in dynamic condition on the in-line direction is 29.28 m and on the cross-flow direction is 36.43 m.

Item Type: Thesis (Undergraduate)
Uncontrolled Keywords: bentangan bebas, panjang bentangan bebas ijin, in-line, cross-flow, Ultimate Limit State ========================================================================================================================free span, allowable span length, in-line, cross-flow, Ultimate Limit State
Subjects: T Technology > TA Engineering (General). Civil engineering (General) > TA660.P55 Underground pipeline design, construction and management
T Technology > TJ Mechanical engineering and machinery > TJ930 Pipelines (General). Underwater pipelines.
T Technology > TN Mining engineering. Metallurgy > TN879.5 Petroleum pipelines
T Technology > TN Mining engineering. Metallurgy > TN880.5 Natural gas pipelines
Divisions: Faculty of Marine Technology (MARTECH) > Ocean Engineering
Depositing User: MARIA DEVIYANTI RISKA PUTRI
Date Deposited: 13 Aug 2021 15:56
Last Modified: 13 Aug 2021 15:56
URI: https://repository.its.ac.id/id/eprint/86269

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